<?php
/**
 * Durable coordination. Pauses, source revisions and pending work survive request boundaries.
 *
 * @package AffStackDevImageManager
 */

namespace AffStackDev\ImageManager;

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

/**
 * An optimization or scan run: starting, pausing, resuming and stopping it, its bounded steps and the snapshot the
 * screens show.
 */
final class Workflow {
	public const OPTION = 'afsd_im_job';
	/**
	 * The current run's saved state over its defaults.
	 *
	 * @return array The run.
	 */
	public static function job(): array {
		return array_merge(
			array(
				'id'        => '',
				'active'    => false,
				'mode'      => 'optimize',
				'cursor'    => 0,
				'started'   => 0,
				'finished'  => 0,
				'resumed'   => 0,
				'cancelled' => false,
			),
			(array) get_option( self::OPTION, array() )
		);
	}
	/**
	 * Start a run: an optimization (with the public-pictures confirmation) or a scan only.
	 *
	 * @param bool $optimize True to optimize, false to scan only.
	 * @param bool $policy   The public-pictures confirmation given with this start.
	 * @param bool $delivery The delivery switch saved with the start.
	 * @throws \RuntimeException With a reason code as its message when the step cannot be done.
	 */
	public static function start( bool $optimize, bool $policy, bool $delivery ): void {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			$s = Settings::fresh();
			if ( $optimize && ! $policy && ! $s['public_policy'] ) {
				throw new \RuntimeException( 'Please confirm that these are public website images.' );
			}
			$token = Repository::acquire();
			if ( ! $token ) {
				throw new \RuntimeException( 'worker_busy' );
			}
			try {
				Settings::fresh_option( self::OPTION, array() );
				if ( self::job()['active'] ) {
					throw new \RuntimeException( 'An existing run is saved. Resume it or stop it before starting another.' );
				}
				Scanner::start( (bool) $s['catalog'], (bool) $s['comments'], $token );
				$values = array(
					'paused'       => false,
					'pause_reason' => '',
					'generation'   => (int) $s['generation'] + 1,
				);
				if ( $optimize ) {
					$values['public_policy'] = true;
					$values['delivery']      = $delivery;
				}
				Settings::patch( $values );
				Reviewed_Store::update_option( 'afsd_im_failures', 0, false );
				Reviewed_Store::update_option(
					self::OPTION,
					array(
						'id'        => bin2hex( random_bytes( 12 ) ),
						'active'    => true,
						'mode'      => $optimize ? 'optimize' : 'scan',
						'cursor'    => 0,
						'started'   => time(),
						'finished'  => 0,
						'resumed'   => 0,
						'cancelled' => false,
					),
					false
				);
				Activity::add( $optimize ? 'started' : 'scan_started' );
			} finally {
				Repository::release( $token );
			}
			Scheduler::check();
			Scheduler::needed();

		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * Pause processing and stop scheduled work; prepared copies and originals stay.
	 */
	public static function pause(): void {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			Settings::pause( __( 'Paused by you. Prepared copies and originals are retained.', 'affstackdev-image-manager' ) );
			Scheduler::stop_work();
			Activity::add( 'paused' );

		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * Resume processing and schedule work again.
	 */
	public static function resume(): void {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			Settings::patch(
				array(
					'paused'       => false,
					'pause_reason' => '',
				)
			);
			Reviewed_Store::update_option( 'afsd_im_failures', 0, false );
			Reviewed_Store::update_option( 'afsd_im_last_resume', time(), false );
			Scheduler::check();
			Scheduler::needed();
			Activity::add( 'resumed' );

		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * Stop the run: pause processing, mark the run cancelled, stop the scan, hold the queued pictures (reason cancelled)
	 * and skip the bulk items not finished; prepared copies and originals stay.
	 *
	 * @throws \RuntimeException With a reason code as its message when the step cannot be done.
