using System.Linq;
using AcDream.App.Audio;
using AcDream.App.Net;
using AcDream.App.Rendering;
using AcDream.App.Rendering.Wb;
using AcDream.App.Streaming;
using AcDream.App.UI;
using AcDream.UI.Abstractions;
using AcDream.UI.Abstractions.Panels.Settings;
using AcDream.UI.Abstractions.Settings;
using Silk.NET.Maths;
using Silk.NET.Windowing;

namespace AcDream.App.Settings;

internal interface IRuntimeDisplayWindowTarget
{
    void Apply(DisplaySettings display);
}

internal interface IRuntimeQualityApplicationTarget
{
    void SetAlphaToCoverage(bool enabled);

    void SetAnisotropic(int level);

    void PublishRenderRange(int nearRadius, int farRadius);

    void ReconfigureStreamingRadii(int nearRadius, int farRadius);

    void SetCompletionBudget(int maxCompletionsPerFrame);
}

internal interface IRuntimeUiLockTarget
{
    void Apply(bool locked);
}

/// <summary>
/// Campaign CH slice CH6c target seam for the Chat tab's transparency sliders,
/// mirroring <see cref="IRuntimeUiLockTarget"/>'s shape.
/// </summary>
internal interface IRuntimeChatOpacityTarget
{
    void Apply(float defaultOpacity, float activeOpacity);
}

/// <summary>The window properties the display apply touches — a narrow
/// seam so the #388 state machine is testable without faking all of
/// <see cref="IWindow"/> (same idiom as <c>FakePacingSurface</c>'s
/// surface).</summary>
internal interface IWindowedSizeSurface
{
    Vector2D<int> Size { get; set; }

    /// <summary>#388 blast M3: a maximized window silently ignores a Size
    /// write — the apply un-maximizes first (the deleted
    /// <c>WindowState = Normal</c> write used to do this incidentally).</summary>
    bool IsMaximized { get; }

    void Restore();
}

internal sealed class SilkWindowSizeSurface(IWindow window) : IWindowedSizeSurface
{
    private readonly IWindow _window = window
        ?? throw new ArgumentNullException(nameof(window));

    public Vector2D<int> Size
    {
        get => _window.Size;
        set => _window.Size = value;
    }

    public bool IsMaximized => _window.WindowState == WindowState.Maximized;

    public void Restore() => _window.WindowState = WindowState.Normal;
}

internal sealed class SilkRuntimeDisplayWindowTarget : IRuntimeDisplayWindowTarget
{
    private readonly IWindowedSizeSurface _window;
    private readonly IDisplayModeSwitcher _modeSwitcher;
    private readonly Func<string, bool> _isOfferedMode;

    public SilkRuntimeDisplayWindowTarget(IWindow window)
        : this(
            new SilkWindowSizeSurface(window),
            new GlfwDisplayModeSwitcher(window),
            // #391's catalog is the validation source. With no catalog
            // installed, the dropdown falls back to the static preset
            // ladder — the validator must fall back to the SAME list
            // (blast M2: an asymmetric fallback made Full Screen a permanent
            // silent no-op on catalog-less hosts). The switcher's own
            // monitor-mode-list check remains the hard guard either way.
            spec => (Rendering.DisplayModeCatalog.Resolutions
                     ?? DisplaySettings.AvailableResolutions).Contains(spec))
    {
    }

    internal SilkRuntimeDisplayWindowTarget(
        IWindowedSizeSurface window,
        IDisplayModeSwitcher modeSwitcher,
        Func<string, bool> isOfferedMode)
    {
        _window = window ?? throw new ArgumentNullException(nameof(window));
        _modeSwitcher = modeSwitcher
            ?? throw new ArgumentNullException(nameof(modeSwitcher));
        _isOfferedMode = isOfferedMode
            ?? throw new ArgumentNullException(nameof(isOfferedMode));
    }

