<?php
/**
 * Icon Registry class - Manages downloaded sets and provides icon search/retrieval.
 *
 * @package MapleIcons
 */

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

/**
 * Class MI_Icon_Registry
 *
 * Manages downloaded icon sets and provides search/retrieval functionality.
 */
class MI_Icon_Registry {

    /**
     * Singleton instance.
     *
     * @var MI_Icon_Registry|null
     */
    private static $instance = null;

    /**
     * Cached settings.
     *
     * @var array|null
     */
    private $settings = null;

    /**
     * Get singleton instance.
     *
     * @return MI_Icon_Registry
     */
    public static function get_instance() {
        if ( null === self::$instance ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    /**
     * Constructor.
     */
    private function __construct() {
        $this->load_settings();
    }

    /**
     * Load settings from database.
     */
    private function load_settings() {
        $this->settings = get_option(
            'maple_icons_settings',
            array(
                'active_set'      => '',
                'downloaded_sets' => array(),
            )
        );
    }

    /**
     * Save settings to database.
     *
     * @return bool True on success.
     */
    private function save_settings() {
        return update_option( 'maple_icons_settings', $this->settings );
    }

    /**
     * Get all downloaded sets.
     *
     * @return array Array of downloaded set data.
     */
    public function get_downloaded_sets() {
        return isset( $this->settings['downloaded_sets'] ) ? $this->settings['downloaded_sets'] : array();
    }

    /**
     * Get the active set slug.
     *
     * @return string|null Active set slug or null if none.
     */
    public function get_active_set() {
        $active = isset( $this->settings['active_set'] ) ? $this->settings['active_set'] : '';
        return ! empty( $active ) ? $active : null;
    }

    /**
     * Set the active icon set.
     *
     * @param string $slug Icon set slug.
     * @return bool|WP_Error True on success, error on failure.
     */
    public function set_active( $slug ) {
        // Allow empty string to deactivate.
        if ( empty( $slug ) ) {
            $this->settings['active_set'] = '';
            return $this->save_settings();
        }

        // Validate slug.
        if ( ! MI_Icon_Sets::is_valid_slug( $slug ) ) {
            return new WP_Error( 'invalid_set', __( 'Invalid icon set.', 'maple-icons' ) );
        }

        // Check if downloaded.
        if ( ! $this->is_downloaded( $slug ) ) {
            return new WP_Error( 'not_downloaded', __( 'Icon set is not downloaded.', 'maple-icons' ) );
        }

        $this->settings['active_set'] = $slug;
        return $this->save_settings();
    }

    /**
     * Check if a set is downloaded.
     *
     * @param string $slug Icon set slug.
     * @return bool True if downloaded.
     */
    public function is_downloaded( $slug ) {
        $downloaded = $this->get_downloaded_sets();
        return isset( $downloaded[ $slug ] );
    }

    /**
     * Mark a set as downloaded.
     *
     * @param string $slug       Icon set slug.
     * @param int    $icon_count Number of icons downloaded.
     * @return bool True on success.
     */
    public function mark_downloaded( $slug, $icon_count ) {
        if ( ! MI_Icon_Sets::is_valid_slug( $slug ) ) {
            return false;
        }

        $set_config = MI_Icon_Sets::get( $slug );

        $this->settings['downloaded_sets'][ $slug ] = array(
            'version'       => $set_config['version'],
            'downloaded_at' => current_time( 'mysql' ),
            'icon_count'    => $icon_count,
        );

        return $this->save_settings();
    }

    /**
     * Remove a set from downloaded list.
     *
     * @param string $slug Icon set slug.
     * @return bool True on success.
     */
    public function unmark_downloaded( $slug ) {
        if ( isset( $this->settings['downloaded_sets'][ $slug ] ) ) {
            unset( $this->settings['downloaded_sets'][ $slug ] );
        }

        // If this was the active set, clear it.
        if ( $this->settings['active_set'] === $slug ) {
            $this->settings['active_set'] = '';
        }

        return $this->save_settings();
    }

    /**
     * Get all icons for a set and style.
     *
     * @param string $slug  Icon set slug.
     * @param string $style Style slug.
     * @return array Array of icon data.
     */
    public function get_icons_for_set( $slug, $style ) {
        if ( ! MI_Icon_Sets::is_valid_slug( $slug ) ) {
            return array();
        }

        if ( ! MI_Icon_Sets::is_valid_style( $slug, $style ) ) {
            return array();
        }

        // Load manifest.
        $manifest = MI_Icon_Sets::load_manifest( $slug );
        if ( is_wp_error( $manifest ) ) {
            return array();
        }

        $icons = isset( $manifest['icons'] ) ? $manifest['icons'] : array();
        $result = array();

        foreach ( $icons as $icon ) {
            $icon_styles = isset( $icon['styles'] ) ? $icon['styles'] : array_keys( MI_Icon_Sets::get( $slug )['styles'] );

            // Only include if this icon has the requested style.
            if ( in_array( $style, $icon_styles, true ) ) {
                $result[] = array(
                    'name'     => $icon['name'],
                    'tags'     => isset( $icon['tags'] ) ? $icon['tags'] : array(),
                    'category' => isset( $icon['category'] ) ? $icon['category'] : '',
                );
            }
        }

        return $result;
    }

    /**
     * Search icons in the active set.
     *
     * @param string $query  Search query.
     * @param string $style  Optional style filter.
     * @param int    $limit  Maximum results.
     * @param int    $offset Offset for pagination.
     * @return array Search results.
     */
    public function search_icons( $query = '', $style = '', $limit = MI_SEARCH_LIMIT, $offset = 0 ) {
        $active_set = $this->get_active_set();
        if ( ! $active_set ) {
            return array(
                'icons' => array(),
                'total' => 0,
            );
        }

