// Package api is OpenMail's agent-facing HTTP surface: the AgentMail-shaped v0
// REST API (see ARCHITECTURE.md §4). v0 routes are stubbed pending the core
// services; health and auth are real.
package api

import (
	"encoding/json"
	"net/http"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"

	"github.com/karti-ai/openmail/internal/config"
	"github.com/karti-ai/openmail/internal/store"
)

type Server struct {
	cfg   config.Config
	store *store.Store
}

func New(cfg config.Config, st *store.Store) *Server {
	return &Server{cfg: cfg, store: st}
}

func (s *Server) Router() http.Handler {
	r := chi.NewRouter()
	r.Use(middleware.RequestID)
	r.Use(middleware.RealIP)
	r.Use(middleware.Recoverer)

	// Unauthenticated liveness/readiness.
	r.Get("/healthz", s.handleHealth)

	// Authenticated v0 surface.
	r.Group(func(r chi.Router) {
		r.Use(s.bearerAuth)

		r.Route("/v0/inboxes", func(r chi.Router) {
			r.Post("/", notImplemented)        // create inbox
			r.Get("/", notImplemented)         // list inboxes
			r.Get("/{id}", notImplemented)     // get inbox
			r.Post("/{id}/messages/send", notImplemented)
			r.Get("/{id}/messages", notImplemented)
			r.Get("/{id}/messages/{msgID}", notImplemented)
			r.Post("/{id}/messages/{msgID}/reply", notImplemented)
			r.Get("/{id}/threads", notImplemented)
			r.Get("/{id}/threads/{threadID}", notImplemented)
		})
	})

	return r
}

func (s *Server) handleHealth(w http.ResponseWriter, r *http.Request) {
	status := map[string]any{"status": "ok"}
	if s.store != nil {
		if err := s.store.Pool.Ping(r.Context()); err != nil {
			status["status"] = "degraded"
			status["db"] = err.Error()
			writeJSON(w, http.StatusServiceUnavailable, status)
			return
		}
		status["db"] = "ok"
	} else {
		status["db"] = "not configured"
	}
	writeJSON(w, http.StatusOK, status)
}

func notImplemented(w http.ResponseWriter, r *http.Request) {
	writeJSON(w, http.StatusNotImplemented, map[string]string{
		"error":   "not_implemented",
		"message": "endpoint scaffolded; core service pending (milestone 1)",
	})
}

func writeJSON(w http.ResponseWriter, code int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(code)
	_ = json.NewEncoder(w).Encode(v)
}