'use strict';

const config = require('config');
const Promise = require('bluebird');
const fs = require('fs');
const fsPromises = require('fs').promises;
const path = require('path');
const { PassThrough } = require('stream');
const nanoid = require('nanoid/non-secure');
const mime = require('mime');
// const fileType = require('file-type');
const sharp = require('sharp');
const blake2 = require('blake2');

const logger = require('./logger')(__filename);
const argv = require('./argv');
const knex = require('./knex');
const http = require('./utils/http');
const { get } = require('./utils/qu');

function sampleMedias(medias, limit = config.media.limit, preferLast = true) {
	// limit media sets, use extras as fallbacks
	if (medias.length <= limit) {
		return medias;
	}

	const chunkSize = Math.floor(medias.length / limit);
	const rest = medias.length - (limit * chunkSize);

	const chunks = Array.from(
		{ length: limit },
		(value, index) => {
			const start = (chunkSize * index) + Math.min(index, rest);

			return medias.slice(
				start,
				start + chunkSize + (index < rest ? 1 : 0),
			);
		},
	);

	// flip last chunk so the very last image (often the best cumshot) is tried first
	const lastPreferredChunks = preferLast
		? chunks.slice(0, -1).concat(chunks.slice(-1).reverse())
		: chunks;

	const groupedMedias = lastPreferredChunks.map((chunk) => {
		// merge chunked medias into single media with grouped fallback priorities,
		// so the first sources of each media is preferred over all second sources, etc.
		const sources = chunk
			.reduce((accSources, media) => {
				media.sources.forEach((source, index) => {
					if (!accSources[index]) {
						accSources.push([source]);
						return;
					}

					accSources[index].push(source);
				});

				return accSources;
			}, [])
			.flat();

		return {
			id: chunk[0].id,
			role: chunk[0].role,
			sources,
		};
	});

	return groupedMedias;
}

function itemsByKey(items, key) {
	return items.reduce((acc, item) => ({ ...acc, [item[key]]: item }), {});
}

function toBaseSource(rawSource) {
	if (rawSource.src || (rawSource.extract && rawSource.url)) {
		const baseSource = {};

		if (rawSource.src) baseSource.src = rawSource.src;
		if (rawSource.quality) baseSource.quality = rawSource.quality;
		if (rawSource.type) baseSource.type = rawSource.type;

		if (rawSource.url) baseSource.url = rawSource.url;
		if (rawSource.extract) baseSource.extract = rawSource.extract;

		if (rawSource.referer) baseSource.referer = rawSource.referer;
		if (rawSource.host) baseSource.host = rawSource.host;

		if (rawSource.copyright) baseSource.copyright = rawSource.copyright;
		if (rawSource.comment) baseSource.comment = rawSource.comment;
		if (rawSource.group) baseSource.group = rawSource.group;

		return baseSource;
	}

	if (typeof rawSource === 'string') {
		return {
			src: rawSource,
		};
	}

	return null;
}

function baseSourceToBaseMedia(baseSource, role) {
	if (Array.isArray(baseSource)) {
		if (baseSource.length > 0) {
			return {
				id: nanoid(),
				role,
				sources: baseSource,
			};
		}

		return null;
	}

	if (baseSource) {
		return {
			id: nanoid(),
			role,
			sources: [baseSource],
		};
	}

	return null;
}

function fallbackMediaToBaseMedia(rawMedia, role) {
	const baseSources = rawMedia
		.map(source => toBaseSource(source))
		.filter(Boolean);

	return baseSourceToBaseMedia(baseSources, role);
}

function toBaseMedias(rawMedias, role) {
	if (!rawMedias || rawMedias.length === 0) {
		return [];
	}

	const baseMedias = rawMedias.map((rawMedia) => {
		if (!rawMedia) {
			return null;
		}

		if (Array.isArray(rawMedia)) {
			// fallback sources provided
			return fallbackMediaToBaseMedia(rawMedia, role);
		}

		const baseSource = toBaseSource(rawMedia);

		return baseSourceToBaseMedia(baseSource, role);
	}).filter(Boolean);

	const sampledBaseMedias = sampleMedias(baseMedias);

	return sampledBaseMedias;
}

async function findSourceDuplicates(baseMedias) {
	const sourceUrls = baseMedias
		.map(baseMedia => baseMedia.sources.map(source => source.src))
		.flat()
		.filter(Boolean);

