import Foundation

// MARK: - Binding (BLE 协议层硬绑/硬解 + 解绑端的软解；OTA 检查/对账/软绑搬到 +Firmware)

extension DuooomiBleSDK {

    /// 完整绑定：内部串四步业务编排（顺序固定），对集成方表现为一次原子调用。
    ///
    /// 1. **BLE 硬绑**（命令 0x0F）：写 sn / isActivated
    /// 2. **getVersion**：写 version / versionLog（type 兼容 Int/String；log 为任意 JSON 对象，缺失则 nil）
    /// 3. **软绑**：POST `/api/auth/loomart/shipment-sn/device/bind`，登记云端绑定关系
    ///    - 软绑失败 → 自动硬解绑（BLE 0x12）回滚 + 重置 `isActivated`/`sn`/`versionLog`，整个 bind 失败
    /// 4. **updateMetadata**（fire-and-forget）：把 versionLog 透传给 `shipment-sn/device/update-metadata`
    ///    - 失败只 warn 不阻断；versionLog 缺失/空则跳过
    ///
    /// 完成后 SDK 状态变化：
    /// - `sdk.sn` 写入设备序列号
    /// - `sdk.version` 写入当前固件版本（getVersion 失败时保持空，但 bind 不算失败）
    /// - `sdk.versionLog` 写入设备 log JSON 对象（缺失则 nil）
    /// - `sdk.isActivated = true`，delegate `didChangeActivation(true)` 回调
    ///
    /// - Parameters:
    ///   - userId: 当前用户 ID（写入 BLE BIND payload + 软绑请求体的 `bindUserId` 字段）
    ///   - completion: 回调 `Result<BindingResponse, Error>`
    ///     - 成功：`BindingResponse(success: 1, sn, contents)`（软绑也已成功，metadata 上报与否不影响结果）
    ///     - 失败：`.notConnected` / `.alreadyBoundByOtherUser`(硬绑 success≠1) / `.timeout(.bindDevice)`
    ///       / `.brandMismatch` / `.softBindFailed`（含硬解绑回滚后）
    /// - Note: `bind` / `unbind` / `setPlayMode` 共享 `0x0F` / `0x12` opId 通道，**不能并发**。
    public func bind(userId: String, completion: @escaping (Result<BindingResponse, Error>) -> Void) {
        guard ensureConnected(completion: completion) else { return }
        verifyBrand { [weak self] result in
            guard let self = self else { return }
            switch result {
            case .failure(let err):
                completion(.failure(err))
            case .success:
                self.performHardBind(userId: userId, completion: completion)
            }
        }
    }

    /// 校验设备 brand 与 SDK 配置 brand 是否一致；缺失则先拉一次 deviceInfo。
    /// 不一致时主动断连并回调 `.brandMismatch`。
    private func verifyBrand(completion: @escaping (Result<Void, Error>) -> Void) {
        if let cached = deviceInfo {
            checkBrand(actual: cached.brand, completion: completion)
            return
        }
        getDeviceInfo { [weak self] result in
            guard let self = self else { return }
            switch result {
            case .failure(let err):
                completion(.failure(err))
            case .success(let info):
                self.checkBrand(actual: info.brand, completion: completion)
            }
        }
    }

    private func checkBrand(actual: String, completion: @escaping (Result<Void, Error>) -> Void) {
        let expected = config.brand
        if actual == expected {
            completion(.success(()))
            return
        }
        BleLog.w("Brand mismatch: expected=\(expected), actual=\(actual); disconnecting", "Command")
        disconnect { _ in
            completion(.failure(DuooomiBleError.brandMismatch(expected: expected, actual: actual)))
        }
    }

    private func performHardBind(userId: String, completion: @escaping (Result<BindingResponse, Error>) -> Void) {
        BleLog.d("Sending bind (userId=\(userId))", "Command")

        sendAsyncAndWait(commandType: .bindDevice, completion: { [weak self] result in
            guard let self = self else { return }
            switch result {
            case .failure(let error):
                completion(.failure(error))
            case .success(let data):
                do {
                    let resp = try self.decodeResponse(BindingResponse.self, from: data)
                    self.isActivated = resp.success == 1
                    if resp.success != 1 {
                        BleLog.w("Hard bind failed: success=0", "Command")
                        completion(.failure(DuooomiBleError.alreadyBoundByOtherUser))
                        return
                    }
                    self.sn = resp.sn
                    BleLog.i("Hard bind success: sn=\(resp.sn)", "Command")
                    // 同步拉版本，写入 self.version / self.versionLog 供软绑后的 updateMetadata 透传
                    self.getVersion { _ in
                        self.performSoftBindAndMetadata(resp: resp, userId: userId, completion: completion)
                    }
                } catch {
                    completion(.failure(error))
                }
            }
        }, send: { done in
            self.deviceInfoService.bindDevice(userId: userId, completion: done)
        })
    }