    /// <summary>
    /// #388: the state-aware display apply. Windowed target = a window
    /// resize (the proven #387 chain); fullscreen target = a validated
    /// native display-mode switch (#376, retail's
    /// <c>Device::ForceDisplayResolution</c> semantics via
    /// <c>glfwSetWindowMonitor</c>). A raw <c>Size</c> write NEVER happens
    /// against a fullscreen window — on GLFW that is a video-mode request
    /// and an unsupported one killed the client mid-session (the 2026-08-13
    /// gate crash). Every failure path logs and leaves the window in a
    /// usable state instead of throwing.
    /// </summary>
    public void Apply(DisplaySettings display)
    {
        ArgumentNullException.ThrowIfNull(display);
        bool haveResolution =
            TryParseResolution(display.Resolution, out int width, out int height);

        if (display.Fullscreen)
        {
            if (!haveResolution)
            {
                // Mechanism M5: never a SILENT bail-out — §D6's acceptance is
                // "any refused/failed switch logs a line".
                Console.WriteLine(
                    $"display: fullscreen refused — unparseable resolution '{display.Resolution}'");
                return;
            }
            // Mechanism/blast M2: idempotence BEFORE any native work — every
            // Display-backed Config row applies per change (sliders per drag
            // tick), and only this guard keeps those from re-issuing a real
            // display-mode change per mouse sample.
            if (_modeSwitcher.CurrentFullscreenMode is (int curW, int curH)
                && curW == width && curH == height)
                return;
            if (!_isOfferedMode.Invoke($"{width}x{height}"))
            {
                Console.WriteLine(
                    $"display: fullscreen {width}x{height} refused — not an offered mode");
                return;
            }
            if (!_modeSwitcher.TryEnterFullscreen(width, height, out string? error))
                Console.WriteLine(
                    $"display: fullscreen {width}x{height} failed ({error}) — window state unchanged (#392 tracks the persisted-flag divergence)");
            return;
        }

        // Windowed target: leave fullscreen first if needed (the native exit
        // sets the client size itself), otherwise plain window resize.
        if (_modeSwitcher.IsFullscreen)
        {
            if (!haveResolution)
            {
                width = _window.Size.X;
                height = _window.Size.Y;
            }
            if (!_modeSwitcher.TryLeaveFullscreen(width, height, out string? error))
                Console.WriteLine(
                    $"display: leaving fullscreen failed ({error})");
            return;
        }

        if (haveResolution && (_window.Size.X != width || _window.Size.Y != height))
        {
            // Blast M3: a maximized window ignores Size writes — restore
            // first (the deleted WindowState=Normal write did this
            // incidentally; now it is explicit and only-when-needed).
            if (_window.IsMaximized)
                _window.Restore();
            // #387 evidence line (permanent): the resolution-pick write path.
            Console.WriteLine(
                $"display: resolution pick {width}x{height} " +
                $"(window was {_window.Size.X}x{_window.Size.Y})");
            _window.Size = new Vector2D<int>(width, height);
        }
    }

    internal static bool TryParseResolution(
        string spec,
        out int width,
        out int height)
    {
        width = height = 0;
        if (string.IsNullOrWhiteSpace(spec))
            return false;
        string[] parts = spec.Split('x', 2);
        return parts.Length == 2
            && int.TryParse(parts[0], out width)
            && int.TryParse(parts[1], out height)
            && width > 0
            && height > 0;
    }
}

internal sealed class RuntimeSettingsStartupTargets : IRuntimeSettingsStartupTarget
{
    private readonly IRuntimeDisplayWindowTarget _displayWindow;
    private readonly DisplayFramePacingController _pacing;
    private readonly CameraController _cameras;
    private readonly OpenAlAudioEngine? _audio;

    public RuntimeSettingsStartupTargets(
        IRuntimeDisplayWindowTarget displayWindow,
        DisplayFramePacingController pacing,
        CameraController cameras,
        OpenAlAudioEngine? audio)
    {
        _displayWindow = displayWindow
            ?? throw new ArgumentNullException(nameof(displayWindow));
        _pacing = pacing ?? throw new ArgumentNullException(nameof(pacing));
        _cameras = cameras ?? throw new ArgumentNullException(nameof(cameras));
        _audio = audio;
    }

    public void ApplyDisplay(DisplaySettings display)
    {
        ArgumentNullException.ThrowIfNull(display);
        _pacing.RefreshActiveMonitor();
        _pacing.ApplyPreference(display.VSync);
        _displayWindow.Apply(display);
        ApplyFieldOfView(_cameras, display.FieldOfView);
    }

    public void ApplyAudio(AudioSettings audio) => ApplyAudio(_audio, audio);

