<?php

use Sphinx\SphinxClient;

class files {

    const string WFF_ARCHIVE_SPHINX_RTINDEX = 'wff_collection';
    const string MDF_ARCHIVE_SPHINX_RTINDEX = 'mdf_archive';
    const string BACONIANA_ARCHIVE_SPHINX_RTINDEX = 'baconiana_archive';

    /**
     * @param string $table
     * @param string $field_id
     * @param int[] $ids
     * @param string[] $keywords  Must already be lower-cased
     * @param int $before
     * @param int $after
     * @return array
     */
    public static function _get_text_excerpts(string $table, string $field_id, array $ids, array $keywords, int $before, int $after) {
        $results = [];
        foreach ($ids as $id)
            $results[$id] = null;

        $db = DB();

        $dynamic_sql_parts = [];
        $combined_parts = [];
        foreach ($keywords as $keyword) {
            $part = "LOCATE('".$db->escape($keyword)."', text)";
            $dynamic_sql_parts[] = $part;
        }
        if (count($dynamic_sql_parts) > 1) {
            foreach ($dynamic_sql_parts as $part)
                $combined_parts[] = "IF({$part} > 0, {$part}, CHAR_LENGTH(text) + 1)";
            $combined_parts = implode(', ', $combined_parts);
            $combined_parts = 'LEAST('.$combined_parts.')';
        } else {
            $combined_parts = "IF({$dynamic_sql_parts[0]} > 0, {$dynamic_sql_parts[0]}, CHAR_LENGTH(text) + 1)";
        }

        $total = $before + $after;
        $sql = "SELECT
            {$field_id} AS id,
            GREATEST(
                1,
                {$combined_parts} - {$before}
            ) AS excerpt_start_index,
            SUBSTRING(
                text,
                GREATEST(
                    1,
                    {$combined_parts} - {$before}
                ),
                LEAST(
                    CHAR_LENGTH(text),
                    {$total} + {$combined_parts} - GREATEST(1, {$combined_parts} - {$before})
                )
            ) AS excerpt
        FROM
            {$table}
        WHERE
            {$field_id} IN (".implode(',', $ids).")";

        $q = $db->query($sql);
        while ($row = $db->fetch($q)) {
            $results[$row['id']] = [
                'excerpt' => preg_replace('/\s+/', ' ', $row['excerpt']),
                'index' => (int)$row['excerpt_start_index']
            ];
        }

        return $results;
    }

    public static function _search(string $index,
                     string $q,
                     int $offset,
                     int $count,
                     callable $items_getter,
                     ?callable $sphinx_client_setup = null): array {
        $query_filtered = sphinx::mkquery($q);

        $cl = sphinx::getClient();
        $cl->setLimits($offset, $count);

        $cl->setMatchMode(Sphinx\SphinxClient::SPH_MATCH_EXTENDED);

        if (is_callable($sphinx_client_setup))
            $sphinx_client_setup($cl);
        else {
            $cl->setRankingMode(Sphinx\SphinxClient::SPH_RANK_PROXIMITY_BM25);
            $cl->setSortMode(Sphinx\SphinxClient::SPH_SORT_RELEVANCE);
        }

        // run search
        $final_query = "$query_filtered";
        $result = $cl->query($final_query, $index);
        $error = $cl->getLastError();
        $warning = $cl->getLastWarning();
        if ($error)
            logError(__FUNCTION__, $error);
        if ($warning)
            logWarning(__FUNCTION__, $warning);
        if ($result === false)
            return ['count' => 0, 'items' => []];

        $total_found = (int)$result['total_found'];

        $items = [];
        if (!empty($result['matches']))
            $items = $items_getter($result['matches']);

        return ['count' => $total_found, 'items' => $items];
    }


    /**
     * @param int $folder_id
     * @param bool $with_parents
     * @return WFFCollectionItem|WFFCollectionItem[]|null
     */
    public static function wff_get_folder(int $folder_id, bool $with_parents = false): WFFCollectionItem|array|null {
        $db = DB();
        $q = $db->query("SELECT * FROM wff_collection WHERE id=?", $folder_id);
        if (!$db->numRows($q))
            return null;
        $item = new WFFCollectionItem($db->fetch($q));
        if (!$item->isFolder())
            return null;
        if ($with_parents) {
            $items = [$item];
            if ($item->parentId) {
                $parents = self::wff_get_folder($item->parentId, true);
                if ($parents !== null)
                    $items = array_merge($items, $parents);
            }
            return $items;
        }
        return $item;
    }

    /**
     * @param int|int[]|null $parent_id
     * @return array
     */
    public static function wff_get(int|array|null $parent_id = null) {
        $db = DB();

