<?php
namespace Formipay\Admin;

use Formipay\Traits\SingletonTrait;

if (!defined('ABSPATH')) exit;

/**
 * FieldConfigBridge - Transforms WPCFTO field config arrays to React-ready JSON
 *
 * Bridges the gap between PHP field configurations and the React FieldRenderer:
 * - Collects field configs from filter system
 * - Loads saved post meta / option values
 * - Transforms PHP config format to React-ready structure
 * - Handles dynamic currency field expansion
 * - Handles dependency transformation
 */
class FieldConfigBridge {

    use SingletonTrait;

    /**
     * Map CPT types to their filter names
     */
    private static $cpt_filter_map = [
        'formipay-coupon'  => 'formipay/coupon-config',
        'formipay-product' => 'formipay/product-config',
        'formipay-form'    => 'formipay/form-config',
        'formipay-access'  => 'formipay/access-config',
    ];

    /**
     * Get complete field configuration for a post with saved values
     *
     * @param int $post_id Post ID
     * @param string $post_type Post type
     * @return array React-ready field configuration
     */
    public static function get_config_for_post($post_id, $post_type) {
        $filter_name = self::$cpt_filter_map[$post_type] ?? null;

        if (!$filter_name) {
            return [];
        }

        // Get field configuration from filters
        $fields = apply_filters($filter_name, []);

        // Load saved values from post meta
        $values = self::load_post_meta_values($post_id, $fields);

        // Transform to React-ready format
        return self::transform_fields_config($fields, $values, $post_id, $post_type);
    }

    /**
     * Get configuration for settings page (wp_options based)
     *
     * @param string $option_name Option name
     * @return array React-ready field configuration
     */
    public static function get_config_for_settings($option_name = 'formipay_settings') {
        // Get settings values
        $settings = get_option($option_name, []);

        // Get field definitions directly from Settings class
        $settings_instance = \Formipay\Settings::get_instance();
        $tabs_config = $settings_instance->get_settings_fields();

        // Transform to React-ready format
        return self::transform_settings_config($settings, $tabs_config, $option_name);
    }

    /**
     * Transform settings config to React-ready format
     *
     * @param array $settings Settings values
     * @param array $tabs_config Tab configuration from Settings class
     * @param string $option_name Option name
     * @return array React-ready configuration
     */
    private static function transform_settings_config($settings, $tabs_config, $option_name) {
        $tabs = [];

        foreach ($tabs_config as $tab_key => $tab_data) {
            if (!isset($tab_data['name']) || !isset($tab_data['fields'])) {
                continue;
            }

            $tab = [
                'id' => self::slugify($tab_data['name']),
                'label' => $tab_data['name'],
                'fields' => [],
            ];

            $current_group = null;

            foreach ($tab_data['fields'] as $field_name => $field) {
                // Handle group_title (section headers)
                if (isset($field['type']) && $field['type'] === 'group_title') {
                    $group_value = $field['group'] ?? '';

                    if ($group_value === 'started') {
                        $current_group = [
                            'type' => 'section',
                            'label' => $field['label'] ?? '',
                            'description' => $field['description'] ?? '',
                        ];
                    } elseif ($group_value === 'ended') {
                        $current_group = null;
                    }
                    continue;
                }

                // Add section if we have one
                if ($current_group !== null) {
                    $tab['fields'][] = $current_group;
                    $current_group = null;
                }

                // Transform field configuration
                $transformed_field = self::transform_settings_field($field_name, $field, $settings);

                // Add to fields
                $tab['fields'][] = $transformed_field;
            }

            $tabs[] = $tab;
        }

        return [
            'tabs' => $tabs,
            'optionName' => $option_name,
            'globalCurrencies' => self::get_global_currencies_data(),
            'nonce' => wp_create_nonce('formipay-field-config'),
        ];
    }

    /**
     * Load saved post meta values for all fields
     *
     * @param int $post_id Post ID
     * @param array $fields Field configuration array
     * @return array Field values keyed by field name
     */
    private static function load_post_meta_values($post_id, $fields) {
        $values = [];

        // The config structure is: $fields['formipay_{cpt}_settings'][tab_key] = ['name' => ..., 'fields' => [...]]
        foreach ($fields as $container_key => $container_data) {
            if (!is_array($container_data)) {
                continue;
            }

            foreach ($container_data as $tab_key => $tab_data) {
                if (!isset($tab_data['fields']) || !is_array($tab_data['fields'])) {
                    continue;
                }

                foreach ($tab_data['fields'] as $field_name => $field) {
                    // Skip group_title fields
                    if (isset($field['type']) && $field['type'] === 'group_title') {
                        continue;
                    }

