using System.Collections.ObjectModel;
using System.Linq;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using HC_APTBS.Models;
using HC_APTBS.Services;

namespace HC_APTBS.ViewModels
{
    /// <summary>
    /// Root ViewModel for the test panel that displays all tests for the selected pump.
    ///
    /// <para>
    /// Replaces the former <c>TestDisplayViewModel</c>.  Holds one
    /// <see cref="TestSectionViewModel"/> per <see cref="TestDefinition"/> and provides
    /// the public API that <see cref="MainViewModel"/> calls in response to
    /// <see cref="Services.IBenchService"/> events.
    /// </para>
    /// </summary>
    public sealed partial class TestPanelViewModel : ObservableObject
    {
        private readonly ILocalizationService _loc;

        /// <summary>Initialises a new test panel with a localization service.</summary>
        public TestPanelViewModel(ILocalizationService loc) => _loc = loc;

        // ── Cached active phase for fast live-indicator lookup ─────────────────────

        private PhaseCardViewModel? _activePhaseCard;

        // ── Global toggles ────────────────────────────────────────────────────────

        /// <summary>
        /// Controls visibility of operation values (RPM, ME, FBKW) on all phase cards.
        /// Cascades to every <see cref="PhaseCardViewModel.ShowOperationValues"/>.
        /// </summary>
        [ObservableProperty] private bool _showOperationValues;

        // ── Status ────────────────────────────────────────────────────────────────

        /// <summary>Current verbose status message from the bench service.</summary>
        [ObservableProperty] private string _statusText = string.Empty;

        /// <summary>True while a test sequence is in progress.</summary>
        [ObservableProperty] private bool _isRunning;

        /// <summary>Estimated remaining time for the entire test sequence (seconds).</summary>
        [ObservableProperty] private int _remainingSeconds;

        // ── Active phase countdown (driven by IBenchService.PhaseTimerTick) ───────

        /// <summary>Name of the currently running phase (empty when idle).</summary>
        [ObservableProperty] private string _currentPhaseName = string.Empty;

        /// <summary>Sub-section of the current phase: "Conditioning", "Measuring", or empty.</summary>
        [ObservableProperty] private string _sectionLabel = string.Empty;

        /// <summary>Seconds remaining in the current sub-section countdown.</summary>
        [ObservableProperty] private int _phaseRemainingSeconds;

        /// <summary>Total seconds for the current sub-section (denominator for progress).</summary>
        [ObservableProperty] private int _phaseTotalSeconds;

        /// <summary>Progress through the current sub-section (0.0 → 1.0).</summary>
        [ObservableProperty] private double _phaseProgress;

        // ── Test sections ─────────────────────────────────────────────────────────

        /// <summary>All test sections for the currently loaded pump.</summary>
        public ObservableCollection<TestSectionViewModel> Tests { get; } = new();

        // ── Show values cascade ───────────────────────────────────────────────────

        partial void OnShowOperationValuesChanged(bool value)
        {
            foreach (var section in Tests)
                foreach (var phase in section.Phases)
                    phase.ShowOperationValues = value;
        }

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

        /// <summary>
        /// Toggles enable/disable for every phase across all test sections.
        /// If any phase is currently disabled, enables all; otherwise disables all.
        /// </summary>
        [RelayCommand]
        private void ToggleCheckAll()
        {
            bool anyDisabled = Tests.Any(s => s.Phases.Any(p => !p.IsEnabled));
            bool newState = anyDisabled;

            foreach (var section in Tests)
            {
                // Bypass per-section cascade guard by setting AllPhasesChecked directly,
                // which will cascade down to children.
                section.AllPhasesChecked = newState;
            }
        }

        // ── Public API: loading ───────────────────────────────────────────────────

        /// <summary>
        /// Populates the test panel with all tests from the given pump definition.
        /// Call when the selected pump changes.
        /// </summary>
        /// <param name="pump">The pump whose tests to display.</param>
        public void LoadAllTests(PumpDefinition pump)
        {
            Tests.Clear();
            _activePhaseCard = null;
            StatusText       = string.Empty;
            RemainingSeconds = 0;

            foreach (var testDef in pump.Tests)
            {
                var section = TestSectionViewModel.FromDefinition(testDef, ShowOperationValues, _loc);
                Tests.Add(section);
            }

