<?php
declare(strict_types=1);

namespace OCA\Memories\Db;

use OCA\Memories\AppInfo\Application;
use OCP\Files\File;
use OCP\IConfig;
use OCP\IDBConnection;

class Util {
	protected IDBConnection $connection;

	public function __construct(IDBConnection $connection) {
		$this->connection = $connection;
	}

    /**
     * Get the path to the user's configured photos directory.
     * @param IConfig $config
     * @param string $userId
     */
    public static function getPhotosPath(IConfig $config, string $userId) {
        $p = $config->getUserValue($userId, Application::APPNAME, 'timelinePath', '');
        if (empty($p)) {
            return '/Photos/';
        }
        return $p;
    }

    /**
     * Get exif data as a JSON object from a Nextcloud file.
     * @param File $file
     */
    public static function getExifFromFile(File &$file) {
        $handle = $file->fopen('rb');
        $exif = self::getExifFromStream($handle);
        fclose($handle);
        return $exif;
    }

    /**
     * Get exif data as a JSON object from a stream.
     * @param resource $handle
     */
    public static function getExifFromStream(&$handle) {
        // Start exiftool and output to json
        $pipes = [];
        $proc = proc_open('exiftool -json -', [
            0 => array('pipe', 'rb'),
            1 => array('pipe', 'w'),
            2 => array('pipe', 'w'),
        ], $pipes);

        // Write the file to exiftool's stdin
        // Assume exif exists in the first 256 kb of the file
        stream_copy_to_stream($handle, $pipes[0], 256 * 1024);
        fclose($pipes[0]);

        // Get output from exiftool
        $stdout = stream_get_contents($pipes[1]);

        // Clean up
        fclose($pipes[1]);
        fclose($pipes[2]);
        proc_close($proc);

        // Parse the json
        $json = json_decode($stdout, true);
        if (!$json) {
            throw new \Exception('Could not read exif data');
        }
        return $json[0];
    }

    /**
     * Get the date taken from either the file or exif data if available.
     * @param File $file
     * @param array $exif
     */
    public static function getDateTaken(File $file, array $exif) {
        $dt = $exif['DateTimeOriginal'];
        if (!isset($dt) || empty($dt)) {
            $dt = $exif['CreateDate'];
        }

        // Check if found something
        if (isset($dt) && !empty($dt)) {
            $dt = \DateTime::createFromFormat('Y:m:d H:i:s', $dt);
            if ($dt && $dt->getTimestamp() > -5364662400) { // 1800 A.D.
                return $dt->getTimestamp();
            }
        }

        // Fall back to creation time
        $dateTaken = $file->getCreationTime();

        // Fall back to upload time
        if ($dateTaken == 0) {
            $dateTaken = $file->getUploadTime();
        }

        // Fall back to modification time
        if ($dateTaken == 0) {
            $dateTaken = $file->getMtime();
        }
        return $dateTaken;
    }

    /**
     * Process a file to insert Exif data into the database
     * @param File $file
     */
    public function processFile(File $file): void {
        // There is no easy way to UPSERT in a standard SQL way, so just
        // do multiple calls. The worst that can happen is more updates,
        // but that's not a big deal.
        // https://stackoverflow.com/questions/15252213/sql-standard-upsert-call

        // Check if we want to process this file
        $mime = $file->getMimeType();
        $is_image = in_array($mime, Application::IMAGE_MIMES);
        $is_video = in_array($mime, Application::VIDEO_MIMES);
        if (!$is_image && !$is_video) {
            return;
        }

        // Get parameters
        $mtime = $file->getMtime();
        $user = $file->getOwner()->getUID();
        $fileId = $file->getId();

        // Check if need to update
        $sql = 'SELECT `mtime`
                FROM *PREFIX*memories
                WHERE file_id = ? AND user_id = ?';
        $prevRow = $this->connection->executeQuery($sql, [
            $fileId, $user,
        ], [
            \PDO::PARAM_INT, \PDO::PARAM_STR,
        ])->fetch();
        if ($prevRow && intval($prevRow['mtime']) === $mtime) {
            return;
        }

        // Get exif data
        $exif = [];
        try {
            $exif = self::getExifFromFile($file);
        } catch (\Exception) {}

        // Get more parameters
        $dateTaken = $this->getDateTaken($file, $exif);
        $dayId = floor($dateTaken / 86400);
        $dateTaken = gmdate('Y-m-d H:i:s', $dateTaken);

        if ($prevRow) {
            // Update existing row
            $sql = 'UPDATE *PREFIX*memories
                    SET day_id = ?, date_taken = ?, is_video = ?, mtime = ?
                    WHERE user_id = ? AND file_id = ?';
            $this->connection->executeStatement($sql, [
                $dayId, $dateTaken, $is_video, $mtime,
                $user, $fileId,
            ], [
                \PDO::PARAM_INT, \PDO::PARAM_STR, \PDO::PARAM_BOOL, \PDO::PARAM_INT,
                \PDO::PARAM_STR, \PDO::PARAM_INT,
            ]);
        } else {
            // Create new row
            $sql = 'INSERT
                    INTO  *PREFIX*memories (day_id, date_taken, is_video, mtime, user_id, file_id)
                    VALUES  (?, ?, ?, ?, ?, ?)';
            $this->connection->executeStatement($sql, [
                $dayId, $dateTaken, $is_video, $mtime,
                $user, $fileId,
            ], [
                \PDO::PARAM_INT, \PDO::PARAM_STR, \PDO::PARAM_BOOL, \PDO::PARAM_INT,
                \PDO::PARAM_STR, \PDO::PARAM_INT,
            ]);
        }
    }