        $where = [];
        $args = [];

        if (!is_null($parent_id)) {
            if (is_int($parent_id)) {
                $where[] = "parent_id=?";
                $args[] = $parent_id;
            } else {
                $where[] = "parent_id IN (".implode(", ", $parent_id).")";
            }
        }
        $sql = "SELECT * FROM wff_collection";
        if (!empty($where))
            $sql .= " WHERE ".implode(" AND ", $where);
        $sql .= " ORDER BY title";
        $q = $db->query($sql, ...$args);

        return array_map('WFFCollectionItem::create_instance', $db->fetchAll($q));
    }

    /**
     * @param int[] $ids
     * @return WFFCollectionItem[]
     */
    public static function wff_get_by_id(array $ids): array {
        $db = DB();
        $q = $db->query("SELECT * FROM wff_collection WHERE id IN (".implode(',', $ids).")");
        return array_map('WFFCollectionItem::create_instance', $db->fetchAll($q));
    }

    public static function wff_search(string $q, int $offset = 0, int $count = 0): array {
        return self::_search(self::WFF_ARCHIVE_SPHINX_RTINDEX, $q, $offset, $count,
            items_getter: function($matches) {
                return self::wff_get_by_id(array_keys($matches));
            },
            sphinx_client_setup: function(SphinxClient $cl) {
                $cl->setFieldWeights([
                    'title' => 50,
                    'document_id' => 60,
                ]);
                $cl->setRankingMode(Sphinx\SphinxClient::SPH_RANK_PROXIMITY_BM25);
                $cl->setSortMode(Sphinx\SphinxClient::SPH_SORT_EXTENDED, '@relevance DESC, is_folder DESC');
            }
        );
    }

    public static function wff_reindex(): void {
        sphinx::execute("TRUNCATE RTINDEX ".self::WFF_ARCHIVE_SPHINX_RTINDEX);
        $db = DB();
        $q = $db->query("SELECT * FROM wff_collection");
        while ($row = $db->fetch($q)) {
            $item = new WFFCollectionItem($row);
            $text = '';
            if ($item->isFile()) {
                $text_q = $db->query("SELECT text FROM wff_texts WHERE wff_id=?", $item->id);
                if ($db->numRows($text_q))
                    $text = $db->result($text_q);
            }
            sphinx::execute("INSERT INTO ".self::WFF_ARCHIVE_SPHINX_RTINDEX." (id, document_id, title, text, is_folder, parent_id) VALUES (?, ?, ?, ?, ?, ?)",
                $item->id, $item->getDocumentId(), $item->title, $text, (int)$item->isFolder(), $item->parentId);
        }
    }

    public static function wff_get_text_excerpts(array $ids, array $keywords, int $before = 50, int $after = 40): array {
        return self::_get_text_excerpts('wff_texts', 'wff_id', $ids, $keywords, $before, $after);
    }

    /**
     * @return MDFCollectionItem[]
     */
    public static function mdf_get(): array {
        $db = DB();
        $q = $db->query("SELECT * FROM mdf_collection ORDER BY `date`");
        return array_map('MDFCollectionItem::create_instance', $db->fetchAll($q));
    }

    /**
     * @param int[] $ids
     * @return MDFCollectionItem[]
     */
    public static function mdf_get_by_id(array $ids): array {
        $db = DB();
        $q = $db->query("SELECT * FROM mdf_collection WHERE id IN (".implode(',', $ids).")");
        return array_map('MDFCollectionItem::create_instance', $db->fetchAll($q));
    }

    public static function mdf_search(string $q, int $offset = 0, int $count = 0): array {
        return self::_search(self::MDF_ARCHIVE_SPHINX_RTINDEX, $q, $offset, $count,
            items_getter: function($matches) {
                return self::mdf_get_by_id(array_keys($matches));
            },
            sphinx_client_setup: function(SphinxClient $cl) {
                $cl->setFieldWeights([
                    'date' => 10,
                    'issue' => 9,
                    'text' => 8
                ]);
                $cl->setRankingMode(Sphinx\SphinxClient::SPH_RANK_PROXIMITY_BM25);
                $cl->setSortMode(Sphinx\SphinxClient::SPH_SORT_RELEVANCE);
            }
        );
    }

    public static function mdf_reindex(): void {
        sphinx::execute("TRUNCATE RTINDEX ".self::MDF_ARCHIVE_SPHINX_RTINDEX);
        $db = DB();
        $mdf = self::mdf_get();
        foreach ($mdf as $item) {
            $text = $db->result($db->query("SELECT text FROM mdf_texts WHERE mdf_id=?", $item->id));
            sphinx::execute("INSERT INTO ".self::MDF_ARCHIVE_SPHINX_RTINDEX." (id, volume, issue, date, text) VALUES (?, ?, ?, ?, ?)",
                $item->id, $item->volume, (string)$item->issue, $item->getHumanFriendlyDate(), $text);
        }
    }

    public static function mdf_get_text_excerpts(array $ids, array $keywords, int $before = 50, int $after = 40): array {
        return self::_get_text_excerpts('mdf_texts', 'mdf_id', $ids, $keywords, $before, $after);
    }


