'use strict';

const config = require('config');

const logger = require('./logger')(__filename);
const argv = require('./argv');
const knex = require('./knex');
const whereOr = require('./utils/where-or');

function curateEntity(entity, includeParameters = false) {
	if (!entity) {
		return null;
	}

	const curatedEntity = entity.id ? {
		id: entity.id,
		name: entity.name,
		url: entity.url,
		description: entity.description,
		slug: entity.slug,
		type: entity.type,
		parameters: includeParameters ? entity.parameters : null,
		parent: curateEntity(entity.parent),
	} : {};

	if (entity.children) {
		curatedEntity.children = entity.children.map(child => curateEntity({
			...child,
			parent: curatedEntity.id ? curatedEntity : null,
		}, includeParameters));
	}

	return curatedEntity;
}

async function curateEntities(entities, includeParameters) {
	return Promise.all(entities.map(async entity => curateEntity(entity, includeParameters)));
}

async function fetchChannelsFromArgv() {
	const rawNetworks = await knex.raw(`
		/* networks from argument with channels as children */
		WITH RECURSIVE children AS (
			SELECT
				entities.*
			FROM
				entities
			WHERE
				slug = ANY(?) AND entities.type = 'network'
			UNION ALL
			SELECT
				entities.*
			FROM
				entities
			INNER JOIN
				children ON children.id = entities.parent_id
		)
		SELECT
			entities.*, row_to_json(parents) as parent, json_agg(children) as children
		FROM
			children
		LEFT JOIN
			entities ON entities.id = children.parent_id
		LEFT JOIN
			entities AS parents ON parents.id = entities.parent_id
		WHERE
			children.type = 'channel'
		GROUP BY
			children.parent_id, entities.id, entities.name, parents.id

		UNION ALL

		/* channels from argument as the child of network with parent */
		SELECT
			entities.*, row_to_json(parents) as parent, json_agg(row_to_json(children))
		FROM
			entities AS children
		LEFT JOIN
			entities ON entities.id = children.parent_id
		LEFT JOIN
			entities AS parents ON parents.id = entities.parent_id
		WHERE
			children.slug = ANY(?) AND children.type = 'channel'
		GROUP BY
			entities.id, parents.id;
	`, [argv.networks || [], argv.channels || []]);

	const curatedNetworks = await curateEntities(rawNetworks.rows, true);
	logger.info(`Found ${curatedNetworks.length} networks in database`);

	return curatedNetworks;
}

async function fetchChannelsFromConfig() {
	const rawNetworks = await knex.raw(`
		WITH RECURSIVE channels AS (
			/* select configured channels and networks */
			SELECT
				entities.*
			FROM
				entities
			WHERE
				CASE WHEN :includeAll
				THEN
					/* select all top level networks and independent channels */
					entities.parent_id IS NULL
				ELSE
					((entities.slug = ANY(:includedNetworks)
					AND entities.type = 'network')
					OR (entities.slug = ANY(:includedChannels)
					AND entities.type = 'channel'))
				END
				AND NOT (
					(entities.slug = ANY(:excludedNetworks)
					AND entities.type = 'network')
					OR (entities.slug = ANY(:excludedChannels)
					AND entities.type = 'channel'))

			UNION ALL

			/* select recursive children of configured networks */
			SELECT
				entities.*
			FROM
				entities
			INNER JOIN
				channels ON channels.id = entities.parent_id
			WHERE
				NOT ((entities.slug = ANY(:excludedNetworks)
				AND entities.type = 'network')
				OR (entities.slug = ANY(:excludedChannels)
				AND entities.type = 'channel'))
		)
		/* select recursive channels as children of networks */
		SELECT
			entities.*, json_agg(channels) as children
		FROM
			channels
		LEFT JOIN
			entities ON entities.id = channels.parent_id
		WHERE
			channels.type = 'channel'
		GROUP BY
			entities.id
	`, {
		includeAll: !config.include?.networks && !config.include?.channels,
		includedNetworks: config.include?.networks || [],
		includedChannels: config.include?.channels || [],
		excludedNetworks: config.exclude?.networks || [],
		excludedChannels: config.exclude?.channels || [],
	});

	const curatedNetworks = rawNetworks.rows.map(entity => curateEntity(entity, true));

	return curatedNetworks;
}

async function fetchIncludedEntities() {
	if (argv.networks || argv.channels) {
		return fetchChannelsFromArgv();
	}

	return fetchChannelsFromConfig();
}

async function fetchChannels(queryObject) {
	const sites = await knex('sites')
		.where(builder => whereOr(queryObject, 'sites', builder))
		.select(
			'sites.*',
			'networks.name as network_name', 'networks.slug as network_slug', 'networks.url as network_url', 'networks.description as network_description', 'networks.parameters as network_parameters',
		)
		.leftJoin('networks', 'sites.network_id', 'networks.id')
		.limit(100);

	return curateEntities(sites);
}

async function fetchChannelsFromReleases() {
	const sites = await knex('releases')
		.select('site_id', '')
		.leftJoin('sites', 'sites.id', 'releases.site_id')
		.groupBy('sites.id')
		.limit(100);

	return curateEntities(sites);
}

module.exports = {
	curateEntity,
	curateEntities,
	fetchIncludedEntities,
	fetchChannels,
	fetchChannelsFromConfig,
	fetchChannelsFromArgv,
	fetchChannelsFromReleases,
};