package persistence

import (
	"bytes"
	"fmt"
	"github.com/openziti/foundation/storage/ast"
	"github.com/openziti/foundation/storage/boltz"
	"github.com/openziti/foundation/util/errorz"
	"github.com/openziti/foundation/util/stringz"
	"github.com/openziti/foundation/validation"
	"github.com/pkg/errors"
	"go.etcd.io/bbolt"
	"strings"
)

type roleAttributeChangeContext struct {
	tx                    *bbolt.Tx
	rolesSymbol           boltz.EntitySetSymbol
	linkCollection        boltz.LinkCollection
	relatedLinkCollection boltz.LinkCollection
	denormLinkCollection  boltz.RefCountedLinkCollection
	errorz.ErrorHolder
}

func (store *baseStore) updateServicePolicyRelatedRoles(ctx *roleAttributeChangeContext, entityId []byte, newRoleAttributes []boltz.FieldTypeAndValue) {
	cursor := ctx.rolesSymbol.GetStore().IterateIds(ctx.tx, ast.BoolNodeTrue)

	entityRoles := FieldValuesToIds(newRoleAttributes)

	semanticSymbol := store.stores.servicePolicy.symbolSemantic
	policyTypeSymbol := store.stores.servicePolicy.symbolPolicyType

	isServices := ctx.rolesSymbol == store.stores.servicePolicy.symbolServiceRoles
	isIdentity := ctx.rolesSymbol == store.stores.servicePolicy.symbolIdentityRoles

	for ; cursor.IsValid(); cursor.Next() {
		policyId := cursor.Current()
		roleSet := ctx.rolesSymbol.EvalStringList(ctx.tx, policyId)
		roles, ids, err := splitRolesAndIds(roleSet)
		if err != nil {
			ctx.SetError(err)
			return
		}

		semantic := SemanticAllOf
		if _, semanticValue := semanticSymbol.Eval(ctx.tx, policyId); semanticValue != nil {
			semantic = string(semanticValue)
		}
		policyType := PolicyTypeDial
		if fieldType, policyTypeValue := policyTypeSymbol.Eval(ctx.tx, policyId); fieldType == boltz.TypeInt32 {
			policyType = *boltz.BytesToInt32(policyTypeValue)
		}
		if policyType == PolicyTypeDial {
			if isServices {
				ctx.denormLinkCollection = store.stores.edgeService.dialIdentitiesCollection
			} else if isIdentity {
				ctx.denormLinkCollection = store.stores.identity.dialServicesCollection
			} else {
				ctx.denormLinkCollection = store.stores.postureCheck.dialServicesCollection
			}
		} else if isServices {
			ctx.denormLinkCollection = store.stores.edgeService.bindIdentitiesCollection
		} else if isIdentity {
			ctx.denormLinkCollection = store.stores.identity.bindServicesCollection
		} else {
			ctx.denormLinkCollection = store.stores.postureCheck.bindServicesCollection
		}
		evaluatePolicyAgainstEntity(ctx, semantic, entityId, policyId, ids, roles, entityRoles)
	}
}

func EvaluatePolicy(ctx *roleAttributeChangeContext, policy Policy, roleAttributesSymbol boltz.EntitySetSymbol) {
	policyId := []byte(policy.GetId())

	roleSet := ctx.rolesSymbol.EvalStringList(ctx.tx, policyId)
	roles, ids, err := splitRolesAndIds(roleSet)
	if err != nil {
		ctx.SetError(err)
		return
	}

	if err := validateEntityIds(ctx.tx, ctx.linkCollection.GetLinkedSymbol().GetStore(), ctx.rolesSymbol.GetName(), ids); err != nil {
		ctx.SetError(err)
		return
	}

