<?php
/**
 * MLS Media Handler
 *
 * Handles on-demand fetching and caching of media files from MLS listings.
 * Images are downloaded when first requested and cached locally.
 *
 * Per MLS Grid rules:
 * - MediaURLs must NOT be used directly on websites
 * - Images must be downloaded and served from our own server
 */

if (!defined('ABSPATH')) {
    exit;
}

class MLS_Media_Handler {

    /**
     * Upload subdirectory for MLS media
     */
    const UPLOAD_SUBDIR = 'mls-listings';

    /**
     * Database instance
     */
    private $db;

    /**
     * Logger instance
     */
    private $logger;

    /**
     * Constructor
     */
    public function __construct(MLS_DB $db, MLS_Logger $logger) {
        $this->db = $db;
        $this->logger = $logger;
    }

    /**
     * Get base upload directory for MLS media
     *
     * @return string Absolute path
     */
    public function get_upload_dir() {
        $upload_dir = wp_upload_dir();
        return $upload_dir['basedir'] . '/' . self::UPLOAD_SUBDIR;
    }

    /**
     * Get base upload URL for MLS media
     *
     * @return string URL
     */
    public function get_upload_url() {
        $upload_dir = wp_upload_dir();
        return $upload_dir['baseurl'] . '/' . self::UPLOAD_SUBDIR;
    }

    /**
     * Get storage directory for a specific listing
     *
     * @param string $listing_key Listing key
     * @return string Absolute path
     */
    public function get_listing_dir($listing_key) {
        $prefix = substr($listing_key, 0, 2);
        return $this->get_upload_dir() . '/' . $prefix . '/' . $listing_key;
    }

    /**
     * Store media metadata from API sync (no download)
     *
     * @param string $listing_key Listing key
     * @param array $media_array Media array from API
     * @param callable|null $progress_callback Callback for progress updates
     * @return array Stats
     */
    public function sync_property_media($listing_key, $media_array, $force = false, $progress_callback = null) {
        global $wpdb;

        if (empty($media_array)) {
            return array('stored' => 0, 'skipped' => 0);
        }

        $received_keys = array();
        $stored = 0;
        $skipped = 0;

        foreach ($media_array as $media) {
            $media_key = $media['MediaKey'] ?? null;
            if (!$media_key) {
                continue;
            }

            $received_keys[] = $media_key;

            // Check if media record exists
            $existing = $wpdb->get_row($wpdb->prepare(
                "SELECT * FROM {$this->db->media_table()}
                 WHERE listing_key = %s AND media_key = %s",
                $listing_key,
                $media_key
            ));

            $data = array(
                'listing_key' => $listing_key,
                'media_key' => $media_key,
                'media_type' => $media['MediaType'] ?? 'Photo',
                'media_order' => $media['Order'] ?? 0,
                'media_url' => $media['MediaURL'] ?? null,
                'image_width' => $media['ImageWidth'] ?? null,
                'image_height' => $media['ImageHeight'] ?? null,
                'media_modification_timestamp' => isset($media['MediaModificationTimestamp'])
                    ? date('Y-m-d H:i:s', strtotime($media['MediaModificationTimestamp']))
                    : null,
                'updated_at' => current_time('mysql'),
            );

            if ($existing) {
                // Check if URL changed - if so, clear cached file
                if ($existing->media_url !== ($media['MediaURL'] ?? null) && $existing->local_path) {
                    $file_path = $this->get_upload_dir() . '/' . $existing->local_path;
                    if (file_exists($file_path)) {
                        unlink($file_path);
                    }
                    $data['local_path'] = null;
                    $data['local_url'] = null;
                    $data['downloaded_at'] = null;
                }

                $wpdb->update(
                    $this->db->media_table(),
                    $data,
                    array('id' => $existing->id)
                );
                $skipped++;
            } else {
                $data['created_at'] = current_time('mysql');
                $wpdb->insert($this->db->media_table(), $data);
                $stored++;
            }

            if ($progress_callback) {
                call_user_func($progress_callback, 'media_stored', array('media_key' => $media_key));
            }
        }

        // Delete orphaned media records
        if (!empty($received_keys)) {
            $placeholders = implode(',', array_fill(0, count($received_keys), '%s'));
            $values = array_merge(array($listing_key), $received_keys);