	 */
	public static function cancel(): void {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			global $wpdb;
			$token = Repository::acquire();
			if ( ! $token ) {
				throw new \RuntimeException( 'worker_busy' );
			}
			try {
				Settings::pause( __( 'Run stopped. Originals and prepared copies are retained.', 'affstackdev-image-manager' ) );
				$job              = self::job();
				$job['active']    = false;
				$job['cancelled'] = true;
				$job['finished']  = time();
				Reviewed_Store::update_option( self::OPTION, $job, false );
				$scan                   = Scanner::state();
				$scan['active']         = false;
				$scan['catalog_page']   = 0;
				$scan['comment_offset'] = -1;
				Scanner::save( $scan );
				// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bounded reads/writes of plugin job, cursor and source totals; independent workers update these tables throughout the run.
				Reviewed_Store::database_query( $wpdb->prepare( "UPDATE %i SET state='held',requested=0,reason='cancelled' WHERE state='queued'", Repository::table( 'sources' ) ) );
				Batch::cancel( $job );
				Activity::add( 'cancelled' );
			} finally {
				Repository::release( $token );
			}
			Scheduler::reconcile();

		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * Bounded inventory traversal; only the worker holding the lease calls this.
	 *
	 * @param string $owned_token The worker's lease.
	 */
	public static function pump( string $owned_token = '' ): void {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			global $wpdb;
			Settings::fresh_option( self::OPTION, array() );
			$job = self::job();
			if ( ! $job['active'] || $job['cancelled'] || Settings::fresh()['paused'] ) {
				return;
			}
			if ( 'bulk' === $job['mode'] ) {
				Batch::pump( $owned_token );
				return;
			}
			$scan  = Scanner::state();
			$pages = Repository::counts( 'pages' );
			if ( ! $scan['active'] && ! empty( $pages['waiting'] ) ) {
				Scanner::continue_scan();
			}
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bounded reads/writes of plugin job, cursor and source totals; independent workers update these tables throughout the run.
			$rows = $wpdb->get_results( $wpdb->prepare( 'SELECT * FROM %i WHERE id>%d ORDER BY id ASC LIMIT 25', Repository::table( 'sources' ), (int) $job['cursor'] ), ARRAY_A );
			foreach ( $rows as  $raw ) {
				$r             = Repository::decode( $raw );
				$job['cursor'] = (int) $r['id'];
				if ( 'optimize' !== $job['mode'] || $r['excluded'] || ! in_array( $r['state'], array( 'discovered', 'held' ), true ) ) {
					continue;
				}
				if ( ! empty( $r['attachment_id'] ) || Theme::is_source( $r ) ) {
					Repository::request( (int) $r['id'] );
				}
			}
			if ( ! $rows && ! Scanner::pending() && empty( $pages['waiting'] ) && 'optimize' === $job['mode'] ) {
				// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bounded reads/writes of plugin job, cursor and source totals; independent workers update these tables throughout the run.
				$late = $wpdb->get_results( $wpdb->prepare( "SELECT * FROM %i WHERE state='discovered' AND excluded=0 ORDER BY id ASC LIMIT 25", Repository::table( 'sources' ) ), ARRAY_A );
				foreach ( $late as  $raw ) {
					$r = Repository::decode( $raw );
					Repository::request( (int) $r['id'] );
				}
			}
			$counts = Repository::counts();
			if ( ! $rows && ! Scanner::pending() && empty( $pages['waiting'] ) && empty( $counts['queued'] ) ) {
				$job['active']   = false;
				$job['finished'] = time();
				Activity::add( 'completed' );
			}
			Reviewed_Store::update_option( self::OPTION, $job, false );

		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * Whether there is work left: a migration, an active run, the scan, queued pictures or page rechecks.
	 *
	 * @return bool True when there is.
	 */
	public static function pending(): bool {
		$counts = Repository::counts();
		return ! get_option( 'afsd_im_totals_migrated', false ) || ! get_option( 'afsd_im_records_migrated', false ) || self::job()['active'] || Scanner::pending() || ! empty( $counts['queued'] ) || Auto_Discovery::pending();
	}
	/**
	 * A soft budget between indivisible operations, NOT an interrupt guarantee for a native encoder.
	 *
	 * @param string $origin browser, cli or background (background steps are shorter).
