import CoreDomain
import CoreModel
import Observation

/// 提交计划页状态。
public enum PlanSubmitUiState: Equatable {
    case loading
    case success(PlanSubmitData)
    case error(String)
}

@MainActor
@Observable
public final class PlanSubmitViewModel {
    public private(set) var uiState: PlanSubmitUiState = .loading
    public var saving = false
    public var saved = false

    private let planUseCase: PlanUseCase
    private let type: PlanType
    private let periodKey: String
    private var loadTask: Task<Void, Never>?

    public init(planUseCase: PlanUseCase, type: PlanType, periodKey: String) {
        self.planUseCase = planUseCase
        self.type = type
        self.periodKey = periodKey
    }

    public func load() {
        loadTask?.cancel()
        loadTask = Task { [weak self] in
            guard let self else { return }
            self.uiState = .loading
            do {
                for try await data in self.planUseCase.observePlanSubmit(type: self.type, periodKey: self.periodKey) {
                    self.uiState = .success(data)
                }
            } catch is CancellationError {
            } catch {
                self.uiState = .error(error.localizedDescription)
            }
        }
    }

    public func save(content: String) {
        guard !saving else { return }
        saving = true
        Task { [weak self] in
            guard let self else { return }
            try? await self.planUseCase.savePlan(type: self.type, periodKey: self.periodKey, content: content, attachments: [])
            self.saving = false
            self.saved = true
        }
    }
}