    /// 软绑 + metadata 上报。软绑失败 → 硬解绑回滚 + 重置状态 + bind 整体失败回传。
    /// metadata 上报 fire-and-forget，失败只 warn。
    private func performSoftBindAndMetadata(
        resp: BindingResponse,
        userId: String,
        completion: @escaping (Result<BindingResponse, Error>) -> Void
    ) {
        let sn = resp.sn
        BleLog.d("Soft bind start: sn=\(sn)", "Command")
        shipmentService.bind(sn: sn, bindUserId: userId) { [weak self] result in
            guard let self = self else { return }
            if case .failure(let err) = result {
                BleLog.e("Soft bind failed: \(err.localizedDescription); rolling back hard unbind", "Command")
                // 硬解绑回滚（fire-and-forget；BLE ack 不影响这次 bind 错误回传）
                self.deviceInfoService.unbindDevice(userId: userId) { rollbackResult in
                    if case .failure(let rbErr) = rollbackResult {
                        BleLog.w("Hard unbind rollback failed (ignored): \(rbErr.localizedDescription)", "Command")
                    } else {
                        BleLog.i("Hard unbind rollback sent", "Command")
                    }
                }
                self.isActivated = false
                self.sn = ""
                self.versionLog = nil
                DispatchQueue.main.async { completion(.failure(err)) }
                return
            }
            BleLog.i("Soft bind success: sn=\(sn)", "Command")

            // metadata 上报（fire-and-forget；versionLog 缺失/空则跳过）
            if let log = self.versionLog, !log.isEmpty {
                self.shipmentService.updateMetadata(sn: sn, data: log) { mdResult in
                    if case .failure(let err) = mdResult {
                        BleLog.w("updateMetadata failed (ignored): \(err.localizedDescription)", "Command")
                    } else {
                        BleLog.i("updateMetadata success: sn=\(sn)", "Command")
                    }
                }
            }

            DispatchQueue.main.async { completion(.success(resp)) }
        }
    }

    /// 解绑：硬解绑（BLE 0x12）→ 软解绑（shipment-sn HTTP）。SDK 内部完成全套。
    ///
    /// 软解失败仅打 warn 不阻断硬解结果回传——对端云记录如果残留，由后续 bind 自然修正。
    ///
    /// 完成后 SDK 状态变化：
    /// - `sdk.sn` 清空
    /// - `sdk.isActivated = false`，delegate `didChangeActivation(false)` 回调
    ///
    /// - Parameters:
    ///   - userId: 当前用户 ID（写入 BLE UNBIND payload + 软解请求体的 `bindUserId`）
    ///   - completion: 回调 `Result<UnbindResponse, Error>`
    ///     - 成功：`UnbindResponse(success: 1)`（软解失败也算成功）
    ///     - 失败：`.notConnected` / `.unbindFailed`(BLE 层 success≠1) / `.timeout(.unbindDevice)`
    /// - Note: `bind` / `unbind` / `setPlayMode` 共享 `0x0F` / `0x12` opId 通道，**不能并发**。
    public func unbind(userId: String, completion: @escaping (Result<UnbindResponse, Error>) -> Void) {
        guard ensureConnected(completion: completion) else { return }
        let cachedSn = self.sn
        BleLog.d("Sending unbind (userId=\(userId))", "Command")

        sendAsyncAndWait(commandType: .unbindDevice, completion: { [weak self] result in
            guard let self = self else { return }
            switch result {
            case .failure(let error):
                completion(.failure(error))
            case .success(let data):
                do {
                    let resp = try self.decodeResponse(UnbindResponse.self, from: data)
                    if resp.success == 1 {
                        self.isActivated = false
                        self.sn = ""
                        self.versionLog = nil
                        BleLog.i("Hard unbind success", "Command")
                        if !cachedSn.isEmpty {
                            self.shipmentService.unbind(sn: cachedSn, bindUserId: userId) { softResult in
                                if case .failure(let err) = softResult {
                                    BleLog.w("Soft unbind failed (ignored): \(err.localizedDescription)", "Command")
                                }
                                completion(.success(resp))
                            }
                        } else {
                            completion(.success(resp))
                        }
                    } else {
                        BleLog.w("Unbind failed", "Command")
                        completion(.failure(DuooomiBleError.unbindFailed))
                    }
                } catch {
                    completion(.failure(error))
                }
            }
        }, send: { done in
            self.deviceInfoService.unbindDevice(userId: userId, completion: done)
        })
    }
}