<?php
/**
 * ChatGPT Request Handler for Accessibility Audio TTS.
 *
 * Handles preparation and execution of ChatGPT API requests.
 *
 * @package Accessibility_Audio_TTS\Features\Text_Correction
 * @since 2.0.0
 */

namespace Accessibility_Audio_TTS\API;

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

/**
 * Manages ChatGPT API request preparation and execution.
 *
 * Single Responsibility: Preparing and executing HTTP requests to ChatGPT API.
 */
class ChatGPT_Request_Handler {

	/**
	 * API key for authentication.
	 *
	 * @var string
	 */
	private string $api_key;

	/**
	 * Model mapping for API compatibility.
	 *
	 * @var array
	 */
	private const MODEL_MAPPING = array(
		'gpt-5'      => 'gpt-5',
		'gpt-5-mini' => 'gpt-5-mini',
		'gpt-4o'     => 'gpt-4o',
	);

	/**
	 * Constructor.
	 *
	 * @param string $api_key OpenAI API key.
	 */
	public function __construct( string $api_key ) {
		$this->api_key = trim( $api_key );
	}

	/**
	 * Execute ChatGPT API request.
	 *
	 * @param string $text    Text to process.
	 * @param string $prompt  System prompt.
	 * @param array  $options Request options.
	 * @return array Raw API response.
	 */
	public function execute_request( string $text, string $prompt, array $options = array() ): array {
		$request_data = $this->prepare_request_data( $text, $prompt, $options );
		return $this->send_http_request( $request_data );
	}

	/**
	 * Prepare request data for ChatGPT API.
	 *
	 * @param string $text    Input text.
	 * @param string $prompt  System prompt.
	 * @param array  $options Request options.
	 * @return array Formatted request data.
	 */
	private function prepare_request_data( string $text, string $prompt, array $options = array() ): array {
		$selected_model = $options['model'] ?? get_option( 'accessibility_audio_tts_chatgpt_model', 'gpt-5' );
		$api_model      = self::MODEL_MAPPING[ $selected_model ] ?? $selected_model;
		$is_gpt5_model  = 0 === strpos( $selected_model, 'gpt-5' ) || 0 === strpos( $api_model, 'gpt-5' );

		if ( function_exists( 'accessibility_audio_tts_debug_log' ) ) {
			accessibility_audio_tts_debug_log( '[ChatGPT_Request_Handler] Using model: ' . $api_model . ' (selected: ' . $selected_model . ')', true );
		}

		// Use Responses API for GPT-5 family.
		if ( $is_gpt5_model ) {
			// GPT-5 reasoning models need more tokens: minimum 2000, or 4x text length.
			$calculated_tokens = max( 2000, min( 8000, strlen( $text ) * 4 ) );

			return array(
				'_endpoint'         => 'responses',
				'model'             => $api_model,
				'input'             => array(
					array(
						'role'    => 'system',
						'content' => $prompt,
					),
					array(
						'role'    => 'user',
						'content' => $text,
					),
				),
				'max_output_tokens' => $options['max_output_tokens'] ?? $calculated_tokens,
			);
		}

		// Default: Chat Completions API for older models.
		$request = array(
			'_endpoint'  => 'chat',
			'model'      => $api_model,
			'messages'   => array(
				array(
					'role'    => 'system',
					'content' => $prompt,
				),
				array(
					'role'    => 'user',
					'content' => $text,
				),
			),
			'max_tokens' => $options['max_tokens'] ?? min( 4000, strlen( $text ) * 2 ),
		);

		$request['temperature'] = $options['temperature'] ?? 0.05;
		$request['top_p']       = $options['top_p'] ?? 0.8;

		return $request;
	}

	/**
	 * Send HTTP request to OpenAI API using WordPress HTTP API.
	 *
	 * @param array $request_data Formatted request data.
	 * @return array Raw HTTP response data.
	 */
	private function send_http_request( array $request_data ): array {
		if ( function_exists( 'accessibility_audio_tts_debug_log' ) ) {
			accessibility_audio_tts_debug_log( '[ChatGPT_Request_Handler] Executing API request', true );
		}

		$endpoint = $request_data['_endpoint'] ?? 'chat';
		unset( $request_data['_endpoint'] );
		// Do not retain application state for text correction or explicit key tests.
		// Provider abuse-monitoring retention is controlled separately by the account.
		$request_data['store'] = false;

		$url = 'responses' === $endpoint
			? 'https://api.openai.com/v1/responses'
			: 'https://api.openai.com/v1/chat/completions';

		$args = array(
			'headers' => array(
				'Content-Type'  => 'application/json',
				'Authorization' => 'Bearer ' . $this->api_key,
				'User-Agent'    => 'WordPress/Accessibility-Audio-TTS',
			),
			'timeout' => 60,
			'body'    => wp_json_encode( $request_data ),
			'method'  => 'POST',
		);

		$start_time = microtime( true );
		$response   = wp_remote_request( $url, $args );
		$elapsed    = microtime( true ) - $start_time;

		if ( is_wp_error( $response ) ) {
			return array(
				'response'     => '',
				'http_code'    => 0,
				'curl_error'   => $response->get_error_message(),
				'request_time' => $elapsed,
			);
		}

		$http_code = wp_remote_retrieve_response_code( $response );
		$body      = wp_remote_retrieve_body( $response );

		if ( function_exists( 'accessibility_audio_tts_debug_log' ) ) {
			accessibility_audio_tts_debug_log( '[ChatGPT_Request_Handler] Request completed in ' . round( $elapsed, 2 ) . 's with HTTP code: ' . $http_code, true );
		}

		return array(
			'response'     => $body,
			'http_code'    => $http_code,
			'curl_error'   => '',
			'request_time' => $elapsed,
		);
	}

	/**
	 * Test API connection.
	 *
	 * @return array Connection test results.
	 */
	public function test_connection(): array {
		$test_data = array(
			'model'       => 'gpt-4o-mini',
			'messages'    => array(
				array(
					'role'    => 'user',
					'content' => 'Hello, this is a connection test. Please respond with "Connection successful".',
				),
			),
			'max_tokens'  => 50,
			'temperature' => 0.1,
		);

		$response = $this->send_http_request( $test_data );

		if ( $response['curl_error'] ) {
			return array(
				'success' => false,
				'error'   => 'cURL Error: ' . $response['curl_error'],
			);
		}

		if ( 200 !== $response['http_code'] ) {
			$error_message = 'HTTP Error: ' . $response['http_code'];

			if ( 401 === $response['http_code'] ) {
				$error_message = 'Invalid API key';
			} elseif ( 429 === $response['http_code'] ) {
				$error_message = 'API quota exceeded';
			}

			return array(
				'success' => false,
				'error'   => $error_message,
			);
		}

		return array(
			'success'       => true,
			'message'       => 'Connection successful',
			'response_time' => round( $response['request_time'], 2 ) . 's',
		);
	}
}