<?php
if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

/**
 * Creates and assigns a 16:9 cover when a 7S Video & Music Gallery item has no featured image.
 */
final class SG7G_Default_Cover {
    private const WIDTH  = 1600;
    private const HEIGHT = 900;
    private const BACKFILL_VERSION = '1';
    private const LOCK_META = '_sg7g_cover_generation_lock';

    public static function init(): void {
        add_action( 'save_post_sg7g_media', array( __CLASS__, 'ensure' ), 50, 3 );
        add_action( 'admin_init', array( __CLASS__, 'backfill_existing' ) );
        add_action( 'before_delete_post', array( __CLASS__, 'cleanup_on_delete' ), 10, 2 );
    }

    /**
     * Give existing coverless items a default cover after the plugin update.
     * Processes at most 50 records per admin request.
     */
    public static function backfill_existing(): void {
        if ( ! current_user_can( 'manage_options' ) || get_option( 'sg7g_cover_backfill_version' ) === self::BACKFILL_VERSION ) {
            return;
        }

        $posts = get_posts(
            array(
                'post_type'      => 'sg7g_media',
                'post_status'    => array( 'publish', 'draft', 'pending', 'private', 'future' ),
                'posts_per_page' => 50,
                'orderby'        => 'ID',
                'order'          => 'ASC',
                // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- One-time backfill query for missing cover metadata.
                'meta_query'     => array(
                    'relation' => 'OR',
                    array(
                        'key'     => '_thumbnail_id',
                        'compare' => 'NOT EXISTS',
                    ),
                    array(
                        'key'     => '_thumbnail_id',
                        'value'   => '0',
                        'compare' => '=',
                    ),
                ),
            )
        );

        foreach ( $posts as $post ) {
            if ( $post instanceof WP_Post ) {
                self::ensure( $post->ID, $post, true );
            }
        }

        if ( count( $posts ) < 50 ) {
            update_option( 'sg7g_cover_backfill_version', self::BACKFILL_VERSION, false );
        }
    }

    public static function ensure( int $post_id, WP_Post $post, bool $update ): void {
        unset( $update );

        if ( class_exists( 'SG7G_Transfer' ) && SG7G_Transfer::is_importing() ) {
            return;
        }

        if ( wp_is_post_autosave( $post_id ) || wp_is_post_revision( $post_id ) ) {
            return;
        }

        if ( in_array( $post->post_status, array( 'auto-draft', 'trash', 'inherit' ), true ) ) {
            return;
        }

        if ( 'sg7g_media' !== $post->post_type ) {
            return;
        }

        $lock_time = (int) get_post_meta( $post_id, self::LOCK_META, true );
        if ( $lock_time && ( time() - $lock_time ) < 300 ) {
            return;
        }
        if ( $lock_time ) {
            delete_post_meta( $post_id, self::LOCK_META );
        }
        if ( ! add_post_meta( $post_id, self::LOCK_META, time(), true ) ) {
            return;
        }

        try {
            $default_id   = absint( get_post_meta( $post_id, '_sg7g_default_cover_id', true ) );
            $thumbnail_id = absint( get_post_thumbnail_id( $post_id ) );

        // A user-selected cover always wins. Remove the now-unused generated
        // attachment so automatic covers do not accumulate in the Media Library.
        if ( $thumbnail_id && $thumbnail_id !== $default_id ) {
            if ( $default_id && get_post_meta( $default_id, '_sg7g_generated_cover', true ) ) {
                wp_delete_attachment( $default_id, true );
                delete_post_meta( $post_id, '_sg7g_default_cover_id' );
                delete_post_meta( $post_id, '_sg7g_default_cover_hash' );
            }
            return;
        }

        $type = get_post_meta( $post_id, '_sg7g_media_type', true );
        $type = 'audio' === $type ? 'audio' : 'video';
        $hash = md5( $post->post_title . '|' . $type );

        if ( $default_id && get_post( $default_id ) ) {
            $file = get_attached_file( $default_id );
            if ( $file && file_exists( $file ) ) {
                if ( $hash !== get_post_meta( $post_id, '_sg7g_default_cover_hash', true ) && self::write_cover( $file, $post->post_title, $type ) ) {
                    self::refresh_attachment_metadata( $default_id, $file );
                    update_post_meta( $post_id, '_sg7g_default_cover_hash', $hash );
                }
                update_post_meta( $default_id, '_wp_attachment_image_alt', $post->post_title ?: __( 'Gallery default cover image', '7sgaleri' ) );
                wp_update_post(
                    array(
                        'ID'         => $default_id,
                        'post_title' => sprintf( /* translators: %s: Content title. */ __( '%s – Default Cover', '7sgaleri' ), $post->post_title ?: __( 'Gallery Content', '7sgaleri' ) ),
                    )
                );
                if ( $thumbnail_id !== $default_id ) {
                    set_post_thumbnail( $post_id, $default_id );
                }
                return;
            }
        }

