package api

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

	"github.com/ponzischeme89/memby/server/internal/cache"
	"github.com/ponzischeme89/memby/server/internal/store"
)

type loginRequest struct {
	Username string `json:"username"`
	Password string `json:"password"`
	DeviceID string `json:"deviceId"`
}

type loginResponse struct {
	Token    string `json:"token"`
	UserID   string `json:"userId"`
	Username string `json:"username"`
	ServerID string `json:"serverId"`
}

// handleLogin exchanges Emby credentials for a gateway token.
//
// The Emby access token stays here: the TV only ever holds the gateway token, so
// revoking a device is a DELETE in Postgres rather than an Emby-side cleanup.
func (s *Server) handleLogin(w http.ResponseWriter, r *http.Request) {
	var req loginRequest
	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 8<<10)).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "malformed request body")
		return
	}
	req.Username = strings.TrimSpace(req.Username)
	if req.Username == "" {
		writeError(w, http.StatusBadRequest, "username is required")
		return
	}
	if req.DeviceID == "" {
		req.DeviceID = "memby-tv"
	}

	auth, err := s.emby.Authenticate(r.Context(), req.Username, req.Password, req.DeviceID)
	if err != nil {
		// Never echo Emby's body here: a failed sign-in is the one place a wrong
		// password could be reflected back.
		s.log.Warn("emby authentication failed", "username", req.Username)
		writeError(w, http.StatusUnauthorized, "sign-in failed")
		return
	}

	token, err := newToken()
	if err != nil {
		s.log.Error("token generation failed", "error", err)
		writeError(w, http.StatusInternalServerError, "could not issue a token")
		return
	}

	sess := store.Session{
		TokenHash:  hashToken(token),
		EmbyUserID: auth.User.ID,
		EmbyToken:  auth.AccessToken,
		Username:   auth.User.Name,
		ServerID:   auth.ServerID,
		DeviceID:   req.DeviceID,
	}
	if sess.Username == "" {
		sess.Username = req.Username
	}
	if err := s.store.CreateSession(r.Context(), sess); err != nil {
		s.log.Error("session persist failed", "error", err)
		writeError(w, http.StatusInternalServerError, "could not start a session")
		return
	}

	writeJSON(w, http.StatusOK, loginResponse{
		Token:    token,
		UserID:   sess.EmbyUserID,
		Username: sess.Username,
		ServerID: sess.ServerID,
	})
}

func (s *Server) handleLogout(w http.ResponseWriter, r *http.Request, sess store.Session) {
	if err := s.store.DeleteSession(r.Context(), sess.TokenHash); err != nil {
		s.log.Error("session delete failed", "error", err)
	}
	_ = s.cache.Delete(r.Context(), cache.SessionKey(hexHash(sess.TokenHash)))
	_ = s.cache.InvalidateUser(r.Context(), sess.EmbyUserID)
	w.WriteHeader(http.StatusNoContent)
}

// handleSession lets the TV confirm a stored token is still good before rendering.
func (s *Server) handleSession(w http.ResponseWriter, _ *http.Request, sess store.Session) {
	writeJSON(w, http.StatusOK, loginResponse{
		UserID:   sess.EmbyUserID,
		Username: sess.Username,
		ServerID: sess.ServerID,
	})
}