<?php

namespace Model\Feed;

use PicoFeed\Serialization\Subscription;
use PicoFeed\Serialization\SubscriptionList;
use PicoFeed\Serialization\SubscriptionListBuilder;
use PicoFeed\Serialization\SubscriptionListParser;
use UnexpectedValueException;
use Model\Config;
use Model\Item;
use Model\Group;
use Model\Favicon;
use Helper;
use SimpleValidator\Validator;
use SimpleValidator\Validators;
use PicoDb\Database;
use PicoFeed\Reader\Reader;
use PicoFeed\PicoFeedException;

const LIMIT_ALL = -1;

// Update feed information
function update(array $values)
{
    Database::getInstance('db')->startTransaction();

    $result = Database::getInstance('db')
            ->table('feeds')
            ->eq('id', $values['id'])
            ->save(array(
                'title' => $values['title'],
                'site_url' => $values['site_url'],
                'feed_url' => $values['feed_url'],
                'enabled' => $values['enabled'],
                'rtl' => $values['rtl'],
                'download_content' => $values['download_content'],
                'cloak_referrer' => $values['cloak_referrer'],
                'parsing_error' => 0,
            ));

    if ($result) {
        if (! Group\update_feed_groups($values['id'], $values['feed_group_ids'], $values['create_group'])) {
            Database::getInstance('db')->cancelTransaction();
            $result = false;
        }
    }

    Database::getInstance('db')->closeTransaction();

    return $result;
}

// Export all feeds
function export_opml()
{
    $feeds = get_all();
    $subscriptionList = SubscriptionList::create()->setTitle(t('Subscriptions'));

    foreach ($feeds as $feed) {
        $groups = Group\get_feed_groups($feed['id']);
        $category = '';

        if (!empty($groups)) {
            $category = $groups[0]['title'];
        }

        $subscriptionList->addSubscription(Subscription::create()
            ->setTitle($feed['title'])
            ->setSiteUrl($feed['site_url'])
            ->setFeedUrl($feed['feed_url'])
            ->setCategory($category)
        );
    }

    return SubscriptionListBuilder::create($subscriptionList)->build();
}

// Import OPML file
function import_opml($content)
{
    $subscriptionList = SubscriptionListParser::create($content)->parse();

    $db = Database::getInstance('db');
    $db->startTransaction();

    foreach ($subscriptionList->subscriptions as $subscription) {
        if (! $db->table('feeds')->eq('feed_url', $subscription->getFeedUrl())->exists()) {
            $db->table('feeds')->insert(array(
                'title' => $subscription->getTitle(),
                'site_url' => $subscription->getSiteUrl(),
                'feed_url' => $subscription->getFeedUrl(),
            ));

            if ($subscription->getCategory() !== '') {
                $feed_id = $db->getLastId();
                $group_id = Group\get_group_id($subscription->getCategory());

                if (empty($group_id)) {
                    $group_id = Group\create($subscription->getCategory());
                }

                Group\add($feed_id, array($group_id));
            }
        }
    }

    $db->closeTransaction();
    Config\write_debug();

    return true;
}

// Add a new feed from an URL
function create($url, $enable_grabber = false, $force_rtl = false, $cloak_referrer = false, $group_ids = array(), $create_group = '')
{
    $feed_id = false;

    $db = Database::getInstance('db');

    // Discover the feed
    $reader = new Reader(Config\get_reader_config());
    $resource = $reader->discover($url);

    // Feed already there
    if ($db->table('feeds')->eq('feed_url', $resource->getUrl())->count()) {
        throw new UnexpectedValueException;
    }

    // Parse the feed
    $parser = $reader->getParser(
        $resource->getUrl(),
        $resource->getContent(),
        $resource->getEncoding()
    );

    if ($enable_grabber) {
        $parser->enableContentGrabber();
    }

    $feed = $parser->execute();

    // Save the feed
    $result = $db->table('feeds')->save(array(
        'title' => $feed->getTitle(),
        'site_url' => $feed->getSiteUrl(),
        'feed_url' => $feed->getFeedUrl(),
        'download_content' => $enable_grabber ? 1 : 0,
        'rtl' => $force_rtl ? 1 : 0,
        'last_modified' => $resource->getLastModified(),
        'last_checked' => time(),
        'etag' => $resource->getEtag(),
        'cloak_referrer' => $cloak_referrer ? 1 : 0,
    ));

    if ($result) {
        $feed_id = $db->getLastId();

        Group\update_feed_groups($feed_id, $group_ids, $create_group);
        Item\update_all($feed_id, $feed->getItems());
        Favicon\create_feed_favicon($feed_id, $feed->getSiteUrl(), $feed->getIcon());
    }

    return $feed_id;
}

// Refresh all feeds
function refresh_all($limit = LIMIT_ALL)
{
    foreach (get_ids($limit) as $feed_id) {
        refresh($feed_id);
    }

    // Auto-vacuum for people using the cronjob
    Database::getInstance('db')->getConnection()->exec('VACUUM');

    return true;
}

// Refresh one feed
function refresh($feed_id)
{
    try {
        $feed = get($feed_id);

        if (empty($feed)) {
            return false;
        }

        $reader = new Reader(Config\get_reader_config());