        $attachment_id = self::create_attachment( $post_id, $post->post_title, $type );
        if ( ! $attachment_id ) {
            return;
        }

        update_post_meta( $post_id, '_sg7g_default_cover_id', $attachment_id );
        update_post_meta( $post_id, '_sg7g_default_cover_hash', $hash );
        set_post_thumbnail( $post_id, $attachment_id );
        } finally {
            delete_post_meta( $post_id, self::LOCK_META );
        }
    }

    public static function cleanup_on_delete( int $post_id, WP_Post $post ): void {
        if ( 'sg7g_media' !== $post->post_type ) {
            return;
        }

        $default_id = absint( get_post_meta( $post_id, '_sg7g_default_cover_id', true ) );
        if ( $default_id && get_post_meta( $default_id, '_sg7g_generated_cover', true ) ) {
            wp_delete_attachment( $default_id, true );
        }
    }

    private static function create_attachment( int $post_id, string $title, string $type ): int {
        $uploads = wp_upload_dir();
        if ( ! empty( $uploads['error'] ) ) {
            return 0;
        }

        $directory = trailingslashit( $uploads['path'] ) . '7sgaleri';
        if ( ! wp_mkdir_p( $directory ) ) {
            return 0;
        }

        $filename = '7sgaleri-varsayilan-kapak-' . $post_id . '.png';
        $filepath = trailingslashit( $directory ) . sanitize_file_name( $filename );

        if ( ! self::write_cover( $filepath, $title, $type ) ) {
            return 0;
        }

        $filetype = wp_check_filetype( basename( $filepath ), null );
        $attachment_id = wp_insert_attachment(
            array(
                'post_mime_type' => $filetype['type'] ?: 'image/png',
                'post_title'     => sprintf( /* translators: %s: Content title. */ __( '%s – Default Cover', '7sgaleri' ), $title ?: __( 'Gallery Content', '7sgaleri' ) ),
                'post_content'   => '',
                'post_status'    => 'inherit',
            ),
            $filepath,
            $post_id,
            true
        );

        if ( is_wp_error( $attachment_id ) ) {
            if ( file_exists( $filepath ) ) {
                wp_delete_file( $filepath );
            }
            return 0;
        }

        self::refresh_attachment_metadata( (int) $attachment_id, $filepath );
        update_post_meta( (int) $attachment_id, '_wp_attachment_image_alt', $title ?: __( 'Gallery default cover image', '7sgaleri' ) );
        update_post_meta( (int) $attachment_id, '_sg7g_generated_cover', 1 );

        return (int) $attachment_id;
    }

    private static function refresh_attachment_metadata( int $attachment_id, string $filepath ): void {
        require_once ABSPATH . 'wp-admin/includes/image.php';
        $metadata = wp_generate_attachment_metadata( $attachment_id, $filepath );
        if ( is_array( $metadata ) ) {
            wp_update_attachment_metadata( $attachment_id, $metadata );
        }
    }

    private static function write_cover( string $filepath, string $title, string $type ): bool {
        try {
            if ( function_exists( 'imagecreatetruecolor' ) && function_exists( 'imagepng' ) ) {
                return self::write_with_gd( $filepath, $title, $type );
            }

            $fallback = SG7G_DIR . 'assets/images/default-' . ( 'audio' === $type ? 'audio' : 'video' ) . '.png';
            if ( ! file_exists( $fallback ) ) {
                return false;
            }

            require_once ABSPATH . 'wp-admin/includes/file.php';
            global $wp_filesystem;

            return WP_Filesystem()
                && $wp_filesystem instanceof WP_Filesystem_Base
                && $wp_filesystem->copy( $fallback, $filepath, true, FS_CHMOD_FILE );
        } catch ( Throwable $error ) {
            unset( $error );
            return false;
        }
    }

    private static function write_with_gd( string $filepath, string $title, string $type ): bool {
        $image = imagecreatetruecolor( self::WIDTH, self::HEIGHT );
        if ( ! $image ) {
            return false;
        }

        imagealphablending( $image, true );
        imagesavealpha( $image, true );

        $palette = 'audio' === $type
            ? array( array( 6, 23, 35 ), array( 15, 92, 88 ), array( 58, 230, 194 ) )
            : array( array( 9, 12, 21 ), array( 63, 15, 91 ), array( 255, 76, 139 ) );

        for ( $y = 0; $y < self::HEIGHT; $y++ ) {
            $ratio = $y / max( 1, self::HEIGHT - 1 );
            $r = (int) round( $palette[0][0] + ( $palette[1][0] - $palette[0][0] ) * $ratio );
            $g = (int) round( $palette[0][1] + ( $palette[1][1] - $palette[0][1] ) * $ratio );
            $b = (int) round( $palette[0][2] + ( $palette[1][2] - $palette[0][2] ) * $ratio );
            $color = imagecolorallocate( $image, $r, $g, $b );
            imageline( $image, 0, $y, self::WIDTH, $y, $color );
        }

