<?php

/**
 * Custom Ninja Forms Field Validation
 *
 * This controller is used to for server-side custom sanitization/validation of
 * user-submitted data.
 *
 * @psalm-type NFFieldError array{slug: string, message: string}|string
 */
class FieldValidationController
{
    public const VALIDATING_FIELD = 'custom_validation_validating';
    public const INVALID_FIELD    = 'custom_validation_field_invalid';

    public function boot() : void
    {
        add_filter( 'ninja_forms/custom_validation/submit_data/validate_field', [ $this, 'filter_field_validation' ], 10, 3 );

        add_filter( 'ninja_forms_display_form_settings', [ $this, 'filter_ninja_forms_display_form_settings' ], 10, 2 );
        add_filter( 'ninja_forms_field_settings',        [ $this, 'filter_ninja_forms_field_settings' ] );
        add_filter( 'ninja_forms_field_load_settings',   [ $this, 'filter_ninja_forms_field_load_settings' ], 10, 3 );
        add_filter( 'ninja_forms_form_display_settings', [ $this, 'filter_ninja_forms_form_display_settings' ] );
        add_filter( 'ninja_forms_submit_data',           [ $this, 'filter_ninja_forms_submit_data' ] );

        add_action( 'init',                       [ $this, 'action_init' ] );
        add_action( 'nf_display_enqueue_scripts', [ $this, 'enqueue_front_assets' ] );
    }

    /**
     * @listens action:init
     */
    public function action_init() : void {
        $this->register_front_assets();
    }

    /**
     * Enqueues the front-end styles and scripts.
     *
     * @listens action:nf_display_enqueue_scripts
     */
    public function enqueue_front_assets() : void {
        wp_enqueue_script( 'nf-custom-validation' );
    }

    /**
     * Adds custom field settings to the pool of all field settings in Ninja Forms.
     *
     * @listens filter:ninja_forms_field_settings
     *
     * @param  array<string, array<string, mixed>> $settings The field settings.
     * @return array<string, array<string, mixed>>
     */
    public function filter_ninja_forms_field_settings( array $settings ) : array {
        return $settings + $this->get_validation_field_settings();
    }

    /**
     * Adds custom field settings to a given field in Ninja Forms.
     *
     * @listens filter:ninja_forms_field_load_settings
     *
     * @param  array<string, array<string, mixed>> $settings    The field settings.
     * @param  string                              $field_type  The field type.
     * @param  string                              $parent_type The parent field type.
     * @return array<string, array<string, mixed>>
     */
    public function filter_ninja_forms_field_load_settings( array $settings, string $field_type, string $parent_type ) : array {
        if ( ! in_array( $field_type, [ 'textbox' ], true ) ) {
            return $settings;
        }

        return $settings + $this->get_validation_field_settings();
    }

    /**
     * Adds custom labeling settings to the pool of all form settings in Ninja Forms.
     *
     * @listens filter:ninja_forms_form_display_settings
     *
     * @param  array<string, array<string, mixed>> $settings The form settings.
     * @return array<string, array<string, mixed>>
     */
    public function filter_ninja_forms_form_display_settings( array $settings ) : array {
        return $settings + $this->get_validation_form_settings();
    }

    /**
     * Adds any custom labels to form settings in Ninja Forms.
     *
     * @listens filter:ninja_forms_display_form_settings
     *
     * @param  array<string, array<string, mixed>> $settings The form settings.
     * @param  int|string                          $form_id  The form ID.
     * @return array<string, array<string, mixed>>
     */
    public function filter_ninja_forms_display_form_settings( array $settings, $form_id ) : array {
        foreach ( $this->retrieve_error_messages() as $name => $label ) {
            if ( empty( $settings[ $name ] ) ) {
                $settings[ $name ] = $label;
            }
        }

