package subsonic

import (
	"database/sql"
	"strconv"

	"git.noroutes.net/NoRoutes/vibetunes/internal/database"
)

func init() {
	register("getPlaylists", handleGetPlaylists)
	register("getPlaylist", handleGetPlaylist)
	register("createPlaylist", handleCreatePlaylist)
	register("updatePlaylist", handleUpdatePlaylist)
	register("deletePlaylist", handleDeletePlaylist)
}

func playlistToModel(db *sql.DB, p *database.Playlist) Playlist {
	entries, _ := database.ListPlaylistEntries(db, p.ID)
	duration := 0
	for _, e := range entries {
		if mf, ok := mediaFileForSongID(db, e.SongID); ok {
			duration += int(mf.DurationSeconds + 0.5)
		}
	}
	owner, _ := database.GetUserByID(db, p.OwnerID)
	ownerName := ""
	if owner != nil {
		ownerName = owner.Username
	}
	return Playlist{
		ID:        p.ID,
		Name:      p.Name,
		Comment:   p.Description,
		Owner:     ownerName,
		Public:    p.IsPublic,
		SongCount: len(entries),
		Duration:  duration,
		Created:   isoTime(p.CreatedAt),
		Changed:   isoTime(p.UpdatedAt),
	}
}

func mediaFileForSongID(db *sql.DB, songID string) (*database.MediaFile, bool) {
	song, err := database.GetSong(db, songID)
	if err != nil {
		return nil, false
	}
	mf, err := database.GetMediaFile(db, song.MediaFileID)
	if err != nil {
		return nil, false
	}
	return mf, true
}

// canSeePlaylist reports whether user may view playlist p: they own it,
// it's public, or they're an admin.
func canSeePlaylist(user *database.User, p *database.Playlist) bool {
	return user.IsAdmin || user.ID == p.OwnerID || p.IsPublic
}

func handleGetPlaylists(rc *Context) *apiError {
	db := rc.Server.DB
	var playlists []*database.Playlist
	var err error

	if username := rc.Params.Get("username"); username != "" {
		if !rc.User.IsAdmin && username != rc.User.Username {
			return errUnauthorized("viewing another user's playlists")
		}
		target, terr := database.GetUserByUsername(db, username)
		if terr != nil {
			return errNotFound("User")
		}
		playlists, err = database.ListPlaylistsByOwner(db, target.ID)
	} else {
		playlists, err = database.ListPlaylistsVisibleToUser(db, rc.User.ID)
	}
	if err != nil {
		return newError(ErrGeneric, err.Error())
	}

	out := &Playlists{}
	for _, p := range playlists {
		out.Playlist = append(out.Playlist, playlistToModel(db, p))
	}
	rc.Response = newResponse()
	rc.Response.Playlists = out
	return nil
}

func handleGetPlaylist(rc *Context) *apiError {
	id, aerr := rc.Params.Required("id")
	if aerr != nil {
		return aerr
	}
	db := rc.Server.DB
	p, err := database.GetPlaylist(db, id)
	if err != nil {
		return errNotFound("Playlist")
	}
	if !canSeePlaylist(rc.User, p) {
		return errUnauthorized("viewing this playlist")
	}

	entries, err := database.ListPlaylistEntries(db, id)
	if err != nil {
		return newError(ErrGeneric, err.Error())
	}
	out := &PlaylistWithSongs{Playlist: playlistToModel(db, p)}
	for _, e := range entries {
		song, serr := database.GetSong(db, e.SongID)
		if serr != nil {
			continue
		}
		mf, merr := database.GetMediaFile(db, song.MediaFileID)
		if merr != nil {
			continue
		}
		out.Entry = append(out.Entry, childFromSong(db, song, mf, albumOfSong(db, song), rc.User.ID))
	}
	rc.Response = newResponse()
	rc.Response.Playlist = out
	return nil
}

func handleCreatePlaylist(rc *Context) *apiError {
	if !rc.User.Allows(rc.User.Permissions.Playlist) {
		return errUnauthorized("creating playlists")
	}
	db := rc.Server.DB
	songIDs := rc.Params.GetAll("songId")

