<?php
/**
 * GitHub API Functions
 *
 * @package RobotsTxt\DocumentationMarkdown
 * @since   1.0.0
 */

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

/**
 * Parse GitHub URL
 *
 * @since 1.0.0
 *
 * @param string $url GitHub repository URL.
 * @return array{owner: string, repo: string}|WP_Error Array with 'owner' and 'repo' or error.
 */
function robotstxt_docmd_parse_github_url( string $url ): array|WP_Error {
	if ( ! str_starts_with( $url, 'https://' ) ) {
		return new WP_Error( 'invalid_url', __( 'GitHub URL must use HTTPS', 'robotstxt-documentation-markdown' ) );
	}

	if ( preg_match( '/github\.com\/([a-zA-Z0-9_-]+)\/([a-zA-Z0-9._-]+?)(?:\.git)?\/?$/', $url, $matches ) ) {
		return array(
			'owner' => $matches[1],
			'repo'  => $matches[2],
		);
	}

	return new WP_Error( 'invalid_format', __( 'Could not parse GitHub URL', 'robotstxt-documentation-markdown' ) );
}

/**
 * Validate and normalize a list of file data from cache or API response
 *
 * Converts untyped cache data back into the expected typed structure.
 * Required for PHPStan level 9 compliance with transient cache usage.
 *
 * @since 1.0.1
 *
 * @param mixed $data Raw data to validate (typically from get_transient()).
 * @return list<array{path: string, name: string, size: int, sha: string}>
 */
function robotstxt_docmd_validate_file_list( mixed $data ): array {
	if ( ! is_array( $data ) ) {
		return array();
	}

	$result = array();
	foreach ( $data as $item ) {
		if ( is_array( $item )
			&& isset( $item['path'], $item['name'], $item['size'], $item['sha'] )
			&& is_string( $item['path'] )
			&& is_string( $item['name'] )
			&& is_int( $item['size'] )
			&& is_string( $item['sha'] )
		) {
			$result[] = array(
				'path' => $item['path'],
				'name' => $item['name'],
				'size' => $item['size'],
				'sha'  => $item['sha'],
			);
		}
	}

	return $result;
}

/**
 * Get all markdown files from repository
 *
 * @since 1.0.0
 *
 * @param string $owner Repository owner.
 * @param string $repo Repository name.
 * @param string $branch Branch name.
 * @param string $token GitHub token (encrypted).
 * @return list<array{path: string, name: string, size: int, sha: string}>|WP_Error Array of files or error.
 */
function robotstxt_docmd_get_all_markdown_files( string $owner, string $repo, string $branch, string $token ): array|WP_Error {
	// Check cache first.
	$cache_key = sprintf( 'robotstxt_docmd_files_%s_%s_%s', $owner, $repo, $branch );
	$cached    = get_transient( $cache_key );

	if ( false !== $cached ) {
		return robotstxt_docmd_validate_file_list( $cached );
	}

	// Decrypt token.
	$decrypted_token = robotstxt_docmd_decrypt_token( $token );

	// Get files recursively.
	$files = robotstxt_docmd_get_repository_contents_recursive( $owner, $repo, '', $branch, $decrypted_token );

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

	// Filter only markdown files and re-index.
	$markdown_files = array();
	foreach ( $files as $file ) {
		if ( preg_match( '/\.(md|markdown)$/i', $file['path'] ) ) {
			$markdown_files[] = $file;
		}
	}

	// Cache for 24 hours.
	set_transient( $cache_key, $markdown_files, DAY_IN_SECONDS );

	return $markdown_files;
}

/**
 * Get repository contents recursively
 *
 * @since 1.0.0
 *
 * @param string $owner Repository owner.
 * @param string $repo Repository name.
 * @param string $path Path in repository.
 * @param string $branch Branch name.
 * @param string $token GitHub token (plain).
 * @param int    $depth Current depth (for recursion limit).
 * @return list<array{path: string, name: string, size: int, sha: string}>|WP_Error Array of files or error.
 */
function robotstxt_docmd_get_repository_contents_recursive( string $owner, string $repo, string $path, string $branch, string $token, int $depth = 0 ): array|WP_Error {
	// Prevent infinite recursion.
	if ( $depth > 10 ) {
		return array();
	}

	$url = sprintf(
		'https://api.github.com/repos/%s/%s/contents/%s?ref=%s',
		rawurlencode( $owner ),
		rawurlencode( $repo ),
		rawurlencode( $path ),
		rawurlencode( $branch )
	);