	 */
	public static function run_batch( string $origin = 'browser' ): void {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			$background = 'background' === $origin;
			$started    = microtime( true );
			$deadline   = $started + ( $background ? 4.0 : 6.0 );
			$units      = 0;
			for ( $i = 0; $i < ( $background ? 4 : 8 ) && microtime( true ) < $deadline; ++$i ) {
				if ( Settings::fresh()['paused'] || ! self::pending() ) {
					break;
				}
				Sources::forget_cache();
				if ( ! Engine::tick() ) {
					break;
				}
				++$units;
			}
			Reviewed_Store::update_option(
				'afsd_im_last_batch',
				array(
					'origin'       => $background ? 'background' : ( 'cli' === $origin ? 'manual CLI' : 'browser assistance' ),
					'finished'     => time(),
					'units'        => $units,
					'milliseconds' => (int) round( 1000 * ( microtime( true ) - $started ) ),
					'peak_memory'  => memory_get_peak_usage( true ),
				),
				false
			);
			if ( ! $background ) {
				Scheduler::reconcile();
			}
		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * The figures and words the Optimize screen and the status command show for the run.
	 *
	 * @return array The snapshot.
	 */
	public static function snapshot(): array {
		global $wpdb;
		$counts = Repository::counts();
		$pages  = Repository::counts( 'pages' );
		$job    = self::job();
		$s      = Settings::get();
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bounded reads/writes of plugin job, cursor and source totals; independent workers update these tables throughout the run.
		$totals    = $wpdb->get_row( $wpdb->prepare( 'SELECT SUM(saved_bytes) AS saved,SUM(copy_count) AS copies,SUM(copy_bytes) AS bytes FROM %i WHERE state<>%s', Repository::table( 'sources' ), 'grouped' ), ARRAY_A ) ?: array();
		$buckets   = Results::buckets( $counts );
		$found     = array_sum( $counts );
		$ready     = $buckets['ready'];
		$kept      = $buckets['no_saving'] + $buckets['unsupported'] + $buckets['held'];
		$done      = $ready + $kept + $buckets['failed'] + $buckets['excluded'];
		$scanning  = Scanner::pending() || ( $job['active'] && ! empty( $pages['waiting'] ) );
		$automatic = Auto_Discovery::snapshot();
		$active    = $job['active'] || $scanning || ! empty( $counts['queued'] ) || ! empty( $automatic['pending'] );
		$percent   = $found ? min( 100, (int) floor( 100 * $done / $found ) ) : 0;
		if ( $active ) {
			$percent = min( 99, $percent );
		} elseif ( $job['finished'] && ! $job['cancelled'] ) {
			$percent = 100;
		}
		$label  = $job['cancelled'] && ! $active ? __( 'Run stopped — your files are retained', 'affstackdev-image-manager' )
			: ( $s['paused'] && $active ? __( 'Optimization paused', 'affstackdev-image-manager' )
				: ( $scanning ? __( 'Finding your public site images', 'affstackdev-image-manager' )
					: ( $active ? __( 'Preparing smaller image copies', 'affstackdev-image-manager' )
						: ( $job['finished']
							? ( 'scan' === $job['mode'] ? __( 'Scan complete — review the results', 'affstackdev-image-manager' ) : ( ( $buckets['failed'] || ! empty( $pages['blocked'] ) ) ? __( 'Run finished — some images need attention', 'affstackdev-image-manager' ) : __( 'Finished — results are ready', 'affstackdev-image-manager' ) ) )
							: __( 'Ready when you are', 'affstackdev-image-manager' ) ) ) ) );
		$detail = $scanning
			/* translators: 1: pages checked; 2: pages found so far. */
			? sprintf( _n( 'Pages checked: %1$d of %2$d found so far. Discovery stays within the selected public sources.', 'Pages checked: %1$d of %2$d found so far. Discovery stays within the selected public sources.', array_sum( $pages ), 'affstackdev-image-manager' ), (int) ( $pages['scanned'] ?? 0 ) + (int) ( $pages['blocked'] ?? 0 ), array_sum( $pages ) )
			: ( $active
