<?php

declare(strict_types=1);

namespace Agent001\Sync;

\defined( 'ABSPATH' ) || exit;

use Agent001\Admin\SyncProgress;
use Agent001\Config\Settings;
use Agent001\Outbox\ProductHooks;
use DateTimeImmutable;
use DateTimeZone;

final class DailySync
{
    public const HOOK          = 'agent001_daily_sync';
    public const OFFSET_OPTION = 'agent001_daily_sync_offset';

    private const MIN_OFFSET_SECONDS = 3600;
    private const MAX_OFFSET_SECONDS = 18000;

    private Settings $settings;

    private SyncRunner $runner;

    private SyncProgress $progress;

    public function __construct( Settings $settings, SyncRunner $runner, SyncProgress $progress )
    {
        $this->settings = $settings;
        $this->runner   = $runner;
        $this->progress = $progress;
    }

    public function register(): void
    {
        \add_action( self::HOOK, [ $this, 'run' ] );
        \add_action( 'action_scheduler_init', [ $this, 'ensureScheduled' ] );
    }

    public function ensureScheduled(): void
    {
        if ( ! \function_exists( 'as_has_scheduled_action' ) || ! \function_exists( 'as_schedule_recurring_action' ) ) {
            return;
        }

        if ( ! $this->isEnabled() ) {
            self::unschedule();
            return;
        }

        if ( \as_has_scheduled_action( self::HOOK, [], ProductHooks::ACTION_GROUP ) ) {
            return;
        }

        \as_schedule_recurring_action(
            self::nextRunAt( time(), $this->offset(), \wp_timezone() ),
            DAY_IN_SECONDS,
            self::HOOK,
            [],
            ProductHooks::ACTION_GROUP
        );
    }

    public function run(): void
    {
        if ( ! $this->isEnabled() || $this->progress->isRunning() ) {
            return;
        }

        $this->runner->schedule();
    }

    public static function unschedule(): void
    {
        if ( \function_exists( 'as_unschedule_all_actions' ) ) {
            \as_unschedule_all_actions( self::HOOK, [], ProductHooks::ACTION_GROUP );
        }
    }

    public static function nextRunAt( int $now, int $offsetSeconds, DateTimeZone $timezone ): int
    {
        $runAt = ( new DateTimeImmutable( '@' . $now ) )
            ->setTimezone( $timezone )
            ->setTime( 0, 0 )
            ->modify( '+' . $offsetSeconds . ' seconds' );

        if ( $runAt->getTimestamp() <= $now ) {
            $runAt = $runAt->modify( '+1 day' );
        }

        return $runAt->getTimestamp();
    }

    private function isEnabled(): bool
    {
        return $this->settings->hasApiKey() && $this->settings->hasSelectedAgents();
    }

    private function offset(): int
    {
        $stored = (int) \get_option( self::OFFSET_OPTION, 0 );
        if ( $stored >= self::MIN_OFFSET_SECONDS && $stored < self::MAX_OFFSET_SECONDS ) {
            return $stored;
        }

        $offset = random_int( self::MIN_OFFSET_SECONDS, self::MAX_OFFSET_SECONDS - 1 );
        \update_option( self::OFFSET_OPTION, $offset, false );

        return $offset;
    }
}