	$response = wp_remote_get(
		$url,
		array(
			'headers' => array(
				'Authorization' => 'Bearer ' . $token,
				'Accept'        => 'application/vnd.github.v3+json',
				'User-Agent'    => 'WordPress-Documentation-Plugin',
			),
			'timeout' => 30,
		)
	);

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

	$code = wp_remote_retrieve_response_code( $response );
	if ( 200 !== $code ) {
		return new WP_Error(
			'github_api_error',
			sprintf(
				/* translators: %d: HTTP response code */
				__( 'GitHub API error: %d', 'robotstxt-documentation-markdown' ),
				$code
			)
		);
	}

	$body     = wp_remote_retrieve_body( $response );
	$contents = json_decode( $body, true );

	if ( ! is_array( $contents ) ) {
		return new WP_Error( 'invalid_response', __( 'Invalid GitHub API response', 'robotstxt-documentation-markdown' ) );
	}

	$files = array();

	foreach ( $contents as $item ) {
		if ( ! is_array( $item )
			|| ! isset( $item['type'], $item['path'], $item['name'], $item['size'], $item['sha'] )
			|| ! is_string( $item['type'] )
			|| ! is_string( $item['path'] )
			|| ! is_string( $item['name'] )
			|| ! is_string( $item['sha'] )
			|| ! is_int( $item['size'] )
		) {
			continue;
		}

		if ( 'file' === $item['type'] ) {
			// Skip files larger than 10MB.
			if ( $item['size'] > 10 * 1024 * 1024 ) {
				continue;
			}

			$files[] = array(
				'path' => $item['path'],
				'name' => $item['name'],
				'size' => $item['size'],
				'sha'  => $item['sha'],
			);
		} elseif ( 'dir' === $item['type'] ) {
			// Recurse into directory.
			$subfiles = robotstxt_docmd_get_repository_contents_recursive(
				$owner,
				$repo,
				$item['path'],
				$branch,
				$token,
				$depth + 1
			);

			if ( ! is_wp_error( $subfiles ) ) {
				$files = array_merge( $files, $subfiles );
			}
		}
	}

	return $files;
}

/**
 * Get file content from GitHub
 *
 * @since 1.0.0
 *
 * @param string $owner Repository owner.
 * @param string $repo Repository name.
 * @param string $file_path File path.
 * @param string $branch Branch name.
 * @param string $token GitHub token (encrypted).
 * @return string|WP_Error File content or error.
 */
function robotstxt_docmd_get_file_content( string $owner, string $repo, string $file_path, string $branch, string $token ): string|WP_Error {
	$decrypted_token = robotstxt_docmd_decrypt_token( $token );

	$url = sprintf(
		'https://api.github.com/repos/%s/%s/contents/%s?ref=%s',
		rawurlencode( $owner ),
		rawurlencode( $repo ),
		rawurlencode( $file_path ),
		rawurlencode( $branch )
	);

	$response = wp_remote_get(
		$url,
		array(
			'headers' => array(
				'Authorization' => 'Bearer ' . $decrypted_token,
				'Accept'        => 'application/vnd.github.v3+json',
				'User-Agent'    => 'WordPress-Documentation-Plugin',
			),
			'timeout' => 30,
		)
	);

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

	$code = wp_remote_retrieve_response_code( $response );
	if ( 200 !== $code ) {
		return new WP_Error(
			'github_api_error',
			sprintf(
				/* translators: %d: HTTP response code */
				__( 'GitHub API error: %d', 'robotstxt-documentation-markdown' ),
				$code
			)
		);
	}

	$body = wp_remote_retrieve_body( $response );
	$data = json_decode( $body, true );

	if ( ! is_array( $data )
		|| ! isset( $data['content'], $data['encoding'] )
		|| ! is_string( $data['content'] )
		|| ! is_string( $data['encoding'] )
	) {
		return new WP_Error( 'invalid_response', __( 'Invalid file response from GitHub', 'robotstxt-documentation-markdown' ) );
	}

	// Decode content (GitHub returns base64).
	if ( 'base64' === $data['encoding'] ) {
		$decoded = base64_decode( $data['content'], true ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_decode
		if ( false === $decoded ) {
			return new WP_Error( 'decode_failed', __( 'Failed to decode file content from GitHub.', 'robotstxt-documentation-markdown' ) );
		}
		return $decoded;
	}

	return $data['content'];
}