From 3c71ab35ffbbd222cc63bf5723b95c2ebbcd70dd Mon Sep 17 00:00:00 2001
From: Abhinav Raut <abhinavrautcs@gmail.com>
Date: Fri, 24 Jan 2025 04:34:51 +0530
Subject: [PATCH] Feat: Add SLAs per team - Feat: Provide the ability to change
 SLAs for conversations; this will start a new deadline calculation from the
 time the SLA is set.

---
 cmd/business_hours.go                         |   7 +-
 cmd/conversation.go                           |  61 +--
 cmd/init.go                                   |   8 +-
 cmd/sla.go                                    |   5 +-
 cmd/teams.go                                  |   6 +-
 .../components/admin/team/teams/TeamForm.vue  |  68 +++-
 .../admin/team/teams/teamFormSchema.js        |   1 +
 .../list/ConversationListItem.vue             |   2 +-
 .../conversation/sidebar/ConversationInfo.vue |   2 +-
 internal/business_hours/business_hours.go     |  21 +-
 internal/conversation/conversation.go         |  24 +-
 internal/conversation/message.go              |   2 +-
 internal/conversation/models/models.go        |   6 +-
 internal/conversation/queries.sql             |   5 +
 internal/sla/calculator.go                    |  13 +-
 internal/sla/models/models.go                 |  32 +-
 internal/sla/queries.sql                      | 144 +++----
 internal/sla/sla.go                           | 371 +++++++++---------
 internal/team/models/models.go                |   3 +-
 internal/team/queries.sql                     |  12 +-
 internal/team/team.go                         |   8 +-
 internal/user/models/models.go                |   6 +-
 internal/workerpool/workerpool.go             |  46 ---
 schema.sql                                    |  29 +-
 24 files changed, 424 insertions(+), 458 deletions(-)
 delete mode 100644 internal/workerpool/workerpool.go

diff --git a/cmd/business_hours.go b/cmd/business_hours.go
index ed7e1cab..3c75a587 100644
--- a/cmd/business_hours.go
+++ b/cmd/business_hours.go
@@ -3,6 +3,7 @@ package main
 import (
 	"strconv"
 
+	businessHours "github.com/abhinavxd/libredesk/internal/business_hours"
 	models "github.com/abhinavxd/libredesk/internal/business_hours/models"
 	"github.com/abhinavxd/libredesk/internal/envelope"
 	"github.com/valyala/fasthttp"
@@ -30,10 +31,12 @@ func handleGetBusinessHour(r *fastglue.Request) error {
 	if err != nil || id == 0 {
 		return r.SendErrorEnvelope(fasthttp.StatusBadRequest, "Invalid business hour `id`.", nil, envelope.InputError)
 	}
-
 	businessHour, err := app.businessHours.Get(id)
 	if err != nil {
-		return r.SendErrorEnvelope(fasthttp.StatusInternalServerError, err.Error(), nil, "")
+		if err == businessHours.ErrBusinessHoursNotFound {
+			return r.SendErrorEnvelope(fasthttp.StatusNotFound, err.Error(), nil, envelope.NotFoundError)
+		}
+		return r.SendErrorEnvelope(fasthttp.StatusInternalServerError, "Error fetching business hour", nil, "")
 	}
 	return r.SendEnvelope(businessHour)
 }
diff --git a/cmd/conversation.go b/cmd/conversation.go
index 582bcdce..aae2fc1d 100644
--- a/cmd/conversation.go
+++ b/cmd/conversation.go
@@ -39,10 +39,10 @@ func handleGetAllConversations(r *fastglue.Request) error {
 		total = conversations[0].Total
 	}
 
-	// Calculate SLA deadlines if conversation has an SLA policy.
+	// Set deadlines for SLA if conversation has a policy
 	for i := range conversations {
 		if conversations[i].SLAPolicyID.Int != 0 {
-			calculateSLA(app, &conversations[i])
+			setSLADeadlines(app, &conversations[i])
 		}
 	}
 
@@ -75,10 +75,10 @@ func handleGetAssignedConversations(r *fastglue.Request) error {
 		total = conversations[0].Total
 	}
 
-	// Calculate SLA deadlines if conversation has an SLA policy.
+	// Set deadlines for SLA if conversation has a policy
 	for i := range conversations {
 		if conversations[i].SLAPolicyID.Int != 0 {
-			calculateSLA(app, &conversations[i])
+			setSLADeadlines(app, &conversations[i])
 		}
 	}
 
@@ -111,10 +111,10 @@ func handleGetUnassignedConversations(r *fastglue.Request) error {
 		total = conversations[0].Total
 	}
 
-	// Calculate SLA deadlines if conversation has an SLA policy.
+	// Set deadlines for SLA if conversation has a policy
 	for i := range conversations {
 		if conversations[i].SLAPolicyID.Int != 0 {
-			calculateSLA(app, &conversations[i])
+			setSLADeadlines(app, &conversations[i])
 		}
 	}
 
@@ -189,10 +189,10 @@ func handleGetViewConversations(r *fastglue.Request) error {
 		total = conversations[0].Total
 	}
 
-	// Calculate SLA deadlines if conversation has an SLA policy.
+	// Set deadlines for SLA if conversation has a policy
 	for i := range conversations {
 		if conversations[i].SLAPolicyID.Int != 0 {
-			calculateSLA(app, &conversations[i])
+			setSLADeadlines(app, &conversations[i])
 		}
 	}
 
@@ -241,10 +241,10 @@ func handleGetTeamUnassignedConversations(r *fastglue.Request) error {
 		total = conversations[0].Total
 	}
 
-	// Calculate SLA deadlines if conversation has an SLA policy.
+	// Set deadlines for SLA if conversation has a policy
 	for i := range conversations {
 		if conversations[i].SLAPolicyID.Int != 0 {
-			calculateSLA(app, &conversations[i])
+			setSLADeadlines(app, &conversations[i])
 		}
 	}
 
@@ -280,9 +280,9 @@ func handleGetConversation(r *fastglue.Request) error {
 		return sendErrorEnvelope(r, envelope.NewError(envelope.PermissionError, "Permission denied", nil))
 	}
 
-	// Calculate SLA deadlines if conversation has an SLA policy.
+	// Set deadlines for SLA if conversation has a policy
 	if conversation.SLAPolicyID.Int != 0 {
-		calculateSLA(app, &conversation)
+		setSLADeadlines(app, &conversation)
 	}
 	return r.SendEnvelope(conversation)
 }
@@ -406,22 +406,26 @@ func handleUpdateTeamAssignee(r *fastglue.Request) error {
 		return sendErrorEnvelope(r, err)
 	}
 
-	conversation, err := app.conversation.GetConversation(0, uuid)
+	conversation, err := enforceConversationAccess(app, uuid, user)
 	if err != nil {
 		return sendErrorEnvelope(r, err)
 	}
-	allowed, err := app.authz.EnforceConversationAccess(user, conversation)
-	if err != nil {
-		return sendErrorEnvelope(r, err)
-	}
-	if !allowed {
-		return sendErrorEnvelope(r, envelope.NewError(envelope.PermissionError, "Permission denied", nil))
-	}
 	if err := app.conversation.UpdateConversationTeamAssignee(uuid, assigneeID, user); err != nil {
 		return sendErrorEnvelope(r, err)
 	}
 
-	// TODO: Set SLA if the team has an SLA policy set.
+	// Apply SLA policy if team has changed and has an SLA policy.
+	if conversation.AssignedTeamID.Int != assigneeID && assigneeID != 0 {
+		team, err := app.team.Get(assigneeID)
+		if err != nil {
+			return r.SendErrorEnvelope(fasthttp.StatusInternalServerError, "Error fetching team for setting SLA", nil, envelope.GeneralError)
+		}
+		if team.SLAPolicyID.Int != 0 {
+			if err := app.conversation.ApplySLA(conversation.UUID, conversation.ID, team.SLAPolicyID.Int, user); err != nil {
+				return r.SendErrorEnvelope(fasthttp.StatusInternalServerError, "Error applying SLA policy", nil, envelope.GeneralError)
+			}
+		}
+	}
 
 	// Evaluate automation rules on team assignment.
 	app.automation.EvaluateConversationUpdateRules(uuid, models.EventConversationTeamAssigned)
@@ -596,15 +600,18 @@ func enforceConversationAccess(app *App, uuid string, user umodels.User) (*cmode
 	return &conversation, nil
 }
 
