<?php
/**
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (see LICENSE.txt in the base directory.  If
 * not, see:
 *
 * @link <http://www.gnu.org/licenses/>.
 *
 * @author niel
 * @copyright 2014 nZEDb
 */

namespace Blacklight\db;

use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\File;

class PreDb
{
    /**
     * @var array Prepared Statement objects
     */
    protected $ps = [
        'AddGroups'        => null,
        'DeleteShort'    => null,
        'Export'        => null,
        'Import'        => null,
        'Insert'        => null,
        'LoadData'        => null,
        'Truncate'        => null,
        'UpdateGroupID'    => null,
    ];

    /**
     * @var string
     */
    private $tableMain = 'predb';

    /**
     * @var \PDO
     */
    private $pdo;

    /**
     * PreDb constructor.
     */
    public function __construct()
    {
        $this->pdo = DB::connection()->getPdo();
    }

    /**
     * @return mixed
     */
    public function executeAddGroups()
    {
        if (! isset($this->ps['AddGroups'])) {
            $this->prepareSQLAddGroups();
        }

        return $this->ps['AddGroups']->execute();
    }

    /**
     * @return mixed
     */
    public function executeDeleteShort()
    {
        if (! isset($this->ps['DeleteShort'])) {
            $this->prepareSQLDeleteShort();
        }

        return $this->ps['DeleteShort']->execute();
    }

    /**
     * @param  array|null  $options  array of parameter.
     *                               'enclosedby'	- string for enclosed by clause. default: empty string,
     *                               'fields'		- string for FIELDS SEPARATED BY clause. default: '\t',
     *                               'limit'			- string for LIMIT clause. Zero indicate no clause. Default:  0,
     *                               'lines'			- string for LINES TERMINATED BY. Default: '\r\n' (Windows style EOLs to allow \n to be used in text),
     *                               'path'			- path (including filename) to write data to.
     *                               All parameter will be escaped before use.
     * @return false|\PDOStatement
     */
    public function executeExport(array $options = null)
    {
        $defaults = [
            'enclosedby'    => '',
            'fields'        => '\t',
            'limit'            => 0,
            'lines'            => '\r\n',    // use Windows style endings so that text can contain \n
            'local'            => false,
            'path'            => null,
        ];
        $options += $defaults;

        if (empty($options['path'])) {
            return;
        }

        if (! is_numeric($options['limit'])) {
            return;
        }

        $limit = $options['limit'] > 0 ? "LIMIT {$options['limit']}" : '';

        $enclosedby = empty($options['enclosedby']) ? '' : 'ENCLOSED BY '.escapeString($options['enclosedby']);

        $sql = <<<SQL_EXPORT
SELECT title, nfo, size, files, filename, nuked, nukereason, category, predate, source, requestid, g.name
	FROM {$this->tableMain} p LEFT OUTER JOIN usenet_groups g ON p.groups_id = g.id {$limit}
	INTO OUTFILE '{$options['path']}'
	FIELDS TERMINATED BY '{$options['fields']}' {$enclosedby}
	LINES TERMINATED BY '{$options['lines']}';
SQL_EXPORT;

        return $this->pdo->query($sql);
    }

    /**
     * @return mixed
     */
    public function executeInsert()
    {
        if (! isset($this->ps['Insert'])) {
            $this->prepareSQLInsert();
        }

        return $this->ps['Insert']->execute();
    }

    /**
     * @param  array|null  $options
     * @return null
     */
    public function executeLoadData(array $options = null)
    {
        $defaults = [
            'path'        => null,
        ];
        $options += $defaults;

        if (empty($options['path'])) {
            return;
        }

        if (! isset($this->ps['LoadData'])) {
            // TODO detect LOCAL here and pass parameter as appropriate
            $this->prepareSQLLoadData($options);
        }

        return $this->ps['LoadData']->execute([':path' => $options['path']]);
    }

    /**
     * @return mixed
     */
    public function executeTruncate()
    {
        if (! isset($this->ps['Truncate'])) {
            $this->prepareSQLTruncate();
        }

        return $this->ps['Truncate']->execute();
    }

    /**
     * @return mixed
     */
    public function executeUpdateGroupID()
    {
        if (! isset($this->ps['UpdateGroupID'])) {
            $this->prepareSQLUpdateGroupIDs();
        }

        return $this->ps['UpdateGroupID']->execute();
    }

    /**
     * @param    $filespec
     * @param  bool  $localDB
     */
    public function import($filespec, $localDB = false)
    {
        if (! ($this->ps['AddGroups'] instanceof \PDOStatement)) {
            $this->prepareImportSQL($localDB);
        }

        $this->ps['Truncate']->execute();

        $this->ps['LoadData']->execute(['path' => $filespec]);

        $this->ps['DeleteShort']->execute();

        $this->ps['AddGroups']->execute();

        $this->ps['UpdateGroupID']->execute();

