import { client as sql } from '#lib/server/db/index.js';

// Read side of the listening tracker. Everything reads music.plays_deduped, which hides a
// Last.fm scrobble when Spotify (live API or export) has the same play, so nothing is
// counted twice. Listening time uses ms_played when known (imports) and otherwise the
// track length (the API only reports plays of 30 s or more, not how long).
const TZ = 'Europe/Amsterdam';
// Fragments are built per query (postgres.js queries are single-use objects).
const playMs = () => sql`coalesce(p.ms_played, t.duration_ms, 210000)`;

export const RANGES = { '7d': 7, '30d': 30, all: null } as const;
export type Range = keyof typeof RANGES;
export const parseRange = (value: string | null): Range =>
	value && value in RANGES ? (value as Range) : '30d';

export type Listening = {
	nowPlaying: boolean;
	at: string;
	track: string;
	artists: string;
	album: string | null;
	image: string | null;
	url: string | null;
	device: string | null;
};

const artistsOf = () => sql`coalesce((select string_agg(ar.name, ', ' order by ta.position)
	from music.track_artists ta join music.artists ar on ar.id = ta.artist_id
	where ta.track_id = t.id), a.name, '')`;

const toListening = (row: Record<string, unknown>, nowPlaying: boolean): Listening => ({
	nowPlaying,
	at: new Date(row.at as string).toISOString(),
	track: row.track as string,
	artists: row.artists as string,
	album: (row.album as string) ?? null,
	image: (row.image as string) ?? null,
	url: row.spotify_id ? `https://open.spotify.com/track/${row.spotify_id}` : null,
	device: (row.device as string) ?? null
});

/** Homepage card: what is playing now (fresh within 3 min), else the last play. Never throws. */
export async function getListening(): Promise<Listening | null> {
	try {
		const [now] = await sql`
			select np.updated_at as at, t.name as track, t.spotify_id, ${artistsOf()} as artists,
			       al.name as album, coalesce(al.image_url_small, al.image_url) as image, np.device_name as device
			from music.now_playing np
			join music.tracks t on t.id = np.track_id
			left join music.artists a on a.id = t.artist_id
			left join music.albums al on al.id = t.album_id
			where np.id = 1 and np.is_playing and np.updated_at > now() - interval '3 minutes'`;
		if (now) return toListening(now, true);
		const [last] = await sql`
			select p.played_at as at, t.name as track, t.spotify_id, ${artistsOf()} as artists,
			       al.name as album, coalesce(al.image_url_small, al.image_url) as image, null as device
			from music.plays p
			join music.tracks t on t.id = p.track_id
			left join music.artists a on a.id = t.artist_id
			left join music.albums al on al.id = t.album_id
			order by p.played_at desc limit 1`;
		return last ? toListening(last, false) : null;
	} catch {
		return null; // e.g. not migrated on this database: the homepage must still render
	}
}