-// calculateSLA calculates the SLA deadlines and sets them on the conversation.
-func calculateSLA(app *App, conversation *cmodels.Conversation) error {
-	firstRespAt, resolutionDueAt, err := app.sla.CalculateConversationDeadlines(conversation.CreatedAt, conversation.AssignedTeamID.Int, conversation.SLAPolicyID.Int)
+// setSLADeadlines gets the latest SLA deadlines for a conversation and sets them.
+func setSLADeadlines(app *App, conversation *cmodels.Conversation) error {
+	if conversation.ID < 1 {
+		return nil
+	}
+	first, resolution, err := app.sla.GetLatestDeadlines(conversation.ID)
 	if err != nil {
-		app.lo.Error("error calculating SLA deadlines for conversation", "id", conversation.ID, "error", err)
+		app.lo.Error("error getting SLA deadlines", "id", conversation.ID, "error", err)
 		return err
 	}
-	conversation.FirstReplyDueAt = null.NewTime(firstRespAt, firstRespAt != time.Time{})
-	conversation.ResolutionDueAt = null.NewTime(resolutionDueAt, resolutionDueAt != time.Time{})
+	conversation.FirstResponseDueAt = null.NewTime(first, first != time.Time{})
+	conversation.ResolutionDueAt = null.NewTime(resolution, resolution != time.Time{})
 	return nil
 }
 
diff --git a/cmd/init.go b/cmd/init.go
index 466b2fdd..3f100f03 100644
--- a/cmd/init.go
+++ b/cmd/init.go
@@ -41,7 +41,6 @@ import (
 	tmpl "github.com/abhinavxd/libredesk/internal/template"
 	"github.com/abhinavxd/libredesk/internal/user"
 	"github.com/abhinavxd/libredesk/internal/view"
-	"github.com/abhinavxd/libredesk/internal/workerpool"
 	"github.com/abhinavxd/libredesk/internal/ws"
 	"github.com/jmoiron/sqlx"
 	"github.com/knadh/go-i18n"
@@ -278,10 +277,9 @@ func initBusinessHours(db *sqlx.DB) *businesshours.Manager {
 func initSLA(db *sqlx.DB, teamManager *team.Manager, settings *setting.Manager, businessHours *businesshours.Manager) *sla.Manager {
 	var lo = initLogger("sla")
 	m, err := sla.New(sla.Opts{
-		DB:              db,
-		Lo:              lo,
-		ScannerInterval: ko.MustDuration("sla.scanner_interval"),
-	}, workerpool.New(ko.MustInt("sla.worker_count"), ko.MustInt("sla.queue_size")), teamManager, settings, businessHours)
+		DB: db,
+		Lo: lo,
+	}, teamManager, settings, businessHours)
 	if err != nil {
 		log.Fatalf("error initializing SLA manager: %v", err)
 	}
diff --git a/cmd/sla.go b/cmd/sla.go
index dfccfa35..b1ec60dc 100644
--- a/cmd/sla.go
+++ b/cmd/sla.go
@@ -44,7 +44,6 @@ func handleCreateSLA(r *fastglue.Request) error {
 		firstRespTime = string(r.RequestCtx.PostArgs().Peek("first_response_time"))
 		resTime       = string(r.RequestCtx.PostArgs().Peek("resolution_time"))
 	)
-
 	// Validate time duration strings
 	if _, err := time.ParseDuration(firstRespTime); err != nil {
 		return r.SendErrorEnvelope(fasthttp.StatusBadRequest, "Invalid `first_response_time` duration.", nil, envelope.InputError)
@@ -52,12 +51,10 @@ func handleCreateSLA(r *fastglue.Request) error {
 	if _, err := time.ParseDuration(resTime); err != nil {
 		return r.SendErrorEnvelope(fasthttp.StatusBadRequest, "Invalid `resolution_time` duration.", nil, envelope.InputError)
 	}
-
 	if err := app.sla.Create(name, desc, firstRespTime, resTime); err != nil {
 		return sendErrorEnvelope(r, err)
 	}
-
-	return r.SendEnvelope(true)
+	return r.SendEnvelope("SLA created successfully.")
 }
 
 func handleDeleteSLA(r *fastglue.Request) error {
diff --git a/cmd/teams.go b/cmd/teams.go
index 6e069213..746cc362 100644
--- a/cmd/teams.go
+++ b/cmd/teams.go
@@ -58,8 +58,9 @@ func handleCreateTeam(r *fastglue.Request) error {
 		emoji                      = string(r.RequestCtx.PostArgs().Peek("emoji"))
 		conversationAssignmentType = string(r.RequestCtx.PostArgs().Peek("conversation_assignment_type"))
 		businessHrsID, _           = strconv.Atoi(string(r.RequestCtx.PostArgs().Peek("business_hours_id")))
+		slaPolicyID, _             = strconv.Atoi(string(r.RequestCtx.PostArgs().Peek("sla_policy_id")))
 	)
-	if err := app.team.Create(name, timezone, conversationAssignmentType, null.NewInt(businessHrsID, businessHrsID > 0), emoji); err != nil {
+	if err := app.team.Create(name, timezone, conversationAssignmentType, null.NewInt(businessHrsID, businessHrsID != 0), null.NewInt(slaPolicyID, slaPolicyID != 0), emoji); err != nil {
 		return sendErrorEnvelope(r, err)
 	}
 	return r.SendEnvelope("Team created successfully.")
@@ -75,11 +76,12 @@ func handleUpdateTeam(r *fastglue.Request) error {
 		conversationAssignmentType = string(r.RequestCtx.PostArgs().Peek("conversation_assignment_type"))
 		id, _                      = strconv.Atoi(r.RequestCtx.UserValue("id").(string))
 		businessHrsID, _           = strconv.Atoi(string(r.RequestCtx.PostArgs().Peek("business_hours_id")))
+		slaPolicyID, _             = strconv.Atoi(string(r.RequestCtx.PostArgs().Peek("sla_policy_id")))
 	)
 	if id < 1 {
 		return r.SendErrorEnvelope(fasthttp.StatusBadRequest, "Invalid team `id`", nil, envelope.InputError)
 	}
-	if err := app.team.Update(id, name, timezone, conversationAssignmentType, null.NewInt(businessHrsID, businessHrsID > 0), emoji); err != nil {
+	if err := app.team.Update(id, name, timezone, conversationAssignmentType, null.NewInt(businessHrsID, businessHrsID != 0), null.NewInt(slaPolicyID, slaPolicyID != 0), emoji); err != nil {
 		return sendErrorEnvelope(r, err)
 	}
 	return r.SendEnvelope("Team updated successfully.")
diff --git a/frontend/src/components/admin/team/teams/TeamForm.vue b/frontend/src/components/admin/team/teams/TeamForm.vue
index 8b17ae41..797684b2 100644
--- a/frontend/src/components/admin/team/teams/TeamForm.vue
+++ b/frontend/src/components/admin/team/teams/TeamForm.vue
@@ -1,6 +1,5 @@
 <template>
   <form @submit="onSubmit" class="space-y-6">
-
     <FormField name="emoji" v-slot="{ componentField }">
       <FormItem ref="emojiPickerContainer" class="relative">
         <FormLabel>Emoji</FormLabel>
@@ -43,7 +42,7 @@
           </Select>
         </FormControl>
         <FormDescription>
-          Round robin: Conversations are assigned to team members in a round-robin fashion. <br>
+          Round robin: Conversations are assigned to team members in a round-robin fashion. <br />
           Manual: Conversations are to be picked by team members.
         </FormDescription>
         <FormMessage />
@@ -89,7 +88,34 @@
             </SelectContent>
           </Select>
         </FormControl>
-        <FormDescription>Default business hours for the team, will be used to calculate SLA.</FormDescription>
+        <FormDescription
+          >Default business hours for the team, will be used to calculate SLA.</FormDescription
+        >
+        <FormMessage />
+      </FormItem>
+    </FormField>
+
+    <FormField v-slot="{ componentField }" name="sla_policy_id">
+      <FormItem>
+        <FormLabel>SLA policy</FormLabel>
+        <FormControl>
+          <Select v-bind="componentField">
+            <SelectTrigger>
+              <SelectValue placeholder="Select policy" />
+            </SelectTrigger>
+            <SelectContent>
+              <SelectGroup>
+                <SelectItem v-for="sla in slaStore.options" :key="sla.value" :value="parseInt(sla.value)">
+                  {{ sla.label }}
+                </SelectItem>
+              </SelectGroup>
+            </SelectContent>
+          </Select>
+        </FormControl>
+        <FormDescription
+          >SLA policy to be auto applied to conversations, when conversations are assigned to this
+          team.</FormDescription
+        >
         <FormMessage />
       </FormItem>
     </FormField>
@@ -127,12 +153,15 @@ import { Input } from '@/components/ui/input'
 import EmojiPicker from 'vue3-emoji-picker'
 import 'vue3-emoji-picker/css'
 import { handleHTTPError } from '@/utils/http'
+import { useSlaStore } from '@/stores/sla'
 import api from '@/api'
 
 const emitter = useEmitter()
+const slaStore = useSlaStore()
 const timezones = computed(() => Intl.supportedValuesOf('timeZone'))
 const assignmentTypes = ['Round robin', 'Manual']
 const businessHours = ref([])
+const slaPolicies = ref([])
 
 const props = defineProps({
   initialValues: { type: Object, required: false },
@@ -161,39 +190,40 @@ const fetchBusinessHours = async () => {
     businessHours.value = response.data.data
   } catch (error) {
     // If unauthorized (no permission), show a toast message.
-    const toastPayload = error.response.status === 403
-      ? {
-        title: 'Unauthorized',
-        variant: 'destructive',
-        description: 'You do not have permission to view business hours.'
-      }
-      : {
-        title: 'Could not fetch business hours',
-        variant: 'destructive',
-        description: handleHTTPError(error).message
-      }
+    const toastPayload =
+      error.response.status === 403
+        ? {
+            title: 'Unauthorized',
+            variant: 'destructive',
+            description: 'You do not have permission to view business hours.'
+          }
+        : {
+            title: 'Could not fetch business hours',
+            variant: 'destructive',
+            description: handleHTTPError(error).message
+          }
     emitter.emit(EMITTER_EVENTS.SHOW_TOAST, toastPayload)
   }
 }
 
-const onSubmit = form.handleSubmit(values => {
+const onSubmit = form.handleSubmit((values) => {
   props.submitForm(values)
 })
 
 watch(
   () => props.initialValues,
-  newValues => {
+  (newValues) => {
     if (Object.keys(newValues).length === 0) return
     form.setValues(newValues)
   },
   { immediate: true }
 )
 