        $this->ps['Insert']->execute();
    }

    /**
     * @param  null  $settings
     * @param  array  $options
     * @return mixed|null
     *
     * @throws \Illuminate\Contracts\Filesystem\FileNotFoundException
     */
    public function progress($settings = null, array $options = [])
    {
        $defaults = [
            'path'    => base_path().'/cli/data/predb_progress.txt',
            'read'    => true,
        ];
        $options += $defaults;

        if (! $options['read'] || ! File::isFile($options['path'])) {
            File::put($options['path'], base64_encode(serialize($settings)));
        } else {
            $settings = unserialize(base64_decode(File::get($options['path'])));
        }

        return $settings;
    }

    /**
     * @param  bool  $localDB
     * @param  string  $enclosedby
     */
    protected function prepareImportSQL($localDB = false, $enclosedby = '')
    {
        $this->prepareSQLTruncate();

        $this->prepareSQLLoadData(['local' => $localDB, 'enclosedby' => $enclosedby, 'optional' => true]);

        $this->prepareSQLDeleteShort();

        $this->prepareSQLAddGroups();

        $this->prepareSQLUpdateGroupIDs();

        $this->prepareSQLInsert();
    }

    /**
     * @param $sql
     * @param  string  $index
     */
    protected function prepareSQLStatement($sql, $index): void
    {
        $this->ps[$index] = $this->pdo->prepare($sql);
    }

    /**
     * Add any groups that are not in our current groups table.
     */
    protected function prepareSQLAddGroups(): void
    {
        $sql = <<<'SQL_ADD_GROUPS'
INSERT IGNORE INTO usenet_groups (name, description)
	SELECT groupname, 'Added by predb import script'
	FROM predb_imports AS pi LEFT JOIN usenet_groups AS g ON pi.groupname = g.name
	WHERE pi.groupname IS NOT NULL AND g.name IS NULL
	GROUP BY groupname;
SQL_ADD_GROUPS;

        $this->prepareSQLStatement($sql, 'AddGroups');
    }

    protected function prepareSQLDeleteShort(): void
    {
        $this->prepareSQLStatement('DELETE FROM predb_imports WHERE LENGTH(title) <= 8', 'DeleteShort');
    }

    protected function prepareSQLInsert(): void
    {
        $sql = <<<SQL_INSERT
INSERT INTO {$this->tableMain} (title, nfo, size, files, filename, nuked, nukereason, category, predate, SOURCE, requestid, groups_id)
  SELECT pi.title, pi.nfo, pi.size, pi.files, pi.filename, pi.nuked, pi.nukereason, pi.category, pi.predate, pi.source, pi.requestid, groups_id
    FROM predb_imports AS pi
  ON DUPLICATE KEY UPDATE predb.nfo = IF(predb.nfo IS NULL, pi.nfo, predb.nfo),
	  predb.size = IF(predb.size IS NULL, pi.size, predb.size),
	  predb.files = IF(predb.files IS NULL, pi.files, predb.files),
	  predb.filename = IF(predb.filename = '', pi.filename, predb.filename),
	  predb.nuked = IF(pi.nuked > 0, pi.nuked, predb.nuked),
	  predb.nukereason = IF(pi.nuked > 0, pi.nukereason, predb.nukereason),
	  predb.category = IF(predb.category IS NULL, pi.category, predb.category),
	  predb.requestid = IF(predb.requestid = 0, pi.requestid, predb.requestid),
	  predb.groups_id = IF(predb.groups_id = 0, pi.groups_id, predb.groups_id);
SQL_INSERT;

        $this->prepareSQLStatement($sql, 'Insert');
    }

    /**
     * @param  array  $options
     */
    protected function prepareSQLLoadData(array $options = []): void
    {
        $enclosedby = '';
        $defaults = [
            'enclosedby'    => "'",
            'fields'        => '\t',
            'lines'            => '\r\n',    // Windows' style EOL to allow \n to be used in text.
            'local'            => true,
            'optional'        => true,
        ];
        $options += $defaults;

        $local = $options['local'] === true ? 'LOCAL' : '';
        if (! empty($options['enclosedby'])) {
            $optional = $options['optional'] === true ? ' OPTIONALLY' : '';
            $enclosedby = "$optional ENCLOSED BY \"{$options['enclosedby']}\"";
        }
        $sql = <<<SQL_LOAD_DATA
LOAD DATA {$local} INFILE '{$options['path']}'
  IGNORE INTO TABLE predb_imports
  FIELDS TERMINATED BY '{$options['fields']}' {$enclosedby}
  LINES TERMINATED BY '{$options['lines']}'
  (title, nfo, size, files, filename, nuked, nukereason, category, predate, source, requestid, groupname);
SQL_LOAD_DATA;

        $this->prepareSQLStatement($sql, 'LoadData');
    }

    protected function prepareSQLTruncate(): void
    {
        $this->prepareSQLStatement('TRUNCATE TABLE predb_imports', 'Truncate');
    }

    protected function prepareSQLUpdateGroupIDs(): void
    {
        $sql = 'UPDATE predb_imports AS pi SET groups_id = (SELECT id FROM usenet_groups WHERE name = pi.groupname) WHERE groupname IS NOT NULL';
        $this->prepareSQLStatement($sql, 'UpdateGroupID');
    }
}