<?php
/**
 * ChatGPT Response Processor for Accessibility Audio TTS.
 *
 * Handles parsing and processing of ChatGPT API responses.
 *
 * @package Accessibility_Audio_TTS\Features\Text_Correction
 * @since 2.0.0
 */

namespace Accessibility_Audio_TTS\API;

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

/**
 * Manages ChatGPT API response processing.
 *
 * Single Responsibility: Parsing and processing ChatGPT API responses.
 */
class ChatGPT_Response_Processor {

	/**
	 * Response validator instance.
	 *
	 * @var ChatGPT_Response_Validator
	 */
	private ChatGPT_Response_Validator $validator;

	/**
	 * Error handler instance.
	 *
	 * @var ChatGPT_Error_Handler
	 */
	private ChatGPT_Error_Handler $error_handler;

	/**
	 * Constructor.
	 *
	 * @return void
	 */
	public function __construct() {
		$this->validator     = new ChatGPT_Response_Validator();
		$this->error_handler = new ChatGPT_Error_Handler();
	}

	/**
	 * Process raw API response.
	 *
	 * @param array $raw_response Raw HTTP response data.
	 * @return array Processed response with success status and data.
	 */
	public function process_response( array $raw_response ): array {
		// Handle cURL errors.
		if ( ! empty( $raw_response['curl_error'] ) ) {
			return $this->error_handler->handle_curl_error( $raw_response['curl_error'] );
		}

		// Handle HTTP errors.
		if ( 200 !== $raw_response['http_code'] ) {
			return $this->error_handler->handle_http_error( $raw_response );
		}

		// Parse JSON response.
		return $this->parse_json_response( $raw_response['response'] );
	}

	/**
	 * Parse JSON response from ChatGPT API.
	 *
	 * @param string $response_body Raw JSON response.
	 * @return array Parsed response with success status and data.
	 */
	private function parse_json_response( string $response_body ): array {
		$decoded = json_decode( $response_body, true );

		if ( JSON_ERROR_NONE !== json_last_error() ) {
			return $this->error_handler->handle_json_error( json_last_error_msg() );
		}

		// Handle API errors in response.
		if ( isset( $decoded['error'] ) ) {
			return $this->error_handler->handle_api_error( $decoded['error'] );
		}

		// Extract content from successful response.
		return $this->extract_content( $decoded );
	}

	/**
	 * Extract content from successful API response.
	 *
	 * @param array $decoded Decoded JSON response.
	 * @return array Success response with content and usage data.
	 */
	private function extract_content( array $decoded ): array {
		$content = null;

		// 1) Responses API (GPT-5): output array with text/message/content.
		if ( isset( $decoded['output'] ) && is_array( $decoded['output'] ) ) {
			foreach ( $decoded['output'] as $output_item ) {
				// Skip reasoning items, only process message items.
				if ( isset( $output_item['type'] ) && 'message' === $output_item['type'] ) {
					// Try: output[].content as array with text field.
					if ( isset( $output_item['content'] ) && is_array( $output_item['content'] ) ) {
						foreach ( $output_item['content'] as $content_item ) {
							if ( isset( $content_item['text'] ) && is_string( $content_item['text'] ) && '' !== trim( $content_item['text'] ) ) {
								$content = trim( $content_item['text'] );
								break 2; // Exit both loops.
							}
						}
					}

					// Fallback: check content field as string.
					if ( isset( $output_item['content'] ) && is_string( $output_item['content'] ) && '' !== trim( $output_item['content'] ) ) {
						$content = trim( $output_item['content'] );
						break;
					}
				}

				// Try: output[].text (direct text field).
				if ( isset( $output_item['text'] ) && is_string( $output_item['text'] ) && '' !== trim( $output_item['text'] ) ) {
					$content = trim( $output_item['text'] );
					break;
				}

				// Try: output[].message.content (legacy format).
				if ( isset( $output_item['message']['content'] ) && is_string( $output_item['message']['content'] ) && '' !== trim( $output_item['message']['content'] ) ) {
					$content = trim( $output_item['message']['content'] );
					break;
				}
			}
		}

		// 2) Standard Chat Completions: choices[0].message.content.
		if ( null === $content && isset( $decoded['choices'][0]['message']['content'] ) && is_string( $decoded['choices'][0]['message']['content'] ) ) {
			$content = trim( $decoded['choices'][0]['message']['content'] );
		}

		// 3) Some responses expose choices[0].content directly.
		if ( null === $content && isset( $decoded['choices'][0]['content'] ) && is_string( $decoded['choices'][0]['content'] ) ) {
			$content = trim( $decoded['choices'][0]['content'] );
		}

		// 4) Responses API: output_text (legacy format).
		if ( null === $content && isset( $decoded['output_text'] ) && is_string( $decoded['output_text'] ) ) {
			$content = trim( $decoded['output_text'] );
		}

		if ( null === $content || '' === $content ) {
			if ( function_exists( 'accessibility_audio_tts_debug_log' ) ) {
				accessibility_audio_tts_debug_log( '[ChatGPT_Response_Processor] No recognized content field in response: ' . substr( wp_json_encode( $decoded ), 0, 400 ), true );
			}

			return array(
				'success' => false,
				'error'   => 'No content in API response',
			);
		}

		$usage       = $decoded['usage'] ?? null;
		$tokens_used = $usage['total_tokens'] ?? 0;

		if ( function_exists( 'accessibility_audio_tts_debug_log' ) ) {
			accessibility_audio_tts_debug_log( '[ChatGPT_Response_Processor] Success - returned ' . strlen( $content ) . ' characters, used ' . $tokens_used . ' tokens', true );
		}

		return array(
			'success' => true,
			'content' => $content,
			'usage'   => $usage,
			'tokens'  => array(
				'input'  => $usage['input_tokens'] ?? $usage['prompt_tokens'] ?? 0,
				'output' => $usage['output_tokens'] ?? $usage['completion_tokens'] ?? 0,
				'total'  => $tokens_used,
				'model'  => $decoded['model'] ?? null,
				'cached_input' => $usage['input_tokens_details']['cached_tokens'] ?? $usage['prompt_tokens_details']['cached_tokens'] ?? 0,
			),
		);
	}

	/**
	 * Validate response content quality.
	 *
	 * @param string $content       Response content.
	 * @param string $original_text Original input text.
	 * @return array Validation results.
	 */
	public function validate_content_quality( string $content, string $original_text ): array {
		return $this->validator->validate_content_quality( $content, $original_text );
	}
}