        return $settings;
    }

    /**
     * Adds a field validation hooks for submitted data in Ninja Forms.
     *
     * Portions of this method are copied from {@see \NF_AJAX_Controllers_Submission::process()}
     * and {@see \NF_AJAX_Controllers_Submission::submit()} since there no convenient field hooks
     * nor proper handling of form validation clean-up (renewing the nonce).
     *
     * The extra hook is needed to avoid duplicating the iteration and avoid multiple
     * iterations of the fields.
     *
     * @listens filter:ninja_forms_submit_data
     * @fires   filter:ninja_forms/custom_validation/submit_data/validate_field
     *
     * @param  array<string, array<string, mixed>> $form_data The form submission data.
     * @return array<string, array<string, mixed>>
     */
    public function filter_ninja_forms_submit_data( array $form_data ) : array {
        if ( empty( $form_data['id'] ) || ! is_numeric( $form_data['id'] ) ) {
            return $form_data;
        }

        // $form = Ninja_Forms()->form( $form_data['id'] )->get();
        $form_fields = Ninja_Forms()->form( $form_data['id'] )->get_fields();
        if ( ! is_iterable( $form_fields ) ) {
            return $form_data;
        }

        foreach ( $form_fields as $field_id => $field ) {
            if ( is_object( $field ) ) {
                $field_data = [
                    'id'       => $field->get_id(),
                    'settings' => $field->get_settings(),
                ];
            }

            $field_data['settings']['id']    = $field_id;
            $field_data['settings']['value'] = ( $form_data['fields'][ $field_id ]['value'] ?? '' );

            $field_data = array_merge( $field_data, $field_data['settings'] );

            /**
             * Filters the field validation error array.
             *
             * @event filter:ninja_forms/custom_validation/submit_data/validate_field
             *
             * @param NFFieldError|null    $field_errors The field errors.
             * @param array<string, mixed> $field_data   The field settings.
             * @param array<string, mixed> $form_data    The form submission data.
             */
            $field_errors = apply_filters( 'ninja_forms/custom_validation/submit_data/validate_field', null, $field_data, $form_data );
            if ( $field_errors ) {
                $form_data['errors']['fields'][ $field_id ] = $field_errors;
            }
        }

        return $form_data;
    }

    /**
     * Validates the submitted field value against any custom field settings in Ninja Forms.
     *
     * @listens filter:ninja_forms/custom_validation/submit_data/validate_field
     *
     * @param  NFFieldError|null    $field_errors The field errors.
     * @param  array<string, mixed> $field_data   The field settings.
     * @param  array<string, mixed> $form_data    The form submission data.
     * @return NFFieldError|null
     */
    public function filter_field_validation( array|string|null $field_errors, array $field_data, array $form_data ) : array|string|null {
        if ( empty( $field_data['settings']['custom_validation'] ) ) {
            return $field_errors;
        }

        $validator = $field_data['settings']['custom_validation'];
        $validator = "validate_{$validator}_field";

        if ( ! method_exists( $this, $validator ) ) {
            return $field_errors;
        }

        $options = [];

        $errors = $this->{$validator}( $field_data, $form_data, $options );
        if ( ! $errors ) {
            return $field_errors;
        }

        return $errors;
    }
    /**
     * Returns an associative array of error strings from the given error
     * constants.
     *
     * @param  ?(list<string>|array<string, mixed>) $codes The error codes to retrieve.
     *     If NULL, return all messages.
     * @return array<string, string> An array of messages keyed
     *     by their error constant values.
     */
    public function get_error_messages( ?array $codes = null ) : array {
        /**
         * Map of error codes and friendly messages.
         */
        static $errors = null;

        $errors ??= $this->retrieve_error_messages();

        if ( is_null( $codes ) ) {
            return $errors;
        }

        $messages = [];

        if ( array_is_list( $codes ) ) {
            foreach ( $codes as $code ) {
                if ( isset( $errors[ $code ] ) ) {
                    $messages[ $code ] = $errors[ $code ];
                }
            }
        } else {
            foreach ( $codes as $code => $details ) {
                if (
                    null === $details ||
                    false === $details ||
                    ! isset( $errors[ $code ] )
                ) {
                    continue;
                }

                if ( is_array( $details ) ) {
                    $details = array_map(
                        fn ( $detail ) => ( is_array( $detail )
                            ? implode( __( ', ' ), $detail )
                            : (string) $detail ),
                        $details
                    );