	cursor := roleAttributesSymbol.GetStore().IterateIds(ctx.tx, ast.BoolNodeTrue)
	for ; cursor.IsValid(); cursor.Next() {
		entityId := cursor.Current()
		entityRoleAttributes := roleAttributesSymbol.EvalStringList(ctx.tx, entityId)
		evaluatePolicyAgainstEntity(ctx, policy.GetSemantic(), entityId, policyId, ids, roles, entityRoleAttributes)
	}
}

func validateEntityIds(tx *bbolt.Tx, store boltz.ListStore, field string, ids []string) error {
	var invalid []string
	for _, val := range ids {
		if !store.IsEntityPresent(tx, val) {
			invalid = append(invalid, val)
		}
	}
	if len(invalid) > 0 {
		return validation.NewFieldError(fmt.Sprintf("no %v found with the given ids", store.GetEntityType()), field, invalid)
	}
	return nil
}

func UpdateRelatedRoles(ctx *roleAttributeChangeContext, entityId []byte, newRoleAttributes []boltz.FieldTypeAndValue, semanticSymbol boltz.EntitySymbol) {
	cursor := ctx.rolesSymbol.GetStore().IterateIds(ctx.tx, ast.BoolNodeTrue)

	entityRoles := FieldValuesToIds(newRoleAttributes)

	for ; cursor.IsValid(); cursor.Next() {
		policyId := cursor.Current()
		roleSet := ctx.rolesSymbol.EvalStringList(ctx.tx, policyId)
		roles, ids, err := splitRolesAndIds(roleSet)
		if err != nil {
			ctx.SetError(err)
			return
		}

		semantic := SemanticAllOf
		if _, semanticValue := semanticSymbol.Eval(ctx.tx, policyId); semanticValue != nil {
			semantic = string(semanticValue)
		}
		evaluatePolicyAgainstEntity(ctx, semantic, entityId, policyId, ids, roles, entityRoles)
	}
}

func evaluatePolicyAgainstEntity(ctx *roleAttributeChangeContext, semantic string, entityId, policyId []byte, ids, roles, roleAttributes []string) {
	if stringz.Contains(ids, string(entityId)) || stringz.Contains(roles, "all") ||
		(strings.EqualFold(semantic, SemanticAllOf) && len(roles) > 0 && stringz.ContainsAll(roleAttributes, roles...)) ||
		(strings.EqualFold(semantic, SemanticAnyOf) && len(roles) > 0 && stringz.ContainsAny(roleAttributes, roles...)) {
		ProcessEntityPolicyMatched(ctx, entityId, policyId)
	} else {
		ProcessEntityPolicyUnmatched(ctx, entityId, policyId)
	}
}

func ProcessEntityPolicyMatched(ctx *roleAttributeChangeContext, entityId, policyId []byte) {
	if added, err := ctx.linkCollection.AddLink(ctx.tx, policyId, entityId); ctx.SetError(err) || !added {
		return
	}
	cursor := ctx.relatedLinkCollection.IterateLinks(ctx.tx, policyId)
	for ; cursor.IsValid(); cursor.Next() {
		relatedEntityId := cursor.Current()
		_, err := ctx.denormLinkCollection.IncrementLinkCount(ctx.tx, entityId, relatedEntityId)
		if ctx.SetError(err) {
			return
		}
	}
}

func ProcessEntityPolicyUnmatched(ctx *roleAttributeChangeContext, entityId, policyId []byte) {
	if removed, err := ctx.linkCollection.RemoveLink(ctx.tx, policyId, entityId); ctx.SetError(err) || !removed {
		return
	}

	cursor := ctx.relatedLinkCollection.IterateLinks(ctx.tx, policyId)
	for ; cursor.IsValid(); cursor.Next() {
		relatedEntityId := cursor.Current()
		_, err := ctx.denormLinkCollection.DecrementLinkCount(ctx.tx, entityId, relatedEntityId)
		if ctx.SetError(err) {
			return
		}
	}
}

