<?php
/**
 * A finished video's MP4 (and its poster) into the Media Library, in the
 * background, and what to do when that fails.
 *
 * @package Ojelio
 */

namespace Ojelio;

use WP_Error;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

// PHP's upload limits do not apply: the server downloads the file itself
// (download_url) and hands it to the Media Library (media_handle_sideload). What
// can stop it is a host's time limit, its disk, a multisite quota, or a firewall.
// So the download never runs in an answer to the webhook or the editor: it is a
// WP-Cron event, tried up to three times, and a video that could not be saved
// stays "Ready in Ojelio" with the reason, "Try again" and a download link.

final class Media {

	const EVENT     = 'ojelio_save_video';
	const MAX_TRIES = 3;
	/** Room left after the file, so a site is never filled to the last byte. */
	const MARGIN = 50 * MB_IN_BYTES;

	public static function boot() {
		add_action( self::EVENT, array( __CLASS__, 'save' ), 10, 2 );
	}

	/** Whether the automatic tries are spent: only "Try again" starts it again. */
	public static function gave_up( array $video ) {
		return isset( $video['save_tries'] ) && $video['save_tries'] >= self::MAX_TRIES;
	}

	/** Saves the video soon, in WP-Cron, once. */
	public static function schedule( $post_id, $video_id ) {
		$args = array( (int) $post_id, (string) $video_id );
		if ( ! wp_next_scheduled( self::EVENT, $args ) ) {
			wp_schedule_single_event( time(), self::EVENT, $args );
		}
	}

	/** "Try again": the tries start over, now, in place of a retry scheduled for later. */
	public static function retry( $post_id, $video_id ) {
		Videos::update( $post_id, $video_id, array( 'save_tries' => 0, 'save_error' => null ) );
		wp_clear_scheduled_hook( self::EVENT, array( (int) $post_id, (string) $video_id ) );
		self::schedule( $post_id, $video_id );
		spawn_cron();
	}

	/** WP-Cron: download the MP4 and the poster, and add them to the Media Library. */
	public static function save( $post_id, $video_id ) {
		$kept = Videos::find( $post_id, $video_id );
		if ( ! $kept || ! empty( $kept['attachment_id'] ) || self::gave_up( $kept ) ) {
			return;
		}
		// One at a time: a webhook and the background check can both ask.
		$lock = 'ojelio_saving_' . md5( $video_id );
		if ( get_transient( $lock ) ) {
			return;
		}
		set_transient( $lock, 1, 15 * MINUTE_IN_SECONDS );
		try {
			$result = self::download_and_add( (int) $post_id, $kept );
		} finally {
			delete_transient( $lock );
		}
		if ( is_wp_error( $result ) ) {
			$tries = ( isset( $kept['save_tries'] ) ? (int) $kept['save_tries'] : 0 ) + 1;
			Videos::update(
				$post_id,
				$video_id,
				array(
					'save_tries' => $tries,
					'save_error' => array(
						'code'    => $result->get_error_code(),
						'message' => $result->get_error_message(),
						'at'      => time(),
					),
				)
			);
			// Space and quota do not free themselves within minutes: no automatic retry.
			if ( $tries < self::MAX_TRIES && ! in_array( $result->get_error_code(), array( 'ojelio_space', 'ojelio_quota', 'ojelio_type' ), true ) ) {
				wp_schedule_single_event( time() + 5 * MINUTE_IN_SECONDS * $tries, self::EVENT, array( (int) $post_id, (string) $video_id ) );
			} elseif ( $tries < self::MAX_TRIES ) {
				Videos::update( $post_id, $video_id, array( 'save_tries' => self::MAX_TRIES ) );
			}
			return;
		}
		Videos::update(
			$post_id,
			$video_id,
			array(
				'attachment_id' => $result['video'],
				'poster_id'     => $result['poster'],
				'saved_at'      => time(),
				'save_error'    => null,
			)
		);
	}

	/**
	 * @return array|WP_Error The attachments: array( 'video' => ID, 'poster' => ID or 0 ).
	 */
	private static function download_and_add( $post_id, array $kept ) {
		require_once ABSPATH . 'wp-admin/includes/file.php';
		require_once ABSPATH . 'wp-admin/includes/media.php';
		require_once ABSPATH . 'wp-admin/includes/image.php';

