<?php
/**
 * Database handler class
 */

if (!defined('ABSPATH')) {
    exit;
}

class MLS_DB {

    /**
     * Schema version for index migrations
     * Increment this when adding new indexes
     */
    const SCHEMA_VERSION = 2;

    /**
     * Get table name with prefix
     *
     * @param string $table Table name constant
     * @return string Full table name
     */
    public function get_table_name($table) {
        global $wpdb;
        return $wpdb->prefix . $table;
    }

    /**
     * Get properties table name
     */
    public function properties_table() {
        return $this->get_table_name(MLS_TABLE_PROPERTIES);
    }

    /**
     * Get media table name
     */
    public function media_table() {
        return $this->get_table_name(MLS_TABLE_MEDIA);
    }

    /**
     * Get sync state table name
     */
    public function sync_state_table() {
        return $this->get_table_name(MLS_TABLE_SYNC_STATE);
    }

    /**
     * Get rate limits table name
     */
    public function rate_limits_table() {
        return $this->get_table_name(MLS_TABLE_RATE_LIMITS);
    }

    /**
     * Get sync log table name
     */
    public function sync_log_table() {
        return $this->get_table_name(MLS_TABLE_SYNC_LOG);
    }

    /**
     * Get media log table name
     */
    public function media_log_table() {
        return $this->get_table_name(MLS_TABLE_MEDIA_LOG);
    }

    /**
     * Create all database tables
     */
    public static function create_tables() {
        global $wpdb;

        $charset_collate = $wpdb->get_charset_collate();

        require_once ABSPATH . 'wp-admin/includes/upgrade.php';

        // Properties table
        $table_properties = $wpdb->prefix . MLS_TABLE_PROPERTIES;
        $sql_properties = "CREATE TABLE {$table_properties} (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            listing_key VARCHAR(50) NOT NULL,
            listing_id VARCHAR(50) NOT NULL,
            originating_system VARCHAR(50) DEFAULT 'northstar',

            standard_status VARCHAR(30) NOT NULL,
            mls_status VARCHAR(50) DEFAULT NULL,
            mlg_can_view TINYINT(1) DEFAULT 1,

            list_price DECIMAL(15,2) DEFAULT NULL,
            original_list_price DECIMAL(15,2) DEFAULT NULL,
            close_price DECIMAL(15,2) DEFAULT NULL,

            street_number VARCHAR(20) DEFAULT NULL,
            street_name VARCHAR(100) DEFAULT NULL,
            street_suffix VARCHAR(30) DEFAULT NULL,
            unit_number VARCHAR(20) DEFAULT NULL,
            city VARCHAR(100) NOT NULL,
            state_or_province VARCHAR(50) DEFAULT 'MN',
            postal_code VARCHAR(20) DEFAULT NULL,
            county VARCHAR(100) DEFAULT NULL,
            latitude DECIMAL(10,8) DEFAULT NULL,
            longitude DECIMAL(11,8) DEFAULT NULL,

            property_type VARCHAR(50) DEFAULT NULL,
            property_sub_type VARCHAR(50) DEFAULT NULL,
            bedrooms_total INT(3) DEFAULT NULL,
            bathrooms_total DECIMAL(4,1) DEFAULT NULL,
            bathrooms_full INT(3) DEFAULT NULL,
            bathrooms_half INT(3) DEFAULT NULL,
            living_area INT(10) DEFAULT NULL,
            lot_size_area DECIMAL(12,4) DEFAULT NULL,
            lot_size_units VARCHAR(20) DEFAULT NULL,
            year_built INT(4) DEFAULT NULL,
            garage_spaces INT(3) DEFAULT NULL,

            public_remarks TEXT DEFAULT NULL,
            directions TEXT DEFAULT NULL,

            list_agent_key VARCHAR(50) DEFAULT NULL,
            list_agent_mls_id VARCHAR(50) DEFAULT NULL,
            list_agent_name VARCHAR(150) DEFAULT NULL,
            list_office_key VARCHAR(50) DEFAULT NULL,
            list_office_mls_id VARCHAR(50) DEFAULT NULL,
            list_office_name VARCHAR(150) DEFAULT NULL,

            photos_count INT(5) DEFAULT 0,
            modification_timestamp DATETIME NOT NULL,
            photos_change_timestamp DATETIME DEFAULT NULL,
            listing_contract_date DATE DEFAULT NULL,
            close_date DATE DEFAULT NULL,
            days_on_market INT(5) DEFAULT NULL,

            raw_data LONGTEXT DEFAULT NULL,

            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
            updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

            PRIMARY KEY (id),
            UNIQUE KEY listing_key (listing_key),
            KEY listing_id (listing_id),
            KEY standard_status (standard_status),
            KEY city (city),
            KEY property_type (property_type),
            KEY modification_timestamp (modification_timestamp),
            KEY list_price (list_price),
            KEY mlg_can_view (mlg_can_view),
            KEY bedrooms_total (bedrooms_total),
            KEY county (county)
        ) {$charset_collate};";

        dbDelta($sql_properties);

