using System;
using System.Windows;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using HC_APTBS.Services;

namespace HC_APTBS.ViewModels.Dialogs
{
    /// <summary>
    /// ViewModel for the Dashboard "Connect &amp; Auto Test" snackbar.
    /// Receives <see cref="AutoTestState"/> transitions and failure reasons from the
    /// orchestrator, exposes snackbar-friendly bindings (progress, phase text, success),
    /// and forwards the Cancel click to the orchestrator's CTS.
    /// Modelled on <see cref="UnlockProgressViewModel"/>.
    /// </summary>
    public sealed partial class AutoTestProgressViewModel : ObservableObject, IDisposable
    {
        private readonly IAutoTestOrchestrator _orchestrator;
        private readonly ILocalizationService _loc;

        /// <summary>Creates the ViewModel and subscribes to orchestrator events.</summary>
        public AutoTestProgressViewModel(IAutoTestOrchestrator orchestrator, ILocalizationService loc)
        {
            _orchestrator = orchestrator;
            _loc = loc;

            _typeLabel = _loc.GetString("AutoTest.TypeLabel");
            _phaseText = _loc.GetString("AutoTest.State.Preflight");
            _isCancellable = true;

            _orchestrator.StateChanged += OnStateChanged;
            _orchestrator.Failed += OnFailed;
        }

        // ── Observable properties ────────────────────────────────────────────────

        /// <summary>Progress percentage (0–100). Meaningful during Unlocking and test Running phases.</summary>
        [ObservableProperty] private int _progress;

        /// <summary>Leading label (localised "Auto Test").</summary>
        [ObservableProperty] private string _typeLabel;

        /// <summary>Current phase description shown in the snackbar.</summary>
        [ObservableProperty] private string _phaseText;

        /// <summary>Terminal result text — populated on Completed/Aborted.</summary>
        [ObservableProperty] private string _resultText = string.Empty;

        /// <summary>True once the sequence reaches Completed or Aborted.</summary>
        [NotifyCanExecuteChangedFor(nameof(CloseCommand))]
        [ObservableProperty] private bool _isComplete;

        /// <summary>True while the Cancel button should be enabled (all non-terminal states).</summary>
        [NotifyCanExecuteChangedFor(nameof(CancelCommand))]
        [ObservableProperty] private bool _isCancellable;

        /// <summary>Tri-state: null while running, true = success, false = failure.</summary>
        [ObservableProperty] private bool? _isSuccess;

        // ── Commands ─────────────────────────────────────────────────────────────

        /// <summary>Cancels the orchestrator's current sequence.</summary>
        [RelayCommand(CanExecute = nameof(IsCancellable))]
        private void Cancel() => _orchestrator.Cancel();

        /// <summary>Closes the snackbar (emits <see cref="RequestClose"/>).</summary>
        [RelayCommand(CanExecute = nameof(IsComplete))]
        private void Close() => RequestClose?.Invoke();

        // ── Events ───────────────────────────────────────────────────────────────

        /// <summary>Raised when the snackbar should close itself (after success / user dismiss).</summary>
        public event Action? RequestClose;

        // ── Orchestrator event handlers ──────────────────────────────────────────

        private void OnStateChanged(AutoTestState state, string? detail)
        {
            Application.Current?.Dispatcher?.Invoke(() =>
            {
                switch (state)
                {
                    case AutoTestState.Preflight:
                        PhaseText = _loc.GetString("AutoTest.State.Preflight");
                        break;
                    case AutoTestState.ConnectingKLine:
                        PhaseText = _loc.GetString("AutoTest.State.Connecting");
                        break;
                    case AutoTestState.ReadingPump:
                        PhaseText = _loc.GetString("AutoTest.State.Reading");
                        if (!string.IsNullOrEmpty(detail) && int.TryParse(detail, out int pct))
                            Progress = pct;
                        break;
                    case AutoTestState.Unlocking:
                        PhaseText = string.IsNullOrEmpty(detail)
                            ? _loc.GetString("AutoTest.State.Unlocking")
                            : string.Format(_loc.GetString("AutoTest.State.UnlockingWithDetail"), detail);
                        break;
                    case AutoTestState.TurningOnBench:
                        PhaseText = _loc.GetString("AutoTest.State.BenchOn");
                        break;
                    case AutoTestState.StartingOilPump:
                        PhaseText = _loc.GetString("AutoTest.State.OilPump");
                        break;
                    case AutoTestState.StartingTest:
                        PhaseText = _loc.GetString("AutoTest.State.TestStart");
                        break;
                    case AutoTestState.Running:
                        PhaseText = string.IsNullOrEmpty(detail)
                            ? _loc.GetString("AutoTest.State.Running")
                            : string.Format(_loc.GetString("AutoTest.State.RunningWithPhase"), detail);
                        break;
                    case AutoTestState.Completed:
                        PhaseText = _loc.GetString("AutoTest.State.Completed");
                        ResultText = PhaseText;
                        Progress = 100;
                        IsComplete = true;
                        IsCancellable = false;
                        IsSuccess = true;
                        break;
                    case AutoTestState.Aborted:
                        // Detail populated by OnFailed; still terminal.
                        IsComplete = true;
                        IsCancellable = false;
                        IsSuccess = false;
                        break;
                }
            });
        }

        private void OnFailed(AutoTestFailureReason reason, string message)
        {
            Application.Current?.Dispatcher?.Invoke(() =>
            {
                string key = "AutoTest.Failure." + reason;
                string localised = _loc.GetString(key);
                if (string.IsNullOrEmpty(localised) || localised == key)
                    localised = reason.ToString();

                ResultText = string.IsNullOrEmpty(message)
                    ? localised
                    : $"{localised}: {message}";
                PhaseText = string.Format(_loc.GetString("AutoTest.State.Aborted"), ResultText);
                IsComplete = true;
                IsCancellable = false;
                IsSuccess = false;
            });
        }

        // ── IDisposable ──────────────────────────────────────────────────────────

        /// <summary>Unsubscribes from orchestrator events.</summary>
        public void Dispose()
        {
            _orchestrator.StateChanged -= OnStateChanged;
            _orchestrator.Failed -= OnFailed;
        }
    }
}