		// Fresh links: the ones a webhook carried may be old by now.
		$video = Connection::call( 'GET', '/videos/' . rawurlencode( $kept['id'] ) );
		if ( is_wp_error( $video ) ) {
			return $video;
		}
		if ( empty( $video['files']['video'] ) ) {
			return new WP_Error( 'ojelio_no_file', __( 'Ojelio has no file for this video yet.', 'ojelio' ) );
		}
		$bytes = isset( $video['files']['video_bytes'] ) ? (int) $video['files']['video_bytes'] : 0;
		$room  = self::room_for( $bytes );
		if ( is_wp_error( $room ) ) {
			return $room;
		}

		self::more_time();
		$tmp = download_url( $video['files']['video'], 300 );
		if ( is_wp_error( $tmp ) ) {
			return new WP_Error(
				'ojelio_download',
				/* translators: %s: the reason from WordPress, such as "Operation timed out". */
				sprintf( __( 'The MP4 could not be downloaded from Ojelio (%s). The server may have stopped it for taking too long, or blocked it.', 'ojelio' ), $tmp->get_error_message() )
			);
		}
		$name     = sanitize_file_name( ( '' !== $kept['title'] ? $kept['title'] : 'ojelio-video' ) . '-' . $kept['id'] . '.mp4' );
		$video_id = media_handle_sideload( array( 'name' => $name, 'tmp_name' => $tmp ), $post_id, $kept['title'] );
		if ( is_wp_error( $video_id ) ) {
			wp_delete_file( $tmp );
			$type = 'upload_error' === $video_id->get_error_code() && false !== stripos( $video_id->get_error_message(), 'type' );
			return new WP_Error(
				$type ? 'ojelio_type' : 'ojelio_save',
				$type
					? __( 'This site does not accept MP4 files in its Media Library (a security plugin or the host may block them).', 'ojelio' )
					/* translators: %s: the reason from WordPress. */
					: sprintf( __( 'The MP4 could not be added to the Media Library (%s).', 'ojelio' ), $video_id->get_error_message() )
			);
		}
		update_post_meta( $video_id, '_ojelio_video', $kept['id'] );

		// The poster is a nicety: a video saved without it is still saved.
		$poster_id = 0;
		if ( ! empty( $video['files']['poster'] ) ) {
			$tmp = download_url( $video['files']['poster'], 60 );
			if ( ! is_wp_error( $tmp ) ) {
				$poster = media_handle_sideload(
					array( 'name' => sanitize_file_name( 'ojelio-poster-' . $kept['id'] . '.jpg' ), 'tmp_name' => $tmp ),
					$post_id,
					/* translators: %s: the video's title. */
					sprintf( __( 'Poster of %s', 'ojelio' ), $kept['title'] )
				);
				if ( is_wp_error( $poster ) ) {
					wp_delete_file( $tmp );
				} else {
					$poster_id = (int) $poster;
					set_post_thumbnail( $video_id, $poster_id );
				}
			}
		}
		return array( 'video' => (int) $video_id, 'poster' => $poster_id );
	}

	/** Whether the site has room for a file of this size: multisite's quota, then the disk. */
	public static function room_for( $bytes ) {
		if ( is_multisite() && ! get_site_option( 'upload_space_check_disabled' ) ) {
			$available = (int) get_upload_space_available();
			if ( $bytes && $available < $bytes ) {
				return new WP_Error(
					'ojelio_quota',
					/* translators: 1: the video's size, 2: the space left, such as "12 MB". */
					sprintf( __( 'This site\'s storage quota is full: the video needs %1$s and %2$s is left. A network administrator can raise the quota.', 'ojelio' ), size_format( $bytes ), size_format( $available ) )
				);
			}
		}
		$free = self::free_disk();
		if ( null !== $free && $bytes && $free < $bytes + self::MARGIN ) {
			return new WP_Error(
				'ojelio_space',
				/* translators: 1: the video's size, 2: the space left. */
				sprintf( __( 'The server is almost out of disk space: the video needs %1$s and %2$s is free.', 'ojelio' ), size_format( $bytes ), size_format( $free ) )
			);
		}
		return true;
	}

	/**
	 * Free bytes where uploads go, or null when the host does not say. The
	 * "ojelio_free_disk" filter can correct it (a host that misreports it, the tests).
	 */
	public static function free_disk() {
		$free = null;
		if ( function_exists( 'disk_free_space' ) ) {
			$uploads = wp_upload_dir( null, false );
			$found   = @disk_free_space( $uploads['basedir'] ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- some hosts disable it.
			$free    = false === $found ? null : (float) $found;
		}
		return apply_filters( 'ojelio_free_disk', $free );
	}

	/** PHP's time limit for this request, in seconds (0: none). */
	public static function time_limit() {
		return (int) ini_get( 'max_execution_time' );
	}

	private static function more_time() {
		if ( function_exists( 'set_time_limit' ) && false === strpos( (string) ini_get( 'disable_functions' ), 'set_time_limit' ) ) {
			// A long MP4 can take more than the default 30 seconds to download in the
			// background task; hosts that forbid it keep their limit (time_limit() warns).
			@set_time_limit( 300 ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged, Squiz.PHP.DiscouragedFunctions.Discouraged
		}
	}
}