<?php
/**
 * Google Cloud Vision Web Detection provider.
 *
 * @package MediaRightsAudit\External
 */

namespace MediaRightsAudit\External;

use MediaRightsAudit\Admin\Settings;

/**
 * Sends images to the Google Cloud Vision API (WEB_DETECTION feature) and
 * normalises the response into a ScanResult.
 *
 * Reads the API key from the plugin settings (google_vision_api_key).
 * Supports public-URL image submissions; for private/staging sites the
 * file_url may not be publicly accessible — a warning is surfaced via
 * the scan error message in that case.
 */
class GoogleVisionProvider extends AbstractProvider {

	/**
	 * Google Vision API endpoint (without key).
	 */
	const ENDPOINT = 'https://vision.googleapis.com/v1/images:annotate';

	/**
	 * Returns the machine-readable provider identifier.
	 *
	 * @return string
	 */
	public function provider_slug(): string {
		return 'google_vision';
	}

	/**
	 * Returns the human-readable provider display name.
	 *
	 * @return string
	 */
	public function provider_name(): string {
		return __( 'Google Cloud Vision', 'robotstxt-mediaaudit' );
	}

	/**
	 * Sends the image to Google Cloud Vision Web Detection and returns a ScanResult.
	 *
	 * @param int    $attachment_id WordPress attachment ID.
	 * @param string $file_url      Public URL of the image.
	 *
	 * @return ScanResult
	 *
	 * @throws \RuntimeException On configuration, HTTP, or parse errors.
	 */
	protected function do_scan( int $attachment_id, string $file_url ): ScanResult {
		$api_key = $this->get_api_key();
		if ( '' === $api_key ) {
			throw new \RuntimeException( 'Google Vision API key is not configured.' );
		}

		$body = wp_json_encode(
			array(
				'requests' => array(
					array(
						'image'    => array( 'source' => array( 'imageUri' => $file_url ) ),
						'features' => array(
							array(
								'type'       => 'WEB_DETECTION',
								'maxResults' => 100,
							),
						),
					),
				),
			)
		);

		if ( false === $body ) {
			throw new \RuntimeException( 'Failed to encode Google Vision request body.' );
		}

		$response = wp_remote_post(
			self::ENDPOINT,
			array(
				'headers' => array(
					'Content-Type'   => 'application/json; charset=utf-8',
					'X-Goog-Api-Key' => $api_key,
				),
				'body'    => $body,
				'timeout' => 30,
			)
		);

		if ( is_wp_error( $response ) ) {
			throw new \RuntimeException( $response->get_error_message() ); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped
		}

		$http_code = (int) wp_remote_retrieve_response_code( $response );
		if ( 200 !== $http_code ) {
			throw new \RuntimeException(
				sprintf( 'Google Vision API returned HTTP %d.', $http_code ) // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped
			);
		}

		$raw_body = wp_remote_retrieve_body( $response );
		$decoded  = json_decode( $raw_body, true );

		if ( ! is_array( $decoded ) ) {
			throw new \RuntimeException( 'Failed to parse Google Vision API response.' );
		}

		return $this->parse_response( $decoded );
	}

	// -------------------------------------------------------------------------
	// Private helpers
	// -------------------------------------------------------------------------

	/**
	 * Reads the Google Vision API key from plugin settings.
	 *
	 * @return string Empty string if not configured.
	 */
	private function get_api_key(): string {
		$raw  = get_option( Settings::OPTION_NAME, array() );
		$opts = is_array( $raw ) ? $raw : array();
		$val  = $opts['google_vision_api_key'] ?? null;
		return is_string( $val ) ? trim( $val ) : '';
	}

	/**
	 * Parses the decoded Vision API response into a ScanResult.
	 *
	 * @param array<mixed, mixed> $decoded json_decode()'d API response.
	 *
	 * @return ScanResult
	 */
	private function parse_response( array $decoded ): ScanResult {
		$web_detection = $this->extract_web_detection( $decoded );

		$pages_raw = $web_detection['pagesWithMatchingImages'] ?? null;
		$pages     = is_array( $pages_raw ) ? $pages_raw : array();

		$full_raw = $web_detection['fullMatchingImages'] ?? null;
		$full     = is_array( $full_raw ) ? $full_raw : array();

		$partial_raw = $web_detection['partialMatchingImages'] ?? null;
		$partial     = is_array( $partial_raw ) ? $partial_raw : array();

		$match_count = count( $pages ) + count( $full );
		$top_domains = $this->extract_top_domains( array_merge( $pages, $full, $partial ) );

		return new ScanResult( $match_count, $top_domains, $decoded );
	}

	/**
	 * Extracts the webDetection sub-object from the full API response.
	 *
	 * @param array<mixed, mixed> $decoded Full decoded API response.
	 *
	 * @return array<mixed, mixed>
	 */
	private function extract_web_detection( array $decoded ): array {
		$responses_raw = $decoded['responses'] ?? null;
		if ( ! is_array( $responses_raw ) ) {
			return array();
		}

		$first = reset( $responses_raw );
		if ( ! is_array( $first ) ) {
			return array();
		}

		$wd = $first['webDetection'] ?? null;
		return is_array( $wd ) ? $wd : array();
	}
}