import Foundation

struct FirmwareInfo: Codable, Equatable {
    let version: String
    let fileUrl: String
    let notes: String?
}

enum FirmwareServiceError: LocalizedError {
    case invalidBrand
    case invalidResponse
    case http(Int)
    case network(String)

    var errorDescription: String? {
        switch self {
        case .invalidBrand: return "Invalid brand"
        case .invalidResponse: return "Invalid firmware info response"
        case .http(let code): return "HTTP error: \(code)"
        case .network(let msg): return msg
        }
    }
}

enum FirmwareUpdateService {
    // 可根据后端实际接口调整
    private static let base = NetworkConfig.apiHost
    private static let latestPath = "/api/auth/firmware/latest"

    /// 获取指定品牌的最新固件信息。
    /// - Parameters:
    ///   - brand: 设备品牌，如 Bowong。
    ///   - status: 固件状态筛选，默认 `PUBLISHED`。
    /// - Returns: 最新固件信息（版本、下载地址、备注）。
    /// - Throws: 参数不合法、网络/HTTP 错误或响应解析失败。
    static func fetchLatest(brand: String, status: String = "PUBLISHED") async throws -> FirmwareInfo {
        guard !brand.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else {
            throw FirmwareServiceError.invalidBrand
        }
        var comps = URLComponents(url: base.appendingPathComponent(latestPath), resolvingAgainstBaseURL: false)!
        comps.queryItems = [
            URLQueryItem(name: "brand", value: brand),
            URLQueryItem(name: "status", value: status)
        ]
        guard let url = comps.url else { throw FirmwareServiceError.invalidResponse }

        var req = URLRequest(url: url)
        req.httpMethod = "GET"
        req.setValue(NetworkConfig.apiKey, forHTTPHeaderField: "x-api-key")
        req.setValue("application/json", forHTTPHeaderField: "accept")

        do {
            let (data, resp) = try await URLSession.shared.data(for: req)
            guard let http = resp as? HTTPURLResponse else { throw FirmwareServiceError.invalidResponse }
            guard (200...299).contains(http.statusCode) else {
                throw FirmwareServiceError.http(http.statusCode)
            }

            // 期望返回 { version: String, fileUrl: String, notes?: String }
            let info = try JSONDecoder().decode(FirmwareInfo.self, from: data)
            return info
        } catch let e as FirmwareServiceError {
            throw e
        } catch {
            throw FirmwareServiceError.network(error.localizedDescription)
        }
    }
}