import Foundation
import SwiftUI

@MainActor
class BeginnerModeViewModel: ObservableObject {
    @Published var config: BeginnerConfig?
    @Published var milestones: [Milestone] = []
    @Published var currentLevel: BeginnerLevel = .justStarted
    @Published var isLoading: Bool = false
    @Published var error: BeginnerModeError?

    private let service: BeginnerModeServiceProtocol

    init(service: BeginnerModeServiceProtocol = BeginnerModeService()) {
        self.service = service
    }

    func fetchConfig() async {
        isLoading = true
        error = nil
        defer { isLoading = false }

        do {
            config = try await service.getConfig()
            currentLevel = config?.currentLevel ?? .justStarted
        } catch let error as BeginnerModeError {
            self.error = error
        } catch {
            print("Failed to fetch beginner config: \(error)")
        }
    }

    func fetchMilestoneProgress() async {
        isLoading = true
        error = nil
        defer { isLoading = false }

        do {
            let result = try await service.getMilestoneProgress()
            milestones = result.milestones
            currentLevel = result.level
        } catch let error as BeginnerModeError {
            self.error = error
        } catch {
            print("Failed to fetch milestone progress: \(error)")
        }
    }

    func toggleBeginnerMode(isEnabled: Bool) async {
        do {
            let request = UpdateBeginnerConfigRequest(isEnabled: isEnabled)
            let updatedConfig = try await service.updateConfig(request: request)
            config = updatedConfig
            objectWillChange.send()
        } catch {
            print("Failed to toggle beginner mode: \(error)")
        }
    }

    func completeOnboardingStep(_ step: OnboardingStep) async {
        guard var currentConfig = config else { return }
        currentConfig.completedOnboardingSteps.append(step)

        do {
            let request = UpdateBeginnerConfigRequest(completedOnboardingSteps: currentConfig.completedOnboardingSteps)
            let updatedConfig = try await service.updateConfig(request: request)
            config = updatedConfig
            objectWillChange.send()
        } catch {
            print("Failed to complete onboarding step: \(error)")
        }
    }

    var onboardingSteps: [OnboardingStep] { OnboardingStep.allCases }

    var completedOnboardingCount: Int {
        config?.completedOnboardingSteps.count ?? 0
    }

    var remainingOnboardingSteps: [OnboardingStep] {
        let completed = config?.completedOnboardingSteps ?? []
        return onboardingSteps.filter { !completed.contains($0) }
    }

    var completedMilestoneCount: Int {
        milestones.filter { $0.isCompleted }.count
    }

    var totalMilestoneCount: Int {
        milestones.count
    }

    var levels: [BeginnerLevel] { BeginnerLevel.allCases }
}