            $orphaned = $wpdb->get_results($wpdb->prepare(
                "SELECT id, local_path FROM {$this->db->media_table()}
                 WHERE listing_key = %s AND media_key NOT IN ({$placeholders})",
                $values
            ));

            foreach ($orphaned as $record) {
                if ($record->local_path) {
                    $file_path = $this->get_upload_dir() . '/' . $record->local_path;
                    if (file_exists($file_path)) {
                        unlink($file_path);
                    }
                }
                $wpdb->delete($this->db->media_table(), array('id' => $record->id));
            }
        }

        return array('stored' => $stored, 'skipped' => $skipped);
    }

    /**
     * Get image URL for a media record, fetching on-demand if needed
     *
     * @param int|object $media Media ID or media record object
     * @param bool $fetch_if_missing Whether to fetch if not cached
     * @return string|null Local URL or null
     */
    public function get_image_url($media, $fetch_if_missing = true) {
        global $wpdb;

        // Get media record if ID passed
        if (is_numeric($media)) {
            $media = $wpdb->get_row($wpdb->prepare(
                "SELECT * FROM {$this->db->media_table()} WHERE id = %d",
                $media
            ));
        }

        if (!$media) {
            return null;
        }

        // Already cached
        if ($media->local_url && $media->local_path) {
            $file_path = $this->get_upload_dir() . '/' . $media->local_path;
            if (file_exists($file_path)) {
                return $media->local_url;
            }
        }

        // Fetch on demand
        if ($fetch_if_missing && $media->media_url) {
            $result = $this->fetch_and_cache($media);
            if ($result) {
                return $result;
            }
        }

        return null;
    }

    /**
     * Get primary image URL for a listing (on-demand)
     *
     * @param string $listing_key Listing key
     * @param bool $fetch_if_missing Whether to fetch if not cached
     * @return string|null Image URL
     */
    public function get_primary_image($listing_key, $fetch_if_missing = true) {
        global $wpdb;

        // First check for already-cached image
        $cached = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM {$this->db->media_table()}
             WHERE listing_key = %s AND local_url IS NOT NULL AND local_path IS NOT NULL
             ORDER BY media_order ASC
             LIMIT 1",
            $listing_key
        ));

        if ($cached) {
            $file_path = $this->get_upload_dir() . '/' . $cached->local_path;
            if (file_exists($file_path)) {
                return $cached->local_url;
            }
        }

        // Get first media record (may not be cached)
        $media = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM {$this->db->media_table()}
             WHERE listing_key = %s AND media_url IS NOT NULL
             ORDER BY media_order ASC
             LIMIT 1",
            $listing_key
        ));

        if (!$media) {
            return null;
        }

        // If already cached and file exists, return it
        if ($media->local_url && $media->local_path) {
            $file_path = $this->get_upload_dir() . '/' . $media->local_path;
            if (file_exists($file_path)) {
                return $media->local_url;
            }
        }

        // Fetch on demand
        if ($fetch_if_missing) {
            return $this->fetch_and_cache($media);
        }

        return null;
    }

    /**
     * Get all images for a listing (on-demand for first N)
     *
     * @param string $listing_key Listing key
     * @param int $fetch_limit Max images to fetch on-demand (0 = none)
     * @return array Media records with local_url populated where available
     */
    public function get_listing_images($listing_key, $fetch_limit = 1) {
        global $wpdb;

        $media = $wpdb->get_results($wpdb->prepare(
            "SELECT * FROM {$this->db->media_table()}
             WHERE listing_key = %s
             ORDER BY media_order ASC",
            $listing_key
        ));

        if (empty($media)) {
            return array();
        }

        $fetched = 0;
        foreach ($media as &$item) {
            // Check if cached and file exists
            if ($item->local_url && $item->local_path) {
                $file_path = $this->get_upload_dir() . '/' . $item->local_path;
                if (file_exists($file_path)) {
                    continue;
                }
            }

            // Fetch on demand up to limit
            if ($fetched < $fetch_limit && $item->media_url) {
                $url = $this->fetch_and_cache($item);
                if ($url) {
                    $item->local_url = $url;
                    $fetched++;
                }
            }
        }

        return $media;
    }

    /**
     * Fetch image from MLS Grid and cache locally
     *
     * @param object $media Media record
     * @return string|null Local URL on success, null on failure
     */
    private function fetch_and_cache($media) {
        global $wpdb;

        if (empty($media->media_url)) {
            return null;
        }

        // Download the image
        $response = wp_remote_get($media->media_url, array(
            'timeout' => 30,
        ));

        if (is_wp_error($response)) {
            $this->logger->warning('Media fetch failed', array(
                'listing_key' => $media->listing_key,
                'media_key' => $media->media_key,
                'error' => $response->get_error_message(),
            ));
            return null;
        }