-function toggleEmojiPicker () {
+function toggleEmojiPicker() {
   isEmojiPickerVisible.value = !isEmojiPickerVisible.value
 }
 
-function onSelectEmoji (emoji) {
+function onSelectEmoji(emoji) {
   form.setFieldValue('emoji', emoji.i || emoji)
 }
-</script>
\ No newline at end of file
+</script>
diff --git a/frontend/src/components/admin/team/teams/teamFormSchema.js b/frontend/src/components/admin/team/teams/teamFormSchema.js
index 1aa84cb9..5f51e141 100644
--- a/frontend/src/components/admin/team/teams/teamFormSchema.js
+++ b/frontend/src/components/admin/team/teams/teamFormSchema.js
@@ -12,4 +12,5 @@ export const teamFormSchema = z.object({
   conversation_assignment_type: z.string({ required_error: 'Conversation assignment type is required.' }),
   timezone: z.string({ required_error: 'Timezone is required.' }),
   business_hours_id: z.number().optional().nullable(),
+  sla_policy_id: z.number().optional().nullable(),
 })
diff --git a/frontend/src/components/conversation/list/ConversationListItem.vue b/frontend/src/components/conversation/list/ConversationListItem.vue
index 579ff4e7..dc0c6119 100644
--- a/frontend/src/components/conversation/list/ConversationListItem.vue
+++ b/frontend/src/components/conversation/list/ConversationListItem.vue
@@ -42,7 +42,7 @@
 
         <div class="flex items-center mt-2 space-x-2">
           <SlaDisplay
-            :dueAt="conversation.first_reply_due_at"
+            :dueAt="conversation.first_response_due_at"
             :actualAt="conversation.first_reply_at"
             :label="'FRD'"
             :showSLAHit="false"
diff --git a/frontend/src/components/conversation/sidebar/ConversationInfo.vue b/frontend/src/components/conversation/sidebar/ConversationInfo.vue
index 1d46c1e5..b214f047 100644
--- a/frontend/src/components/conversation/sidebar/ConversationInfo.vue
+++ b/frontend/src/components/conversation/sidebar/ConversationInfo.vue
@@ -23,7 +23,7 @@
     <div class="flex justify-start items-center space-x-2">
       <p class="font-medium">First reply at</p>
       <SlaDisplay
-        :dueAt="conversation.first_reply_due_at"
+        :dueAt="conversation.first_response_due_at"
         :actualAt="conversation.first_reply_at"
       />
     </div>
diff --git a/internal/business_hours/business_hours.go b/internal/business_hours/business_hours.go
index 6d133f4a..26c96f6e 100644
--- a/internal/business_hours/business_hours.go
+++ b/internal/business_hours/business_hours.go
@@ -2,7 +2,9 @@
 package businesshours
 
 import (
+	"database/sql"
 	"embed"
+	"errors"
 
 	"github.com/abhinavxd/libredesk/internal/business_hours/models"
 	"github.com/abhinavxd/libredesk/internal/dbutil"
@@ -15,7 +17,8 @@ import (
 
 var (
 	//go:embed queries.sql
-	efs embed.FS
+	efs                      embed.FS
+	ErrBusinessHoursNotFound = errors.New("business hours not found")
 )
 
 // Manager manages business hours.
@@ -45,25 +48,25 @@ type queries struct {
 // New creates and returns a new instance of the Manager.
 func New(opts Opts) (*Manager, error) {
 	var q queries
-
 	if err := dbutil.ScanSQLFile("queries.sql", &q, opts.DB, efs); err != nil {
 		return nil, err
 	}
-
 	return &Manager{
 		q:  q,
 		lo: opts.Lo,
 	}, nil
 }
 
-// Get retrieves business hours by ID.
+// Get retrieves business hours.
 func (m *Manager) Get(id int) (models.BusinessHours, error) {
-	var bh models.BusinessHours
-	if err := m.q.GetBusinessHours.Get(&bh, id); err != nil {
-		m.lo.Error("error fetching business hours", "error", err)
-		return bh, envelope.NewError(envelope.GeneralError, "Error fetching business hours", nil)
+	var businessHours models.BusinessHours
+	if err := m.q.GetBusinessHours.Get(&businessHours, id); err != nil {
+		if err == sql.ErrNoRows {
+			return businessHours, ErrBusinessHoursNotFound
+		}
+		return businessHours, err
 	}
-	return bh, nil
+	return businessHours, nil
 }
 
 // GetAll retrieves all business hours.
diff --git a/internal/conversation/conversation.go b/internal/conversation/conversation.go
index f24d9730..5aa23ba2 100644
--- a/internal/conversation/conversation.go
+++ b/internal/conversation/conversation.go
@@ -73,7 +73,7 @@ type Manager struct {
 }
 
 type slaStore interface {
-	ApplySLA(conversationID, slaID int) (slaModels.SLAPolicy, error)
+	ApplySLA(conversationID, assignedTeamID, slaID int) (slaModels.SLAPolicy, error)
 }
 
 type statusStore interface {
@@ -694,6 +694,20 @@ func (m *Manager) UnassignOpen(userID int) error {
 	return nil
 }
 
+// ApplySLA applies the SLA policy to a conversation.
+func (m *Manager) ApplySLA(conversationUUID string, conversationID, policyID int, actor umodels.User) error {
+	policy, err := m.slaStore.ApplySLA(conversationID, 0, policyID)
+	if err != nil {
+		return envelope.NewError(envelope.GeneralError, "Error applying SLA", nil)
+	}
+
+	// Record the SLA application as an activity.
+	if err := m.RecordSLASet(conversationUUID, policy.Name, actor); err != nil {
+		return envelope.NewError(envelope.GeneralError, "Error recording SLA application", nil)
+	}
+	return nil
+}
+
 // ApplyAction applies an action to a conversation, this can be called from multiple packages across the app to perform actions on conversations.
 // all actions are executed on behalf of the provided user if the user is not provided, system user is used.
 func (m *Manager) ApplyAction(action amodels.RuleAction, conversation models.Conversation, user umodels.User) error {
@@ -748,14 +762,10 @@ func (m *Manager) ApplyAction(action amodels.RuleAction, conversation models.Con
 		}
 	case amodels.ActionSetSLA:
 		m.lo.Debug("executing apply SLA action", "value", action.Value[0], "conversation_uuid", conversation.UUID)
-		slaID, _ := strconv.Atoi(action.Value[0])
-		slaPolicy, err := m.slaStore.ApplySLA(conversation.ID, slaID)
-		if err != nil {
+		slaPolicyID, _ := strconv.Atoi(action.Value[0])
+		if err := m.ApplySLA(conversation.UUID, conversation.ID, slaPolicyID, user); err != nil {
 			return fmt.Errorf("could not apply %s action: %w", action.Type, err)
 		}
-		if err := m.RecordSLASet(conversation.UUID, slaPolicy.Name, user); err != nil {
-			m.lo.Error("error recording SLA set activity", "error", err)
-		}
 	case amodels.ActionSetTags:
 		m.lo.Debug("executing set tags action", "value", action.Value, "conversation_uuid", conversation.UUID)
 		if err := m.UpsertConversationTags(conversation.UUID, action.Value); err != nil {
diff --git a/internal/conversation/message.go b/internal/conversation/message.go
index fcfbc3cc..c3657b2f 100644
--- a/internal/conversation/message.go
+++ b/internal/conversation/message.go
@@ -147,7 +147,7 @@ func (m *Manager) processOutgoingMessage(message models.Message) {
 	// Helper function to handle errors
 	handleError := func(err error, errorMsg string) bool {
 		if err != nil {
-			m.lo.Error(errorMsg, "error", err, "id", message.ID)
+			m.lo.Error(errorMsg, "error", err, "message_id", message.ID)
 			m.UpdateMessageStatus(message.UUID, MessageStatusFailed)
 			return true
 		}
diff --git a/internal/conversation/models/models.go b/internal/conversation/models/models.go
index c2da626a..1d585f4a 100644
--- a/internal/conversation/models/models.go
+++ b/internal/conversation/models/models.go
@@ -33,7 +33,7 @@ type Conversation struct {
 	CreatedAt          time.Time      `db:"created_at" json:"created_at"`
 	UpdatedAt          time.Time      `db:"updated_at" json:"updated_at"`
 	UUID               string         `db:"uuid" json:"uuid"`
-	InboxID            int            `db:"inbox_id" json:"inbox_id"`
+	InboxID            int            `db:"inbox_id" json:"inbox_id,omitempty"`
 	ClosedAt           null.Time      `db:"closed_at" json:"closed_at,omitempty"`
 	ResolvedAt         null.Time      `db:"resolved_at" json:"resolved_at,omitempty"`
 	ReferenceNumber    string         `db:"reference_number" json:"reference_number,omitempty"`
@@ -56,11 +56,11 @@ type Conversation struct {
 	LastMessageAt      null.Time      `db:"last_message_at" json:"last_message_at"`
 	LastMessage        null.String    `db:"last_message" json:"last_message"`
 	Contact            umodels.User   `db:"contact" json:"contact"`
-	FirstReplyDueAt    null.Time      `db:"first_reply_due_at" json:"first_reply_due_at"`
-	ResolutionDueAt    null.Time      `db:"resolution_due_at" json:"resolution_due_at"`
 	SLAPolicyID        null.Int       `db:"sla_policy_id" json:"sla_policy_id"`
 	SlaPolicyName      null.String    `db:"sla_policy_name" json:"sla_policy_name"`
 	NextSLADeadlineAt  null.Time      `db:"next_sla_deadline_at" json:"next_sla_deadline_at"`
+	FirstResponseDueAt null.Time      `db:"-" json:"first_response_due_at"`
+	ResolutionDueAt    null.Time      `db:"-" json:"resolution_due_at"`
 	Total              int            `db:"total" json:"-"`
 }
 