	const extractUrls = baseMedias
		.map(baseMedia => baseMedia.sources.map(source => source.url))
		.flat()
		.filter(Boolean);

	const [existingSourceMedia, existingExtractMedia] = await Promise.all([
		knex('media').whereIn('source', sourceUrls),
		knex('media').whereIn('source_page', extractUrls),
	]);

	const existingSourceMediaByUrl = itemsByKey(existingSourceMedia, 'source');
	const existingExtractMediaByUrl = itemsByKey(existingExtractMedia, 'source_page');

	return [existingSourceMediaByUrl, existingExtractMediaByUrl];
}

async function findHashDuplicates(medias) {
	const hashes = medias.map(media => media.meta?.hash || media.entry?.hash).filter(Boolean);

	const existingHashMediaEntries = await knex('media').whereIn('hash', hashes);
	const existingHashMediaEntriesByHash = itemsByKey(existingHashMediaEntries, 'hash');

	const uniqueHashMedias = medias.filter(media => !media.entry && !existingHashMediaEntriesByHash[media.meta?.hash]);

	const { selfDuplicateMedias, selfUniqueMediasByHash } = uniqueHashMedias.reduce((acc, media) => {
		if (!media.meta?.hash) {
			return acc;
		}

		if (acc.selfUniqueMediasByHash[media.meta.hash]) {
			acc.selfDuplicateMedias.push({
				...media,
				use: acc.selfUniqueMediasByHash[media.meta.hash].id,
			});

			return acc;
		}

		acc.selfUniqueMediasByHash[media.meta.hash] = media;

		return acc;
	}, {
		selfDuplicateMedias: [],
		selfUniqueMediasByHash: {},
	});

	const selfUniqueHashMedias = Object.values(selfUniqueMediasByHash);

	const existingHashMedias = medias
		.filter(media => existingHashMediaEntriesByHash[media.entry?.hash || media.meta?.hash])
		.map(media => ({
			...media,
			entry: existingHashMediaEntriesByHash[media.entry?.hash || media.meta?.hash],
		}))
		.concat(selfDuplicateMedias);

	return [selfUniqueHashMedias, existingHashMedias];
}

async function extractSource(baseSource, { existingExtractMediaByUrl }) {
	if (typeof baseSource.extract !== 'function' || !baseSource.url) {
		return baseSource;
	}

	const existingExtractMedia = existingExtractMediaByUrl[baseSource.url];

	if (existingExtractMedia) {
		// media entry found by extract URL
		return {
			...baseSource,
			entry: existingExtractMedia,
		};
	}

	const res = await get(baseSource.url);

	if (res.ok) {
		const src = await baseSource.extract(res.item);

		return {
			...baseSource,
			src,
		};
	}

	throw new Error(`Could not extract source from ${baseSource.url}: ${res.status}`);
}

async function storeImageFile(media, hashDir, hashSubDir, filename, filedir, filepath) {
	const thumbdir = path.join(media.role, 'thumbs', hashDir, hashSubDir);
	const thumbpath = path.join(thumbdir, filename);

	const lazydir = path.join(media.role, 'lazy', hashDir, hashSubDir);
	const lazypath = path.join(lazydir, filename);

	await Promise.all([
		fsPromises.mkdir(path.join(config.media.path, filedir), { recursive: true }),
		fsPromises.mkdir(path.join(config.media.path, thumbdir), { recursive: true }),
		fsPromises.mkdir(path.join(config.media.path, lazydir), { recursive: true }),
	]);

	const image = sharp(media.file.path);
	const info = await image.metadata();

	// generate thumbnail and lazy
	await Promise.all([
		image
			.resize({
				height: config.media.thumbnailSize,
				withoutEnlargement: true,
			})
			.jpeg({ quality: config.media.thumbnailQuality })
			.toFile(path.join(config.media.path, thumbpath)),
		image
			.resize({
				height: config.media.lazySize,
				withoutEnlargement: true,
			})
			.jpeg({ quality: config.media.lazyQuality })
			.toFile(path.join(config.media.path, lazypath)),
	]);

	if (media.meta.subtype === 'jpeg') {
		// move temp file to permanent location
		await fsPromises.rename(media.file.path, path.join(config.media.path, filepath));
	} else {
		// convert to JPEG and write to permanent location
		await sharp(media.file.path)
			.jpeg()
			.toFile(path.join(config.media.path, filepath));

