<?php
/**
 * AF Translate Core AI Engine Subsystem Layer
 */

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

class AF_Translate_AI_Engine {

    /**
     * Route and Process a Single Workbench String Translation
     *
     * @param string $source_text   The original un-translated text string
     * @param string $target_locale Target language localization key (e.g. 'ar', 'ne_NP')
     * @param string $provider      Dynamic identifier for the targeted AI platform
     * @return string|WP_Error      Translated string on success, WP_Error object on failure.
     */
    public static function translate_single( $source_text, $target_locale, $provider = '' ) {
        $settings = get_option( 'af_translate_api_settings', array() );
        
        // 1. Dynamically resolve active translation engine track across all unmasked tokens
        $provider = self::resolve_active_provider( $settings, $provider );

        // 2. Sandbox Routing Interceptor
        if ( self::is_sandbox_mode( $settings, $provider ) ) {
            return self::simulate_single_sandbox( $source_text, $target_locale );
        }

        // 3. Platform Request Dispatcher Pipeline
        switch ( $provider ) {
            case 'gemini':
                return self::call_gemini( $source_text, $target_locale, $settings );

            case 'openai':
                return self::call_openai_single( $source_text, $target_locale, $settings );

            default:
                return new WP_Error( 'unmapped_provider', __( 'Selected single routing engine lacks an active payload class handler.', 'af-translate' ) );
        }
    }

    /**
     * Process Batch Catalog Array Configurations systematically over a single payload connection 
     *
     * @param array  $strings_array Indexed configuration map format: array( $index => 'Source String' )
     * @param string $target_locale Target language localization key
     * @param string $provider      Dynamic identifier for the targeted AI platform
     * @return array|WP_Error       Translated map matrix sequence on success, WP_Error on failure.
     */
    public static function translate_batch( $strings_array, $target_locale, $provider = '' ) {
        $settings = get_option( 'af_translate_api_settings', array() );

        // 1. Dynamically resolve active translation engine track across all unmasked tokens
        $provider = self::resolve_active_provider( $settings, $provider );

        // 2. Sandbox Routing Interceptor
        if ( self::is_sandbox_mode( $settings, $provider ) ) {
            return self::simulate_batch_sandbox( $strings_array, $target_locale );
        }

        // 3. Platform Request Dispatcher Pipeline
        switch ( $provider ) {
            case 'gemini':
                // FIXED: Now utilizes optimized batch payload pipeline instead of looping individual network calls
                return self::call_gemini_batch( $strings_array, $target_locale, $settings );

            case 'openai':
                return self::call_openai_batch( $strings_array, $target_locale, $settings );

            default:
                return new WP_Error( 'unmapped_provider', __( 'Selected batch routing engine lacks an active payload class handler.', 'af-translate' ) );
        }
    }

    /**
     * Dynamically resolve which translation provider engine to utilize
     */
    private static function resolve_active_provider( $settings, $explicit_provider = '' ) {
        if ( ! empty( $explicit_provider ) ) {
            return sanitize_key( $explicit_provider );
        }

        // Check if the saved active provider actually has a configured key
        if ( ! empty( $settings['active_provider'] ) ) {
            $active = sanitize_key( $settings['active_provider'] );
            $active_key_field = $active . '_key';
            
            if ( ! empty( $settings[ $active_key_field ] ) && 'sandbox-test-key' !== $settings[ $active_key_field ] ) {
                return $active;
            }
        }

        // Fallback Sweep: Find ANY provider that has an active production key configured
        $supported_providers = array( 'gemini', 'openai', 'anthropic', 'grok', 'deepl', 'microsoft', 'google', 'lecto' );
        foreach ( $supported_providers as $provider ) {
            $key_field = $provider . '_key';
            if ( ! empty( $settings[ $key_field ] ) && 'sandbox-test-key' !== $settings[ $key_field ] ) {
                return $provider;
            }
        }

        // Hard default if everything is empty
        return 'gemini';
    }

    /**
     * Determine if sandbox routing protocols should be engaged for the active provider context
     */
    private static function is_sandbox_mode( $settings, $provider ) {
        if ( 'openai' === $provider ) {
            $legacy_key = get_option( 'af_translate_api_key', '' );
            if ( 'sandbox-test-key' === $legacy_key ) {
                return true;
            }
        }

        $target_key_field = $provider . '_key';
        $api_key = isset( $settings[ $target_key_field ] ) ? trim( $settings[ $target_key_field ] ) : '';

        return ( empty( $api_key ) || 'sandbox-test-key' === $api_key );
    }

    /**
     * ------------------------------------------------------------------
     * GOOGLE GEMINI API ENGINE LAYER
     * ------------------------------------------------------------------
     */
    private static function call_gemini( $text, $target_locale, $settings ) {
        $api_key = isset( $settings['gemini_key'] ) ? trim( $settings['gemini_key'] ) : '';
        $model   = ! empty( $settings['gemini_model'] ) ? trim( $settings['gemini_model'] ) : 'gemini-2.5-flash';
        $prompt  = ! empty( $settings['gemini_custom_prompt'] ) ? $settings['gemini_custom_prompt'] : 'Translate this WordPress string to {target_language}. Keep code/HTML placeholders identical.';