	if playlistID := rc.Params.Get("playlistId"); playlistID != "" {
		p, err := database.GetPlaylist(db, playlistID)
		if err != nil {
			return errNotFound("Playlist")
		}
		if p.OwnerID != rc.User.ID && !rc.User.IsAdmin {
			return errUnauthorized("modifying this playlist")
		}
		if err := database.ReplacePlaylistSongs(db, playlistID, songIDs); err != nil {
			return newError(ErrGeneric, err.Error())
		}
		return respondWithPlaylist(rc, playlistID)
	}

	name, aerr := rc.Params.Required("name")
	if aerr != nil {
		return aerr
	}
	p, err := database.CreatePlaylist(db, rc.User.ID, name, "", false)
	if err != nil {
		return newError(ErrGeneric, err.Error())
	}
	if len(songIDs) > 0 {
		if err := database.ReplacePlaylistSongs(db, p.ID, songIDs); err != nil {
			return newError(ErrGeneric, err.Error())
		}
	}
	return respondWithPlaylist(rc, p.ID)
}

func respondWithPlaylist(rc *Context, playlistID string) *apiError {
	db := rc.Server.DB
	p, err := database.GetPlaylist(db, playlistID)
	if err != nil {
		return newError(ErrGeneric, err.Error())
	}
	entries, err := database.ListPlaylistEntries(db, playlistID)
	if err != nil {
		return newError(ErrGeneric, err.Error())
	}
	out := &PlaylistWithSongs{Playlist: playlistToModel(db, p)}
	for _, e := range entries {
		song, serr := database.GetSong(db, e.SongID)
		if serr != nil {
			continue
		}
		mf, merr := database.GetMediaFile(db, song.MediaFileID)
		if merr != nil {
			continue
		}
		out.Entry = append(out.Entry, childFromSong(db, song, mf, albumOfSong(db, song), rc.User.ID))
	}
	rc.Response = newResponse()
	rc.Response.Playlist = out
	return nil
}

func handleUpdatePlaylist(rc *Context) *apiError {
	id, aerr := rc.Params.Required("playlistId")
	if aerr != nil {
		return aerr
	}
	db := rc.Server.DB
	p, err := database.GetPlaylist(db, id)
	if err != nil {
		return errNotFound("Playlist")
	}
	if p.OwnerID != rc.User.ID && !rc.User.IsAdmin {
		return errUnauthorized("modifying this playlist")
	}

	name := p.Name
	if v := rc.Params.Get("name"); v != "" {
		name = v
	}
	comment := p.Description
	if rc.Params.Has("comment") {
		comment = rc.Params.Get("comment")
	}
	public := p.IsPublic
	if rc.Params.Has("public") {
		public = rc.Params.Bool("public", p.IsPublic)
	}
	if err := database.RenamePlaylist(db, id, name, comment, public); err != nil {
		return newError(ErrGeneric, err.Error())
	}

	toRemove := rc.Params.GetAll("songIndexToRemove")
	toAdd := rc.Params.GetAll("songIdToAdd")
	if len(toRemove) > 0 || len(toAdd) > 0 {
		entries, err := database.ListPlaylistEntries(db, id)
		if err != nil {
			return newError(ErrGeneric, err.Error())
		}
		removeSet := map[int]bool{}
		for _, s := range toRemove {
			if n, err := strconv.Atoi(s); err == nil {
				removeSet[n] = true
			}
		}
		var songIDs []string
		for i, e := range entries {
			if !removeSet[i] {
				songIDs = append(songIDs, e.SongID)
			}
		}
		songIDs = append(songIDs, toAdd...)
		if err := database.ReplacePlaylistSongs(db, id, songIDs); err != nil {
			return newError(ErrGeneric, err.Error())
		}
	}

	rc.Response = newResponse()
	return nil
}

func handleDeletePlaylist(rc *Context) *apiError {
	id, aerr := rc.Params.Required("id")
	if aerr != nil {
		return aerr
	}
	db := rc.Server.DB
	p, err := database.GetPlaylist(db, id)
	if err != nil {
		return errNotFound("Playlist")
	}
	if p.OwnerID != rc.User.ID && !rc.User.IsAdmin {
		return errUnauthorized("deleting this playlist")
	}
	if err := database.DeletePlaylist(db, id); err != nil {
		return newError(ErrGeneric, err.Error())
	}
	rc.Response = newResponse()
	return nil
}