Phase 2/4 done, working on phase 3/5

internal/api/api.go

@@ -0,0 +1,163 @@
+// Package api implements the REST API handlers for uopi.
+package api
+
+import (
+	"encoding/json"
+	"log/slog"
+	"net/http"
+
+	"github.com/uopi/uopi/internal/broker"
+	"github.com/uopi/uopi/internal/datasource"
+)
+
+// Handler holds the dependencies shared across all API endpoints.
+type Handler struct {
+	broker *broker.Broker
+	log    *slog.Logger
+}
+
+// New creates an API Handler.
+func New(b *broker.Broker, log *slog.Logger) *Handler {
+	return &Handler{broker: b, log: log}
+}
+
+// Register mounts all API routes onto mux under the given prefix.
+// Requires Go 1.22+ for method+path routing.
+func (h *Handler) Register(mux *http.ServeMux, prefix string) {
+	mux.HandleFunc("GET "+prefix+"/datasources", h.listDataSources)
+	mux.HandleFunc("GET "+prefix+"/signals", h.listSignals)
+	mux.HandleFunc("GET "+prefix+"/interfaces", h.listInterfaces)
+	mux.HandleFunc("POST "+prefix+"/interfaces", h.createInterface)
+	mux.HandleFunc("GET "+prefix+"/interfaces/{id}", h.getInterface)
+	mux.HandleFunc("PUT "+prefix+"/interfaces/{id}", h.updateInterface)
+	mux.HandleFunc("DELETE "+prefix+"/interfaces/{id}", h.deleteInterface)
+	mux.HandleFunc("POST "+prefix+"/interfaces/{id}/clone", h.cloneInterface)
+}
+
+// ── /datasources ──────────────────────────────────────────────────────────────
+
+type dsInfo struct {
+	Name   string `json:"name"`
+	Status string `json:"status"`
+}
+
+func (h *Handler) listDataSources(w http.ResponseWriter, r *http.Request) {
+	sources := h.broker.DataSources()
+	out := make([]dsInfo, len(sources))
+	for i, ds := range sources {
+		out[i] = dsInfo{Name: ds.Name(), Status: "connected"}
+	}
+	jsonOK(w, out)
+}
+
+// ── /signals ──────────────────────────────────────────────────────────────────
+
+type signalInfo struct {
+	Name        string   `json:"name"`
+	Type        string   `json:"type"`
+	Unit        string   `json:"unit,omitempty"`
+	Description string   `json:"description,omitempty"`
+	DisplayLow  float64  `json:"displayLow"`
+	DisplayHigh float64  `json:"displayHigh"`
+	Writable    bool     `json:"writable"`
+	EnumStrings []string `json:"enumStrings,omitempty"`
+}
+
+func (h *Handler) listSignals(w http.ResponseWriter, r *http.Request) {
+	dsName := r.URL.Query().Get("ds")
+	if dsName == "" {
+		jsonError(w, http.StatusBadRequest, "query parameter 'ds' is required")
+		return
+	}
+
+	ds, ok := h.broker.Source(dsName)
+	if !ok {
+		jsonError(w, http.StatusNotFound, "unknown data source: "+dsName)
+		return
+	}
+
+	metas, err := ds.ListSignals(r.Context())
+	if err != nil {
+		h.log.Error("list signals", "ds", dsName, "err", err)
+		jsonError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+
+	out := make([]signalInfo, len(metas))
+	for i, m := range metas {
+		out[i] = metaToSignalInfo(m)
+	}
+	jsonOK(w, out)
+}
+
+// ── /interfaces ───────────────────────────────────────────────────────────────
+// Stub implementations — full persistence lands in Phase 6.
+
+func (h *Handler) listInterfaces(w http.ResponseWriter, r *http.Request) {
+	jsonOK(w, []any{})
+}
+
+func (h *Handler) createInterface(w http.ResponseWriter, r *http.Request) {
+	jsonError(w, http.StatusNotImplemented, "interface storage not yet implemented")
+}
+
+func (h *Handler) getInterface(w http.ResponseWriter, r *http.Request) {
+	jsonError(w, http.StatusNotFound, "interface not found")
+}
+
+func (h *Handler) updateInterface(w http.ResponseWriter, r *http.Request) {
+	jsonError(w, http.StatusNotImplemented, "interface storage not yet implemented")
+}
+
+func (h *Handler) deleteInterface(w http.ResponseWriter, r *http.Request) {
+	jsonError(w, http.StatusNotImplemented, "interface storage not yet implemented")
+}
+
+func (h *Handler) cloneInterface(w http.ResponseWriter, r *http.Request) {
+	jsonError(w, http.StatusNotImplemented, "interface storage not yet implemented")
+}
+
+// ── Helpers ───────────────────────────────────────────────────────────────────
+
+func metaToSignalInfo(m datasource.Metadata) signalInfo {
+	return signalInfo{
+		Name:        m.Name,
+		Type:        dataTypeName(m.Type),
+		Unit:        m.Unit,
+		Description: m.Description,
+		DisplayLow:  m.DisplayLow,
+		DisplayHigh: m.DisplayHigh,
+		Writable:    m.Writable,
+		EnumStrings: m.EnumStrings,
+	}
+}
+
+func dataTypeName(t datasource.DataType) string {
+	switch t {
+	case datasource.TypeFloat64:
+		return "float64"
+	case datasource.TypeFloat64Array:
+		return "float64[]"
+	case datasource.TypeString:
+		return "string"
+	case datasource.TypeInt64:
+		return "int64"
+	case datasource.TypeBool:
+		return "bool"
+	case datasource.TypeEnum:
+		return "enum"
+	default:
+		return "unknown"
+	}
+}
+
+func jsonOK(w http.ResponseWriter, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	_ = json.NewEncoder(w).Encode(v)
+}
+
+func jsonError(w http.ResponseWriter, code int, message string) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(code)
+	_ = json.NewEncoder(w).Encode(map[string]string{"error": message})
+}