diff --git a/internal/conversation/queries.sql b/internal/conversation/queries.sql
index 4de6bf6a..97b51e89 100644
--- a/internal/conversation/queries.sql
+++ b/internal/conversation/queries.sql
@@ -12,10 +12,13 @@ RETURNING id, uuid;
 -- name: get-conversations
 SELECT
 COUNT(*) OVER() as total,
+conversations.id,
 conversations.created_at,
 conversations.updated_at,
 conversations.uuid,
 conversations.assignee_last_seen_at,
+users.created_at as "contact.created_at",
+users.updated_at as "contact.updated_at",
 users.first_name as "contact.first_name",
 users.last_name as "contact.last_name",
 users.avatar_url as "contact.avatar_url", 
@@ -76,6 +79,8 @@ SELECT
         WHERE ct.conversation_id = c.id),
         '[]'::json
     )) AS tags,
+    ct.created_at as "contact.created_at",
+    ct.updated_at as "contact.updated_at",
     ct.first_name as "contact.first_name",
     ct.last_name as "contact.last_name",
     ct.email as "contact.email",
diff --git a/internal/sla/calculator.go b/internal/sla/calculator.go
index 07fbd44c..43ac7dcc 100644
--- a/internal/sla/calculator.go
+++ b/internal/sla/calculator.go
@@ -8,11 +8,16 @@ import (
 	"github.com/abhinavxd/libredesk/internal/business_hours/models"
 )
 
+var (
+	ErrInvalidSLADuration = fmt.Errorf("invalid SLA duration")
+	ErrMaxIterations      = fmt.Errorf("sla: exceeded maximum iterations - check configuration")
+)
+
 // CalculateDeadline computes the SLA deadline from a start time and SLA duration in minutes
 // considering the provided holidays, working hours, and time zone.
 func (m *Manager) CalculateDeadline(start time.Time, slaMinutes int, businessHours models.BusinessHours, timeZone string) (time.Time, error) {
 	if slaMinutes <= 0 {
-		return time.Time{}, fmt.Errorf("SLA duration must be positive")
+		return time.Time{}, ErrInvalidSLADuration
 	}
 
 	// If business is always open, return the deadline as the start time plus the SLA duration.
@@ -34,13 +39,13 @@ func (m *Manager) CalculateDeadline(start time.Time, slaMinutes int, businessHou
 	// Unmarshal working hours.
 	var workingHours map[string]models.WorkingHours
 	if err := json.Unmarshal(businessHours.Hours, &workingHours); err != nil {
-		return time.Time{}, fmt.Errorf("could not unmarshal working hours: %v", err)
+		return time.Time{}, fmt.Errorf("could not unmarshal working hours for SLA deadline calcuation: %v", err)
 	}
 
 	// Unmarshal holidays.
 	var holidays = []models.Holiday{}
 	if err := json.Unmarshal(businessHours.Holidays, &holidays); err != nil {
-		return time.Time{}, fmt.Errorf("could not unmarshal holidays: %v", err)
+		return time.Time{}, fmt.Errorf("could not unmarshal holidays for SLA deadline calcuation: %v", err)
 	}
 
 	// Create a map of holidays.
@@ -53,7 +58,7 @@ func (m *Manager) CalculateDeadline(start time.Time, slaMinutes int, businessHou
 	for remainingMinutes > 0 {
 		iterations++
 		if iterations > maxIterations {
-			return time.Time{}, fmt.Errorf("sla: exceeded maximum iterations - check configuration")
+			return time.Time{}, ErrMaxIterations
 		}
 
 		// Skip holidays.
diff --git a/internal/sla/models/models.go b/internal/sla/models/models.go
index 0aba1eba..9f089167 100644
--- a/internal/sla/models/models.go
+++ b/internal/sla/models/models.go
@@ -1,4 +1,3 @@
-// package models contains the model definitions for the SLA package.
 package models
 
 import (
@@ -7,7 +6,7 @@ import (
 	"github.com/volatiletech/null/v9"
 )
 
-// SLAPolicy represents an SLA policy.
+// SLAPolicy represents a service level agreement policy definition
 type SLAPolicy struct {
 	ID                int       `db:"id" json:"id"`
 	CreatedAt         time.Time `db:"created_at" json:"created_at"`
@@ -15,23 +14,20 @@ type SLAPolicy struct {
 	Name              string    `db:"name" json:"name"`
 	Description       string    `db:"description" json:"description"`
 	FirstResponseTime string    `db:"first_response_time" json:"first_response_time"`
-	ResolutionTime    string    `db:"resolution_time" json:"resolution_time"`
 	EveryResponseTime string    `db:"every_response_time" json:"every_response_time"`
+	ResolutionTime    string    `db:"resolution_time" json:"resolution_time"`
 }
 
-// ConversationSLA represents an SLA policy applied to a conversation.
-type ConversationSLA struct {
-	ID                         int       `db:"id"`
-	CreatedAt                  time.Time `db:"created_at"`
-	UpdatedAt                  time.Time `db:"updated_at"`
-	ConversationID             int       `db:"conversation_id"`
-	ConversationCreatedAt      time.Time `db:"conversation_created_at"`
-	ConversationFirstReplyAt   null.Time `db:"conversation_first_reply_at"`
-	ConversationLastMessageAt  null.Time `db:"conversation_last_message_at"`
-	ConversationResolvedAt     null.Time `db:"conversation_resolved_at"`
-	ConversationAssignedTeamID null.Int  `db:"conversation_assigned_team_id"`
-	SLAPolicyID                int       `db:"sla_policy_id"`
-	SLAType                    string    `db:"sla_type"`
-	DueAt                      null.Time `db:"due_at"`
-	BreachedAt                 null.Time `db:"breached_at"`
+// AppliedSLA represents an SLA policy applied to a conversation with its deadlines and breach status
+type AppliedSLA struct {
+	ID                      int       `db:"id"`
+	CreatedAt               time.Time `db:"created_at"`
+	ConversationID          int       `db:"conversation_id"`
+	SLAPolicyID             int       `db:"sla_policy_id"`
+	FirstResponseDeadlineAt time.Time `db:"first_response_deadline_at"`
+	ResolutionDeadlineAt    time.Time `db:"resolution_deadline_at"`
+	FirstResponseBreachedAt null.Time `db:"first_response_breached_at"`
+	ResolutionBreachedAt    null.Time `db:"resolution_breached_at"`
+	FirstResponseAt         null.Time `db:"first_response_at"`
+	ResolvedAt              null.Time `db:"resolved_at"`
 }
diff --git a/internal/sla/queries.sql b/internal/sla/queries.sql
index f0fff6b7..7f2b401f 100644
--- a/internal/sla/queries.sql
+++ b/internal/sla/queries.sql
@@ -1,105 +1,71 @@
 -- name: get-sla-policy
-SELECT id,
-    created_at,
-    updated_at,
-    "name",
-    description,
-    first_response_time,
-    resolution_time
-FROM sla_policies
-WHERE id = $1;
+SELECT * FROM sla_policies WHERE id = $1;
 
 -- name: get-all-sla-policies
-SELECT id,
-    created_at,
-    updated_at,
-    "name",
-    description,
-    first_response_time,
-    resolution_time
-FROM sla_policies
-ORDER BY updated_at DESC;
+SELECT * FROM sla_policies ORDER BY updated_at DESC;
 
 -- name: insert-sla-policy
 INSERT INTO sla_policies (
-        "name",
-        description,
-        first_response_time,
-        resolution_time
-    )
-VALUES ($1, $2, $3, $4);
+   name,
+   description, 
+   first_response_time,
+   resolution_time
+) VALUES ($1, $2, $3, $4);
 
 -- name: delete-sla-policy
-DELETE FROM sla_policies
-WHERE id = $1;
+DELETE FROM sla_policies WHERE id = $1;
 
 -- name: update-sla-policy
-UPDATE sla_policies
-SET "name" = $2,
-    description = $3,
-    first_response_time = $4,
-    resolution_time = $5,
-    updated_at = NOW()
+UPDATE sla_policies SET
+   name = $2,
+   description = $3,
+   first_response_time = $4,
+   resolution_time = $5,
+   updated_at = NOW()
 WHERE id = $1;
 
