<?php
/**
 * Logger class for WooCommerce Business Central Integration
 *
 * @package WooBusinessCentral
 */

// Prevent direct access
if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

/**
 * Class WBC_Logger
 *
 * Handles logging to database with different severity levels.
 */
class WBC_Logger {

    /**
     * Log level constants
     */
    const DEBUG   = 'DEBUG';
    const INFO    = 'INFO';
    const WARNING = 'WARNING';
    const ERROR   = 'ERROR';

    /**
     * Database table name
     *
     * @var string
     */
    private static $table_name = null;

    /**
     * Create the logs database table
     */
    public static function create_table() {
        global $wpdb;

        $table_name = $wpdb->prefix . 'wbc_logs';
        $charset_collate = $wpdb->get_charset_collate();

        $sql = "CREATE TABLE IF NOT EXISTS $table_name (
            id bigint(20) NOT NULL AUTO_INCREMENT,
            timestamp datetime DEFAULT CURRENT_TIMESTAMP NOT NULL,
            level varchar(20) NOT NULL,
            context varchar(100) NOT NULL,
            message text NOT NULL,
            data longtext,
            PRIMARY KEY (id),
            KEY level (level),
            KEY context (context),
            KEY timestamp (timestamp)
        ) $charset_collate;";

        require_once ABSPATH . 'wp-admin/includes/upgrade.php';
        dbDelta( $sql );
    }

    /**
     * Get the table name
     *
     * @return string
     */
    private static function get_table_name() {
        if ( self::$table_name === null ) {
            global $wpdb;
            self::$table_name = $wpdb->prefix . 'wbc_logs';
        }
        return self::$table_name;
    }

    /**
     * Log a debug message
     *
     * @param string $context The context/source of the log.
     * @param string $message The log message.
     * @param mixed  $data    Optional. Additional data to log.
     */
    public static function debug( $context, $message, $data = null ) {
        self::log( self::DEBUG, $context, $message, $data );
    }

    /**
     * Log an info message
     *
     * @param string $context The context/source of the log.
     * @param string $message The log message.
     * @param mixed  $data    Optional. Additional data to log.
     */
    public static function info( $context, $message, $data = null ) {
        self::log( self::INFO, $context, $message, $data );
    }

    /**
     * Log a warning message
     *
     * @param string $context The context/source of the log.
     * @param string $message The log message.
     * @param mixed  $data    Optional. Additional data to log.
     */
    public static function warning( $context, $message, $data = null ) {
        self::log( self::WARNING, $context, $message, $data );
    }

    /**
     * Log an error message
     *
     * @param string $context The context/source of the log.
     * @param string $message The log message.
     * @param mixed  $data    Optional. Additional data to log.
     */
    public static function error( $context, $message, $data = null ) {
        self::log( self::ERROR, $context, $message, $data );
    }

    /**
     * Log a message to the database
     *
     * @param string $level   The log level.
     * @param string $context The context/source of the log.
     * @param string $message The log message.
     * @param mixed  $data    Optional. Additional data to log.
     */
    private static function log( $level, $context, $message, $data = null ) {
        global $wpdb;

        $table_name = self::get_table_name();

        // Prepare data for storage
        $data_json = null;
        if ( $data !== null ) {
            $data_json = wp_json_encode( $data, JSON_PRETTY_PRINT );
        }

        // Insert log entry
        $wpdb->insert(
            $table_name,
            array(
                'timestamp' => current_time( 'mysql' ),
                'level'     => $level,
                'context'   => sanitize_text_field( $context ),
                'message'   => sanitize_textarea_field( $message ),
                'data'      => $data_json,
            ),
            array( '%s', '%s', '%s', '%s', '%s' )
        );

        // Also log to WooCommerce logger if available
        if ( function_exists( 'wc_get_logger' ) ) {
            $wc_logger = wc_get_logger();
            $log_level = strtolower( $level );
            if ( method_exists( $wc_logger, $log_level ) ) {
                $wc_message = "[$context] $message";
                if ( $data !== null ) {
                    $wc_message .= ' | Data: ' . wp_json_encode( $data );
                }
                $wc_logger->$log_level( $wc_message, array( 'source' => 'woo-business-central' ) );
            }
        }
    }

    /**
     * Get log entries
     *
     * @param array $args Query arguments.
     * @return array Array of log entries.
     */
    public static function get_logs( $args = array() ) {
        global $wpdb;

