package httpapi

import (
	"database/sql"
	"encoding/json"
	"errors"
	"net/http"
	"os"
	"strings"
	"time"

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

	"github.com/benya/temporserv/internal/auth"
	"github.com/benya/temporserv/internal/config"
	"github.com/benya/temporserv/internal/library"
	"github.com/benya/temporserv/internal/scanner"
	"github.com/benya/temporserv/internal/subsonic"
)

type app struct {
	auth    *auth.Service
	library *library.Service
	scanner *scanner.Service
}

func NewRouter(cfg config.Config, database *sql.DB, scanService *scanner.Service) http.Handler {
	application := app{
		auth:    auth.NewService(database),
		library: library.NewService(database),
		scanner: scanService,
	}

	r := chi.NewRouter()
	r.Use(requestLogger)
	r.Use(recoverer)
	r.Use(cors(cfg.CORSOrigins))

	r.Get("/health", func(w http.ResponseWriter, r *http.Request) {
		writeJSON(w, http.StatusOK, map[string]any{
			"status": "ok",
			"time":   time.Now().UTC(),
			"env":    cfg.AppEnv,
		})
	})

	r.Route("/api", func(api chi.Router) {
		api.Post("/auth/login", application.login)

		api.Group(func(private chi.Router) {
			private.Use(application.requireAuth)
			private.Get("/me", application.me)
			private.Get("/home", application.home)
			private.Get("/tracks", application.tracks)
			private.Post("/admin/scan", application.scanLibrary)
		})

		api.Get("/stream/{id}", application.streamTrack)
	})

	r.Route("/rest", func(rest chi.Router) {
		rest.Get("/ping.view", func(w http.ResponseWriter, r *http.Request) {
			writeJSON(w, http.StatusOK, subsonic.PingResponse())
		})
		rest.Get("/getLicense.view", func(w http.ResponseWriter, r *http.Request) {
			writeJSON(w, http.StatusOK, subsonic.PingResponse())
		})
		rest.Get("/getArtists.view", application.subsonicArtists)
		rest.Get("/getRandomSongs.view", application.subsonicRandomSongs)
	})

	fs := http.FileServer(http.Dir("./web"))
	r.Handle("/*", spaFallback(fs))

	return r
}

func (a app) login(w http.ResponseWriter, r *http.Request) {
	var payload struct {
		Username string `json:"username"`
		Password string `json:"password"`
	}

	if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid request body"})
		return
	}

	session, err := a.auth.Login(r.Context(), payload.Username, payload.Password)
	if err != nil {
		if errors.Is(err, auth.ErrInvalidCredentials) {
			writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "invalid credentials"})
			return
		}
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "login failed"})
		return
	}

	writeJSON(w, http.StatusOK, session)
}

func (a app) me(w http.ResponseWriter, r *http.Request) {
	user := currentUserFromContext(r)
	writeJSON(w, http.StatusOK, user)
}

func (a app) home(w http.ResponseWriter, r *http.Request) {
	home, err := a.library.Home(r.Context())
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to load home"})
		return
	}
	writeJSON(w, http.StatusOK, home)
}

func (a app) tracks(w http.ResponseWriter, r *http.Request) {
	items, err := a.library.Tracks(r.Context(), 200)
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to load tracks"})
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"items": items})
}

func (a app) subsonicArtists(w http.ResponseWriter, r *http.Request) {
	artists, err := a.library.Artists(r.Context(), 1000)
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, subsonic.PingResponse())
		return
	}
	writeJSON(w, http.StatusOK, subsonic.ArtistsResponse(artists))
}

func (a app) subsonicRandomSongs(w http.ResponseWriter, r *http.Request) {
	tracks, err := a.library.Tracks(r.Context(), 20)
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, subsonic.PingResponse())
		return
	}
	writeJSON(w, http.StatusOK, subsonic.RandomSongsResponse(tracks))
}

func (a app) scanLibrary(w http.ResponseWriter, r *http.Request) {
	result, err := a.scanner.Scan(r.Context())
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
		return
	}
	writeJSON(w, http.StatusOK, result)
}

func (a app) streamTrack(w http.ResponseWriter, r *http.Request) {
	token := r.URL.Query().Get("token")
	if token == "" {
		token = strings.TrimSpace(strings.TrimPrefix(r.Header.Get("Authorization"), "Bearer "))
	}

	if _, err := a.auth.CurrentUserByToken(r.Context(), token); err != nil {
		writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
		return
	}

	track, err := a.library.TrackByID(r.Context(), chi.URLParam(r, "id"))
	if err != nil {
		writeJSON(w, http.StatusNotFound, map[string]string{"error": "track not found"})
		return
	}

	file, err := os.Open(track.FilePath)
	if err != nil {
		writeJSON(w, http.StatusNotFound, map[string]string{"error": "audio file not available"})
		return
	}
	defer file.Close()

	info, err := file.Stat()
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to stat file"})
		return
	}

	w.Header().Set("Content-Type", track.ContentType)
	http.ServeContent(w, r, info.Name(), info.ModTime(), file)
}

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

func spaFallback(next http.Handler) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if strings.HasPrefix(r.URL.Path, "/api") || strings.HasPrefix(r.URL.Path, "/rest") || strings.HasPrefix(r.URL.Path, "/health") {
			http.NotFound(w, r)
			return
		}
		next.ServeHTTP(w, r)
	}
}