    /// <summary>#389: the stored Field of View is retail's <c>m_fGameFOV</c>
    /// in DEGREES (registered range [10,160], default 90 —
    /// <c>gmClient::InitUIPreferences @0x004035b0</c>), converted exactly as
    /// retail's option setter does (<c>× 0.017453292519943295</c>,
    /// <c>0x00451e6a</c>) and applied through the smartbox law in
    /// <see cref="CameraController.SetGameFov"/> — NEVER written to a camera's
    /// vertical FOV directly (the pre-#389 behavior, which made the slider
    /// mean a different, aspect-ignorant thing than retail's).</summary>
    internal static void ApplyFieldOfView(
        CameraController cameras,
        float degrees)
    {
        cameras.SetGameFov(degrees * (MathF.PI / 180f));
    }

    internal static void ApplyAudio(
        OpenAlAudioEngine? engine,
        AudioSettings audio)
    {
        ArgumentNullException.ThrowIfNull(audio);
        if (engine is not { IsAvailable: true })
            return;
        engine.MasterVolume = audio.Master;
        (float sfx, float ambient) = ComputeEffectiveCategoryVolumes(audio);
        engine.SfxVolume = sfx;
        engine.AmbientVolume = ambient;
    }

    /// <summary>
    /// Campaign OP slice OP6 (2026-08-11), CORRECTED at the OP6 rework round
    /// (review <c>docs/research/2026-08-11-op6-review.md</c> finding M2): the
    /// Config tab's toggle halves of the Sound/Ambient volume trios
    /// (<see cref="AudioSettings.SfxEnabled"/>/<see cref="AudioSettings.AmbientEnabled"/>
    /// — retail's own ENABLED-sense <c>SoundManager::effect_sounds_enabled</c>/
    /// <c>ambient_sounds_enabled</c> statics, see <see cref="AudioSettings"/>'s
    /// class doc for the byte evidence) gate the SAME slider value: the
    /// effective volume sent to the engine is the slider value when enabled,
    /// zero when not — exactly as if the user dragged the slider to zero.
    /// Extracted as a pure function (no <see cref="OpenAlAudioEngine"/>
    /// dependency) so the mapping itself — not just that some target was
    /// called — is unit-testable without OpenAL hardware/mocking (S5: the
    /// rejected slice's only audio test asserted event ORDER, never the
    /// VALUE that reached the engine, which is exactly how M2's muted-by-
    /// default inversion shipped unnoticed).
    /// </summary>
    internal static (float Sfx, float Ambient) ComputeEffectiveCategoryVolumes(AudioSettings audio)
    {
        ArgumentNullException.ThrowIfNull(audio);
        float sfx = audio.SfxEnabled ? audio.Sfx : 0f;
        float ambient = audio.AmbientEnabled ? audio.Ambient : 0f;
        return (sfx, ambient);
    }
}

internal sealed class RuntimeQualityApplicationTarget
    : IRuntimeQualityApplicationTarget
{
    // Campaign V slice V6h: absent on a backend that composes no world
    // renderers. Alpha-to-coverage and anisotropy are properties of renderers
    // that do not exist there; render range and streaming radii still apply.
    private readonly WbDrawDispatcher? _dispatcher;
    private readonly TerrainAtlas? _terrainAtlas;
    private readonly StreamingController _streaming;
    private readonly WorldRenderRangeState _renderRange;

    public RuntimeQualityApplicationTarget(
        WbDrawDispatcher? dispatcher,
        TerrainAtlas? terrainAtlas,
        StreamingController streaming,
        WorldRenderRangeState renderRange)
    {
        _dispatcher = dispatcher;
        _terrainAtlas = terrainAtlas;
        _streaming = streaming ?? throw new ArgumentNullException(nameof(streaming));
        _renderRange = renderRange ?? throw new ArgumentNullException(nameof(renderRange));
    }

    public void SetAlphaToCoverage(bool enabled)
    {
        if (_dispatcher is not null)
            _dispatcher.AlphaToCoverage = enabled;
    }

    public void SetAnisotropic(int level) => _terrainAtlas?.SetAnisotropic(level);

    public void PublishRenderRange(int nearRadius, int farRadius)
    {
        _renderRange.NearRadius = nearRadius;
        _renderRange.FarRadius = farRadius;
    }

    public void ReconfigureStreamingRadii(int nearRadius, int farRadius) =>
        _streaming.ReconfigureRadii(nearRadius, farRadius);

    public void SetCompletionBudget(int maxCompletionsPerFrame) =>
        _streaming.MaxCompletionsPerFrame = maxCompletionsPerFrame;
}

