//
//  LocationPermissionManager.swift
//  SportsTime
//
//  Manages location permission requests and status
//

import Foundation
import CoreLocation
import SwiftUI

@MainActor
@Observable
final class LocationPermissionManager: NSObject {
    static let shared = LocationPermissionManager()

    private(set) var authorizationStatus: CLAuthorizationStatus = .notDetermined
    private(set) var currentLocation: CLLocation?
    private(set) var isRequestingPermission = false

    private let locationManager = CLLocationManager()

    override private init() {
        super.init()
        locationManager.delegate = self
        authorizationStatus = locationManager.authorizationStatus
    }

    // MARK: - Computed Properties

    var isAuthorized: Bool {
        authorizationStatus == .authorizedWhenInUse || authorizationStatus == .authorizedAlways
    }

    var needsPermission: Bool {
        authorizationStatus == .notDetermined
    }

    var isDenied: Bool {
        authorizationStatus == .denied || authorizationStatus == .restricted
    }

    var statusMessage: String {
        switch authorizationStatus {
        case .notDetermined:
            return "Location access helps find nearby stadiums and optimize your route."
        case .restricted:
            return "Location access is restricted on this device."
        case .denied:
            return "Location access was denied. Enable it in Settings to use this feature."
        case .authorizedAlways, .authorizedWhenInUse:
            return "Location access granted."
        @unknown default:
            return "Unknown location status."
        }
    }

    // MARK: - Actions

    func requestPermission() {
        guard authorizationStatus == .notDetermined else { return }
        isRequestingPermission = true
        locationManager.requestWhenInUseAuthorization()
    }

    func requestCurrentLocation() {
        guard isAuthorized else { return }
        locationManager.requestLocation()
    }

    func openSettings() {
        guard let settingsURL = URL(string: UIApplication.openSettingsURLString) else { return }
        UIApplication.shared.open(settingsURL)
    }
}

// MARK: - CLLocationManagerDelegate

extension LocationPermissionManager: CLLocationManagerDelegate {
    nonisolated func locationManagerDidChangeAuthorization(_ manager: CLLocationManager) {
        Task { @MainActor in
            self.authorizationStatus = manager.authorizationStatus
            self.isRequestingPermission = false

            // Auto-request location if newly authorized
            if self.isAuthorized {
                self.requestCurrentLocation()
            }
        }
    }

    nonisolated func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        Task { @MainActor in
            self.currentLocation = locations.last
        }
    }

    nonisolated func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        // Location error handled silently
    }
}

// MARK: - Location Permission View

struct LocationPermissionView: View {
    @Bindable var manager = LocationPermissionManager.shared

    var body: some View {
        VStack(spacing: 16) {
            Image(systemName: "location.circle.fill")
                .font(.system(size: 60))
                .foregroundStyle(.blue)

            Text("Enable Location")
                .font(.title2)
                .fontWeight(.bold)

            Text(manager.statusMessage)
                .font(.subheadline)
                .foregroundStyle(.secondary)
                .multilineTextAlignment(.center)
                .padding(.horizontal)

            if manager.needsPermission {
                Button {
                    manager.requestPermission()
                } label: {
                    Text("Allow Location Access")
                        .fontWeight(.semibold)
                        .frame(maxWidth: .infinity)
                        .padding()
                        .background(Color.blue)
                        .foregroundStyle(.white)
                        .clipShape(RoundedRectangle(cornerRadius: 12))
                }
                .padding(.horizontal)
            } else if manager.isDenied {
                Button {
                    manager.openSettings()
                } label: {
                    Text("Open Settings")
                        .fontWeight(.semibold)
                        .frame(maxWidth: .infinity)
                        .padding()
                        .background(Color.blue)
                        .foregroundStyle(.white)
                        .clipShape(RoundedRectangle(cornerRadius: 12))
                }
                .padding(.horizontal)
            } else if manager.isAuthorized {
                Label("Location Enabled", systemImage: "checkmark.circle.fill")
                    .foregroundStyle(.green)
            }
        }
        .padding()
    }
}

// MARK: - Location Permission Banner

struct LocationPermissionBanner: View {
    @Bindable var manager = LocationPermissionManager.shared
    @Binding var isPresented: Bool

    var body: some View {
        if manager.needsPermission || manager.isDenied {
            HStack(spacing: 12) {
                Image(systemName: "location.slash")
                    .foregroundStyle(.orange)

                VStack(alignment: .leading, spacing: 2) {
                    Text("Location Not Available")
                        .font(.subheadline)
                        .fontWeight(.medium)
                    Text(manager.needsPermission ? "Enable for better route planning" : "Tap to enable in Settings")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }

                Spacer()

                Button {
                    if manager.needsPermission {
                        manager.requestPermission()
                    } else {
                        manager.openSettings()
                    }
                } label: {
                    Text(manager.needsPermission ? "Enable" : "Settings")
                        .font(.caption)
                        .fontWeight(.semibold)
                        .padding(.horizontal, 12)
                        .padding(.vertical, 6)
                        .background(Color.blue)
                        .foregroundStyle(.white)
                        .clipShape(Capsule())
                }

                Button {
                    isPresented = false
                } label: {
                    Image(systemName: "xmark")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }
            }
            .padding()
            .background(Color(.secondarySystemBackground))
            .clipShape(RoundedRectangle(cornerRadius: 12))
        }
    }
}

#Preview {
    LocationPermissionView()
}