        // Media table
        $table_media = $wpdb->prefix . MLS_TABLE_MEDIA;
        $sql_media = "CREATE TABLE {$table_media} (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            listing_key VARCHAR(50) NOT NULL,
            media_key VARCHAR(100) NOT NULL,

            media_type VARCHAR(30) DEFAULT 'Photo',
            media_order INT(5) DEFAULT 0,
            media_url VARCHAR(1000) DEFAULT NULL,

            local_path VARCHAR(500) DEFAULT NULL,
            local_url VARCHAR(500) DEFAULT NULL,
            file_size INT(11) DEFAULT NULL,
            mime_type VARCHAR(50) DEFAULT NULL,
            image_width INT(5) DEFAULT NULL,
            image_height INT(5) DEFAULT NULL,

            media_modification_timestamp DATETIME DEFAULT NULL,
            downloaded_at DATETIME DEFAULT NULL,
            download_attempts INT(3) DEFAULT 0,
            download_error TEXT DEFAULT NULL,
            retry_after DATETIME DEFAULT NULL,
            queued_at DATETIME DEFAULT NULL,
            download_status VARCHAR(20) DEFAULT 'pending',

            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
            updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

            PRIMARY KEY (id),
            UNIQUE KEY listing_media (listing_key, media_key),
            KEY listing_key (listing_key),
            KEY media_order (media_order),
            KEY download_status (download_status),
            KEY retry_after (retry_after),
            KEY queued_at (queued_at)
        ) {$charset_collate};";

        dbDelta($sql_media);

        // Sync state table
        $table_sync_state = $wpdb->prefix . MLS_TABLE_SYNC_STATE;
        $sql_sync_state = "CREATE TABLE {$table_sync_state} (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            sync_type VARCHAR(30) NOT NULL,
            entity_type VARCHAR(30) NOT NULL DEFAULT 'Property',

            status VARCHAR(20) DEFAULT 'pending',
            started_at DATETIME DEFAULT NULL,
            completed_at DATETIME DEFAULT NULL,

            last_modification_timestamp DATETIME DEFAULT NULL,
            last_next_link VARCHAR(2000) DEFAULT NULL,
            records_processed INT(11) DEFAULT 0,
            records_created INT(11) DEFAULT 0,
            records_updated INT(11) DEFAULT 0,
            records_deleted INT(11) DEFAULT 0,

            error_count INT(11) DEFAULT 0,
            last_error TEXT DEFAULT NULL,

            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
            updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

            PRIMARY KEY (id),
            KEY sync_type_entity (sync_type, entity_type),
            KEY status (status)
        ) {$charset_collate};";

        dbDelta($sql_sync_state);

        // Rate limits table
        $table_rate_limits = $wpdb->prefix . MLS_TABLE_RATE_LIMITS;
        $sql_rate_limits = "CREATE TABLE {$table_rate_limits} (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            window_type VARCHAR(20) NOT NULL,
            window_start DATETIME NOT NULL,
            request_count INT(11) DEFAULT 0,
            bytes_transferred BIGINT(20) DEFAULT 0,

            PRIMARY KEY (id),
            UNIQUE KEY window_type_start (window_type, window_start),
            KEY window_start (window_start)
        ) {$charset_collate};";

        dbDelta($sql_rate_limits);

        // Sync log table
        $table_sync_log = $wpdb->prefix . MLS_TABLE_SYNC_LOG;
        $sql_sync_log = "CREATE TABLE {$table_sync_log} (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            sync_state_id BIGINT(20) UNSIGNED DEFAULT NULL,
            level VARCHAR(20) DEFAULT 'info',
            message TEXT NOT NULL,
            context LONGTEXT DEFAULT NULL,
            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,

            PRIMARY KEY (id),
            KEY sync_state_id (sync_state_id),
            KEY level (level),
            KEY created_at (created_at)
        ) {$charset_collate};";

        dbDelta($sql_sync_log);

        // Media download log table
        $table_media_log = $wpdb->prefix . MLS_TABLE_MEDIA_LOG;
        $sql_media_log = "CREATE TABLE {$table_media_log} (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            media_id BIGINT(20) UNSIGNED NOT NULL,
            listing_key VARCHAR(50) NOT NULL,
            media_key VARCHAR(100) NOT NULL,
            action VARCHAR(30) NOT NULL,
            status_code INT(5) DEFAULT NULL,
            response_time_ms INT(11) DEFAULT NULL,
            error_message TEXT DEFAULT NULL,
            url VARCHAR(1000) DEFAULT NULL,
            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,

            PRIMARY KEY (id),
            KEY media_id (media_id),
            KEY listing_key (listing_key),
            KEY action (action),
            KEY created_at (created_at)
        ) {$charset_collate};";

        dbDelta($sql_media_log);

        // Run index migrations
        self::run_index_migrations();
    }

    /**
     * Run index migrations that dbDelta cannot handle
     *
     * dbDelta can create tables and add columns, but cannot add indexes
     * to existing tables. This method handles incremental index additions.
     */
    public static function run_index_migrations() {
        global $wpdb;

