import Foundation
import SwiftUI

@MainActor
class RaceDiscoveryViewModel: ObservableObject {
    @Published var races: [Race] = []
    @Published var savedRaces: [Race] = []
    @Published var selectedRace: Race?
    @Published var isLoading: Bool = false
    @Published var error: RaceError?
    @Published var filter: RaceFilter = RaceFilter()

    private let service: RaceServiceProtocol

    init(service: RaceServiceProtocol = RaceService()) {
        self.service = service
    }

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

        do {
            races = try await service.listRaces(filter: filter)
        } catch let error as RaceError {
            self.error = error
        } catch {
            print("Failed to fetch races: \(error)")
        }
    }

    func selectRace(id: String) async {
        isLoading = true
        error = nil
        defer { isLoading = false }

        do {
            let race = try await service.getRace(id: id)
            selectedRace = race
            if let index = races.firstIndex(where: { $0.id == id }) {
                races[index] = race
                objectWillChange.send()
            }
        } catch let error as RaceError {
            self.error = error
        } catch {
            print("Failed to get race: \(error)")
        }
    }

    func toggleSaveRace(id: String) async {
        guard let race = races.first(where: { $0.id == id }) else { return }
        let newSavedState = !race.isSaved

        do {
            try await service.saveRace(id: id, isSaved: newSavedState)
            if let index = races.firstIndex(where: { $0.id == id }) {
                races[index].isSaved = newSavedState
                objectWillChange.send()
            }
            if newSavedState {
                savedRaces.append(races.first(where: { $0.id == id }) ?? race)
            } else {
                savedRaces.removeAll { $0.id == id }
            }
            objectWillChange.send()
        } catch {
            print("Failed to toggle save race: \(error)")
        }
    }

    func registerForRace(id: String) async {
        do {
            try await service.registerForRace(id: id)
            if let index = races.firstIndex(where: { $0.id == id }) {
                races[index].isRegistered = true
                objectWillChange.send()
            }
        } catch {
            print("Failed to register for race: \(error)")
        }
    }

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

        do {
            savedRaces = try await service.listRaces(filter: RaceFilter(limit: 50, offset: 0))
                .filter { $0.isSaved }
        } catch let error as RaceError {
            self.error = error
        } catch {
            print("Failed to fetch saved races: \(error)")
        }
    }

    var upcomingRaces: [Race] {
        races.filter { $0.isUpcoming }.sorted { $0.raceDate < $1.raceDate }
    }

    var raceTypes: [RaceType] { RaceType.allCases }
    var terrainTypes: [TerrainType] { TerrainType.allCases }
}