        $status_code = wp_remote_retrieve_response_code($response);

        if ($status_code !== 200) {
            $this->logger->warning('Media fetch HTTP error', array(
                'listing_key' => $media->listing_key,
                'media_key' => $media->media_key,
                'status' => $status_code,
            ));
            return null;
        }

        $body = wp_remote_retrieve_body($response);
        if (empty($body)) {
            return null;
        }

        // Determine extension
        $content_type = wp_remote_retrieve_header($response, 'content-type');
        $extension = $this->get_extension_from_content_type($content_type, $media->media_url);

        // Create directory
        $listing_dir = $this->get_listing_dir($media->listing_key);
        if (!file_exists($listing_dir)) {
            wp_mkdir_p($listing_dir);
        }

        // Save file
        $filename = $media->media_order . '.' . $extension;
        $file_path = $listing_dir . '/' . $filename;

        if (file_put_contents($file_path, $body) === false) {
            $this->logger->error('Failed to write media file', array(
                'path' => $file_path,
            ));
            return null;
        }

        // Update database
        $prefix = substr($media->listing_key, 0, 2);
        $relative_path = $prefix . '/' . $media->listing_key . '/' . $filename;
        $local_url = $this->get_upload_url() . '/' . $relative_path;

        $wpdb->update(
            $this->db->media_table(),
            array(
                'local_path' => $relative_path,
                'local_url' => $local_url,
                'file_size' => strlen($body),
                'mime_type' => $content_type,
                'downloaded_at' => current_time('mysql'),
            ),
            array('id' => $media->id)
        );

        $this->logger->debug('Media fetched and cached', array(
            'listing_key' => $media->listing_key,
            'media_key' => $media->media_key,
            'size' => strlen($body),
        ));

        return $local_url;
    }

    /**
     * Get file extension from content type
     *
     * @param string $content_type Content type header
     * @param string $url Original URL as fallback
     * @return string File extension
     */
    private function get_extension_from_content_type($content_type, $url) {
        $content_type = strtolower(explode(';', $content_type)[0]);

        $map = array(
            'image/jpeg' => 'jpg',
            'image/jpg' => 'jpg',
            'image/png' => 'png',
            'image/gif' => 'gif',
            'image/webp' => 'webp',
        );

        if (isset($map[$content_type])) {
            return $map[$content_type];
        }

        // Fallback to URL extension
        $path = parse_url($url, PHP_URL_PATH);
        $ext = pathinfo($path, PATHINFO_EXTENSION);

        return $ext ?: 'jpg';
    }

    /**
     * Delete all media for a property
     *
     * @param string $listing_key Listing key
     */
    public function delete_property_media($listing_key) {
        global $wpdb;

        // Delete files
        $listing_dir = $this->get_listing_dir($listing_key);
        if (file_exists($listing_dir)) {
            $this->recursive_delete($listing_dir);
        }

        // Delete records
        $wpdb->delete(
            $this->db->media_table(),
            array('listing_key' => $listing_key)
        );
    }

    /**
     * Recursively delete a directory
     *
     * @param string $dir Directory path
     */
    private function recursive_delete($dir) {
        if (!is_dir($dir)) {
            return;
        }

        $files = array_diff(scandir($dir), array('.', '..'));

        foreach ($files as $file) {
            $path = $dir . '/' . $file;
            if (is_dir($path)) {
                $this->recursive_delete($path);
            } else {
                unlink($path);
            }
        }

        rmdir($dir);
    }

    /**
     * Get media for a listing (legacy compatibility)
     *
     * @param string $listing_key Listing key
     * @return array Media records
     */
    public function get_listing_media($listing_key) {
        global $wpdb;

        return $wpdb->get_results($wpdb->prepare(
            "SELECT * FROM {$this->db->media_table()}
             WHERE listing_key = %s
             ORDER BY media_order ASC",
            $listing_key
        ));
    }

    /**
     * Check if a media URL has expired
     *
     * MLS Grid media URLs contain an 'expires' parameter with Unix timestamp.
     * Returns true if the URL is expired or will expire within the buffer time.
     *
     * @param string $media_url The media URL to check
     * @param int $buffer_seconds Buffer time before actual expiration (default: 300 = 5 min)
     * @return bool True if expired or expiring soon
     */
    public function is_url_expired($media_url, $buffer_seconds = 300) {
        if (empty($media_url)) {
            return true;
        }

