<?php
/**
 * WordPress Error API.
 *
 * Contains the WP_Error class and the is_wp_error() function.
 *
 * @package WordPress
 */

/**
 * WordPress Error class.
 *
 * Container for checking for WordPress errors and error messages. Return
 * WP_Error and use is_wp_error() to check if this class is returned. Many
 * core WordPress functions pass this class in the event of an error and
 * if not handled properly will result in code errors.
 *
 * @package WordPress
 * @since 2.1.0
 */
class WP_Error {
    /**
     * Stores the list of errors.
     *
     * @since 2.1.0
     * @var array
     */
    public $errors = array();

    /**
     * Stores the list of data for error codes.
     *
     * @since 2.1.0
     * @var array
     */
    public $error_data = array();

    /**
     * Initialize the error.
     *
     * If `$code` is empty, the other parameters will be ignored.
     * When `$code` is not empty, `$message` will be used even if
     * it is empty. The `$data` parameter will be used only if it
     * is not empty.
     *
     * Though the class is constructed with a single error code and
     * message, multiple codes can be added using the `add()` method.
     *
     * @since 2.1.0
     *
     * @param string|int $code Error code
     * @param string $message Error message
     * @param mixed $data Optional. Error data.
     */
    public function __construct( $code = '', $message = '', $data = '' ) {
        if ( empty($code) )
            return;

        $this->errors[$code][] = $message;

        if ( ! empty($data) )
            $this->error_data[$code] = $data;
    }

    /**
     * Retrieve all error codes.
     *
     * @since 2.1.0
     * @access public
     *
     * @return array List of error codes, if available.
     */
    public function get_error_codes() {
        if ( empty($this->errors) )
            return array();

        return array_keys($this->errors);
    }

    /**
     * Retrieve first error code available.
     *
     * @since 2.1.0
     * @access public
     *
     * @return string|int Empty string, if no error codes.
     */
    public function get_error_code() {
        $codes = $this->get_error_codes();

        if ( empty($codes) )
            return '';

        return $codes[0];
    }

    /**
     * Retrieve all error messages or error messages matching code.
     *
     * @since 2.1.0
     *
     * @param string|int $code Optional. Retrieve messages matching code, if exists.
     * @return array Error strings on success, or empty array on failure (if using code parameter).
     */
    public function get_error_messages($code = '') {
        // Return all messages if no code specified.
        if ( empty($code) ) {
            $all_messages = array();
            foreach ( (array) $this->errors as $code => $messages )
                $all_messages = array_merge($all_messages, $messages);

            return $all_messages;
        }

        if ( isset($this->errors[$code]) )
            return $this->errors[$code];
        else
            return array();
    }

    /**
     * Get single error message.
     *
     * This will get the first message available for the code. If no code is
     * given then the first code available will be used.
     *
     * @since 2.1.0
     *
     * @param string|int $code Optional. Error code to retrieve message.
     * @return string
     */
    public function get_error_message($code = '') {
        if ( empty($code) )
            $code = $this->get_error_code();
        $messages = $this->get_error_messages($code);
        if ( empty($messages) )
            return '';
        return $messages[0];
    }

    /**
     * Retrieve error data for error code.
     *
     * @since 2.1.0
     *
     * @param string|int $code Optional. Error code.
     * @return mixed Error data, if it exists.
     */
    public function get_error_data($code = '') {
        if ( empty($code) )
            $code = $this->get_error_code();

        if ( isset($this->error_data[$code]) )
            return $this->error_data[$code];
    }

    /**
     * Add an error or append additional message to an existing error.
     *
     * @since 2.1.0
     * @access public
     *
     * @param string|int $code Error code.
     * @param string $message Error message.
     * @param mixed $data Optional. Error data.
     */
    public function add($code, $message, $data = '') {
        $this->errors[$code][] = $message;
        if ( ! empty($data) )
            $this->error_data[$code] = $data;
    }

    /**
     * Add data for error code.
     *
     * The error code can only contain one error data.
     *
     * @since 2.1.0
     *
     * @param mixed $data Error data.
     * @param string|int $code Error code.
     */
    public function add_data($data, $code = '') {
        if ( empty($code) )
            $code = $this->get_error_code();

        $this->error_data[$code] = $data;
    }

    /**
     * Removes the specified error.
     *
     * This function removes all error messages associated with the specified
     * error code, along with any error data for that code.
     *
     * @since 4.1.0
     *
     * @param string|int $code Error code.
     */
    public function remove( $code ) {
        unset( $this->errors[ $code ] );
        unset( $this->error_data[ $code ] );
    }
}