'use strict';

const Promise = require('bluebird');

const argv = require('./argv');
const include = require('./utils/argv-include')(argv);
const logger = require('./logger')(__filename);
const knex = require('./knex');
const scrapers = require('./scrapers/scrapers');

function urlToSiteSlug(url) {
	try {
		const slug = new URL(url)
			.hostname
			.match(/([\w-]+)\.\w+$/)?.[1]
			.replace(/[-_]+/g, '');

		return slug;
	} catch (error) {
		logger.warn(`Failed to derive entity slug from '${url}': ${error.message}`);

		return null;
	}
}

async function findEntities(baseReleases) {
	const baseReleasesWithoutEntity = baseReleases.filter(release => release.url && !release.site && !release.entity);

	const entitySlugs = Array.from(new Set(
		baseReleasesWithoutEntity
			.map(baseRelease => urlToSiteSlug(baseRelease.url))
			.filter(Boolean),
	));

	const entities = await knex('entities')
		.select(knex.raw('entities.*, row_to_json(parents) as parent, json_agg(children) as children'))
		.leftJoin('entities as parents', 'parents.id', 'entities.parent_id')
		.leftJoin('entities as children', 'children.parent_id', 'entities.id')
		.whereIn('entities.slug', entitySlugs)
		.groupBy('entities.id', 'parents.id')
		.orderBy('entities.type', 'asc');

	// channel entity will overwrite network entity
	const entitiesBySlug = entities.reduce((accEntities, entity) => ({ ...accEntities, [entity.slug]: accEntities[entity.slug] || entity }), {});

	return entitiesBySlug;
}

function toBaseReleases(baseReleasesOrUrls, entity = null) {
	if (!baseReleasesOrUrls) {
		return [];
	}

	return baseReleasesOrUrls
		.map((baseReleaseOrUrl) => {
			if (baseReleaseOrUrl.url) {
				// base release with URL
				return {
					...baseReleaseOrUrl,
					entity: baseReleaseOrUrl.entity || entity,
					deep: false,
				};
			}

			if (/^http/.test(baseReleaseOrUrl)) {
				// URL
				return {
					url: baseReleaseOrUrl,
					entity,
					deep: false,
				};
			}

			if (typeof baseReleaseOrUrl === 'object' && !Array.isArray(baseReleaseOrUrl)) {
				// base release without URL, prepare for passthrough
				return {
					...baseReleaseOrUrl,
					entity: baseReleaseOrUrl.entity || entity,
					deep: false,
				};
			}

			logger.warn(`Malformed base release, discarding '${baseReleaseOrUrl}'`);
			return null;
		})
		.filter(Boolean);
}

async function scrapeRelease(baseRelease, entities, type = 'scene') {
	const entity = baseRelease.entity || entities[urlToSiteSlug(baseRelease.url)];

	if (!entity) {
		logger.warn(`No entity available for ${baseRelease.url}`);
		return baseRelease;
	}

	if ((!baseRelease.url && !baseRelease.path) || !argv.deep) {
		return {
			...baseRelease,
			entity,
		};
	}

	const scraper = scrapers.releases[entity.slug] || scrapers.releases[entity.parent?.slug];
	const layoutScraper = scraper[entity.parameters?.layout] || scraper;

	if (!layoutScraper) {
		logger.warn(`Could not find scraper for ${baseRelease.url}`);
		return baseRelease;
	}

	if ((type === 'scene' && !layoutScraper.fetchScene) || (type === 'movie' && !layoutScraper.fetchMovie)) {
		logger.warn(`The '${entity.name}'-scraper cannot fetch individual ${type}s`);
		return baseRelease;
	}

	try {
		logger.verbose(`Fetching ${type} ${baseRelease.url}`);

		const scrapedRelease = type === 'scene'
			? await layoutScraper.fetchScene(baseRelease.url, entity, baseRelease, include, null)
			: await layoutScraper.fetchMovie(baseRelease.url, entity, baseRelease, include, null);

		const mergedRelease = {
			...baseRelease,
			...scrapedRelease,
			deep: !!scrapedRelease,
			entity,
		};

		if (!mergedRelease.entryId) {
			throw Object.assign(new Error('No entry ID supplied'), { code: 'NO_ENTRY_ID' });
		}

		if (scrapedRelease && baseRelease?.tags) {
			// accumulate all available tags
			mergedRelease.tags = baseRelease.tags.concat(scrapedRelease.tags);
		}

		return mergedRelease;
	} catch (error) {
		logger.error(`Deep scrape failed for ${baseRelease.url}: ${error.message}`);

		if (argv.debug) {
			console.error(error);
		}

		if (error.code === 'NO_ENTRY_ID') {
			return null;
		}

		return baseRelease;
	}
}

async function scrapeReleases(baseReleases, entities, type) {
	return Promise.map(
		baseReleases,
		async baseRelease => scrapeRelease(baseRelease, entities, type),
		{ concurrency: 10 },
	);
}

async function fetchReleases(baseReleasesOrUrls, type = 'scene') {
	const baseReleases = toBaseReleases(baseReleasesOrUrls);
	const entities = await findEntities(baseReleases);

	const deepReleases = await scrapeReleases(baseReleases, entities, type);

	return deepReleases.filter(Boolean);
}

async function fetchScenes(baseReleasesOrUrls) {
	return fetchReleases(baseReleasesOrUrls, 'scene');
}

async function fetchMovies(baseReleasesOrUrls) {
	const movies = await fetchReleases(baseReleasesOrUrls, 'movie');

	return movies;
}

module.exports = {
	fetchReleases,
	fetchScenes,
	fetchMovies,
	toBaseReleases,
};