import Foundation

public struct ApiResponse<T: Decodable>: Decodable {
    public let code: Int
    public let status: String
    public let data: T?
    public let message: String
}

public struct EmptyResponse: Decodable, Sendable {
    public init() {}
}

public final class ApiClient: @unchecked Sendable {

    public static let shared = ApiClient()
    private var config: SDKConfig?
    private var session: URLSession = .shared

    private init() {}

    func configure(with config: SDKConfig) {
        self.config = config
    }

    public func request<T: Decodable>(
        path: String,
        method: String = "GET",
        queryItems: [URLQueryItem]? = nil,
        body: (some Encodable)? = nil as String?
    ) async throws -> T {
        guard let config else { throw URLError(.badURL) }
        let tokenStore = await XuqmSDK.shared.tokenStore

        var components = URLComponents(url: SDKEndpoints.apiBaseURL.appendingPathComponent(path), resolvingAgainstBaseURL: false)!
        if let qi = queryItems { components.queryItems = qi }

        var req = URLRequest(url: components.url!)
        req.httpMethod = method
        req.setValue("application/json", forHTTPHeaderField: "Content-Type")
        if let token = tokenStore?.get() {
            req.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
        }
        if let b = body {
            req.httpBody = try JSONEncoder().encode(b)
        }

        if config.debug {
            print("[XuqmSDK][HTTP] request", method, req.url?.absoluteString ?? path)
        }

        let (data, response) = try await session.data(for: req)
        guard let http = response as? HTTPURLResponse, (200..<300).contains(http.statusCode) else {
            if config.debug, let http = response as? HTTPURLResponse {
                print("[XuqmSDK][HTTP] response", http.statusCode, req.url?.absoluteString ?? path)
            }
            throw URLError(.badServerResponse)
        }

        if config.debug {
            print("[XuqmSDK][HTTP] response", http.statusCode, req.url?.absoluteString ?? path)
        }

        let wrapper = try JSONDecoder().decode(ApiResponse<T>.self, from: data)
        if let result = wrapper.data {
            return result
        }
        if T.self == EmptyResponse.self {
            return EmptyResponse() as! T
        }
        throw URLError(.cannotDecodeContentData)
    }
}