HC_APTBS/ViewModels/Pages/PumpPageViewModel.cs

using System;
using System.ComponentModel;
using System.Windows.Media;
using System.Windows.Threading;
using CommunityToolkit.Mvvm.ComponentModel;
using HC_APTBS.Models;
using HC_APTBS.ViewModels.Dialogs;
using SkiaSharp;

namespace HC_APTBS.ViewModels.Pages
{
    /// <summary>
    /// ViewModel for the Pump navigation page.
    ///
    /// <para>Thin façade that groups the pump-related child ViewModels owned by
    /// <see cref="MainViewModel"/> and adds banner flags. Holds a <see cref="Root"/>
    /// reference so page XAML can bind to MainViewModel-owned properties (PumpRpm,
    /// PumpTemp, KLineState, …) via <c>{Binding Root.X}</c>.</para>
    /// </summary>
    public sealed partial class PumpPageViewModel : ObservableObject
    {
        /// <summary>Root ViewModel — owns services, live readings, and global commands.</summary>
        public MainViewModel Root { get; }

        // ── Child VM façades ──────────────────────────────────────────────────────

        /// <summary>Pump selector and K-Line read.</summary>
        public PumpIdentificationViewModel Identification => Root.PumpIdentification;

        /// <summary>Diagnostic Trouble Code list.</summary>
        public DtcListViewModel DtcList { get; }

        /// <summary>DFI management.</summary>
        public DfiManageViewModel DfiViewModel => Root.DfiViewModel;

        /// <summary>Manual pump control sliders.</summary>
        public PumpControlViewModel PumpControl => Root.PumpControl;

        /// <summary>First pump status display — Status word.</summary>
        public StatusDisplayViewModel StatusDisplay1 => Root.StatusDisplay1;

        /// <summary>Second pump status display — Empf3 word.</summary>
        public StatusDisplayViewModel StatusDisplay2 => Root.StatusDisplay2;

        /// <summary>BIP-STATUS display (PSG5-PI pumps only; hidden via HasDefinition for others).</summary>
        public BipDisplayViewModel BipDisplay => Root.BipDisplay;

        /// <summary>Current immobilizer unlock VM. Null when no unlock is in progress.</summary>
        public UnlockProgressViewModel? UnlockVm => Root.CurrentUnlockVm;

        /// <summary>Real-time RPM chart (120-sample rolling window).</summary>
        public SingleFlowChartViewModel RpmChart { get; }

        private readonly DispatcherTimer _rpmChartTimer;

        // ── Banner flags (derived from Root state) ────────────────────────────────

        /// <summary>True when a pump has been loaded from the database.</summary>
        [ObservableProperty] private bool _isPumpSelected;

        /// <summary>True when the K-Line session is currently open.</summary>
        [ObservableProperty] private bool _isKLineSessionOpen;

        /// <summary>True when the K-Line session is in the failed state.</summary>
        [ObservableProperty] private bool _isKLineSessionFailed;

        /// <summary>True for pumps that require a Ford immobilizer unlock (Type 1 or 2).</summary>
        [ObservableProperty] private bool _isUnlockApplicable;

        /// <summary>Constructs the page VM and subscribes to relevant Root state changes.</summary>
        public PumpPageViewModel(
            MainViewModel root,
            DtcListViewModel dtcList)
        {
            Root    = root;
            DtcList = dtcList;
            RpmChart = new SingleFlowChartViewModel(
                "RPM",
                new SKColor(0x21, 0x96, 0xF3),
                maxSamples: 120,
                smoothScroll: true);

            _rpmChartTimer = new DispatcherTimer
            {
                Interval = HzToInterval(root.Config.Settings.RpmChartUpdateHz)
            };
            _rpmChartTimer.Tick += (_, _) => RpmChart.AddValue(Root.PumpRpm);
            _rpmChartTimer.Start();

            // Per-frame viewport slide — produces smooth continuous leftward motion independent
            // of data cadence. Safe to leave subscribed for the VM's lifetime (one DateTime.UtcNow
            // and two property sets per render frame).
            CompositionTarget.Rendering += OnRenderFrame;

            RefreshDerivedFlags();

            Root.PropertyChanged += OnRootPropertyChanged;
            Root.SettingsSaved   += OnSettingsSaved;
            Root.PumpIdentification.PumpChanged += _ => RefreshDerivedFlags();
        }

        private void OnRenderFrame(object? sender, EventArgs e)
        {
            int hz = Root.Config.Settings.RpmChartUpdateHz;
            if (hz <= 0) hz = 15;
            RpmChart.UpdateViewport(DateTime.UtcNow, 1000.0 / hz);
        }

        private void OnRootPropertyChanged(object? sender, PropertyChangedEventArgs e)
        {
            switch (e.PropertyName)
            {
                case nameof(MainViewModel.KLineState):
                    IsKLineSessionOpen   = Root.KLineState == KLineConnectionState.Connected;
                    IsKLineSessionFailed = Root.KLineState == KLineConnectionState.Failed;
                    break;

                case nameof(MainViewModel.CurrentUnlockVm):
                    OnPropertyChanged(nameof(UnlockVm));
                    break;
            }
        }

        private void OnSettingsSaved()
        {
            _rpmChartTimer.Interval = HzToInterval(Root.Config.Settings.RpmChartUpdateHz);
        }

        private static System.TimeSpan HzToInterval(int hz) =>
            System.TimeSpan.FromMilliseconds(hz > 0 ? 1000.0 / hz : 1000.0 / 15);

        private void RefreshDerivedFlags()
        {
            IsPumpSelected       = Root.CurrentPump != null;
            IsKLineSessionOpen   = Root.KLineState == KLineConnectionState.Connected;
            IsKLineSessionFailed = Root.KLineState == KLineConnectionState.Failed;
            IsUnlockApplicable   = Root.CurrentPump != null && Root.CurrentPump.UnlockType != 0;
            OnPropertyChanged(nameof(UnlockVm));

            DtcList.Reset();
            RpmChart.Clear();
        }
    }
}