				? sprintf( /* translators: 1: images reviewed; 2: images found. */ _n( '%1$d of %2$d images reviewed. Progress is saved automatically.', '%1$d of %2$d images reviewed. Progress is saved automatically.', $found, 'affstackdev-image-manager' ), $done, $found )
				: ( $job['cancelled'] ? __( 'Stopped work has not been deleted. Start a new run when ready.', 'affstackdev-image-manager' )
					: ( 'scan' === $job['mode'] && $job['finished']
						? __( 'Discovery finished. Scan only does not add images to the optimization queue. Previously queued image work is handled separately.', 'affstackdev-image-manager' )
						: ( $found ? __( 'See the result breakdown below and the reason on each image. Prepared-file savings are not browser-transfer measurements.', 'affstackdev-image-manager' ) : __( 'Ready to scan your public pages and prepare smaller copies.', 'affstackdev-image-manager' ) ) ) ) );
		if ( ! $active && $job['finished'] && ! $job['cancelled'] ) {
			if ( ! $found ) {
				$detail = __( 'No images were found in the scanned public sources. Review scanned pages in Tools before changing the scan scope.', 'affstackdev-image-manager' );
			}
			/* translators: %d: number of pages checked. */
			$detail .= ' ' . sprintf( _n( 'Pages checked: %d.', 'Pages checked: %d.', (int) ( ( $pages['scanned'] ?? 0 ) + ( $pages['blocked'] ?? 0 ) ), 'affstackdev-image-manager' ), (int) ( ( $pages['scanned'] ?? 0 ) + ( $pages['blocked'] ?? 0 ) ) );
			if ( ! empty( $pages['blocked'] ) ) {
				/* translators: %d: number of pages that could not be scanned. */
				$detail .= ' ' . sprintf( _n( '%d page(s) could not be scanned; review Tools.', '%d page(s) could not be scanned; review Tools.', (int) $pages['blocked'], 'affstackdev-image-manager' ), (int) $pages['blocked'] );
			}
		}
		$summary = null;
		if ( 'bulk' === $job['mode'] ) {
			$summary = Batch::summary( $job );
			$done    = $summary['done'];
			$total   = $summary['total'];
			$percent = $total ? min( 100, (int) floor( 100 * $done / $total ) ) : ( ! $active && ! $job['cancelled'] && $job['finished'] ? 100 : 0 );
			if ( $active ) {
				$percent = min( 99, $percent );
			}
			$label  = $s['paused'] && $active ? __( 'Bulk run paused', 'affstackdev-image-manager' )
				: ( $scanning ? __( 'Finding public images for your selected policy', 'affstackdev-image-manager' ) : ( $active ? __( 'Applying your bulk choices', 'affstackdev-image-manager' ) : ( $job['cancelled'] ? __( 'Bulk run stopped', 'affstackdev-image-manager' ) : __( 'Bulk run finished', 'affstackdev-image-manager' ) ) ) );
			$detail = $scanning
				/* translators: 1: Checked pages; 2: Pages found so far; 3: Waiting pages; 4: Unavailable pages. */
				? sprintf( __( 'Pages checked: %1$d of %2$d found so far. %3$d waiting; %4$d unavailable. Eligible images are selected after discovery finishes.', 'affstackdev-image-manager' ), (int) ( $pages['scanned'] ?? 0 ) + (int) ( $pages['blocked'] ?? 0 ), array_sum( $pages ), (int) ( $pages['waiting'] ?? 0 ), (int) ( $pages['blocked'] ?? 0 ) )
				: sprintf(
					/* translators: 1: selected images finished; 2: images selected; 3: completed; 4: ready for review; 5: skipped; 6: need attention. */
					_n(
						'%1$d of %2$d selected images finished. %3$d completed; %4$d ready for review; %5$d skipped; %6$d need attention.',
						'%1$d of %2$d selected images finished. %3$d completed; %4$d ready for review; %5$d skipped; %6$d need attention.',
						$total,
						'affstackdev-image-manager'
					),
					$done,
					$total,
					$summary['complete'],
					$summary['review'],
					$summary['skipped'],
					$summary['failed']
				);
			if ( 'optimize' === $job['action'] ) {
				$detail .= ' ' . __( 'Compression and size choices apply to this run, not your global defaults.', 'affstackdev-image-manager' );
			}
		}
		if ( 'bulk' === $job['mode'] && ! $job['active'] && $active ) {
			$label   = $s['paused'] ? __( 'Other queued image work is paused', 'affstackdev-image-manager' ) : __( 'Processing other queued image work', 'affstackdev-image-manager' );