        $resource = $reader->download(
            $feed['feed_url'],
            $feed['last_modified'],
            $feed['etag']
        );

        // Update the `last_checked` column each time, HTTP cache or not
        update_last_checked($feed_id);

        // Feed modified
        if ($resource->isModified()) {
            $parser = $reader->getParser(
                $resource->getUrl(),
                $resource->getContent(),
                $resource->getEncoding()
            );

            if ($feed['download_content']) {
                $parser->enableContentGrabber();

                // Don't fetch previous items, only new one
                $parser->setGrabberIgnoreUrls(
                    Database::getInstance('db')->table('items')->eq('feed_id', $feed_id)->findAllByColumn('url')
                );
            }

            $feed = $parser->execute();

            update_cache($feed_id, $resource->getLastModified(), $resource->getEtag());

            Item\update_all($feed_id, $feed->getItems());
            Favicon\create_feed_favicon($feed_id, $feed->getSiteUrl(), $feed->getIcon());
        }

        update_parsing_error($feed_id, 0);
        Config\write_debug();

        return true;
    } catch (PicoFeedException $e) {
    }

    update_parsing_error($feed_id, 1);
    Config\write_debug();

    return false;
}

// Get the list of feeds ID to refresh
function get_ids($limit = LIMIT_ALL)
{
    $query = Database::getInstance('db')->table('feeds')->eq('enabled', 1)->asc('last_checked');

    if ($limit !== LIMIT_ALL) {
        $query->limit((int) $limit);
    }

    return $query->findAllByColumn('id');
}

// get number of feeds with errors
function count_failed_feeds()
{
    return Database::getInstance('db')
        ->table('feeds')
        ->eq('parsing_error', '1')
        ->count();
}

// Get all feeds
function get_all()
{
    return Database::getInstance('db')
        ->table('feeds')
        ->asc('title')
        ->findAll();
}

// Get all feeds with the number unread/total items in the order failed, working, disabled
function get_all_item_counts()
{
    return Database::getInstance('db')
        ->table('feeds')
        ->columns(
            'feeds.*',
            'SUM(CASE WHEN items.status IN ("unread") THEN 1 ELSE 0 END) as "items_unread"',
            'SUM(CASE WHEN items.status IN ("read", "unread") THEN 1 ELSE 0 END) as "items_total"'
          )
        ->join('items', 'feed_id', 'id')
        ->groupBy('feeds.id')
        ->desc('feeds.parsing_error')
        ->desc('feeds.enabled')
        ->asc('feeds.title')
        ->findAll();
}

// Get unread/total count for one feed
function count_items($feed_id)
{
    $counts = Database::getInstance('db')
        ->table('items')
        ->columns('status', 'count(*) as item_count')
        ->in('status', array('read', 'unread'))
        ->eq('feed_id', $feed_id)
        ->groupBy('status')
        ->findAll();

    $result = array(
        'items_unread' => 0,
        'items_total' => 0,
    );

    foreach ($counts as &$count) {
        if ($count['status'] === 'unread') {
            $result['items_unread'] = (int) $count['item_count'];
        }

        $result['items_total'] += $count['item_count'];
    }

    return $result;
}

// Get one feed
function get($feed_id)
{
    return Database::getInstance('db')
        ->table('feeds')
        ->eq('id', $feed_id)
        ->findOne();
}

// Update parsing error column
function update_parsing_error($feed_id, $value)
{
    Database::getInstance('db')->table('feeds')->eq('id', $feed_id)->save(array('parsing_error' => $value));
}

// Update last check date
function update_last_checked($feed_id)
{
    Database::getInstance('db')
        ->table('feeds')
        ->eq('id', $feed_id)
        ->save(array(
            'last_checked' => time()
        ));
}

// Update Etag and last Modified columns
function update_cache($feed_id, $last_modified, $etag)
{
    Database::getInstance('db')
        ->table('feeds')
        ->eq('id', $feed_id)
        ->save(array(
            'last_modified' => $last_modified,
            'etag'          => $etag
        ));
}

// Remove one feed
function remove($feed_id)
{
    Group\remove_all($feed_id);

    // Items are removed by a sql constraint
    $result = Database::getInstance('db')->table('feeds')->eq('id', $feed_id)->remove();
    Favicon\purge_favicons();
    return $result;
}

// Remove all feeds
function remove_all()
{
    $result = Database::getInstance('db')->table('feeds')->remove();
    Favicon\purge_favicons();
    return $result;
}

// Enable a feed (activate refresh)
function enable($feed_id)
{
    return Database::getInstance('db')->table('feeds')->eq('id', $feed_id)->save((array('enabled' => 1)));
}

// Disable feed
function disable($feed_id)
{
    return Database::getInstance('db')->table('feeds')->eq('id', $feed_id)->save((array('enabled' => 0)));
}

// Validation for edit
function validate_modification(array $values)
{
    $v = new Validator($values, array(
        new Validators\Required('id', t('The feed id is required')),
        new Validators\Required('title', t('The title is required')),
        new Validators\Required('site_url', t('The site url is required')),
        new Validators\Required('feed_url', t('The feed url is required')),
    ));

    $result = $v->execute();
    $errors = $v->getErrors();

    return array(
        $result,
        $errors
    );
}