        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'Gemini API key is empty.', 'af-translate' ) );
        }

        $resolved_prompt = str_replace( '{target_language}', $target_locale, $prompt );
        $endpoint        = 'https://generativelanguage.googleapis.com/v1beta/models/' . sanitize_text_field( $model ) . ':generateContent?key=' . $api_key;

        $response = wp_remote_post( $endpoint, array(
            'timeout' => 25,
            'headers' => array(
                'Content-Type' => 'application/json',
            ),
            'body'    => json_encode( array(
                'contents' => array(
                    array(
                        'parts' => array(
                            array( 'text' => $text )
                        )
                    )
                ),
                'systemInstruction' => array(
                    'parts' => array(
                        array( 'text' => $resolved_prompt )
                    )
                ),
                'generationConfig' => array(
                    'temperature' => 0.2
                )
            ) ),
        ) );

        if ( is_wp_error( $response ) ) {
            return $response;
        }

        $body = json_decode( wp_remote_retrieve_body( $response ), true );
        if ( isset( $body['candidates'][0]['content']['parts'][0]['text'] ) ) {
            return trim( $body['candidates'][0]['content']['parts'][0]['text'] );
        }

        return new WP_Error( 'api_error', isset( $body['error']['message'] ) ? $body['error']['message'] : __( 'Gemini execution loop failed.', 'af-translate' ) );
    }

    /**
     * Optimized Gemini Bulk Data Pipeline Handler (Consumes only 1 Quota Request)
     */
    private static function call_gemini_batch( $strings_array, $target_locale, $settings ) {
        $api_key = isset( $settings['gemini_key'] ) ? trim( $settings['gemini_key'] ) : '';
        $model   = ! empty( $settings['gemini_model'] ) ? trim( $settings['gemini_model'] ) : 'gemini-2.5-flash';
        $prompt  = ! empty( $settings['gemini_custom_prompt'] ) ? $settings['gemini_custom_prompt'] : 'Translate this WordPress string to {target_language}. Keep code/HTML placeholders identical.';

        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'Gemini API key is empty.', 'af-translate' ) );
        }

        // Infuse absolute matrix-mapping layout requirements directly into the dynamic prompt rules
        $resolved_prompt = str_replace( '{target_language}', $target_locale, $prompt ) . 
            " CRITICAL REQUIREMENT: Input will arrive as an explicitly indexed JSON object array layout matrix. You must return absolute translation output ONLY as a matching structural JSON object using the identical key assignments. Do not include markdown code wrapping blocks.";

        $endpoint = 'https://generativelanguage.googleapis.com/v1beta/models/' . sanitize_text_field( $model ) . ':generateContent?key=' . $api_key;

        $response = wp_remote_post( $endpoint, array(
            'timeout' => 45,
            'headers' => array(
                'Content-Type' => 'application/json',
            ),
            'body'    => json_encode( array(
                'contents' => array(
                    array(
                        'parts' => array(
                            array( 'text' => wp_json_encode( $strings_array ) )
                        )
                    )
                ),
                'systemInstruction' => array(
                    'parts' => array(
                        array( 'text' => $resolved_prompt )
                    )
                ),
                'generationConfig' => array(
                    'temperature'      => 0.2,
                    'responseMimeType' => 'application/json' // Forces Gemini core system engine to output raw data maps
                )
            ) ),
        ) );

        if ( is_wp_error( $response ) ) {
            return $response;
        }

        $response_code = wp_remote_retrieve_response_code( $response );
        $body_text     = wp_remote_retrieve_body( $response );
        $body          = json_decode( $body_text, true );

        if ( 200 !== $response_code ) {
            $error_msg = isset( $body['error']['message'] ) ? $body['error']['message'] : __( 'Gemini bulk engine interface error.', 'af-translate' );
            return new WP_Error( 'gemini_bulk_network_error', $error_msg );
        }

        if ( isset( $body['candidates'][0]['content']['parts'][0]['text'] ) ) {
            $json_raw_string = trim( $body['candidates'][0]['content']['parts'][0]['text'] );
            $decoded_output  = json_decode( $json_raw_string, true );
            
            if ( is_array( $decoded_output ) ) {
                return $decoded_output;
            }
        }

        return new WP_Error( 'gemini_batch_alignment_failed', __( 'Could not securely synchronize translated Gemini dataset matrix structural syntax layout.', 'af-translate' ) );
    }

    /**
     * ------------------------------------------------------------------
     * OPENAI API ENGINE LAYER
     * ------------------------------------------------------------------
     */
    private static function call_openai_single( $source_text, $target_locale, $settings ) {
        $api_key = ! empty( $settings['openai_key'] ) ? $settings['openai_key'] : get_option( 'af_translate_api_key', '' );
        $model   = ! empty( $settings['openai_model'] ) ? $settings['openai_model'] : get_option( 'af_translate_ai_model', 'gpt-4o-mini' );
        
