import Foundation

/// 服务端 shipment-sn 软绑/软解绑：本地 BLE 硬绑成功后由 SDK 内部调用，集成方无需手动调起。
final class ShipmentSnDeviceService {
    private let config: DuooomiBleConfig
    private let session: URLSession

    init(config: DuooomiBleConfig, session: URLSession = .shared) {
        self.config = config
        self.session = session
    }

    func bind(
        sn: String,
        bindUserId: String,
        completion: @escaping (Result<Void, Error>) -> Void
    ) {
        post(
            path: "/api/auth/loomart/shipment-sn/device/bind",
            body: ["sn": sn, "bindUserId": bindUserId],
            completion: completion
        )
    }

    func unbind(
        sn: String,
        bindUserId: String? = nil,
        completion: @escaping (Result<Void, Error>) -> Void
    ) {
        var body: [String: String] = ["sn": sn]
        if let bindUserId = bindUserId, !bindUserId.isEmpty {
            body["bindUserId"] = bindUserId
        }
        post(
            path: "/api/auth/loomart/shipment-sn/device/unbind",
            body: body,
            completion: completion
        )
    }

    private func post(
        path: String,
        body: [String: String],
        completion: @escaping (Result<Void, Error>) -> Void
    ) {
        guard let url = URL(string: config.apiHost.absoluteString + path) else {
            completion(.failure(DuooomiBleError.softBindFailed("URL 拼装失败")))
            return
        }

        var req = URLRequest(url: url)
        req.httpMethod = "POST"
        req.timeoutInterval = 10
        req.setValue("application/json", forHTTPHeaderField: "Content-Type")
        req.setValue("application/json", forHTTPHeaderField: "Accept")
        req.setValue(config.apiKey, forHTTPHeaderField: "x-api-key")
        req.setValue(config.brand, forHTTPHeaderField: "x-owner")

        do {
            req.httpBody = try JSONEncoder().encode(body)
        } catch {
            completion(.failure(error))
            return
        }

        session.dataTask(with: req) { data, resp, error in
            if let error = error {
                completion(.failure(DuooomiBleError.softBindFailed(error.localizedDescription)))
                return
            }
            guard let http = resp as? HTTPURLResponse else {
                completion(.failure(DuooomiBleError.softBindFailed("无响应")))
                return
            }
            guard (200...299).contains(http.statusCode) else {
                let message = Self.parseErrorMessage(data: data) ?? "HTTP \(http.statusCode)"
                completion(.failure(DuooomiBleError.softBindFailed(message)))
                return
            }
            // 后端响应 `{ success, data }`；2xx 即视为成功，不强制解 data 字段。
            completion(.success(()))
        }.resume()
    }

    /// 剥离 `API error: ` 前缀，必要时从 JSON 中抽 `message` 字段，与 RN 端 stripApiErrorPrefix 行为对齐。
    private static func parseErrorMessage(data: Data?) -> String? {
        guard let data = data, let raw = String(data: data, encoding: .utf8) else { return nil }
        var stripped = raw
        if stripped.hasPrefix("API error:") {
            stripped = String(stripped.dropFirst("API error:".count)).trimmingCharacters(in: .whitespaces)
        }
        if stripped.hasPrefix("{"),
           let json = try? JSONSerialization.jsonObject(with: Data(stripped.utf8)) as? [String: Any] {
            if let msg = json["message"] as? String { return msg }
            if let err = json["error"] as? [String: Any], let msg = err["message"] as? String { return msg }
        }
        return stripped.isEmpty ? nil : stripped
    }
}