        $current_schema = (int) get_option('mls_schema_version', 1);

        // Migration to schema version 2: Add search and geo indexes
        if ($current_schema < 2) {
            $table_properties = $wpdb->prefix . MLS_TABLE_PROPERTIES;
            $table_media = $wpdb->prefix . MLS_TABLE_MEDIA;

            // Check and add indexes only if they don't exist
            $existing_indexes = self::get_existing_indexes($table_properties);

            // Geospatial indexes for bounding box queries
            if (!isset($existing_indexes['idx_latitude'])) {
                $wpdb->query("ALTER TABLE {$table_properties} ADD INDEX idx_latitude (latitude)");
            }
            if (!isset($existing_indexes['idx_longitude'])) {
                $wpdb->query("ALTER TABLE {$table_properties} ADD INDEX idx_longitude (longitude)");
            }

            // Composite index for common search pattern (status + city + price)
            if (!isset($existing_indexes['idx_status_city_price'])) {
                $wpdb->query("ALTER TABLE {$table_properties} ADD INDEX idx_status_city_price (standard_status, city, list_price)");
            }

            // Composite index for status + property_type searches
            if (!isset($existing_indexes['idx_status_type'])) {
                $wpdb->query("ALTER TABLE {$table_properties} ADD INDEX idx_status_type (standard_status, property_type)");
            }

            // Media table: composite index for listing + order (eliminates filesort)
            $media_indexes = self::get_existing_indexes($table_media);
            if (!isset($media_indexes['idx_listing_order'])) {
                $wpdb->query("ALTER TABLE {$table_media} ADD INDEX idx_listing_order (listing_key, media_order)");
            }

            update_option('mls_schema_version', 2);
        }

        // Future migrations go here:
        // if ($current_schema < 3) { ... }
    }

    /**
     * Get existing indexes for a table
     *
     * @param string $table Full table name
     * @return array Index names as keys
     */
    private static function get_existing_indexes($table) {
        global $wpdb;

        $indexes = array();
        $results = $wpdb->get_results("SHOW INDEX FROM {$table}");

        foreach ($results as $row) {
            $indexes[$row->Key_name] = true;
        }

        return $indexes;
    }

    /**
     * Drop all tables (for uninstall)
     */
    public static function drop_tables() {
        global $wpdb;

        $tables = array(
            MLS_TABLE_PROPERTIES,
            MLS_TABLE_MEDIA,
            MLS_TABLE_SYNC_STATE,
            MLS_TABLE_RATE_LIMITS,
            MLS_TABLE_SYNC_LOG,
            MLS_TABLE_MEDIA_LOG,
        );

        foreach ($tables as $table) {
            $table_name = $wpdb->prefix . $table;
            $wpdb->query("DROP TABLE IF EXISTS {$table_name}");
        }
    }

    /**
     * Truncate all data tables (keep structure)
     */
    public function truncate_data() {
        global $wpdb;

        $wpdb->query("TRUNCATE TABLE {$this->properties_table()}");
        $wpdb->query("TRUNCATE TABLE {$this->media_table()}");
        $wpdb->query("TRUNCATE TABLE {$this->sync_state_table()}");
        $wpdb->query("TRUNCATE TABLE {$this->sync_log_table()}");
    }

    /**
     * Get database statistics
     */
    public function get_stats() {
        global $wpdb;

        $stats = array(
            'total_properties' => 0,
            'active_properties' => 0,
            'pending_properties' => 0,
            'sold_properties' => 0,
            'total_media' => 0,
            'downloaded_media' => 0,
        );

        // Property counts
        $stats['total_properties'] = (int) $wpdb->get_var(
            "SELECT COUNT(*) FROM {$this->properties_table()} WHERE mlg_can_view = 1"
        );

        $status_counts = $wpdb->get_results(
            "SELECT standard_status, COUNT(*) as count
             FROM {$this->properties_table()}
             WHERE mlg_can_view = 1
             GROUP BY standard_status",
            OBJECT_K
        );

        if (isset($status_counts['Active'])) {
            $stats['active_properties'] = (int) $status_counts['Active']->count;
        }
        if (isset($status_counts['Pending'])) {
            $stats['pending_properties'] = (int) $status_counts['Pending']->count;
        }
        if (isset($status_counts['Closed']) || isset($status_counts['Sold'])) {
            $stats['sold_properties'] = (int) ($status_counts['Closed']->count ?? 0)
                                      + (int) ($status_counts['Sold']->count ?? 0);
        }

        // Media counts
        $stats['total_media'] = (int) $wpdb->get_var(
            "SELECT COUNT(*) FROM {$this->media_table()}"
        );

        $stats['downloaded_media'] = (int) $wpdb->get_var(
            "SELECT COUNT(*) FROM {$this->media_table()} WHERE local_path IS NOT NULL"
        );

        return $stats;
    }
}