        // Extract expires parameter from URL
        if (preg_match('/expires=(\d+)/', $media_url, $matches)) {
            $expires = (int) $matches[1];
            return (time() + $buffer_seconds) >= $expires;
        }

        // If no expires param found, assume expired to be safe
        return true;
    }

    /**
     * Refresh media URLs for a listing from the API
     *
     * Fetches fresh media data from MLS Grid and updates the database.
     * This is used when cached URLs have expired.
     *
     * Note: MLS Grid API only allows filtering by ListingId, not ListingKey.
     * This method looks up the listing_id from the local database first.
     *
     * @param string $listing_key Listing key
     * @return bool True on success, false on failure
     */
    public function refresh_media_urls($listing_key) {
        global $wpdb;

        $plugin = mls_plugin();
        $api_client = $plugin->get_api_client();

        // Look up listing_id from database (MLS Grid API requires ListingId for filtering)
        $listing_id = $wpdb->get_var($wpdb->prepare(
            "SELECT listing_id FROM {$this->db->properties_table()} WHERE listing_key = %s",
            $listing_key
        ));

        if (!$listing_id) {
            $this->logger->warning('Cannot refresh media: listing_id not found', array(
                'listing_key' => $listing_key,
            ));
            return false;
        }

        // Fetch property with media from API using ListingId
        $property = $api_client->get_property_media($listing_id);

        if (is_wp_error($property) || !$property) {
            $this->logger->warning('Failed to refresh media URLs', array(
                'listing_key' => $listing_key,
                'listing_id' => $listing_id,
                'error' => is_wp_error($property) ? $property->get_error_message() : 'Property not found',
            ));
            return false;
        }

        // Update media records with fresh URLs
        if (isset($property['Media']) && is_array($property['Media'])) {
            $this->sync_property_media($listing_key, $property['Media']);
            $this->logger->debug('Refreshed media URLs', array(
                'listing_key' => $listing_key,
                'media_count' => count($property['Media']),
            ));
            return true;
        }

        return false;
    }

    /**
     * Clean up orphaned media files (files without database records)
     *
     * @return int Number of directories deleted
     */
    public function cleanup_orphaned_files() {
        global $wpdb;

        $deleted = 0;
        $base_dir = $this->get_upload_dir();

        if (!is_dir($base_dir)) {
            return 0;
        }

        foreach (scandir($base_dir) as $prefix) {
            if ($prefix === '.' || $prefix === '..' || !is_dir($base_dir . '/' . $prefix)) {
                continue;
            }

            $prefix_dir = $base_dir . '/' . $prefix;

            foreach (scandir($prefix_dir) as $listing_key) {
                if ($listing_key === '.' || $listing_key === '..') {
                    continue;
                }

                $listing_dir = $prefix_dir . '/' . $listing_key;
                if (!is_dir($listing_dir)) {
                    continue;
                }

                $exists = $wpdb->get_var($wpdb->prepare(
                    "SELECT COUNT(*) FROM {$this->db->properties_table()} WHERE listing_key = %s",
                    $listing_key
                ));

                if (!$exists) {
                    $this->recursive_delete($listing_dir);
                    $deleted++;
                }
            }
        }

        return $deleted;
    }

    /**
     * Get cache statistics
     *
     * @return array Cache stats
     */
    public function get_cache_stats() {
        global $wpdb;

        return array(
            'total_media' => (int) $wpdb->get_var(
                "SELECT COUNT(*) FROM {$this->db->media_table()}"
            ),
            'cached' => (int) $wpdb->get_var(
                "SELECT COUNT(*) FROM {$this->db->media_table()} WHERE local_url IS NOT NULL"
            ),
            'uncached' => (int) $wpdb->get_var(
                "SELECT COUNT(*) FROM {$this->db->media_table()} WHERE local_url IS NULL"
            ),
        );
    }

    /**
     * Get path to missing media log file (legacy compatibility)
     *
     * @return string File path
     */
    public function get_missing_log_path() {
        $upload_dir = wp_upload_dir();
        return $upload_dir['basedir'] . '/mls-missing-media.log';
    }

    /**
     * Get missing media count (legacy compatibility)
     *
     * @return int
     */
    public function get_missing_count() {
        $log_file = $this->get_missing_log_path();
        if (!file_exists($log_file)) {
            return 0;
        }
        $content = file_get_contents($log_file);
        return substr_count($content, "\n");
    }

    /**
     * Clear missing log (legacy compatibility)
     */
    public function clear_missing_log() {
        $log_file = $this->get_missing_log_path();
        if (file_exists($log_file)) {
            unlink($log_file);
        }
    }
}