export async function getMusicStats(range: Range) {
	const days = RANGES[range];
	const since = (days ? new Date(Date.now() - days * 86_400_000) : new Date(0)).toISOString();
	const chartDays = days ?? 90;
	const [totals, artists, tracks, albums, daily, streak, recent, sources] = await Promise.all([
		sql`
			select count(*)::int as plays,
			       coalesce(sum(${playMs()}), 0)::float8 / 3600000 as hours,
			       count(distinct p.track_id)::int as tracks,
			       count(distinct t.artist_id)::int as artists,
			       min(p.played_at) as first
			from music.plays_deduped p join music.tracks t on t.id = p.track_id
			where p.played_at >= ${since}::timestamptz`,
		sql`
			select a.id, a.name, a.spotify_id, count(*)::int as plays,
			       coalesce(sum(${playMs()}), 0)::float8 / 3600000 as hours,
			       coalesce(a.image_url, (select coalesce(al.image_url_small, al.image_url) from music.albums al
			         where al.artist_id = a.id and al.image_url is not null
			         order by al.spotify_id is null, al.id desc limit 1)) as image
			from music.plays_deduped p
			join music.tracks t on t.id = p.track_id
			join music.artists a on a.id = t.artist_id
			where p.played_at >= ${since}::timestamptz
			group by a.id order by plays desc, a.name limit 10`,
		sql`
			select t.id, t.name, t.spotify_id, ${artistsOf()} as artists, count(*)::int as plays,
			       coalesce(al.image_url_small, al.image_url) as image
			from music.plays_deduped p
			join music.tracks t on t.id = p.track_id
			left join music.artists a on a.id = t.artist_id
			left join music.albums al on al.id = t.album_id
			where p.played_at >= ${since}::timestamptz
			group by t.id, a.name, al.id order by plays desc, t.name limit 10`,
		sql`
			select al.id, al.name, al.spotify_id, a.name as artist, count(*)::int as plays,
			       coalesce(al.image_url_small, al.image_url) as image
			from music.plays_deduped p
			join music.tracks t on t.id = p.track_id
			join music.albums al on al.id = t.album_id
			left join music.artists a on a.id = al.artist_id
			where p.played_at >= ${since}::timestamptz
			group by al.id, a.name order by plays desc, al.name limit 10`,
		sql`
			with days as (
				select generate_series((now() at time zone ${TZ})::date - ${chartDays - 1}::int,
				                       (now() at time zone ${TZ})::date, interval '1 day')::date as day)
			select d.day::text as day, count(p.id)::int as plays,
			       coalesce(sum(${playMs()}), 0)::float8 / 3600000 as hours
			from days d
			left join music.plays_deduped p
			  on p.played_at >= now() - make_interval(days => ${chartDays + 1})
			 and (p.played_at at time zone ${TZ})::date = d.day
			left join music.tracks t on t.id = p.track_id
			group by d.day order by d.day`,
		sql`
			with d as (select distinct (played_at at time zone ${TZ})::date as day from music.plays_deduped),
			g as (select day, day - (row_number() over (order by day))::int as grp from d),
			s as (select min(day) as start_day, max(day) as end_day, count(*)::int as len from g group by grp)
			select
				coalesce((select len from s where end_day >= (now() at time zone ${TZ})::date - 1
				          order by end_day desc limit 1), 0) as current,
				coalesce((select len from s order by len desc, end_day desc limit 1), 0) as longest,
				(select start_day::text from s order by len desc, end_day desc limit 1) as longest_start,
				(select end_day::text from s order by len desc, end_day desc limit 1) as longest_end,
				(select count(*)::int from d) as days`,
		sql`
			select p.id, p.played_at, p.source, t.name as track, t.spotify_id, ${artistsOf()} as artists,
			       coalesce(al.image_url_small, al.image_url) as image
			from music.plays_deduped p
			join music.tracks t on t.id = p.track_id
			left join music.artists a on a.id = t.artist_id
			left join music.albums al on al.id = t.album_id
			order by p.played_at desc limit 50`,
		sql`select source, count(*)::int as plays from music.plays_deduped group by source order by plays desc`
	]);
	const t = totals[0];
	return {
		range,
		totals: {
			plays: t.plays as number,
			hours: Number(t.hours),
			tracks: t.tracks as number,
			artists: t.artists as number,
			first: t.first ? new Date(t.first).toISOString() : null
		},
		topArtists: artists.map((r) => ({
			name: r.name as string,
			plays: r.plays as number,
			hours: Number(r.hours),
			image: (r.image as string) ?? null,
			url: r.spotify_id ? `https://open.spotify.com/artist/${r.spotify_id}` : null
		})),
		topTracks: tracks.map((r) => ({
			name: r.name as string,
			artists: r.artists as string,
			plays: r.plays as number,
			image: (r.image as string) ?? null,
			url: r.spotify_id ? `https://open.spotify.com/track/${r.spotify_id}` : null
		})),
		topAlbums: albums.map((r) => ({
			name: r.name as string,
			artist: (r.artist as string) ?? '',
			plays: r.plays as number,
			image: (r.image as string) ?? null,
			url: r.spotify_id ? `https://open.spotify.com/album/${r.spotify_id}` : null
		})),
		daily: daily.map((r) => ({
			day: r.day as string,
			plays: r.plays as number,
			hours: Number(r.hours)
		})),
		streak: {
			current: Number(streak[0].current),
			longest: Number(streak[0].longest),
			longestStart: (streak[0].longest_start as string) ?? null,
			longestEnd: (streak[0].longest_end as string) ?? null,
			days: Number(streak[0].days)
		},
		recent: recent.map((r) => ({
			id: r.id as number,
			at: new Date(r.played_at).toISOString(),
			source: r.source as string,
			track: r.track as string,
			artists: r.artists as string,
			image: (r.image as string) ?? null,
			url: r.spotify_id ? `https://open.spotify.com/track/${r.spotify_id}` : null
		})),
		sources: sources.map((r) => ({ source: r.source as string, plays: r.plays as number }))
	};
}

/** Owner-only connection status for /trackers/music. Never includes tokens. */
export async function getSpotifyConnection() {
	const [row] = await sql`
		select spotify_user_id, display_name, needs_reauth, last_poll_at, last_error, connected_at
		from music.spotify_auth where id = 1`;
	if (!row) return null;
	return {
		user: (row.display_name as string) || (row.spotify_user_id as string),
		needsReauth: row.needs_reauth as boolean,
		lastPollAt: row.last_poll_at ? new Date(row.last_poll_at).toISOString() : null,
		lastError: (row.last_error as string) ?? null,
		connectedAt: new Date(row.connected_at).toISOString()
	};
}