//
//  TripWizardViewModel.swift
//  SportsTime
//
//  ViewModel for progressive-reveal trip wizard.
//

import Foundation
import SwiftUI

@Observable
final class TripWizardViewModel {

    // MARK: - Planning Mode

    var planningMode: PlanningMode? = nil {
        didSet {
            if oldValue != nil && oldValue != planningMode {
                resetDownstreamFromPlanningMode()
            }
        }
    }

    // MARK: - Sports Selection

    var selectedSports: Set<Sport> = []

    // MARK: - Dates

    var startDate: Date = Date()
    var endDate: Date = Date().addingTimeInterval(86400 * 7)
    var hasSetDates: Bool = false

    // MARK: - Regions

    var selectedRegions: Set<Region> = []

    // MARK: - Route Preferences

    var routePreference: RoutePreference = .balanced
    var hasSetRoutePreference: Bool = false

    // MARK: - Repeat Cities

    var allowRepeatCities: Bool = false
    var hasSetRepeatCities: Bool = false

    // MARK: - Must Stops

    var mustStopLocations: [LocationInput] = []

    // MARK: - Planning State

    var isPlanning: Bool = false

    // MARK: - Sport Availability

    var sportAvailability: [Sport: Bool] = [:]
    var isLoadingSportAvailability: Bool = false

    // MARK: - Reveal State (computed)

    var isPlanningModeStepVisible: Bool { true }

    var isDatesStepVisible: Bool {
        planningMode != nil
    }

    var isSportsStepVisible: Bool {
        isDatesStepVisible && hasSetDates
    }

    var isRegionsStepVisible: Bool {
        isSportsStepVisible && !selectedSports.isEmpty
    }

    var isRoutePreferenceStepVisible: Bool {
        isRegionsStepVisible && !selectedRegions.isEmpty
    }

    var isRepeatCitiesStepVisible: Bool {
        isRoutePreferenceStepVisible && hasSetRoutePreference
    }

    var isMustStopsStepVisible: Bool {
        isRepeatCitiesStepVisible && hasSetRepeatCities
    }

    var isReviewStepVisible: Bool {
        isMustStopsStepVisible
    }

    /// Combined state for animation tracking
    var revealState: Int {
        var state = 0
        if isSportsStepVisible { state += 1 }
        if isDatesStepVisible { state += 2 }
        if isRegionsStepVisible { state += 4 }
        if isRoutePreferenceStepVisible { state += 8 }
        if isRepeatCitiesStepVisible { state += 16 }
        if isMustStopsStepVisible { state += 32 }
        if isReviewStepVisible { state += 64 }
        return state
    }

    // MARK: - Sport Availability

    func canSelectSport(_ sport: Sport) -> Bool {
        sportAvailability[sport] ?? true // Default to available if not checked
    }

    func fetchSportAvailability() async {
        guard hasSetDates else { return }

        isLoadingSportAvailability = true
        defer { isLoadingSportAvailability = false }

        var availability: [Sport: Bool] = [:]

        for sport in Sport.supported {
            do {
                let games = try await AppDataProvider.shared.filterGames(
                    sports: [sport],
                    startDate: startDate,
                    endDate: endDate
                )
                availability[sport] = !games.isEmpty
            } catch {
                availability[sport] = true // Default to available on error
            }
        }

        await MainActor.run {
            self.sportAvailability = availability
        }
    }

    // MARK: - Reset Logic

    private func resetDownstreamFromPlanningMode() {
        selectedSports = []
        hasSetDates = false
        selectedRegions = []
        hasSetRoutePreference = false
        hasSetRepeatCities = false
        mustStopLocations = []
    }
}