import CoreDomain
import Foundation
import Observation

@MainActor
@Observable
public final class AuthViewModel {
    public var isSendingCode = false
    public var countdownSeconds = 0
    public var isSubmitting = false
    public var errorMessage: String?
    public var didLogin = false

    private let sessionUseCase: SessionUseCase
    private var countdownTask: Task<Void, Never>?

    public init(sessionUseCase: SessionUseCase) {
        self.sessionUseCase = sessionUseCase
    }

    public func requestSmsCode(phone: String) {
        guard !isSendingCode, countdownSeconds == 0 else { return }
        isSendingCode = true
        errorMessage = nil
        Task { [weak self] in
            guard let self else { return }
            do {
                try await self.sessionUseCase.requestSmsCode(phone: phone)
                self.startCountdown()
            } catch {
                self.errorMessage = (error as? LocalizedError)?.errorDescription ?? error.localizedDescription
            }
            self.isSendingCode = false
        }
    }

    public func login(phone: String, code: String) {
        guard !isSubmitting else { return }
        isSubmitting = true
        errorMessage = nil
        Task { [weak self] in
            guard let self else { return }
            do {
                try await self.sessionUseCase.login(phone: phone, code: code)
                self.didLogin = true
            } catch {
                self.errorMessage = (error as? LocalizedError)?.errorDescription ?? error.localizedDescription
            }
            self.isSubmitting = false
        }
    }

    private func startCountdown() {
        countdownTask?.cancel()
        countdownSeconds = 60
        countdownTask = Task { [weak self] in
            guard let self else { return }
            while self.countdownSeconds > 0 {
                try? await Task.sleep(for: .seconds(1))
                guard !Task.isCancelled else { return }
                self.countdownSeconds -= 1
            }
        }
    }
}