			$detail  = __( 'The saved bulk run has ended. Separately queued image work remains; last-run counts do not measure that work.', 'affstackdev-image-manager' );
			$percent = 0;
		}
		if ( ! $job['active'] && ! $scanning && $automatic['pending'] ) {
			$label = $s['paused'] ? __( 'Automatic page rechecks paused', 'affstackdev-image-manager' ) : __( 'Checking changed public pages', 'affstackdev-image-manager' );
			/* translators: %d: Number of pending automatic page rechecks. */
			$detail  = sprintf( __( '%d automatic page rechecks waiting. New eligible images join the queue; saved-run counts remain separate.', 'affstackdev-image-manager' ), $automatic['pending'] );
			$percent = 0;
		}
		$health = Scheduler::status( $active && ! $s['paused'] );
		$run    = Progress::describe( $job, $pages, $counts, $summary, $active, $scanning, (bool) $s['paused'], $health );
		if ( ! $job['active'] && $automatic['pending'] && 'no_recent_checkpoint' === $run['wait_code'] ) {
			// An old run checkpoint does not age a newly queued automatic recheck.
			if ( max( $automatic['oldest'], (int) ( $automatic['last']['at'] ?? 0 ) ) >= time() - 300 ) {
				$run['wait_code']   = '';
				$run['wait_detail'] = '';
			} else {
				$run['wait_detail'] = __( 'Automatic page rechecks have been waiting with no recent automatic checkpoint. Review background processing or use Process here now; the saved run is separate.', 'affstackdev-image-manager' );
			}
		}
		return array(
			'run'              => $run,
			'automatic'        => $automatic,
			'found'            => $found,
			'ready'            => $ready,
			'kept'             => $kept,
			'done'             => $done,
			'buckets'          => $buckets,
			'saved'            => max( 0, (int) ( $totals['saved'] ?? 0 ) ),
			'copy_bytes'       => max( 0, (int) ( $totals['bytes'] ?? 0 ) ),
			'copies'           => max( 0, (int) ( $totals['copies'] ?? 0 ) ),
			'active'           => $active,
			'paused'           => (bool) $s['paused'],
			'scanning'         => $scanning,
			'cancelled'        => (bool) $job['cancelled'],
			'percent'          => $percent,
			'label'            => $label,
			'detail'           => $detail,
			'delivery'         => (bool) $s['delivery'],
			'counts'           => $counts,
			'page_counts'      => $pages,
			'background'       => $health,
			'assist'           => $health['assist'],
			'watch'            => $active || $health['watch'],
			/* translators: %s: the run's status, such as "Finished — results are ready". */
			'run_notice'       => $job['finished'] && ! $active ? sprintf( __( '%s. Original files are unchanged.', 'affstackdev-image-manager' ), $label ) : '',
			'browser_verified' => false,
		);
	}
	/**
	 * Recount each source's saved bytes and copies, 50 rows per step, after an update from a release that kept no totals.
	 */
	public static function migrate_totals(): void {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			global $wpdb;
			if ( get_option( 'afsd_im_totals_migrated', false ) ) {
				return;
			}
			$cursor = (int) get_option( 'afsd_im_totals_cursor', 0 );
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bounded reads/writes of plugin job, cursor and source totals; independent workers update these tables throughout the run.
			$rows = $wpdb->get_results( $wpdb->prepare( 'SELECT id,manifest FROM %i WHERE id>%d ORDER BY id ASC LIMIT 50', Repository::table( 'sources' ), $cursor ), ARRAY_A );
			foreach ( $rows as  $row ) {
				Repository::update( (int) $row['id'], array( 'manifest' => json_decode( $row['manifest'], true ) ?: array() ) );
				$cursor = (int) $row['id'];
			}
			Reviewed_Store::update_option( 'afsd_im_totals_cursor', $cursor, false );
			if ( count( $rows ) < 50 ) {
				Reviewed_Store::update_option( 'afsd_im_totals_migrated', true, false );
			}
		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
}