--- name: apply-sla-policy
-INSERT INTO applied_slas (
-    status,
-    conversation_id,
-    sla_policy_id
-    )
-VALUES ($1, $2, $3);
-
--- name: get-unbreached-slas
--- TODO: name this better.
-SELECT 
-	cs.id,
-    cs.created_at,
-    cs.updated_at,
-    cs.sla_policy_id, 
-    cs.sla_type, 
-    cs.breached_at,
-    cs.due_at,
-    c.created_at as conversation_created_at,
-    c.first_reply_at as conversation_first_reply_at,
-    c.last_message_at as conversation_last_message_at,
-    c.resolved_at as conversation_resolved_at,
-    c.assigned_team_id as conversation_assigned_team_id
-FROM conversation_slas cs
-INNER JOIN conversations c ON cs.conversation_id = c.id AND c.sla_policy_id = cs.sla_policy_id
-WHERE cs.breached_at is NULL AND cs.met_at is NULL
-
--- name: update-breached-at
-UPDATE conversation_slas
-SET breached_at = NOW(), updated_at = NOW()
-WHERE id = $1;
-
--- name: update-due-at
-WITH updated_slas AS (
-    UPDATE conversation_slas
-    SET due_at = $2,
-        updated_at = NOW()
-    WHERE id = $1
-    RETURNING conversation_id
+-- name: apply-sla
+WITH new_sla AS (
+ INSERT INTO applied_slas (
+   conversation_id,
+   sla_policy_id,
+   first_response_deadline_at,
+   resolution_deadline_at
+ ) VALUES ($1, $2, $3, $4)
+ RETURNING conversation_id
 )
--- Also set the earliest due_at in the conversation
-UPDATE conversations
-SET next_sla_deadline_at = $2
-WHERE id IN (SELECT conversation_id FROM updated_slas)
-  AND (next_sla_deadline_at IS NULL OR next_sla_deadline_at > $2);
+UPDATE conversations 
+SET sla_policy_id = $2,
+next_sla_deadline_at = LEAST(
+   NULLIF($3, NULL),
+   NULLIF($4, NULL)
+)
+WHERE id IN (SELECT conversation_id FROM new_sla);
 
--- name: update-met-at
-UPDATE conversation_slas
-SET met_at = $2, updated_at = NOW()
+-- name: get-pending-slas
+SELECT a.id, a.first_response_deadline_at, c.first_reply_at as first_response_at,
+a.resolution_deadline_at, c.resolved_at as resolved_at
+FROM applied_slas a 
+JOIN conversations c ON a.conversation_id = c.id and c.sla_policy_id = a.sla_policy_id
+WHERE (first_response_breached_at IS NULL AND first_response_met_at IS NULL)
+  OR (resolution_breached_at IS NULL AND resolution_met_at IS NULL);
+
+-- name: update-breach
+UPDATE applied_slas SET
+   first_response_breached_at = CASE WHEN $2 = 'first_response' THEN NOW() ELSE first_response_breached_at END,
+   resolution_breached_at = CASE WHEN $2 = 'resolution' THEN NOW() ELSE resolution_breached_at END,
+   updated_at = NOW()
 WHERE id = $1;
 
--- name: insert-conversation-sla
-WITH inserted AS (
-    INSERT INTO conversation_slas (conversation_id, sla_policy_id, sla_type)
-    VALUES ($1, $2, $3)
-    RETURNING conversation_id, sla_policy_id
-)
-UPDATE conversations
-SET sla_policy_id = inserted.sla_policy_id
-FROM inserted
-WHERE conversations.id = inserted.conversation_id;
\ No newline at end of file
+-- name: update-met
+UPDATE applied_slas SET
+   first_response_met_at = CASE WHEN $2 = 'first_response' THEN NOW() ELSE first_response_met_at END,
+   resolution_met_at = CASE WHEN $2 = 'resolution' THEN NOW() ELSE resolution_met_at END,
+   updated_at = NOW()
+WHERE id = $1;
+
+-- name: get-latest-sla-deadlines
+SELECT first_response_deadline_at, resolution_deadline_at
+FROM applied_slas 
+WHERE conversation_id = $1 
+ORDER BY created_at DESC LIMIT 1;
\ No newline at end of file
diff --git a/internal/sla/sla.go b/internal/sla/sla.go
index 96d8afa2..20db1b46 100644
--- a/internal/sla/sla.go
+++ b/internal/sla/sla.go
@@ -1,53 +1,58 @@
-// Package sla implements service-level agreement (SLA) calculations for conversations.
 package sla
 
 import (
 	"context"
+	"database/sql"
 	"embed"
 	"encoding/json"
 	"fmt"
 	"strconv"
+	"sync"
 	"time"
 
+	businessHours "github.com/abhinavxd/libredesk/internal/business_hours"
 	bmodels "github.com/abhinavxd/libredesk/internal/business_hours/models"
 	"github.com/abhinavxd/libredesk/internal/dbutil"
 	"github.com/abhinavxd/libredesk/internal/envelope"
 	models "github.com/abhinavxd/libredesk/internal/sla/models"
 	tmodels "github.com/abhinavxd/libredesk/internal/team/models"
-	"github.com/abhinavxd/libredesk/internal/workerpool"
 	"github.com/jmoiron/sqlx"
 	"github.com/jmoiron/sqlx/types"
+	"github.com/volatiletech/null/v9"
 	"github.com/zerodha/logf"
 )
 
 var (
 	//go:embed queries.sql
 	efs            embed.FS
-	slaGracePeriod = 5 * time.Minute
 )
 
 const (
 	SLATypeFirstResponse = "first_response"
 	SLATypeResolution    = "resolution"
-	SLATypeEveryResponse = "every_response"
 )
 
-// Manager provides SLA management and calculations.
+// Manager manages SLA policies and calculations.
 type Manager struct {
 	q                queries
 	lo               *logf.Logger
-	pool             *workerpool.Pool
 	teamStore        teamStore
 	appSettingsStore appSettingsStore
 	businessHrsStore businessHrsStore
+	wg               sync.WaitGroup
 	opts             Opts
 }
 
-// Opts defines options for initializing Manager.
+// Opts defines the options for creating SLA manager.
 type Opts struct {
-	DB              *sqlx.DB
-	Lo              *logf.Logger
-	ScannerInterval time.Duration
+	DB *sqlx.DB
+	Lo *logf.Logger
+}
+
+// Deadlines holds the deadlines for an SLA policy.
+type Deadlines struct {
+	FirstResponse time.Time
+	Resolution    time.Time
 }
 
 type teamStore interface {
@@ -62,38 +67,30 @@ type businessHrsStore interface {
 	Get(id int) (bmodels.BusinessHours, error)
 }
 
-// queries holds prepared SQL statements.
+// queries hold prepared SQL queries.
 type queries struct {
-	GetSLA                *sqlx.Stmt `query:"get-sla-policy"`
-	GetAllSLA             *sqlx.Stmt `query:"get-all-sla-policies"`
-	InsertSLA             *sqlx.Stmt `query:"insert-sla-policy"`
-	DeleteSLA             *sqlx.Stmt `query:"delete-sla-policy"`
-	UpdateSLA             *sqlx.Stmt `query:"update-sla-policy"`
-	GetUnbreachedSLAs     *sqlx.Stmt `query:"get-unbreached-slas"`
-	UpdateBreachedAt      *sqlx.Stmt `query:"update-breached-at"`
-	UpdateDueAt           *sqlx.Stmt `query:"update-due-at"`
-	UpdateMetAt           *sqlx.Stmt `query:"update-met-at"`
-	InsertConversationSLA *sqlx.Stmt `query:"insert-conversation-sla"`
+	GetSLA             *sqlx.Stmt `query:"get-sla-policy"`
+	GetAllSLA          *sqlx.Stmt `query:"get-all-sla-policies"`
+	InsertSLA          *sqlx.Stmt `query:"insert-sla-policy"`
+	DeleteSLA          *sqlx.Stmt `query:"delete-sla-policy"`
+	UpdateSLA          *sqlx.Stmt `query:"update-sla-policy"`
+	ApplySLA           *sqlx.Stmt `query:"apply-sla"`
+	GetPendingSLAs     *sqlx.Stmt `query:"get-pending-slas"`
+	UpdateBreach       *sqlx.Stmt `query:"update-breach"`
+	UpdateMet          *sqlx.Stmt `query:"update-met"`
+	GetLatestDeadlines *sqlx.Stmt `query:"get-latest-sla-deadlines"`
 }
 
-// New returns a new Manager.
-func New(opts Opts, pool *workerpool.Pool, teamStore teamStore, appSettingsStore appSettingsStore, businessHrsStore businessHrsStore) (*Manager, error) {
+// New creates a new SLA manager.
+func New(opts Opts, teamStore teamStore, appSettingsStore appSettingsStore, businessHrsStore businessHrsStore) (*Manager, error) {
 	var q queries
 	if err := dbutil.ScanSQLFile("queries.sql", &q, opts.DB, efs); err != nil {
 		return nil, err
 	}
-	return &Manager{
-		q:                q,
-		lo:               opts.Lo,
-		pool:             pool,
-		teamStore:        teamStore,
-		appSettingsStore: appSettingsStore,
-		businessHrsStore: businessHrsStore,
-		opts:             opts,
-	}, nil
+	return &Manager{q: q, lo: opts.Lo, teamStore: teamStore, appSettingsStore: appSettingsStore, businessHrsStore: businessHrsStore, opts: opts}, nil
 }
 
-// Get retrieves an SLA by its ID.
+// Get retrieves an SLA by ID.
 func (m *Manager) Get(id int) (models.SLAPolicy, error) {
 	var sla models.SLAPolicy
 	if err := m.q.GetSLA.Get(&sla, id); err != nil {
@@ -114,15 +111,15 @@ func (m *Manager) GetAll() ([]models.SLAPolicy, error) {
 }
 
 // Create adds a new SLA policy.
-func (m *Manager) Create(name, description, firstResponseDuration, resolutionDuration string) error {
-	if _, err := m.q.InsertSLA.Exec(name, description, firstResponseDuration, resolutionDuration); err != nil {
+func (m *Manager) Create(name, description string, firstResponseTime, resolutionTime string) error {
+	if _, err := m.q.InsertSLA.Exec(name, description, firstResponseTime, resolutionTime); err != nil {
 		m.lo.Error("error inserting SLA", "error", err)
 		return envelope.NewError(envelope.GeneralError, "Error creating SLA", nil)
 	}
 	return nil
 }
 