                    $meta_value = get_post_meta($post_id, $field_name, true);
                    $values[$field_name] = $meta_value !== '' ? $meta_value : ($field['value'] ?? null);
                }
            }
        }

        return $values;
    }

    /**
     * Transform fields config to React-ready format
     *
     * @param array $fields Raw field configuration from PHP
     * @param array $values Saved field values
     * @param int $post_id Post ID
     * @param string $post_type Post type
     * @return array React-ready configuration
     */
    private static function transform_fields_config($fields, $values, $post_id, $post_type) {
        $tabs = [];

        // The config structure is: $fields['formipay_{cpt}_settings'][tab_key] = ['name' => ..., 'fields' => [...]]
        foreach ($fields as $container_key => $container_data) {
            if (!is_array($container_data)) {
                continue;
            }

            foreach ($container_data as $tab_key => $tab_data) {
                if (!isset($tab_data['name']) || !isset($tab_data['fields'])) {
                    continue;
                }

                $tab = [
                    'id' => $tab_key,
                    'label' => $tab_data['name'],
                    'fields' => [],
                ];

                $current_group = null;

                foreach ($tab_data['fields'] as $field_name => $field) {
                    // Handle group_title (section headers)
                    if (isset($field['type']) && $field['type'] === 'group_title') {
                        $group_value = $field['group'] ?? '';

                        if ($group_value === 'started') {
                            $current_group = [
                                'type' => 'section',
                                'label' => $field['label'] ?? '',
                                'description' => $field['description'] ?? '',
                            ];
                        } elseif ($group_value === 'ended') {
                            $current_group = null;
                        }
                        continue;
                    }

                    // Add section if we have one
                    if ($current_group !== null) {
                        $tab['fields'][] = $current_group;
                        $current_group = null;
                    }

                    // Transform field configuration
                    $transformed_field = self::transform_single_field($field_name, $field, $values);

                    // Add to fields
                    $tab['fields'][] = $transformed_field;
                }

                $tabs[] = $tab;
            }
        }

        return [
            'tabs' => $tabs,
            'postId' => $post_id,
            'postType' => $post_type,
            'globalCurrencies' => self::get_global_currencies_data(),
            'nonce' => wp_create_nonce('formipay-field-config'),
        ];
    }

    /**
     * Transform a single field configuration
     *
     * @param string $field_name Field name
     * @param array $field Field configuration
     * @param array $values Saved values
     * @return array Transformed field config
     */
    private static function transform_single_field($field_name, $field, $values) {
        $transformed = [
            'name' => $field_name,
            'type' => self::transform_field_type($field['type'] ?? 'text'),
            'label' => $field['label'] ?? '',
            'description' => $field['description'] ?? '',
            'value' => $values[$field_name] ?? $field['value'] ?? '',
            'required' => !empty($field['required']),
            'dependency' => isset($field['dependency']) ? self::transform_dependency($field['dependency']) : null,
        ];

        // Add options for select/radio fields
        if (isset($field['options'])) {
            $transformed['options'] = $field['options'];
        }

        // Add subtype info for currency fields
        if (isset($field['step'])) {
            $transformed['step'] = $field['step'];
        }
        if (isset($field['min'])) {
            $transformed['min'] = $field['min'];
        }
        if (isset($field['placeholder'])) {
            $transformed['placeholder'] = $field['placeholder'];
        }

        // Handle special field types
        if (isset($field['repeater_fields'])) {
            $transformed['fields'] = $field['repeater_fields'];
        }

        // Pass post_type for autocomplete fields (CPTs)
        if (isset($field['post_type'])) {
            $transformed['post_type'] = $field['post_type'];
        }