type denormCheckCtx struct {
	name                   string
	tx                     *bbolt.Tx
	sourceStore            boltz.CrudStore
	targetStore            boltz.CrudStore
	policyStore            boltz.CrudStore
	sourceCollection       boltz.LinkCollection
	targetCollection       boltz.LinkCollection
	targetDenormCollection boltz.RefCountedLinkCollection
	policyFilter           func(policyId []byte) bool
	errorSink              func(err error, fixed bool)
	repair                 bool
}

func validatePolicyDenormalization(ctx *denormCheckCtx) error {
	for sourceCursor := ctx.sourceStore.IterateIds(ctx.tx, ast.BoolNodeTrue); sourceCursor.IsValid(); sourceCursor.Next() {
		sourceEntityId := sourceCursor.Current()
		for targetCursor := ctx.targetStore.IterateIds(ctx.tx, ast.BoolNodeTrue); targetCursor.IsValid(); targetCursor.Next() {
			targetEntityId := targetCursor.Current()

			var relatedPolicies []string

			for policyCursor := ctx.policyStore.IterateIds(ctx.tx, ast.BoolNodeTrue); policyCursor.IsValid(); policyCursor.Next() {
				policyId := policyCursor.Current()
				if ctx.policyFilter == nil || ctx.policyFilter(policyId) {
					sourceRelated := isRelatedByLinkCollection(ctx.tx, ctx.sourceCollection, policyId, sourceEntityId)
					targetRelated := isRelatedByLinkCollection(ctx.tx, ctx.targetCollection, policyId, targetEntityId)
					if sourceRelated && targetRelated {
						relatedPolicies = append(relatedPolicies, string(policyId))
					}
				}
			}
			linkCount := len(relatedPolicies)
			var sourceLinkCount, targetLinkCount *int32
			var err error
			if ctx.repair {
				sourceLinkCount, targetLinkCount, err = ctx.targetDenormCollection.SetLinkCount(ctx.tx, sourceEntityId, targetEntityId, linkCount)
			} else {
				sourceLinkCount, targetLinkCount = ctx.targetDenormCollection.GetLinkCounts(ctx.tx, sourceEntityId, targetEntityId)
			}
			if err != nil {
				return err
			}
			logDiscrepencies(ctx, linkCount, sourceEntityId, targetEntityId, sourceLinkCount, targetLinkCount)
		}
	}
	return nil
}

func logDiscrepencies(ctx *denormCheckCtx, count int, sourceId, targetId []byte, sourceLinkCount, targetLinkCount *int32) {
	oldValuesMatch := (sourceLinkCount == nil && targetLinkCount == nil) || (sourceLinkCount != nil && targetLinkCount != nil && *sourceLinkCount == *targetLinkCount)
	if !oldValuesMatch {
		err := errors.Errorf("%v: ismatched link counts. %v %v (%v) <-> %v %v (%v), should be both are %v", ctx.name,
			ctx.sourceStore.GetSingularEntityType(), string(sourceId), sourceLinkCount,
			ctx.targetStore.GetSingularEntityType(), string(targetId), targetLinkCount, count)
		ctx.errorSink(err, ctx.repair)
	}

	if ((sourceLinkCount == nil || *sourceLinkCount == 0) && count != 0) ||
		(sourceLinkCount != nil && *sourceLinkCount != int32(count)) {
		sourceCount := int32(0)
		if sourceLinkCount != nil {
			sourceCount = *sourceLinkCount
		}
		err := errors.Errorf("%v: incorrect link counts for %v %v <-> %v %v is %v, should be %v", ctx.name,
			ctx.sourceStore.GetSingularEntityType(), string(sourceId),
			ctx.targetStore.GetSingularEntityType(), string(targetId),
			sourceCount, count)
		ctx.errorSink(err, ctx.repair)
	}
}

func isRelatedByLinkCollection(tx *bbolt.Tx, linkCollection boltz.LinkCollection, entityId, relatedId []byte) bool {
	cursor := linkCollection.IterateLinks(tx, entityId)
	cursor.Seek(relatedId)
	return bytes.Equal(cursor.Current(), relatedId)
}