-// Delete removes an SLA policy by its ID.
+// Delete removes an SLA policy.
 func (m *Manager) Delete(id int) error {
 	if _, err := m.q.DeleteSLA.Exec(id); err != nil {
 		m.lo.Error("error deleting SLA", "error", err)
@@ -131,94 +128,43 @@ func (m *Manager) Delete(id int) error {
 	return nil
 }
 
-// Update modifies an SLA policy by its ID.
-func (m *Manager) Update(id int, name, description, firstResponseDuration, resolutionDuration string) error {
-	if _, err := m.q.UpdateSLA.Exec(id, name, description, firstResponseDuration, resolutionDuration); err != nil {
+// Update updates an existing SLA policy.
+func (m *Manager) Update(id int, name, description string, firstResponseTime, resolutionTime string) error {
+	if _, err := m.q.UpdateSLA.Exec(id, name, description, firstResponseTime, resolutionTime); err != nil {
 		m.lo.Error("error updating SLA", "error", err)
 		return envelope.NewError(envelope.GeneralError, "Error updating SLA", nil)
 	}
 	return nil
 }
 
-// ApplySLA associates an SLA policy with a conversation.
-func (m *Manager) ApplySLA(conversationID, slaPolicyID int) (models.SLAPolicy, error) {
-	sla, err := m.Get(slaPolicyID)
-	if err != nil {
-		return sla, err
-	}
-	for _, t := range []string{SLATypeFirstResponse, SLATypeResolution} {
-		if t == SLATypeFirstResponse && sla.FirstResponseTime == "" {
-			continue
-		}
-		if t == SLATypeResolution && sla.ResolutionTime == "" {
-			continue
-		}
-		if _, err := m.q.InsertConversationSLA.Exec(conversationID, slaPolicyID, t); err != nil && !dbutil.IsUniqueViolationError(err) {
-			m.lo.Error("error applying SLA to conversation", "error", err)
-			return sla, envelope.NewError(envelope.GeneralError, "Error applying SLA to conversation", nil)
-		}
-	}
-	return sla, nil
-}
-
-// Run starts the SLA worker pool and periodically processes unbreached SLAs (blocking).
-func (m *Manager) Run(ctx context.Context) {
-	ticker := time.NewTicker(m.opts.ScannerInterval)
-	defer ticker.Stop()
-	m.pool.Run()
-
-	for {
-		select {
-		case <-ctx.Done():
-			return
-		case <-ticker.C:
-			if err := m.processUnbreachedSLAs(); err != nil {
-				m.lo.Error("error during SLA periodic check", "error", err)
-			}
-		}
-	}
-}
-
-// Close shuts down the SLA worker pool.
-func (m *Manager) Close() error {
-	m.pool.Close()
-	return nil
-}
-
-// CalculateConversationDeadlines calculates deadlines for SLA policies attached to a conversation.
-func (m *Manager) CalculateConversationDeadlines(conversationCreatedAt time.Time, assignedTeamID, slaPolicyID int) (time.Time, time.Time, error) {
+// getBusinessHours returns the business hours ID and timezone for a team.
+func (m *Manager) getBusinessHours(assignedTeamID int) (bmodels.BusinessHours, string, error) {
 	var (
-		businessHrsID, timezone                   = 0, ""
-		firstResponseDeadline, resolutionDeadline = time.Time{}, time.Time{}
+		businessHrsID int
+		timezone      string
+		bh            bmodels.BusinessHours
 	)
 
-	// Fetch SLA policy.
-	slaPolicy, err := m.Get(slaPolicyID)
-	if err != nil {
-		return firstResponseDeadline, resolutionDeadline, err
-	}
-
-	// First fetch business hours and timezone from assigned team if available.
+	// Fetch from team if assigned.
 	if assignedTeamID != 0 {
 		team, err := m.teamStore.Get(assignedTeamID)
 		if err != nil {
-			return firstResponseDeadline, resolutionDeadline, err
+			return bh, "", err
 		}
 		businessHrsID = team.BusinessHoursID.Int
 		timezone = team.Timezone
 	}
 
-	// If not found in team, fetch from app settings.
+	// Else fetch from app settings, this is System default.
 	if businessHrsID == 0 || timezone == "" {
 		settingsJ, err := m.appSettingsStore.GetByPrefix("app")
 		if err != nil {
-			return firstResponseDeadline, resolutionDeadline, err
+			return bh, "", err
 		}
 
 		var out map[string]interface{}
 		if err := json.Unmarshal([]byte(settingsJ), &out); err != nil {
-			m.lo.Error("error parsing settings", "error", err)
-			return firstResponseDeadline, resolutionDeadline, envelope.NewError(envelope.GeneralError, "Error parsing settings", nil)
+			return bh, "", fmt.Errorf("parsing settings: %v", err)
 		}
 
 		businessHrsIDStr, _ := out["app.business_hours_id"].(string)
@@ -226,129 +172,170 @@ func (m *Manager) CalculateConversationDeadlines(conversationCreatedAt time.Time
 		timezone, _ = out["app.timezone"].(string)
 	}
 
-	// Not set, skip SLA calculation.
+	// If still not found, return error.
 	if businessHrsID == 0 || timezone == "" {
-		m.lo.Warn("default business hours or timezone not set, skipping SLA calculation")
-		return firstResponseDeadline, resolutionDeadline, nil
+		return bh, "", fmt.Errorf("business hours or timezone not configured")
 	}
 
 	bh, err := m.businessHrsStore.Get(businessHrsID)
 	if err != nil {
-		m.lo.Error("error fetching business hours", "error", err)
-		return firstResponseDeadline, resolutionDeadline, err
+		if err == businessHours.ErrBusinessHoursNotFound {
+			m.lo.Warn("business hours not found", "team_id", assignedTeamID)
+			return bh, "", fmt.Errorf("business hours not found")
+		}
+		m.lo.Error("error fetching business hours for SLA", "error", err)
+		return bh, "", err
+	}
+	return bh, timezone, nil
+}
+
+// CalculateDeadline calculates the deadline for a given start time and duration.
+func (m *Manager) CalculateDeadlines(startTime time.Time, slaPolicyID, assignedTeamID int) (Deadlines, error) {
+	var deadlines Deadlines
+
+	businessHrs, timezone, err := m.getBusinessHours(assignedTeamID)
+	if err != nil {
+		return deadlines, err
+	}
+
+	m.lo.Info("calculating deadlines", "business_hours", businessHrs.Hours, "timezone", timezone, "always_open", businessHrs.IsAlwaysOpen)
+
+	sla, err := m.Get(slaPolicyID)
+	if err != nil {
+		return deadlines, err
 	}
 
 	calculateDeadline := func(durationStr string) (time.Time, error) {
 		if durationStr == "" {
 			return time.Time{}, nil
 		}
-		dur, parseErr := time.ParseDuration(durationStr)
-		if parseErr != nil {
-			return time.Time{}, fmt.Errorf("parsing duration: %v", parseErr)
+		dur, err := time.ParseDuration(durationStr)
+		if err != nil {
+			return time.Time{}, fmt.Errorf("parsing SLA duration: %v", err)
 		}
-		deadline, err := m.CalculateDeadline(
-			conversationCreatedAt,
-			int(dur.Minutes()),
-			bh,
-			timezone,
-		)
+		deadline, err := m.CalculateDeadline(startTime, int(dur.Minutes()), businessHrs, timezone)
 		if err != nil {
 			return time.Time{}, err
 		}
-		return deadline.Add(slaGracePeriod), nil
+		return deadline, nil
 	}
-	firstResponseDeadline, err = calculateDeadline(slaPolicy.FirstResponseTime)
-	if err != nil {
-		return firstResponseDeadline, resolutionDeadline, err
+	if deadlines.FirstResponse, err = calculateDeadline(sla.FirstResponseTime); err != nil {
+		return deadlines, err
 	}
-	resolutionDeadline, err = calculateDeadline(slaPolicy.ResolutionTime)
-	if err != nil {
-		return firstResponseDeadline, resolutionDeadline, err
+	if deadlines.Resolution, err = calculateDeadline(sla.ResolutionTime); err != nil {
+		return deadlines, err
 	}
-	return firstResponseDeadline, resolutionDeadline, nil
+	return deadlines, nil
 }
 