                    $messages[ $code ] = strtr( $errors[ $code ], $details );
                } else {
                    $messages[ $code ] = $errors[ $code ];
                }
            }
        }

        return $messages;
    }

    /**
     * Retrieves custom validation field settings to Ninja Forms.
     *
     * @return array<string, array<string, mixed>>
     */
    public function get_validation_field_settings() : array {
        return [
            'custom_validation' => [
                'name'    => 'custom_validation',
                'type'    => 'select',
                'label'   => esc_html__( 'Input Validation', 'nf-custom-validation' ),
                'width'   => 'one-half',
                'group'   => 'restrictions',
                'value'   => '',
                'options' => [
                    [
                        'label' => '-- ' . esc_html__( 'None', 'nf-custom-validation' ) . ' --',
                        'value' => '',
                    ],
                    [
                        'label' => esc_html_x( 'Example', 'validation type', 'nf-custom-validation' ),
                        'value' => 'example',
                    ],
                ],
            ],
        ];
    }

    /**
     * Retrieves custom validation form settings to Ninja Forms.
     *
     * @return array<string, array<string, mixed>>
     */
    public function get_validation_form_settings() : array {
        $custom_settings = [];

        foreach ( $this->retrieve_error_messages() as $name => $label ) {
            $label_setting = [
                'name'  => $name,
                'type'  => 'textbox',
                'label' => esc_html( $label ),
                'width' => 'full',
            ];

            $custom_settings[] = $label_setting;
        }

        return [
            'custom_validation_messages' => [
                'name'     => 'custom_validation_messages',
                'type'     => 'fieldset',
                'label'    => esc_html__( 'Custom Validation Labels', 'nf-custom-validation' ),
                'width'    => 'full',
                'group'    => 'advanced',
                'settings' => $custom_settings,
            ],
        ];
    }

    /**
     * Registers the front-end styles and scripts.
     */
    public function register_front_assets() : void {
        wp_register_script(
            'nf-custom-validation',
            plugin_dir_url( __FILE__ ) . 'resources/scripts/nf-validation.js',
            [
                'nf-front-end-deps',
            ]
        );
    }

    /**
     * Returns an associative array of error strings from the given error
     * constants.
     *
     * @return array<string, string>
     */
    public function retrieve_error_messages() : array {
        $messages = [
            static::VALIDATING_FIELD => _x( 'Validating…', 'form validation', 'nf-custom-validation' ),
            static::INVALID_FIELD    => _x( 'Please enter a valid value.', 'form validation', 'nf-custom-validation' ),
        ];

        return $messages;
    }

    /**
     * Performs the expensive/remote validation.
     *
     * @param  array<string, mixed> $field_data The field to validate.
     * @param  array<string, mixed> $form_data  The form submission data.
     * @param  array<string, bool>  $options    Validation options.
     * @return NFFieldError|null
     */
    public function validate_example_field( array $field_data, array $form_data, array $options = [] ) : array|string|null {
        /**
         * EXPENSIVE/REMOTE VALIDATION DONE HERE
         * 
         * THIS EXAMPLE IS INCOMPLETE
         */
        $valid = $response = wp_remote_get( 'https://example.com/', [
            'body' => $field_data['value'],
        ] );

        if ( ! $valid ) {
            if ( ! $errors ) {
                $messages = $this->get_error_messages();

                return [
                    'slug'    => static::INVALID_FIELD,
                    'message' => $messages[ static::INVALID_FIELD ],
                ];
            }

            $messages = $this->get_error_messages( array_slice( $errors, 0, 1, true ) );

            return [
                'slug'    => static::INVALID_FIELD,
                'message' => $messages[ array_key_first( $messages ) ],
            ];
        }

        return null;
    }
}