		// remove temp file
		await fsPromises.unlink(media.file.path);
	}

	logger.silly(`Stored thumbnail, lazy and permanent media file for ${media.id} from ${media.src} at ${filepath}`);

	return {
		...media,
		file: {
			path: filepath,
			thumbnail: thumbpath,
			lazy: lazypath,
		},
		meta: {
			...media.meta,
			width: info.width,
			height: info.height,
		},
	};
}

async function storeFile(media) {
	try {
		const hashDir = media.meta.hash.slice(0, 2);
		const hashSubDir = media.meta.hash.slice(2, 4);
		const hashFilename = media.meta.hash.slice(4);

		const filename = media.quality
			? `${hashFilename}_${media.quality}.${media.meta.extension}`
			: `${hashFilename}.${media.meta.extension}`;

		const filedir = path.join(media.role, hashDir, hashSubDir);
		const filepath = path.join(filedir, filename);

		if (media.meta.type === 'image') {
			return storeImageFile(media, hashDir, hashSubDir, filename, filedir, filepath);
		}

		const [stat] = await Promise.all([
			fsPromises.stat(media.file.path),
			fsPromises.mkdir(path.join(config.media.path, filedir), { recursive: true }),
		]);

		await fsPromises.rename(media.file.path, path.join(config.media.path, filepath));

		logger.silly(`Stored permanent media file for ${media.id} from ${media.src} at ${filepath}`);

		return {
			...media,
			file: {
				path: filepath,
			},
			meta: {
				...media.meta,
				size: stat.size,
			},
		};
	} catch (error) {
		logger.warn(`Failed to store ${media.src}: ${error.message}`);

		return null;
	}
}

async function fetchSource(source, baseMedia) {
	logger.silly(`Fetching media from ${source.src}`);
	// attempts

	async function attempt(attempts = 1) {
		try {
			const tempFilePath = path.join(config.media.path, 'temp', `${baseMedia.id}`);

			const hasher = new blake2.Hash('blake2b');
			hasher.setEncoding('hex');

			const tempFileTarget = fs.createWriteStream(tempFilePath);
			const hashStream = new PassThrough();
			let size = 0;

			hashStream.on('data', (chunk) => {
				size += chunk.length;
				hasher.write(chunk);
			});

			const res = await http.get(source.src, {
				...(source.referer && { referer: source.referer }),
				...(source.host && { host: source.host }),
			}, {
				stream: true, // sources are fetched in parallel, don't gobble up memory
				transforms: [hashStream],
				destination: tempFileTarget,
			});

			hasher.end();

			const hash = hasher.read();
			const { pathname } = new URL(source.src);
			const mimetype = res.headers['content-type'] || mime.getType(pathname);
			const [type, subtype] = mimetype.split('/');
			const extension = mime.getExtension(mimetype);

			if (!res.ok) {
				throw new Error(`Response ${res.status} not OK`);
			}

			return {
				...source,
				file: {
					path: tempFilePath,
				},
				meta: {
					hash,
					mimetype,
					extension,
					type,
					subtype,
					size,
				},
			};
		} catch (error) {
			logger.warn(`Failed attempt ${attempts}/3 to fetch ${source.src}: ${error.message}`);

			if (attempts < 3) {
				await Promise.delay(1000);

				return attempt(attempts + 1);
			}

			throw new Error(`Failed to fetch ${source.src}: ${error.message}`);
		}
	}

	return attempt(1);
}

async function trySource(baseSource, existingMedias, baseMedia) {
	// catch error and try the next source
	const extractedSource = await extractSource(baseSource, existingMedias);
	const existingSourceMedia = existingMedias.existingSourceMediaByUrl[extractedSource.src];

	if (!argv.force && extractedSource.entry) {
		logger.silly(`Media page URL already in database, not extracting ${baseSource.url}`);

		// media entry found during extraction, don't fetch
		return extractedSource;
	}

	if (!argv.force && existingSourceMedia) {
		logger.silly(`Media source URL already in database, skipping ${baseSource.src}`);