-// processUnbreachedSLAs fetches unbreached SLAs and pushes them to the worker pool for processing.
-func (m *Manager) processUnbreachedSLAs() error {
-	var unbreachedSLAs []models.ConversationSLA
-	if err := m.q.GetUnbreachedSLAs.Select(&unbreachedSLAs); err != nil {
-		m.lo.Error("error fetching unbreached SLAs", "error", err)
+// ApplySLA applies an SLA policy to a conversation.
+func (m *Manager) ApplySLA(conversationID, assignedTeamID, slaPolicyID int) (models.SLAPolicy, error) {
+	var sla models.SLAPolicy
+
+	deadlines, err := m.CalculateDeadlines(time.Now(), slaPolicyID, assignedTeamID)
+	if err != nil {
+		return sla, err
+	}
+	if _, err := m.q.ApplySLA.Exec(
+		conversationID,
+		slaPolicyID,
+		deadlines.FirstResponse,
+		deadlines.Resolution,
+	); err != nil {
+		m.lo.Error("error applying SLA", "error", err)
+		return sla, envelope.NewError(envelope.GeneralError, "Error applying SLA", nil)
+	}
+	sla, err = m.Get(slaPolicyID)
+	if err != nil {
+		return sla, err
+	}
+	return sla, nil
+}
+
+// GetLatestDeadlines returns the latest deadlines for a conversation.
+func (m *Manager) GetLatestDeadlines(conversationID int) (time.Time, time.Time, error) {
+	var first, resolution time.Time
+	err := m.q.GetLatestDeadlines.QueryRow(conversationID).Scan(&first, &resolution)
+	if err == sql.ErrNoRows {
+		return first, resolution, nil
+	}
+	return first, resolution, err
+}
+
+// Run starts the SLA evaluation loop and evaluates pending SLAs.
+func (m *Manager) Run(ctx context.Context) {
+	m.wg.Add(1)
+	defer m.wg.Done()
+
+	ticker := time.NewTicker(2 * time.Minute)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			if err := m.evaluatePendingSLAs(ctx); err != nil {
+				m.lo.Error("error processing pending SLAs", "error", err)
+			}
+		}
+	}
+}
+
+// Close closes the SLA evaluation loop by stopping the worker pool.
+func (m *Manager) Close() error {
+	m.wg.Wait()
+	return nil
+}
+
+// evaluatePendingSLAs fetches unbreached SLAs and evaluates them.
+func (m *Manager) evaluatePendingSLAs(ctx context.Context) error {
+	var pendingSLAs []models.AppliedSLA
+	if err := m.q.GetPendingSLAs.SelectContext(ctx, &pendingSLAs); err != nil {
+		m.lo.Error("error fetching pending SLAs", "error", err)
 		return err
 	}
-	m.lo.Debug("processing unbreached SLAs", "count", len(unbreachedSLAs))
-	for _, u := range unbreachedSLAs {
-		slaData := u
-		m.pool.Push(func() {
-			if err := m.evaluateSLA(slaData); err != nil {
-				m.lo.Error("error processing SLA", "error", err)
+	m.lo.Info("evaluating pending SLAs", "count", len(pendingSLAs))
+	for _, sla := range pendingSLAs {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+			if err := m.evaluateSLA(sla); err != nil {
+				m.lo.Error("error evaluating SLA", "error", err)
 			}
-		})
+		}
 	}
 	return nil
 }
 
-// evaluateSLA checks if an SLA has been breached or met and updates the database accordingly.
-func (m *Manager) evaluateSLA(cSLA models.ConversationSLA) error {
-	var deadline, compareTime time.Time
-
-	// Calculate deadlines using the `created_at` which is the time SLA was applied to the conversation.
-	// This will take care of the case where SLA is changed for a conversation.
-	m.lo.Info("calculating SLA deadlines", "start_time", cSLA.CreatedAt, "conversation_id", cSLA.ConversationID, "sla_policy_id", cSLA.SLAPolicyID)
-	firstResponseDeadline, resolutionDeadline, err := m.CalculateConversationDeadlines(cSLA.CreatedAt, cSLA.ConversationAssignedTeamID.Int, cSLA.SLAPolicyID)
-	if err != nil {
-		return err
-	}
-
-	switch cSLA.SLAType {
-	case SLATypeFirstResponse:
-		deadline = firstResponseDeadline
-		compareTime = cSLA.ConversationFirstReplyAt.Time
-	case SLATypeResolution:
-		deadline = resolutionDeadline
-		compareTime = cSLA.ConversationResolvedAt.Time
-	default:
-		return fmt.Errorf("unknown SLA type: %s", cSLA.SLAType)
-	}
-
-	if deadline.IsZero() {
-		m.lo.Warn("could not calculate SLA deadline", "conversation_id", cSLA.ConversationID, "sla_policy_id", cSLA.SLAPolicyID)
+// evaluateSLA evaluates an SLA policy on an applied SLA.
+func (m *Manager) evaluateSLA(sla models.AppliedSLA) error {
+	now := time.Now()
+	checkDeadline := func(deadline time.Time, metAt null.Time, slaType string) error {
+		if deadline.IsZero() {
+			return nil
+		}
+		if !metAt.Valid && now.After(deadline) {
+			_, err := m.q.UpdateBreach.Exec(sla.ID, slaType)
+			return err
+		}
+		if metAt.Valid {
+			if metAt.Time.After(deadline) {
+				_, err := m.q.UpdateBreach.Exec(sla.ID, slaType)
+				return err
+			}
+			_, err := m.q.UpdateMet.Exec(sla.ID, slaType)
+			return err
+		}
 		return nil
 	}
 
-	// Save deadline in DB.
-	if _, err := m.q.UpdateDueAt.Exec(cSLA.ID, deadline); err != nil {
-		m.lo.Error("error updating SLA due_at", "error", err)
-		return fmt.Errorf("updating SLA due_at: %v", err)
+	if err := checkDeadline(sla.FirstResponseDeadlineAt, sla.FirstResponseAt, SLATypeFirstResponse); err != nil {
+		return err
 	}
-
-	if !compareTime.IsZero() {
-		if compareTime.After(deadline) {
-			return m.markSLABreached(cSLA.ID)
-		}
-		return m.markSLAMet(cSLA.ID, compareTime)
-	}
-
-	if time.Now().After(deadline) {
-		return m.markSLABreached(cSLA.ID)
-	}
-
-	return nil
-}
-
-// markSLABreached updates the breach time for a conversation SLA.
-func (m *Manager) markSLABreached(id int) error {
-	if _, err := m.q.UpdateBreachedAt.Exec(id); err != nil {
-		m.lo.Error("error updating SLA breach time", "error", err)
-		return fmt.Errorf("updating SLA breach time: %v", err)
-	}
-	return nil
-}
-
-// markSLAMet updates the met time for a conversation SLA.
-func (m *Manager) markSLAMet(id int, t time.Time) error {
-	if _, err := m.q.UpdateMetAt.Exec(id, t); err != nil {
-		m.lo.Error("error updating SLA met time", "error", err)
-		return fmt.Errorf("updating SLA met time: %v", err)
+	if err := checkDeadline(sla.ResolutionDeadlineAt, sla.ResolvedAt, SLATypeResolution); err != nil {
+		return err
 	}
 	return nil
 }
diff --git a/internal/team/models/models.go b/internal/team/models/models.go
index f54ce5e2..e6d3170d 100644
--- a/internal/team/models/models.go
+++ b/internal/team/models/models.go
@@ -17,7 +17,8 @@ type Team struct {
 	Name                       string      `db:"name" json:"name"`
 	ConversationAssignmentType string      `db:"conversation_assignment_type" json:"conversation_assignment_type,omitempty"`
 	Timezone                   string      `db:"timezone" json:"timezone,omitempty"`
-	BusinessHoursID            null.Int         `db:"business_hours_id" json:"business_hours_id,omitempty"`
+	BusinessHoursID            null.Int    `db:"business_hours_id" json:"business_hours_id,omitempty"`
+	SLAPolicyID                null.Int    `db:"sla_policy_id" json:"sla_policy_id,omitempty"`
 }
 
 type Teams []Team
diff --git a/internal/team/queries.sql b/internal/team/queries.sql
index 75b0cfb3..c954ccdc 100644
--- a/internal/team/queries.sql
+++ b/internal/team/queries.sql
@@ -1,14 +1,14 @@
 -- name: get-teams
 SELECT id, emoji, created_at, updated_at, name, conversation_assignment_type, timezone from teams order by updated_at desc;
 
--- name: get-user-teams
-SELECT id, emoji, created_at, updated_at, name, conversation_assignment_type, timezone from teams WHERE id IN (SELECT team_id FROM team_members WHERE user_id = $1) order by updated_at desc;
-
 -- name: get-teams-compact
 SELECT id, name, emoji from teams order by name;
 
+-- name: get-user-teams
+SELECT id, emoji, created_at, updated_at, name, conversation_assignment_type, timezone from teams WHERE id IN (SELECT team_id FROM team_members WHERE user_id = $1) order by updated_at desc;
+
 -- name: get-team
-SELECT id, emoji, name, conversation_assignment_type, timezone, business_hours_id from teams where id = $1;
+SELECT id, emoji, name, conversation_assignment_type, timezone, business_hours_id, sla_policy_id from teams where id = $1;
 
 -- name: get-team-members
 SELECT u.id, t.id as team_id
@@ -18,10 +18,10 @@ JOIN teams t ON t.id = tm.team_id
 WHERE t.id = $1;
 
 -- name: insert-team
-INSERT INTO teams (name, timezone, conversation_assignment_type, business_hours_id, emoji) VALUES ($1, $2, $3, $4, $5) RETURNING id;
+INSERT INTO teams (name, timezone, conversation_assignment_type, business_hours_id, sla_policy_id, emoji) VALUES ($1, $2, $3, $4, $5, $6) RETURNING id;
 
 -- name: update-team
-UPDATE teams set name = $2, timezone = $3, conversation_assignment_type = $4, business_hours_id = $5, emoji = $6, updated_at = now() where id = $1;
+UPDATE teams set name = $2, timezone = $3, conversation_assignment_type = $4, business_hours_id = $5, sla_policy_id = $6, emoji = $7, updated_at = now() where id = $1;
 
