import Foundation
import Darwin

struct SettingsRuntime: Equatable {
    let appName: String
    let marketingVersion: String
    let buildVersion: String
    let platform: String
    let deviceModel: String
}

@MainActor
final class SettingsViewModel: ObservableObject {
    @Published private(set) var runtime: SettingsRuntime?
    @Published private(set) var isLoading = false
    @Published var storageLabel = "--"
    @Published var notice: String?
    @Published var errorMessage: String?

    private let store: any LogStore

    init(store: any LogStore) {
        self.store = store
    }

    func refresh() async {
        isLoading = true
        errorMessage = nil

        runtime = SettingsRuntime(
            appName: AppMetadata.name,
            marketingVersion: AppMetadata.marketingVersion,
            buildVersion: AppMetadata.buildVersion,
            platform: "iOS",
            deviceModel: Self.deviceModel()
        )
        await loadStorageLabel()

        isLoading = false
    }

    func clearRuntimeLogs() async -> Int {
        do {
            let removed = try await store.clearRuntimeLogs()
            notice = removed > 0 ? "已清除 \(removed) 条运行日志。" : "没有可清除的运行日志。"
            errorMessage = nil
            await loadStorageLabel()
            return removed
        } catch {
            notice = nil
            errorMessage = "清除运行日志失败。"
            return 0
        }
    }

    private func loadStorageLabel() async {
        do {
            let runtimeCount = try await store.runtimeLogs().count
            let connectionCount = try await store.connectionLogs().count
            storageLabel = "\(runtimeCount) 条运行日志 · \(connectionCount) 条连接日志"
        } catch {
            storageLabel = "--"
            errorMessage = "无法读取本地数据状态。"
        }
    }

    private static func deviceModel() -> String {
        var systemInfo = utsname()
        guard uname(&systemInfo) == 0 else { return "未知设备" }
        let bytes = withUnsafeBytes(of: systemInfo.machine) { Data($0) }
        let model = String(
            decoding: bytes.prefix { $0 != 0 },
            as: UTF8.self
        )
        return model.isEmpty ? "未知设备" : model
    }
}