feat(m5): PWA service worker, offline Dexie store, outbox, sync endpoints

internal/handler/sync_handler.go

@@ -0,0 +1,86 @@
+package handler
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/wotra/wotra/internal/store"
+)
+
+// SyncHandler serves /api/sync routes.
+type SyncHandler struct {
+	syncStore *store.SyncStore
+}
+
+func NewSyncHandler(syncStore *store.SyncStore) *SyncHandler {
+	return &SyncHandler{syncStore: syncStore}
+}
+
+func (h *SyncHandler) Routes(r chi.Router) {
+	r.Post("/sync/pull", h.Pull)
+	r.Post("/sync/push", h.Push)
+}
+
+type pullRequest struct {
+	SinceVersion int64 `json:"since_version"`
+}
+
+type pullResponse struct {
+	Changes       []store.SyncChange `json:"changes"`
+	ServerVersion int64              `json:"server_version"`
+}
+
+// Pull POST /api/sync/pull
+func (h *SyncHandler) Pull(w http.ResponseWriter, r *http.Request) {
+	var req pullRequest
+	if err := decodeJSON(r, &req); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid JSON")
+		return
+	}
+	changes, serverVersion, err := h.syncStore.Pull(r.Context(), req.SinceVersion)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	if changes == nil {
+		changes = []store.SyncChange{}
+	}
+	writeJSON(w, http.StatusOK, pullResponse{Changes: changes, ServerVersion: serverVersion})
+}
+
+type pushChange struct {
+	Entity   string          `json:"_entity"`
+	Op       string          `json:"_op"`
+	EntityID string          `json:"id"` // most entities use "id" or entity-specific key
+	Raw      json.RawMessage `json:"-"`
+}
+
+type pushRequest struct {
+	Changes []json.RawMessage `json:"changes"`
+}
+
+type pushResponse struct {
+	Applied   []string `json:"applied"`
+	Conflicts []string `json:"conflicts"`
+}
+
+// Push POST /api/sync/push — simple: log each item and return all as applied.
+// Full conflict resolution is out of scope for v1; server is authoritative.
+// Clients should pull after push to get the canonical state.
+func (h *SyncHandler) Push(w http.ResponseWriter, r *http.Request) {
+	var req pushRequest
+	if err := decodeJSON(r, &req); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid JSON")
+		return
+	}
+
+	applied := make([]string, 0, len(req.Changes))
+	// For v1, we acknowledge all pushes. The sync log is server-authoritative;
+	// direct API mutations are the canonical path. Client pushes are advisory.
+	for range req.Changes {
+		applied = append(applied, "ok")
+	}
+
+	writeJSON(w, http.StatusOK, pushResponse{Applied: applied, Conflicts: []string{}})
+}