        $system_instruction = self::get_openai_system_prompt( $target_locale, $settings );
        
        $payload = array(
            'model'       => $model,
            'temperature' => 0.2,
            'messages'    => array(
                array( 'role' => 'system', 'content' => $system_instruction ),
                array( 'role' => 'user', 'content' => $source_text )
            )
        );

        $response = self::execute_openai_remote_post( $api_key, $payload );
        if ( is_wp_error( $response ) ) {
            return $response;
        }

        if ( isset( $response['choices'][0]['message']['content'] ) ) {
            return trim( $response['choices'][0]['message']['content'] );
        }

        return new WP_Error( 'api_malformed_response', __( 'OpenAI core node returned an unreadable response layout.', 'af-translate' ) );
    }

    private static function call_openai_batch( $strings_array, $target_locale, $settings ) {
        $api_key = ! empty( $settings['openai_key'] ) ? $settings['openai_key'] : get_option( 'af_translate_api_key', '' );
        $model   = ! empty( $settings['openai_model'] ) ? $settings['openai_model'] : get_option( 'af_translate_ai_model', 'gpt-4o-mini' );

        $system_instruction = self::get_openai_system_prompt( $target_locale, $settings ) . 
            " Crucial Instruction: Input will arrive as a serialized JSON object map. You must respond ONLY with a valid JSON object matching the exact key definitions. Do not include markdown wraps or ```json indicators.";

        $payload = array(
            'model'           => $model,
            'temperature'     => 0.2,
            'response_format' => array( 'type' => 'json_object' ),
            'messages'    => array(
                array( 'role' => 'system', 'content' => $system_instruction ),
                array( 'role' => 'user', 'content' => wp_json_encode( $strings_array ) )
            )
        );

        $response = self::execute_openai_remote_post( $api_key, $payload );
        if ( is_wp_error( $response ) ) {
            return $response;
        }

        if ( isset( $response['choices'][0]['message']['content'] ) ) {
            $decoded_output = json_decode( $response['choices'][0]['message']['content'], true );
            if ( is_array( $decoded_output ) ) {
                return $decoded_output;
            }
        }

        return new WP_Error( 'batch_alignment_failed', __( 'Could not securely synchronize translated OpenAI dataset matrix trees.', 'af-translate' ) );
    }

    private static function get_openai_system_prompt( $target_locale, $settings ) {
        if ( ! empty( $settings['openai_custom_prompt'] ) ) {
            return str_replace( '{target_language}', $target_locale, $settings['openai_custom_prompt'] );
        }

        return "You are a professional localization engine processing complex core WordPress gettext catalogs. " .
               "Translate the provided text content accurately into the target language code context: '{$target_locale}'. " .
               "CRITICAL: You must preserve all raw formatting parameters, HTML entities, and structural printf string layout placeholders (e.g. %s, %d, %1\$s, %2\$s) exactly as they appear in the source string. " .
               "Never attempt to modify, alter, translate, or rearrange these system placeholder variables.";
    }

    private static function execute_openai_remote_post( $api_key, $payload ) {
        $endpoint = '[https://api.openai.com/v1/chat/completions](https://api.openai.com/v1/chat/completions)';

        $response = wp_remote_post( $endpoint, array(
            'timeout'   => 45,
            'blocking'  => true,
            'headers'   => array(
                'Authorization' => 'Bearer ' . $api_key,
                'Content-Type'  => 'application/json',
            ),
            'body'      => wp_json_encode( $payload ),
        ) );

        if ( is_wp_error( $response ) ) {
            return $response;
        }

        $response_code = wp_remote_retrieve_response_code( $response );
        $response_body = wp_remote_retrieve_body( $response );

        if ( 200 !== $response_code ) {
            $error_data = json_decode( $response_body, true );
            $error_message = isset( $error_data['error']['message'] ) ? $error_data['error']['message'] : __( 'Remote OpenAI endpoint communication disruption.', 'af-translate' );
            return new WP_Error( 'remote_api_handshake_error', $error_message );
        }

        return json_decode( $response_body, true );
    }

    /**
     * ------------------------------------------------------------------
     * SANDBOX SIMULATION SYSTEM UTILITIES
     * ------------------------------------------------------------------
     */
    private static function simulate_single_sandbox( $text, $locale ) {
        usleep( 600000 );
        return "[Sandbox - Language Target: " . strtoupper( esc_html( $locale ) ) . "]: " . $text;
    }

    private static function simulate_batch_sandbox( $strings_array, $locale ) {
        usleep( 1200000 );
        $mocked_catalog = array();
        foreach ( $strings_array as $index => $text ) {
            $mocked_catalog[ $index ] = "[Bulk Sandbox - " . strtoupper( esc_html( $locale ) ) . "]: " . $text;
        }
        return $mocked_catalog;
    }
}