import Foundation

enum APIClientError: LocalizedError {
    case invalidBaseURL
    case invalidResponse
    case server(String)

    var errorDescription: String? {
        switch self {
        case .invalidBaseURL:
            return "API_BASE_URL geçersiz."
        case .invalidResponse:
            return "Sunucudan geçerli yanıt alınamadı."
        case .server(let message):
            return message
        }
    }
}

final class APIClient {
    static let shared = APIClient()

    private init() {}

    private var baseURL: URL? {
        guard let raw = Bundle.main.object(forInfoDictionaryKey: "API_BASE_URL") as? String else {
            return nil
        }
        return URL(string: raw)
    }

    private var mobileAPIKey: String {
        Bundle.main.object(forInfoDictionaryKey: "MOBILE_API_KEY") as? String
            ?? "mobile-dev-key-change-me"
    }

    func getInfo(url: String) async throws -> GetInfoResponse {
        guard let baseURL else { throw APIClientError.invalidBaseURL }

        var request = URLRequest(url: baseURL.appending(path: "/api/getinfo"))
        request.httpMethod = "POST"
        request.timeoutInterval = 20
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.setValue(mobileAPIKey, forHTTPHeaderField: "X-API-Key")
        request.httpBody = try JSONEncoder().encode(GetInfoRequest(url: url))

        let (data, response) = try await URLSession.shared.data(for: request)
        guard let http = response as? HTTPURLResponse else {
            throw APIClientError.invalidResponse
        }

        let decoder = JSONDecoder()
        let envelope = try decoder.decode(APIEnvelope<GetInfoResponse>.self, from: data)

        if (200..<300).contains(http.statusCode), envelope.success, let payload = envelope.data {
            return payload
        }

        if let errorMessage = envelope.error?.message {
            throw APIClientError.server(errorMessage)
        }

        throw APIClientError.server("İstek başarısız oldu (\(http.statusCode)).")
    }
}