        $defaults = array(
            'level'    => '',
            'context'  => '',
            'limit'    => 100,
            'offset'   => 0,
            'orderby'  => 'timestamp',
            'order'    => 'DESC',
        );

        $args = wp_parse_args( $args, $defaults );
        $table_name = self::get_table_name();

        // Build WHERE clause
        $where = array( '1=1' );
        $values = array();

        if ( ! empty( $args['level'] ) ) {
            $where[] = 'level = %s';
            $values[] = $args['level'];
        }

        if ( ! empty( $args['context'] ) ) {
            $where[] = 'context = %s';
            $values[] = $args['context'];
        }

        $where_clause = implode( ' AND ', $where );

        // Sanitize orderby and order
        $allowed_orderby = array( 'id', 'timestamp', 'level', 'context' );
        $orderby = in_array( $args['orderby'], $allowed_orderby, true ) ? $args['orderby'] : 'timestamp';
        $order = strtoupper( $args['order'] ) === 'ASC' ? 'ASC' : 'DESC';

        // Build query
        $limit = absint( $args['limit'] );
        $offset = absint( $args['offset'] );

        $sql = "SELECT * FROM $table_name WHERE $where_clause ORDER BY $orderby $order LIMIT $limit OFFSET $offset";

        if ( ! empty( $values ) ) {
            $sql = $wpdb->prepare( $sql, $values );
        }

        return $wpdb->get_results( $sql, ARRAY_A );
    }

    /**
     * Get total log count
     *
     * @param array $args Query arguments.
     * @return int Total count.
     */
    public static function get_log_count( $args = array() ) {
        global $wpdb;

        $table_name = self::get_table_name();

        // Build WHERE clause
        $where = array( '1=1' );
        $values = array();

        if ( ! empty( $args['level'] ) ) {
            $where[] = 'level = %s';
            $values[] = $args['level'];
        }

        if ( ! empty( $args['context'] ) ) {
            $where[] = 'context = %s';
            $values[] = $args['context'];
        }

        $where_clause = implode( ' AND ', $where );

        $sql = "SELECT COUNT(*) FROM $table_name WHERE $where_clause";

        if ( ! empty( $values ) ) {
            $sql = $wpdb->prepare( $sql, $values );
        }

        return (int) $wpdb->get_var( $sql );
    }

    /**
     * Clear all logs
     *
     * @return bool|int Number of rows deleted or false on error.
     */
    public static function clear_logs() {
        global $wpdb;
        $table_name = self::get_table_name();
        return $wpdb->query( "TRUNCATE TABLE $table_name" );
    }

    /**
     * Delete old logs
     *
     * @param int $days Number of days to keep logs.
     * @return int Number of rows deleted.
     */
    public static function cleanup_old_logs( $days = 30 ) {
        global $wpdb;

        $table_name = self::get_table_name();
        $cutoff_date = gmdate( 'Y-m-d H:i:s', strtotime( "-{$days} days" ) );

        return $wpdb->query(
            $wpdb->prepare(
                "DELETE FROM $table_name WHERE timestamp < %s",
                $cutoff_date
            )
        );
    }

    /**
     * Export logs to CSV format
     *
     * @param array $args Query arguments.
     * @return string CSV content.
     */
    public static function export_to_csv( $args = array() ) {
        $logs = self::get_logs( array_merge( $args, array( 'limit' => 10000 ) ) );

        $output = "ID,Timestamp,Level,Context,Message,Data\n";

        foreach ( $logs as $log ) {
            $row = array(
                $log['id'],
                $log['timestamp'],
                $log['level'],
                self::sanitize_csv_field( $log['context'] ),
                self::sanitize_csv_field( $log['message'] ),
                self::sanitize_csv_field( $log['data'] ?? '' ),
            );
            $output .= implode( ',', $row ) . "\n";
        }

        return $output;
    }

    /**
     * Sanitize a field value for CSV export to prevent formula injection
     *
     * @param string $value The value to sanitize.
     * @return string Sanitized and quoted CSV value.
     */
    private static function sanitize_csv_field( $value ) {
        // Prevent formula injection by prefixing dangerous characters with a single quote
        if ( preg_match( '/^[=+\-@\t\r]/', $value ) ) {
            $value = "'" . $value;
        }
        return '"' . str_replace( '"', '""', $value ) . '"';
    }
}