        $set_config = MI_Icon_Sets::get( $active_set );
        if ( ! $set_config ) {
            return array(
                'icons' => array(),
                'total' => 0,
            );
        }

        // Default to first style if not specified.
        if ( empty( $style ) ) {
            $style = $set_config['default_style'];
        }

        // Validate style.
        if ( ! MI_Icon_Sets::is_valid_style( $active_set, $style ) ) {
            $style = $set_config['default_style'];
        }

        // Load manifest.
        $manifest = MI_Icon_Sets::load_manifest( $active_set );
        if ( is_wp_error( $manifest ) ) {
            return array(
                'icons' => array(),
                'total' => 0,
            );
        }

        $icons   = isset( $manifest['icons'] ) ? $manifest['icons'] : array();
        $query   = strtolower( trim( $query ) );
        $results = array();

        foreach ( $icons as $icon ) {
            $icon_styles = isset( $icon['styles'] ) ? $icon['styles'] : array_keys( $set_config['styles'] );

            // Skip if this icon doesn't have the requested style.
            if ( ! in_array( $style, $icon_styles, true ) ) {
                continue;
            }

            // If no query, include all.
            if ( empty( $query ) ) {
                $results[] = $icon;
                continue;
            }

            // Search in name.
            if ( strpos( strtolower( $icon['name'] ), $query ) !== false ) {
                $results[] = $icon;
                continue;
            }

            // Search in tags.
            if ( isset( $icon['tags'] ) && is_array( $icon['tags'] ) ) {
                foreach ( $icon['tags'] as $tag ) {
                    if ( strpos( strtolower( $tag ), $query ) !== false ) {
                        $results[] = $icon;
                        break;
                    }
                }
            }
        }

        $total = count( $results );

        // Apply offset and limit.
        $results = array_slice( $results, $offset, $limit );

        // Format results.
        $formatted = array();
        foreach ( $results as $icon ) {
            $formatted[] = array(
                'name'     => $icon['name'],
                'tags'     => isset( $icon['tags'] ) ? $icon['tags'] : array(),
                'category' => isset( $icon['category'] ) ? $icon['category'] : '',
                'set'      => $active_set,
                'style'    => $style,
            );
        }

        return array(
            'icons'   => $formatted,
            'total'   => $total,
            'set'     => $active_set,
            'style'   => $style,
            'styles'  => MI_Icon_Sets::get_style_labels( $active_set ),
        );
    }

    /**
     * Get SVG content for a specific icon.
     *
     * @param string $slug  Icon set slug.
     * @param string $style Style slug.
     * @param string $name  Icon name.
     * @return string|WP_Error SVG content or error.
     */
    public function get_icon_svg( $slug, $style, $name ) {
        // Validate inputs.
        if ( ! MI_Icon_Sets::is_valid_slug( $slug ) ) {
            return new WP_Error( 'invalid_set', __( 'Invalid icon set.', 'maple-icons' ) );
        }

        if ( ! MI_Icon_Sets::is_valid_style( $slug, $style ) ) {
            return new WP_Error( 'invalid_style', __( 'Invalid icon style.', 'maple-icons' ) );
        }

        // Validate icon name.
        if ( ! preg_match( '/^[a-z0-9\-_]+$/i', $name ) ) {
            return new WP_Error( 'invalid_name', __( 'Invalid icon name.', 'maple-icons' ) );
        }

        $local_path = MI_Icon_Sets::get_local_path( $slug, $style, $name );

        // Validate path is within icons directory (prevent path traversal).
        $real_path    = realpath( $local_path );
        $allowed_base = realpath( MI_ICONS_DIR );

        if ( false === $real_path ) {
            return new WP_Error( 'not_found', __( 'Icon not found.', 'maple-icons' ) );
        }

        if ( false === $allowed_base || strpos( $real_path, $allowed_base ) !== 0 ) {
            return new WP_Error( 'invalid_path', __( 'Invalid icon path.', 'maple-icons' ) );
        }

        if ( ! file_exists( $real_path ) ) {
            return new WP_Error( 'not_found', __( 'Icon not found.', 'maple-icons' ) );
        }

        $svg = file_get_contents( $real_path ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents

        if ( false === $svg ) {
            return new WP_Error( 'read_error', __( 'Could not read icon file.', 'maple-icons' ) );
        }

        return $svg;
    }

    /**
     * Delete a downloaded set.
     *
     * @param string $slug Icon set slug.
     * @return bool|WP_Error True on success, error on failure.
     */
    public function delete_set( $slug ) {
        if ( ! MI_Icon_Sets::is_valid_slug( $slug ) ) {
            return new WP_Error( 'invalid_set', __( 'Invalid icon set.', 'maple-icons' ) );
        }

        if ( ! $this->is_downloaded( $slug ) ) {
            return new WP_Error( 'not_downloaded', __( 'Icon set is not downloaded.', 'maple-icons' ) );
        }

        // Delete files.
        $downloader = new MI_Downloader();
        $deleted    = $downloader->delete_set( $slug );

        if ( ! $deleted ) {
            return new WP_Error( 'delete_error', __( 'Could not delete icon files.', 'maple-icons' ) );
        }

        // Update settings.
        $this->unmark_downloaded( $slug );

        return true;
    }

    /**
     * Get info about a downloaded set.
     *
     * @param string $slug Icon set slug.
     * @return array|null Set info or null if not downloaded.
     */
    public function get_downloaded_info( $slug ) {
        $downloaded = $this->get_downloaded_sets();
        return isset( $downloaded[ $slug ] ) ? $downloaded[ $slug ] : null;
    }

    /**
     * Refresh settings from database.
     */
    public function refresh() {
        $this->load_settings();
    }
}