        $accent_soft = imagecolorallocatealpha( $image, $palette[2][0], $palette[2][1], $palette[2][2], 88 );
        $accent      = imagecolorallocate( $image, $palette[2][0], $palette[2][1], $palette[2][2] );
        $white       = imagecolorallocate( $image, 248, 249, 252 );
        $muted       = imagecolorallocatealpha( $image, 248, 249, 252, 36 );
        $dark        = imagecolorallocatealpha( $image, 0, 0, 0, 58 );

        imagefilledellipse( $image, 1420, 120, 620, 620, $accent_soft );
        imagefilledellipse( $image, 1360, 780, 760, 760, $accent_soft );
        imagefilledrectangle( $image, 0, 742, self::WIDTH, self::HEIGHT, $dark );
        imagefilledrectangle( $image, 110, 105, 220, 113, $accent );

        if ( 'audio' === $type ) {
            self::draw_waveform( $image, 1170, 380, $accent, $muted );
        } else {
            self::draw_play_symbol( $image, 1290, 385, $accent, $white );
        }

        self::draw_text( $image, '7SGALERI', 110, 150, 28, $muted );
        $media_label = 'audio' === $type ? __( 'Audio / Music', '7sgaleri' ) : __( 'Video', '7sgaleri' );
        self::draw_text( $image, strtoupper( remove_accents( $media_label ) ), 110, 215, 34, $accent );

        $clean_title = trim( wp_strip_all_tags( $title ) );
        if ( '' === $clean_title ) {
            $clean_title = __( 'Gallery Content', '7sgaleri' );
        }
        self::draw_wrapped_title( $image, $clean_title, 110, 360, 990, $white );

        $result = imagepng( $image, $filepath, 8 );
        imagedestroy( $image );

        return (bool) $result;
    }

    private static function draw_play_symbol( $image, int $center_x, int $center_y, int $accent, int $white ): void {
        imagefilledellipse( $image, $center_x, $center_y, 230, 230, $accent );
        imagefilledpolygon(
            $image,
            array(
                $center_x - 28, $center_y - 54,
                $center_x - 28, $center_y + 54,
                $center_x + 66, $center_y,
            ),
            $white
        );
    }

    private static function draw_waveform( $image, int $center_x, int $center_y, int $accent, int $muted ): void {
        $heights = array( 80, 160, 250, 340, 230, 390, 300, 190, 290, 145, 90 );
        $start_x = $center_x - 275;
        foreach ( $heights as $index => $height ) {
            $x = $start_x + ( $index * 52 );
            $color = 5 === $index ? $accent : $muted;
            imagefilledrectangle( $image, $x, $center_y - (int) ( $height / 2 ), $x + 20, $center_y + (int) ( $height / 2 ), $color );
        }
    }

    private static function draw_wrapped_title( $image, string $title, int $x, int $y, int $max_width, int $color ): void {
        $font = self::font_path();
        if ( $font && function_exists( 'imagettftext' ) ) {
            $size = 64;
            $lines = self::wrap_ttf( $title, $font, $size, $max_width, 3 );
            foreach ( $lines as $index => $line ) {
                imagettftext( $image, $size, 0, $x, $y + ( $index * 84 ), $color, $font, $line );
            }
            return;
        }

        $plain = strtoupper( remove_accents( $title ) );
        $lines = explode( "\n", wordwrap( $plain, 44, "\n", true ) );
        $lines = array_slice( $lines, 0, 3 );
        foreach ( $lines as $index => $line ) {
            imagestring( $image, 5, $x, $y + ( $index * 34 ), $line, $color );
        }
    }

    private static function draw_text( $image, string $text, int $x, int $y, int $size, int $color ): void {
        $font = self::font_path();
        if ( $font && function_exists( 'imagettftext' ) ) {
            imagettftext( $image, $size, 0, $x, $y, $color, $font, $text );
            return;
        }
        imagestring( $image, 5, $x, $y - 20, $text, $color );
    }

    private static function wrap_ttf( string $text, string $font, int $size, int $max_width, int $max_lines ): array {
        $words = preg_split( '/\s+/u', trim( $text ) ) ?: array();
        $lines = array();
        $line  = '';

        foreach ( $words as $word ) {
            $candidate = '' === $line ? $word : $line . ' ' . $word;
            $box = imagettfbbox( $size, 0, $font, $candidate );
            $width = $box ? abs( $box[2] - $box[0] ) : 0;

            if ( $width > $max_width && '' !== $line ) {
                $lines[] = $line;
                $line = $word;
                if ( count( $lines ) >= $max_lines - 1 ) {
                    break;
                }
            } else {
                $line = $candidate;
            }
        }

        if ( '' !== $line && count( $lines ) < $max_lines ) {
            $lines[] = $line;
        }

        if ( count( $lines ) === $max_lines && count( $words ) > 0 ) {
            $last = array_pop( $lines );
            $lines[] = rtrim( $last, " .…" ) . '…';
        }

        return $lines ?: array( $text );
    }

    private static function font_path(): string {
        $candidates = array(
            '/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf',
            '/usr/share/fonts/dejavu/DejaVuSans-Bold.ttf',
            '/usr/share/fonts/truetype/liberation2/LiberationSans-Bold.ttf',
            '/usr/share/fonts/truetype/freefont/FreeSansBold.ttf',
        );

        foreach ( $candidates as $candidate ) {
            if ( is_readable( $candidate ) ) {
                return $candidate;
            }
        }

        return '';
    }
}