    /**
     * @return BaconianaCollectionItem[]
     */
    public static function baconiana_get(?int $parent_id = 0): array {
        $db = DB();
        $sql = "SELECT * FROM baconiana_collection";
        if ($parent_id !== null)
            $sql .= " WHERE parent_id='".$db->escape($parent_id)."'";
        $sql .= " ORDER BY type, year, id";
        $q = $db->query($sql);
        return array_map('BaconianaCollectionItem::create_instance', $db->fetchAll($q));
    }

    /**
     * @param int[] $ids
     * @return BaconianaCollectionItem[]
     */
    public static function baconiana_get_by_id(array $ids): array {
        $db = DB();
        $q = $db->query("SELECT * FROM baconiana_collection WHERE id IN (".implode(',', $ids).")");
        return array_map('BaconianaCollectionItem::create_instance', $db->fetchAll($q));
    }

    /**
     * @param int $folder_id
     * @param bool $with_parents
     * @return BaconianaCollectionItem|BaconianaCollectionItem[]|null
     */
    public static function baconiana_get_folder(int $folder_id, bool $with_parents = false): WFFCollectionItem|array|null {
        $db = DB();
        $q = $db->query("SELECT * FROM baconiana_collection WHERE id=?", $folder_id);
        if (!$db->numRows($q))
            return null;
        $item = new BaconianaCollectionItem($db->fetch($q));
        if (!$item->isFolder())
            return null;
        if ($with_parents) {
            $items = [$item];
            if ($item->parentId) {
                $parents = self::baconiana_get_folder($item->parentId, true);
                if ($parents !== null)
                    $items = array_merge($items, $parents);
            }
            return $items;
        }
        return $item;
    }

    public static function baconiana_search(string $q, int $offset = 0, int $count = 0): array {
        return self::_search(self::BACONIANA_ARCHIVE_SPHINX_RTINDEX, $q, $offset, $count,
            items_getter: function($matches) {
                return self::baconiana_get_by_id(array_keys($matches));
            },
            sphinx_client_setup: function(SphinxClient $cl) {
                $cl->setFieldWeights([
                    'year' => 10,
                    'issues' => 9,
                    'text' => 8
                ]);
                $cl->setRankingMode(Sphinx\SphinxClient::SPH_RANK_PROXIMITY_BM25);
                $cl->setSortMode(Sphinx\SphinxClient::SPH_SORT_RELEVANCE);
            }
        );
    }

    public static function baconiana_reindex(): void {
        sphinx::execute("TRUNCATE RTINDEX ".self::BACONIANA_ARCHIVE_SPHINX_RTINDEX);
        $db = DB();
        $baconiana = self::baconiana_get(null);
        foreach ($baconiana as $item) {
            $text_q = $db->query("SELECT text FROM baconiana_texts WHERE bcn_id=?", $item->id);
            if (!$db->numRows($text_q))
                continue;
            $text = $db->result($text_q);
            sphinx::execute("INSERT INTO ".self::BACONIANA_ARCHIVE_SPHINX_RTINDEX." (id, title, year, text) VALUES (?, ?, ?, ?)",
                $item->id, "$item->year ($item->issues)", $item->year, $text);
        }
    }

    public static function baconiana_get_text_excerpts(array $ids, array $keywords, int $before = 50, int $after = 40): array {
        return self::_get_text_excerpts('baconiana_texts', 'bcn_id', $ids, $keywords, $before, $after);
    }


    /**
     * @return BookItem[]
     */
    public static function books_get(int $parent_id = 0, BookCategory $category = BookCategory::BOOKS): array {
        $db = DB();

        if ($category == BookCategory::BOOKS) {
            $order_by = "type, ".($parent_id != 0 ? 'year, ': '')."author, title";
        }
        else
            $order_by = "type, title";

        $q = $db->query("SELECT * FROM books WHERE category=? AND parent_id=? ORDER BY $order_by",
            $category->value, $parent_id);
        return array_map('BookItem::create_instance', $db->fetchAll($q));
    }

    public static function books_get_folder(int $id, bool $with_parents = false): BookItem|array|null {
        $db = DB();
        $q = $db->query("SELECT * FROM books WHERE id=?", $id);
        if (!$db->numRows($q))
            return null;
        $item = new BookItem($db->fetch($q));
        if (!$item->isFolder())
            return null;
        if ($with_parents) {
            $items = [$item];
            if ($item->parentId) {
                $parents = self::books_get_folder($item->parentId, true);
                if ($parents !== null)
                    $items = array_merge($items, $parents);
            }
            return $items;
        }
        return $item;
    }

}