import Foundation

enum NetworkSupport {
    static func data(for request: URLRequest, context: String) async throws -> (Data, HTTPURLResponse) {
        do {
            let (data, response) = try await URLSession.shared.data(for: request)
            guard let http = response as? HTTPURLResponse else {
                throw PostingError(message: "\(context): invalid server response.")
            }
            return (data, http)
        } catch let error as PostingError {
            throw error
        } catch let error as URLError {
            throw PostingError(message: "\(context): \(networkMessage(for: error.code))")
        } catch {
            throw PostingError(message: "\(context): \(error.localizedDescription)")
        }
    }

    static func responseBody(_ data: Data) -> String {
        let body = String(data: data, encoding: .utf8)?
            .trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        return body.isEmpty ? "Empty response body" : body
    }

    private static func networkMessage(for code: URLError.Code) -> String {
        switch code {
        case .notConnectedToInternet:
            return "No internet connection."
        case .timedOut:
            return "Request timed out."
        case .cannotFindHost, .cannotConnectToHost:
            return "Cannot connect to host."
        case .secureConnectionFailed:
            return "TLS/SSL connection failed."
        default:
            return "Network error (\(code.rawValue))."
        }
    }
}