 -- name: upsert-user-teams
 WITH delete_old_teams AS (
diff --git a/internal/team/team.go b/internal/team/team.go
index acf83eb5..709a57cd 100644
--- a/internal/team/team.go
+++ b/internal/team/team.go
@@ -101,8 +101,8 @@ func (u *Manager) Get(id int) (models.Team, error) {
 }
 
 // Create creates a new team.
-func (u *Manager) Create(name, timezone, conversationAssignmentType string, businessHrsID null.Int, emoji string) error {
-	if _, err := u.q.InsertTeam.Exec(name, timezone, conversationAssignmentType, businessHrsID, emoji); err != nil {
+func (u *Manager) Create(name, timezone, conversationAssignmentType string, businessHrsID, slaPolicyID null.Int, emoji string) error {
+	if _, err := u.q.InsertTeam.Exec(name, timezone, conversationAssignmentType, businessHrsID, slaPolicyID, emoji); err != nil {
 		if dbutil.IsUniqueViolationError(err) {
 			return envelope.NewError(envelope.GeneralError, "Team with the same name already exists", nil)
 		}
@@ -113,8 +113,8 @@ func (u *Manager) Create(name, timezone, conversationAssignmentType string, busi
 }
 
 // Update updates an existing team.
-func (u *Manager) Update(id int, name, timezone, conversationAssignmentType string, businessHrsID null.Int, emoji string) error {
-	if _, err := u.q.UpdateTeam.Exec(id, name, timezone, conversationAssignmentType, businessHrsID, emoji); err != nil {
+func (u *Manager) Update(id int, name, timezone, conversationAssignmentType string, businessHrsID, slaPolicyID null.Int, emoji string) error {
+	if _, err := u.q.UpdateTeam.Exec(id, name, timezone, conversationAssignmentType, businessHrsID, slaPolicyID, emoji); err != nil {
 		u.lo.Error("error updating team", "error", err)
 		return envelope.NewError(envelope.GeneralError, "Error updating team", nil)
 	}
diff --git a/internal/user/models/models.go b/internal/user/models/models.go
index b85b3bc5..d4fd71ab 100644
--- a/internal/user/models/models.go
+++ b/internal/user/models/models.go
@@ -9,7 +9,7 @@ import (
 )
 
 type User struct {
-	ID               int            `db:"id" json:"id"`
+	ID               int            `db:"id" json:"id,omitempty"`
 	CreatedAt        time.Time      `db:"created_at" json:"created_at"`
 	UpdatedAt        time.Time      `db:"updated_at" json:"updated_at"`
 	FirstName        string         `db:"first_name" json:"first_name"`
@@ -18,14 +18,14 @@ type User struct {
 	Type             string         `db:"type" json:"type"`
 	PhoneNumber      null.String    `db:"phone_number" json:"phone_number,omitempty"`
 	AvatarURL        null.String    `db:"avatar_url" json:"avatar_url"`
-	Enabled          bool           `db:"enabled" json:"enabled"`
+	Enabled          bool           `db:"enabled" json:"enabled,omitempty"`
 	Password         string         `db:"password" json:"-"`
 	Roles            pq.StringArray `db:"roles" json:"roles,omitempty"`
 	Permissions      pq.StringArray `db:"permissions" json:"permissions,omitempty"`
 	Meta             pq.StringArray `db:"meta" json:"meta,omitempty"`
 	CustomAttributes pq.StringArray `db:"custom_attributes" json:"custom_attributes,omitempty"`
 	Teams            tmodels.Teams  `db:"teams" json:"teams,omitempty"`
-	ContactChannelID int            `db:"contact_channel_id,omitempty"`
+	ContactChannelID int            `db:"contact_channel_id" json:"contact_channel_id,omitempty"`
 	NewPassword      string         `db:"-" json:"new_password,omitempty"`
 	SendWelcomeEmail bool           `db:"-" json:"send_welcome_email,omitempty"`
 	InboxID          int            `json:"-"`
diff --git a/internal/workerpool/workerpool.go b/internal/workerpool/workerpool.go
deleted file mode 100644
index 6bbf05f6..00000000
--- a/internal/workerpool/workerpool.go
+++ /dev/null
@@ -1,46 +0,0 @@
-// package workerpool contains a single goroutine worker pool that executes arbitrary
-// encapsulated functions.
-package workerpool
-
-import (
-	"sync"
-)
-
-// Pool is a single goroutine worker pool.
-type Pool struct {
-	num int
-	q   chan func()
-	wg  sync.WaitGroup
-}
-
-// New returns a new goroutine workerpool.
-func New(num, queueSize int) *Pool {
-	return &Pool{
-		num: num,
-		q:   make(chan func(), queueSize),
-		wg:  sync.WaitGroup{},
-	}
-}
-
-// Run initializes the goroutine worker pool.
-func (w *Pool) Run() {
-	for i := 0; i < w.num; i++ {
-		w.wg.Add(1)
-		go func() {
-			for f := range w.q {
-				f()
-			}
-			w.wg.Done()
-		}()
-	}
-}
-
-// Push pushes a job to the worker queue to execute.
-func (w *Pool) Push(f func()) {
-	w.q <- f
-}
-
-func (w *Pool) Close() {
-	close(w.q)
-	w.wg.Wait()
-}
diff --git a/schema.sql b/schema.sql
index 03c83fc5..d7193c68 100644
--- a/schema.sql
+++ b/schema.sql
@@ -6,28 +6,28 @@ DROP TYPE IF EXISTS "message_type" CASCADE; CREATE TYPE "message_type" AS ENUM (
 DROP TYPE IF EXISTS "message_sender_type" CASCADE; CREATE TYPE "message_sender_type" AS ENUM ('user','contact');
 DROP TYPE IF EXISTS "message_status" CASCADE; CREATE TYPE "message_status" AS ENUM ('received','sent','failed','pending');
 DROP TYPE IF EXISTS "content_type" CASCADE; CREATE TYPE "content_type" AS ENUM ('text','html');
-DROP TYPE IF EXISTS "sla_status" CASCADE; CREATE TYPE "sla_status" AS ENUM ('active','missed');
 DROP TYPE IF EXISTS "conversation_assignment_type" CASCADE; CREATE TYPE "conversation_assignment_type" AS ENUM ('Round robin','Manual');
-DROP TYPE IF EXISTS "sla_type" CASCADE; CREATE TYPE "sla_type" AS ENUM ('first_response','resolution');
 DROP TYPE IF EXISTS "template_type" CASCADE; CREATE TYPE "template_type" AS ENUM ('email_outgoing', 'email_notification');
 DROP TYPE IF EXISTS "user_type" CASCADE; CREATE TYPE "user_type" AS ENUM ('agent', 'contact');
 DROP TYPE IF EXISTS "ai_provider" CASCADE; CREATE TYPE "ai_provider" AS ENUM ('openai');
 DROP TYPE IF EXISTS "automation_execution_mode" CASCADE; CREATE TYPE "automation_execution_mode" AS ENUM ('all', 'first_match');
 DROP TYPE IF EXISTS "macro_visibility" CASCADE; CREATE TYPE "macro_visibility" AS ENUM ('all', 'team', 'user');
 
-DROP TABLE IF EXISTS conversation_slas CASCADE;
-CREATE TABLE conversation_slas (
-	id SERIAL PRIMARY KEY,
-	created_at TIMESTAMPTZ DEFAULT NOW() NOT NULL,
-	updated_at TIMESTAMPTZ DEFAULT NOW() NOT NULL,
-	conversation_id BIGINT NOT NULL REFERENCES conversations(id),
-	sla_policy_id INT NOT NULL REFERENCES sla_policies(id),
-	sla_type sla_type NOT NULL,
-	due_at TIMESTAMPTZ NULL,
-	met_at TIMESTAMPTZ NULL,
-	breached_at TIMESTAMPTZ NULL,
-	CONSTRAINT constraint_conversation_slas_unique UNIQUE (sla_policy_id, conversation_id, sla_type)
+DROP TABLE IF EXISTS applied_slas CASCADE;
+CREATE TABLE applied_slas (
+   id BIGSERIAL PRIMARY KEY,
+   created_at TIMESTAMPTZ DEFAULT NOW(),
+   updated_at TIMESTAMPTZ DEFAULT NOW(),
+   conversation_id BIGINT REFERENCES conversations(id),
+   sla_policy_id BIGINT REFERENCES sla_policies(id),
+   first_response_deadline_at TIMESTAMPTZ NULL,
+   resolution_deadline_at TIMESTAMPTZ NULL,
+   first_response_breached_at TIMESTAMPTZ NULL,
+   resolution_breached_at TIMESTAMPTZ NULL,
+   first_response_met_at TIMESTAMPTZ NULL,
+   resolution_met_at TIMESTAMPTZ NULL
 );
+CREATE INDEX index_applied_slas_on_conversation_id ON applied_slas (conversation_id);
 
 DROP TABLE IF EXISTS teams CASCADE;
 CREATE TABLE teams (
@@ -38,6 +38,7 @@ CREATE TABLE teams (
 	emoji TEXT NULL,
 	conversation_assignment_type conversation_assignment_type NOT NULL,
 	business_hours_id INT REFERENCES business_hours(id) ON DELETE SET NULL ON UPDATE CASCADE NULL,
+	sla_policy_id INT REFERENCES sla_policies(id) ON DELETE SET NULL ON UPDATE CASCADE NULL,
 	timezone TEXT NULL,
 	CONSTRAINT constraint_teams_on_emoji CHECK (length(emoji) <= 1),
 	CONSTRAINT constraint_teams_on_name CHECK (length("name") <= 140),