chore: reorganize go code

internal/hp_ipn/jsfunc.go

@@ -0,0 +1,100 @@
+//go:build js && wasm
+
+package hp_ipn
+
+import (
+	"errors"
+	"fmt"
+	"syscall/js"
+
+	"tailscale.com/ipn"
+	"tailscale.com/types/netmap"
+)
+
+// Maps ipn.State values to their string representations for the frontend.
+var BackendState = map[ipn.State]string{
+	ipn.NoState:          "NoState",
+	ipn.Stopped:          "Stopped",
+	ipn.Starting:         "Starting",
+	ipn.Running:          "Running",
+	ipn.InUseOtherUser:   "InUseOtherUser",
+	ipn.NeedsMachineAuth: "NeedsMachineAuth",
+	ipn.NeedsLogin:       "NeedsLogin",
+}
+
+// Represents the callbacks that the TsWasmNet module can invoke to register
+// data retrieval and notifications on the frontend.
+type TsWasmNetCallbacks struct {
+	// Changes in the backend state.
+	NotifyState func(ipn.State)
+
+	// Updates to the backend's network map.
+	NotifyNetMap func(*netmap.NetworkMap)
+
+	// If interactive login is required, this passes a login URL.
+	NotifyBrowseToURL func(string)
+
+	// If the process panics, this function is called in go.recover.
+	NotifyPanicRecover func(string)
+}
+
+// Parses a JavaScript object containing the necessary callbacks for the
+// TsWasmNet module to properly interact with the frontend.
+func ParseTsWasmNetCallbacks(obj js.Value) (*TsWasmNetCallbacks, error) {
+	if obj.IsUndefined() || obj.IsNull() {
+		return nil, errors.New("callbacks object is undefined or null")
+	}
+
+	state, err := validateCallback("NotifyState", obj)
+	if err != nil {
+		return nil, fmt.Errorf("invalid callback NotifyState: %w", err)
+	}
+
+	// TODO: This is complicated, as the NetworkMap is a complex type.
+	_, err = validateCallback("NotifyNetMap", obj)
+	if err != nil {
+		return nil, fmt.Errorf("invalid callback NotifyNetMap: %w", err)
+	}
+
+	browseURL, err := validateCallback("NotifyBrowseToURL", obj)
+	if err != nil {
+		return nil, fmt.Errorf("invalid callback NotifyBrowseToURL: %w", err)
+	}
+
+	panicRecover, err := validateCallback("NotifyPanicRecover", obj)
+	if err != nil {
+		return nil, fmt.Errorf("invalid callback NotifyPanicRecover: %w", err)
+	}
+
+	return &TsWasmNetCallbacks{
+		NotifyState: func(ipnState ipn.State) {
+			state.Invoke(BackendState[ipnState])
+		},
+
+		NotifyNetMap: func(nm *netmap.NetworkMap) {
+			// TODO: This is complicated
+		},
+
+		NotifyBrowseToURL: func(url string) {
+			browseURL.Invoke(url)
+		},
+
+		NotifyPanicRecover: func(msg string) {
+			panicRecover.Invoke(msg)
+		},
+	}, nil
+}
+
+// Validates the specified key is a JS function and returns it.
+func validateCallback(key string, obj js.Value) (*js.Value, error) {
+	val := obj.Get(key)
+	if val.IsUndefined() || val.IsNull() {
+		return nil, errors.New("callback is undefined or null")
+	}
+
+	if val.Type() != js.TypeFunction {
+		return nil, errors.New("callback is not a function")
+	}
+
+	return &val, nil
+}