import Combine
import CoreDomain
import CoreModel

/// Fake 打卡仓库（骨架阶段返回假数据，可提交）。
public final class FakeCheckinRepository: CheckinRepository, @unchecked Sendable {
    private let record: CurrentValueSubject<CheckinRecord, Never>

    public init() {
        record = CurrentValueSubject(Self.seed())
    }

    public func observeCheckin() -> AsyncThrowingStream<CheckinRecord, Error> {
        Self.stream(record)
    }

    public func submitCheckin(status: CheckinStatus) async throws {
        try await Task.sleep(for: .milliseconds(300))
        var current = record.value
        current = CheckinRecord(
            classDate: current.classDate,
            weekday: current.weekday,
            dayNum: current.dayNum,
            checked: true,
            status: status,
            groupName: current.groupName,
            groupMembers: current.groupMembers.map { member in
                guard member.id == "me" else { return member }
                return GroupMember(id: member.id, name: member.name, checkedIn: true, checkinTime: "现在", status: status)
            },
            personalHistory: current.personalHistory
        )
        record.value = current
    }

    private static func stream<T>(_ subject: CurrentValueSubject<T, Never>) -> AsyncThrowingStream<T, Error> {
        AsyncThrowingStream { continuation in
            let cancellable = subject.sink { continuation.yield($0) }
            continuation.onTermination = { _ in cancellable.cancel() }
        }
    }

    private static func seed() -> CheckinRecord {
        CheckinRecord(
            classDate: "2026-09-09",
            weekday: "周三",
            dayNum: 9,
            checked: false,
            status: nil,
            groupName: "进阶一组",
            groupMembers: [
                GroupMember(id: "m1", name: "张三", checkedIn: true, checkinTime: "19:02", status: .normal),
                GroupMember(id: "m2", name: "李四", checkedIn: true, checkinTime: "19:30", status: .late),
                GroupMember(id: "me", name: "我", checkedIn: false, checkinTime: nil, status: nil),
                GroupMember(id: "m3", name: "王五", checkedIn: true, checkinTime: "09:10", status: .leave),
                GroupMember(id: "m4", name: "赵六", checkedIn: false, checkinTime: nil, status: nil),
            ],
            personalHistory: [
                PersonalCheckinRecord(date: "2026-09-06", status: .normal, time: "19:05"),
                PersonalCheckinRecord(date: "2026-09-02", status: .late, time: "19:32"),
            ]
        )
    }
}