            // Compute initial remaining seconds estimate.
            RemainingSeconds = pump.Tests.Sum(t => t.EstimatedTotalSeconds());
        }

        // ── Public API: real-time updates from BenchService events ─────────────────

        /// <summary>
        /// Marks the named phase as actively executing and clears any previous active state.
        /// Caches the active phase card for fast live-indicator updates.
        /// </summary>
        /// <param name="phaseName">Name of the phase that is now running.</param>
        public void SetActivePhase(string phaseName)
        {
            StatusText       = phaseName;
            CurrentPhaseName = phaseName;
            ClearPhaseTimer();
            _activePhaseCard = null;

            foreach (var section in Tests)
            {
                bool sectionActive = false;
                foreach (var phase in section.Phases)
                {
                    if (phase.Name == phaseName && !phase.IsPassed && !phase.IsFailed)
                    {
                        phase.IsActive   = true;
                        _activePhaseCard = phase;
                        sectionActive    = true;
                    }
                    else
                    {
                        phase.IsActive = false;
                    }
                }
                section.IsActiveTest = sectionActive;
            }
        }

        /// <summary>
        /// Marks a phase as completed with the given pass/fail result.
        /// </summary>
        /// <param name="phaseName">Name of the completed phase.</param>
        /// <param name="passed">True if the phase passed all criteria.</param>
        public void SetPhaseResult(string phaseName, bool passed)
        {
            foreach (var section in Tests)
            {
                foreach (var phase in section.Phases)
                {
                    if (phase.Name != phaseName || (!phase.IsActive && !phase.IsPassed && !phase.IsFailed))
                        continue;

                    // Only update if this is the active phase (avoid overwriting already-completed phases
                    // with the same name in different tests).
                    if (!phase.IsActive) continue;

                    phase.IsActive   = false;
                    phase.IsPassed   = passed;
                    phase.IsFailed   = !passed;
                    phase.ResultText = passed ? _loc.GetString("Common.Pass") : _loc.GetString("Common.Fail");
                    break;
                }

                // Recalculate section active state.
                section.IsActiveTest = section.Phases.Any(p => p.IsActive);
            }

            if (_activePhaseCard?.Name == phaseName)
                _activePhaseCard = null;
        }

        /// <summary>
        /// Updates the live measurement value on the graphic indicator for the currently
        /// active phase that has a matching receive parameter.
        /// </summary>
        /// <param name="paramName">CAN parameter name (e.g. "QDelivery").</param>
        /// <param name="value">Current measured value.</param>
        public void UpdateLiveIndicator(string paramName, double value)
        {
            if (_activePhaseCard == null) return;

            foreach (var indicator in _activePhaseCard.ResultIndicators)
            {
                if (indicator.ParameterName == paramName)
                {
                    indicator.CurrentValue = value;
                    return;
                }
            }
        }

        /// <summary>
        /// Applies a phase-timer tick from <see cref="IBenchService.PhaseTimerTick"/>.
        /// Updates the sub-section label, remaining/total seconds and computed progress.
        /// Must be called on the UI thread.
        /// </summary>
        public void ApplyPhaseTimerTick(string section, int remaining, int total)
        {
            SectionLabel           = section;
            PhaseRemainingSeconds  = remaining;
            PhaseTotalSeconds      = total;
            PhaseProgress          = total > 0 ? 1.0 - (double)remaining / total : 0.0;
        }

        /// <summary>Clears the active-phase countdown (call on phase change and test end).</summary>
        public void ClearPhaseTimer()
        {
            SectionLabel          = string.Empty;
            PhaseRemainingSeconds = 0;
            PhaseTotalSeconds     = 0;
            PhaseProgress         = 0;
        }

        /// <summary>
        /// Resets all phase execution states and graphic indicators for a fresh test run.
        /// </summary>
        public void ResetResults()
        {
            _activePhaseCard = null;
            StatusText       = string.Empty;
            CurrentPhaseName = string.Empty;
            ClearPhaseTimer();

            foreach (var section in Tests)
            {
                section.IsActiveTest = false;
                foreach (var phase in section.Phases)
                    phase.Reset();
            }

            // Recalculate remaining seconds.
            int total = 0;
            foreach (var section in Tests)
            {
                if (section.Source != null)
                    total += section.Source.EstimatedTotalSeconds();
            }
            RemainingSeconds = total;
        }
    }
}