package httpserver

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

	"git.saqut.com/saqut/mwse/internal/ws"
)

// apiKeyStore holds the issued server-to-server API keys. The original kept these
// in a process-local Map; this matches that (keys do not survive a restart).
type apiKeyStore struct {
	mu   sync.RWMutex
	keys map[string]string // key -> domain
}

func newAPIKeyStore() *apiKeyStore {
	return &apiKeyStore{keys: make(map[string]string)}
}

func (s *apiKeyStore) issue(domain string) string {
	key := newToken()
	s.mu.Lock()
	s.keys[key] = domain
	s.mu.Unlock()
	return key
}

func (s *apiKeyStore) domain(key string) (string, bool) {
	s.mu.RLock()
	d, ok := s.keys[key]
	s.mu.RUnlock()
	return d, ok
}

// auth wraps a handler with x-api-key validation, passing the caller's domain on
// the request context-free closure argument.
func (s *apiKeyStore) auth(next func(http.ResponseWriter, *http.Request, string)) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		key := r.Header.Get("x-api-key")
		if key == "" {
			writeJSON(w, http.StatusUnauthorized, fail("API_KEY_REQUIRED"))
			return
		}
		domain, ok := s.domain(key)
		if !ok {
			writeJSON(w, http.StatusUnauthorized, fail("INVALID_API_KEY"))
			return
		}
		next(w, r, domain)
	}
}

// registerAPI mounts the /api control-plane routes onto mux. It ports the read
// endpoints and the core server-initiated messaging endpoints from api.js. The
// server-as-room-participant (join/leave) and webhook endpoints are intentionally
// deferred to feature-parity work (see REVIEW.md).
func registerAPI(mux *http.ServeMux, hub *ws.Hub) {
	keys := newAPIKeyStore()

	mux.HandleFunc("POST /api/auth/key", func(w http.ResponseWriter, r *http.Request) {
		var body struct {
			Domain string `json:"domain"`
		}
		if !decode(w, r, &body) {
			return
		}
		if body.Domain == "" {
			writeJSON(w, http.StatusOK, fail("DOMAIN_REQUIRED"))
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{"status": "success", "key": keys.issue(body.Domain)})
	})

	mux.HandleFunc("GET /api/rooms", func(w http.ResponseWriter, r *http.Request) {
		rooms := make([]map[string]any, 0)
		for _, room := range hub.Rooms() {
			rooms = append(rooms, map[string]any{
				"id":          room.ID,
				"name":        room.Name,
				"accessType":  room.AccessType,
				"joinType":    room.JoinType,
				"description": room.Description,
				"clientCount": room.Size(),
			})
		}
		writeJSON(w, http.StatusOK, map[string]any{"status": "success", "rooms": rooms})
	})

	mux.HandleFunc("GET /api/clients", func(w http.ResponseWriter, r *http.Request) {
		clients := make([]map[string]any, 0)
		for _, c := range hub.Clients() {
			clients = append(clients, map[string]any{
				"id":    c.ID,
				"rooms": c.Rooms(),
				"pairs": c.Pairs(),
			})
		}
		writeJSON(w, http.StatusOK, map[string]any{"status": "success", "clients": clients})
	})

	mux.HandleFunc("GET /api/room/{id}", func(w http.ResponseWriter, r *http.Request) {
		room, ok := hub.Room(r.PathValue("id"))
		if !ok {
			writeJSON(w, http.StatusOK, fail("ROOM_NOT_FOUND"))
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{"status": "success", "room": room.ToJSON(false)})
	})

	mux.HandleFunc("POST /api/client/{id}/send", keys.auth(func(w http.ResponseWriter, r *http.Request, domain string) {
		var body struct {
			Pack any `json:"pack"`
		}
		if !decode(w, r, &body) {
			return
		}
		client, ok := hub.Client(r.PathValue("id"))
		if !ok {
			writeJSON(w, http.StatusOK, fail("CLIENT_NOT_FOUND"))
			return
		}
		if body.Pack == nil {
			writeJSON(w, http.StatusOK, fail("PACK_REQUIRED"))
			return
		}
		client.Signal("server/pack", map[string]any{"from": "server", "fromServer": domain, "pack": body.Pack})
		writeJSON(w, http.StatusOK, map[string]any{"status": "success"})
	}))

	mux.HandleFunc("POST /api/room/{id}/send", keys.auth(func(w http.ResponseWriter, r *http.Request, domain string) {
		var body struct {
			Pack any  `json:"pack"`
			Wom  bool `json:"wom"`
		}
		if !decode(w, r, &body) {
			return
		}
		id := r.PathValue("id")
		room, ok := hub.Room(id)
		if !ok {
			writeJSON(w, http.StatusOK, fail("ROOM_NOT_FOUND"))
			return
		}
		if body.Pack == nil {
			writeJSON(w, http.StatusOK, fail("PACK_REQUIRED"))
			return
		}
		room.Broadcast(
			"server/pack/room",
			map[string]any{"from": "server", "fromServer": domain, "pack": body.Pack, "roomId": id},
			"",
			nil,
		)
		writeJSON(w, http.StatusOK, map[string]any{"status": "success"})
	}))

	mux.HandleFunc("POST /api/room/create", keys.auth(func(w http.ResponseWriter, r *http.Request, domain string) {
		var body struct {
			Name        string `json:"name"`
			AccessType  string `json:"accessType"`
			JoinType    string `json:"joinType"`
			Description string `json:"description"`
			Credential  string `json:"credential"`
		}
		if !decode(w, r, &body) {
			return
		}
		if body.Name == "" {
			writeJSON(w, http.StatusOK, fail("NAME_REQUIRED"))
			return
		}
		if _, exists := hub.RoomByName(body.Name); exists {
			writeJSON(w, http.StatusOK, fail("ROOM_ALREADY_EXISTS"))
			return
		}
		room := ws.NewRoom(hub)
		room.Name = body.Name
		room.AccessType = orDefault(body.AccessType, "public")
		room.JoinType = orDefault(body.JoinType, "free")
		room.Description = body.Description
		room.OwnerID = "server"
		if body.Credential != "" {
			room.Credential = sha256hex(body.Credential)
		}
		room.Publish()
		writeJSON(w, http.StatusOK, map[string]any{"status": "success", "room": room.ToJSON(false)})
	}))
}

func orDefault(v, def string) string {
	if v == "" {
		return def
	}
	return v
}

func fail(message string) map[string]any {
	return map[string]any{"status": "fail", "message": message}
}

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

// decode reads a JSON request body, writing a fail response and returning false
// when the body is malformed.
func decode(w http.ResponseWriter, r *http.Request, dst any) bool {
	if r.Body == nil {
		return true
	}
	if err := json.NewDecoder(r.Body).Decode(dst); err != nil && err.Error() != "EOF" {
		writeJSON(w, http.StatusBadRequest, fail("INVALID_JSON"))
		return false
	}
	return true
}