'use strict';

const conf = require('>/conf');

async function fetchJSON(url, options){
	let res = await fetch(url, options);
	if(!res.ok){
		let error = new Error('UpstreamError');
		error.message = `Request to ${url.split('?')[0]} failed( ${res.status})`;
		error.status = 502;
		throw error;
	}
	return await res.json();
}

async function tmdbSearch(query){
	let url = `https://api.themoviedb.org/3/search/multi?include_adult=false`
		+ `&query=${encodeURIComponent(query)}&api_key=${conf.tmdb.apiKey}`;

	let data = await fetchJSON(url);

	return (data.results || [])
		.filter(item => item.media_type === 'movie' || item.media_type === 'tv')
		.slice(0, 4)
		.map(item => {
			let date = item.release_date || item.first_air_date || '';
			return {
				tmdbId: item.id,
				mediaType: item.media_type,
				title: item.title || item.name,
				year: date ? date.slice(0, 4) : '',
				posterUrl: item.poster_path ? `https://image.tmdb.org/t/p/w200${item.poster_path}` : null,
			};
		});
}

async function tmdbDetails(tmdbId, mediaType){
	let url = `https://api.themoviedb.org/3/${mediaType}/${tmdbId}`
		+ `?append_to_response=external_ids&api_key=${conf.tmdb.apiKey}`;

	let data = await fetchJSON(url);
	let date = data.release_date || data.first_air_date || '';

	return {
		title: data.title || data.name,
		year: date ? date.slice(0, 4) : '',
		imdbId: data.imdb_id || (data.external_ids && data.external_ids.imdb_id) || null,
	};
}

// Canonicalize a( possibly messy) title + year to the authoritative TMDB record.
// Returns null when nothing matches so callers can flag instead of guessing.
async function tmdbFindBest(title, year, mediaType){
	let results = await tmdbSearch(title);

	let pool = results.filter(r => r.mediaType === mediaType);
	if(!pool.length) pool = results;
	if(!pool.length) return null;

	let pick = (year && pool.find(r => r.year === String(year))) || pool[0];
	let details = await tmdbDetails(pick.tmdbId, pick.mediaType);

	return {
		title: details.title,
		year: details.year,
		tmdbId: pick.tmdbId,
		mediaType: pick.mediaType,
		imdbId: details.imdbId,
	};
}

// Per-season episode counts for a show( season 0 / specials excluded).
async function tmdbSeasons(tmdbId){
	let data = await fetchJSON(`https://api.themoviedb.org/3/tv/${tmdbId}?api_key=${conf.tmdb.apiKey}`);
	let date = data.first_air_date || '';
	return {
		title: data.name,
		year: date ? date.slice(0, 4) : '',
		seasons: (data.seasons || [])
			.filter(s => s.season_number >= 1 && s.episode_count > 0)
			.map(s => ({ season: s.season_number, episodeCount: s.episode_count })),
	};
}

module.exports = { fetchJSON, tmdbSearch, tmdbDetails, tmdbFindBest, tmdbSeasons };