        // Pass object_type for autocomplete fields (e.g., 'user' for WP Users)
        if (isset($field['object_type'])) {
            $transformed['object_type'] = $field['object_type'];
        }

        return $transformed;
    }

    /**
     * Transform field type from PHP to React format
     *
     * @param string $type PHP field type
     * @return string React field type
     */
    private static function transform_field_type($type) {
        $type_map = [
            'checkbox' => 'switch',             // Use toggle switch UI
            'tinymce' => 'editor',              // Rich text editor
            'editor' => 'editor',                // Map 'editor' type to tinymce field
            'image' => 'image',                 // WordPress Media Library picker
            'notification_message' => 'notification', // Notification banner component
        ];

        return $type_map[$type] ?? $type;
    }

    /**
     * Transform dependency from PHP to React format
     *
     * @param array $dependency PHP dependency config
     * @return array React dependency config
     */
    private static function transform_dependency($dependency) {
        // Handle multiple dependencies (AND logic)
        if (isset($dependency[0]) && is_array($dependency[0])) {
            return [
                'mode' => 'and',
                'rules' => array_map([self::class, 'transform_single_dependency'], $dependency),
            ];
        }

        return self::transform_single_dependency($dependency);
    }

    /**
     * Transform a single dependency rule
     *
     * @param array $dependency PHP dependency
     * @return array React dependency rule
     */
    private static function transform_single_dependency($dependency) {
        $rule = [
            'field' => $dependency['key'] ?? '',
        ];

        $value = $dependency['value'] ?? '';

        // Handle special values
        if ($value === 'not_empty') {
            $rule['operator'] = 'not_empty';
        } elseif ($value === 'empty') {
            $rule['operator'] = 'empty';
        } else {
            $rule['value'] = $value;
            $rule['operator'] = 'eq';
        }

        return $rule;
    }

    /**
     * Get global currencies data for React
     *
     * @return array Currencies data
     */
    private static function get_global_currencies_data() {
        $currencies = get_global_currency_array();

        return array_map(function($currency) {
            $parts = explode(':::', $currency['currency']);

            return [
                'currency' => $currency['currency'],
                'code' => $parts[0] ?? '',
                'title' => $parts[1] ?? '',
                'symbol' => $parts[2] ?? $parts[1] ?? '',
                'decimalDigits' => intval($currency['decimal_digits'] ?? 2),
                'decimalSymbol' => $currency['decimal_symbol'] ?? '.',
                'thousandSeparator' => $currency['thousand_separator'] ?? ',',
                'flag' => formipay_get_flag_by_currency($currency['currency']),
            ];
        }, $currencies);
    }

    /**
     * Transform a single settings field configuration
     *
     * @param string $field_name Field name
     * @param array $field Field configuration
     * @param array $settings Saved settings values
     * @return array Transformed field config
     */
    private static function transform_settings_field($field_name, $field, $settings) {
        $transformed = [
            'name' => $field_name,
            'type' => self::transform_field_type($field['type'] ?? 'text'),
            'label' => $field['label'] ?? '',
            'description' => $field['description'] ?? '',
            'value' => $settings[$field_name] ?? $field['value'] ?? '',
            'required' => !empty($field['required']),
            'dependency' => isset($field['dependency']) ? self::transform_dependency($field['dependency']) : null,
        ];

        // Add options for select/radio/multi_checkbox fields
        if (isset($field['options'])) {
            $transformed['options'] = $field['options'];
        }

        // Add options for image_select
        if (isset($field['options']) && $field['type'] === 'image_select') {
            $transformed['width'] = $field['width'] ?? 100;
            $transformed['height'] = $field['height'] ?? 100;
        }

        // Add hints for hint_textarea
        if (isset($field['hints'])) {
            $transformed['hints'] = $field['hints'];
        }

        // Add step/min for number fields
        if (isset($field['step'])) {
            $transformed['step'] = $field['step'];
        }
        if (isset($field['min'])) {
            $transformed['min'] = $field['min'];
        }
        if (isset($field['placeholder'])) {
            $transformed['placeholder'] = $field['placeholder'];
        }
        if (isset($field['rows'])) {
            $transformed['rows'] = $field['rows'];
        }

        // Handle repeater fields
        if (isset($field['fields'])) {
            // Transform sub-fields to include name property
            $sub_fields = [];
            foreach ($field['fields'] as $sub_field_name => $sub_field) {
                $sub_field['name'] = $sub_field_name;
                $sub_fields[] = $sub_field;
            }
            $transformed['fields'] = $sub_fields;
        }

        return $transformed;
    }

    /**
     * Convert string to URL-safe slug
     *
     * @param string $text Text to slugify
     * @return string URL-safe slug
     */
    private static function slugify($text) {
        return strtolower(sanitize_title($text));
    }
}