import SwiftUI

/// 福利页主数据:金币余额 + 签到状态 + 任务列表,以及签到/领取操作。
@MainActor
@Observable
final class WelfareViewModel {
    private(set) var account: CoinAccountDTO?
    private(set) var signin: SigninStatusDTO?
    private(set) var tasks: [TaskDTO] = []
    private(set) var isLoading = false
    private(set) var loaded = false
    private(set) var signinInProgress = false
    private(set) var toast: String?

    private let welfare = WelfareService()
    private let wallet = WalletService()

    func loadAll() async {
        guard !isLoading else { return }
        isLoading = true
        defer { isLoading = false; loaded = true }
        await refresh()
    }

    func doSignin() async {
        guard signin?.canClaim == true, !signinInProgress else { return }
        signinInProgress = true
        defer { signinInProgress = false }
        do {
            let result = try await welfare.doSignin()
            toast = "签到成功,+\(result.coinAwarded) 金币"
            await refresh()
        } catch {
            toast = (error as? LocalizedError)?.errorDescription ?? "签到失败"
        }
    }

    func claimTask(_ key: String) async {
        do {
            let result = try await welfare.claimTask(taskKey: key)
            toast = "领取成功,+\(result.coinAwarded) 金币"
            await refresh()
        } catch {
            toast = (error as? LocalizedError)?.errorDescription ?? "领取失败"
        }
    }

    func clearToast() { toast = nil }

    /// 登出时清空,避免换用户后残留上一用户的金币/签到/任务数据。
    func reset() {
        account = nil
        signin = nil
        tasks = []
        loaded = false
        toast = nil
    }

    /// 三接口并发拉,各自容错。
    private func refresh() async {
        async let accountTask = wallet.account()
        async let signinTask = welfare.signinStatus()
        async let tasksTask = welfare.tasks()
        account = try? await accountTask
        signin = try? await signinTask
        tasks = (try? await tasksTask)?.items ?? []
    }
}