		// media entry found by source URL, don't fetch
		return {
			...baseSource,
			entry: existingSourceMedia,
		};
	}

	return fetchSource(extractedSource, baseMedia);
}

async function fetchMedia(baseMedia, existingMedias) {
	try {
		const source = await baseMedia.sources.reduce(
			// try each source until success
			(result, baseSource, baseSourceIndex) => result.catch(async (error) => {
				if (error.message) {
					logger.warn(error.message);
				}

				return trySource(baseSource, existingMedias, baseMedia, baseSourceIndex);
			}),
			Promise.reject(new Error()),
		);

		return {
			...baseMedia,
			...source,
		};
	} catch (error) {
		logger.warn(error.message);

		return baseMedia;
	}
}

function curateMediaEntry(media, index) {
	if (media.entry) {
		return media;
	}

	const curatedMediaEntry = {
		id: media.id,
		path: media.file.path,
		thumbnail: media.file.thumbnail,
		lazy: media.file.lazy,
		index,
		mime: media.meta.mimetype,
		hash: media.meta.hash,
		size: media.meta.size,
		width: media.meta.width,
		height: media.meta.height,
		entropy: media.meta.entropy,
		source: media.src,
		source_page: media.url,
		scraper: media.scraper,
		copyright: media.copyright,
		comment: media.comment,
	};

	return {
		...media,
		newEntry: true,
		entry: curatedMediaEntry,
	};
}

async function storeMedias(baseMedias) {
	await fsPromises.mkdir(path.join(config.media.path, 'temp'), { recursive: true });

	const [existingSourceMediaByUrl, existingExtractMediaByUrl] = await findSourceDuplicates(baseMedias);

	const fetchedMedias = await Promise.map(
		baseMedias,
		async baseMedia => fetchMedia(baseMedia, { existingSourceMediaByUrl, existingExtractMediaByUrl }),
	);

	const [uniqueHashMedias, existingHashMedias] = await findHashDuplicates(fetchedMedias);

	const savedMedias = await Promise.map(
		uniqueHashMedias,
		async baseMedia => storeFile(baseMedia),
	);

	const newMediaWithEntries = savedMedias.map((media, index) => curateMediaEntry(media, index));
	const newMediaEntries = newMediaWithEntries.filter(media => media.newEntry).map(media => media.entry);

	await knex('media').insert(newMediaEntries);

	return [...newMediaWithEntries, ...existingHashMedias];
}

async function associateReleaseMedia(releases) {
	if (!argv.media) {
		return;
	}

	const baseMediasByReleaseId = releases.reduce((acc, release) => ({
		...acc,
		[release.id]: [
			...(argv.images && argv.poster ? toBaseMedias([release.poster], 'posters') : []),
			...(argv.images && argv.poster ? toBaseMedias(release.covers, 'covers') : []),
			...(argv.images && argv.photos ? toBaseMedias(release.photos, 'photos') : []),
			...(argv.videos && argv.trailer ? toBaseMedias([release.trailer], 'trailers') : []),
			...(argv.videos && argv.teaser ? toBaseMedias([release.teaser], 'teasers') : []),
		],
	}), {});

	const baseMediasByRole = Object.values(baseMediasByReleaseId)
		.flat()
		.filter(Boolean)
		.reduce((acc, baseMedia) => {
			if (!acc[baseMedia.role]) acc[baseMedia.role] = [];
			acc[baseMedia.role].push(baseMedia);

			return acc;
		}, {});

	await Promise.reduce(['posters', 'covers', 'photos', 'teasers', 'trailers'], async (chain, role) => {
		// stage by role so posters are prioritized over photos and videos
		await chain;

		const baseMedias = baseMediasByRole[role];

		if (!baseMedias) {
			return;
		}

		const storedMedias = await storeMedias(baseMedias);
		const storedMediasById = itemsByKey(storedMedias, 'id');

		const associations = Object
			.entries(baseMediasByReleaseId)
			.reduce((acc, [releaseId, releaseBaseMedias]) => {
				releaseBaseMedias.forEach((baseMedia) => {
					const media = storedMediasById[baseMedia.id];

					if (media) {
						acc.push({
							release_id: releaseId,
							media_id: media.use || media.entry.id,
						});
					}
				});

				return acc;
			}, [])
			.filter(Boolean);

		if (associations.length > 0) {
			await knex.raw(`${knex(`releases_${role}`).insert(associations)} ON CONFLICT DO NOTHING`);
		}
	}, Promise.resolve());
}

module.exports = {
	associateReleaseMedia,
};