    /**
     * Remove a file from the exif database
     * @param File $file
     */
    public function deleteFile(File $file) {
        $sql = 'DELETE
                FROM *PREFIX*memories
                WHERE file_id = ?';
        $this->connection->executeStatement($sql, [$file->getId()], [\PDO::PARAM_INT]);
    }

    /**
     * Process the days response
     * @param array $days
     */
    private function processDays(&$days) {
        foreach($days as &$row) {
            $row["day_id"] = intval($row["day_id"]);
            $row["count"] = intval($row["count"]);
        }
        return $days;
    }

    /**
     * Get the days response from the database for the timeline
     * @param IConfig $config
     * @param string $userId
     */
    public function getDays(
        IConfig $config,
        string $user,
    ): array {
        $sql = 'SELECT day_id, COUNT(file_id) AS count
                FROM `*PREFIX*memories`
                INNER JOIN `*PREFIX*filecache`
                    ON `*PREFIX*filecache`.`fileid` = `*PREFIX*memories`.`file_id`
                    AND `*PREFIX*filecache`.`path` LIKE ?
                WHERE user_id=?
                GROUP BY day_id
                ORDER BY day_id DESC';

        $path = "files" . self::getPhotosPath($config, $user) . "%";
        $rows = $this->connection->executeQuery($sql, [$path, $user], [
            \PDO::PARAM_STR, \PDO::PARAM_STR,
        ])->fetchAll();
        return $this->processDays($rows);
    }

    /**
     * Get the days response from the database for one folder
     * @param int $folderId
     */
    public function getDaysFolder(int $folderId) {
        $sql = 'SELECT day_id, COUNT(file_id) AS count
                FROM `*PREFIX*memories`
                INNER JOIN `*PREFIX*filecache`
                    ON `*PREFIX*filecache`.`fileid` = `*PREFIX*memories`.`file_id`
                    AND (`*PREFIX*filecache`.`parent`=? OR `*PREFIX*filecache`.`fileid`=?)
                GROUP BY day_id
                ORDER BY day_id DESC';
        $rows = $this->connection->executeQuery($sql, [$folderId, $folderId], [
            \PDO::PARAM_INT, \PDO::PARAM_INT,
        ])->fetchAll();
        return $this->processDays($rows);
    }

    /**
     * Process the single day response
     * @param array $day
     */
    private function processDay(&$day) {
        foreach($day as &$row) {
            $row["file_id"] = intval($row["file_id"]);
            $row["is_video"] = intval($row["is_video"]);
            if (!$row["is_video"]) {
                unset($row["is_video"]);
            }
        }
        return $day;
    }

    /**
     * Get a day response from the database for the timeline
     * @param IConfig $config
     * @param string $userId
     * @param int $dayId
     */
    public function getDay(
        IConfig $config,
        string $user,
        int $dayId,
    ): array {
        $sql = 'SELECT file_id, *PREFIX*filecache.etag, is_video
                FROM *PREFIX*memories
                INNER JOIN *PREFIX*filecache
                    ON *PREFIX*filecache.fileid = *PREFIX*memories.file_id
                    AND `*PREFIX*filecache`.`path` LIKE ?
                WHERE user_id = ? AND day_id = ?
                ORDER BY date_taken DESC';

        $path = "files" . self::getPhotosPath($config, $user) . "%";
		$rows = $this->connection->executeQuery($sql, [$path, $user, $dayId], [
            \PDO::PARAM_STR, \PDO::PARAM_STR, \PDO::PARAM_INT,
        ])->fetchAll();
        return $this->processDay($rows);
    }

    /**
     * Get a day response from the database for one folder
     * @param int $folderId
     * @param int $dayId
     */
    public function getDayFolder(
        int $folderId,
        int $dayId,
    ): array {
        $sql = 'SELECT file_id, *PREFIX*filecache.etag, is_video
                FROM `*PREFIX*memories`
                INNER JOIN `*PREFIX*filecache`
                    ON `*PREFIX*filecache`.`fileid` = `*PREFIX*memories`.`file_id`
                    AND (`*PREFIX*filecache`.`parent`=? OR `*PREFIX*filecache`.`fileid`=?)
                WHERE  `*PREFIX*memories`.`day_id`=?';
		$rows = $this->connection->executeQuery($sql, [$folderId, $folderId, $dayId], [
            \PDO::PARAM_INT, \PDO::PARAM_INT, \PDO::PARAM_INT,
        ])->fetchAll();
        return $this->processDay($rows);
    }
}