internal sealed class RuntimeUiLockTarget(UiRoot root) : IRuntimeUiLockTarget
{
    private readonly UiRoot _root = root ?? throw new ArgumentNullException(nameof(root));

    public void Apply(bool locked) => _root.UiLocked = locked;
}

internal sealed class NullRuntimeUiLockTarget : IRuntimeUiLockTarget
{
    public static NullRuntimeUiLockTarget Instance { get; } = new();

    private NullRuntimeUiLockTarget()
    {
    }

    public void Apply(bool locked)
    {
    }
}

internal sealed class RuntimeChatOpacityTarget(RetailWindowOpacityController controller)
    : IRuntimeChatOpacityTarget
{
    private readonly RetailWindowOpacityController _controller =
        controller ?? throw new ArgumentNullException(nameof(controller));

    public void Apply(float defaultOpacity, float activeOpacity) =>
        _controller.SetOpacity(defaultOpacity, activeOpacity);
}

internal sealed class NullRuntimeChatOpacityTarget : IRuntimeChatOpacityTarget
{
    public static NullRuntimeChatOpacityTarget Instance { get; } = new();

    private NullRuntimeChatOpacityTarget()
    {
    }

    public void Apply(float defaultOpacity, float activeOpacity)
    {
    }
}

/// <summary>
/// Complete late-bound target for changes made after startup. Construction and
/// binding are inert; only an explicit controller command mutates borrowers.
/// </summary>
internal sealed class RuntimeSettingsTargets : IRuntimeSettingsTargets
{
    private readonly IRuntimeDisplayWindowTarget _displayWindow;
    private readonly IRuntimeQualityApplicationTarget _quality;
    private readonly IRuntimeUiLockTarget _uiLock;
    private readonly IRuntimeChatOpacityTarget _chatOpacity;
    private readonly ICommandBus _commands;
    private readonly Action<string> _log;
    private readonly OpenAlAudioEngine? _audio;
    private readonly CameraController? _cameras;

    public RuntimeSettingsTargets(
        IRuntimeDisplayWindowTarget displayWindow,
        WbDrawDispatcher? dispatcher,
        TerrainAtlas? terrainAtlas,
        StreamingController streaming,
        WorldRenderRangeState renderRange,
        UiRoot? uiRoot,
        ICommandBus commands,
        RetailWindowOpacityController? chatOpacity = null,
        Action<string>? log = null,
        // Campaign OP slice OP6: the live engine reference — see
        // ApplyAudio's doc. Optional/trailing so every pre-existing
        // construction site keeps compiling unchanged (matches
        // chatOpacity/log's own optional-trailing shape).
        OpenAlAudioEngine? audio = null,
        // #389 blast-review MUST-FIX 2: retail's FOV preference applies LIVE
        // (Render::GRPCallback_OnRenderPreferenceChanged @0x0054d999 →
        // SmartBox::SetDefaultFov → m_fGameFOV, re-read by the smartbox
        // sites every render) — the saved Field of View must reach the
        // cameras on Save, not on the next launch. Null on hosts with no
        // camera graph (headless / fixture callers).
        CameraController? cameras = null)
        : this(
            displayWindow,
            new RuntimeQualityApplicationTarget(
                dispatcher,
                terrainAtlas,
                streaming,
                renderRange),
            uiRoot is null
                ? NullRuntimeUiLockTarget.Instance
                : new RuntimeUiLockTarget(uiRoot),
            commands,
            log,
            chatOpacity is null
                ? NullRuntimeChatOpacityTarget.Instance
                : new RuntimeChatOpacityTarget(chatOpacity),
            audio,
            cameras)
    {
    }

    internal RuntimeSettingsTargets(
        IRuntimeDisplayWindowTarget displayWindow,
        IRuntimeQualityApplicationTarget quality,
        IRuntimeUiLockTarget uiLock,
        ICommandBus commands,
        Action<string>? log = null,
        IRuntimeChatOpacityTarget? chatOpacity = null,
        OpenAlAudioEngine? audio = null,
        CameraController? cameras = null)
    {
        _displayWindow = displayWindow
            ?? throw new ArgumentNullException(nameof(displayWindow));
        _quality = quality ?? throw new ArgumentNullException(nameof(quality));
        _uiLock = uiLock ?? throw new ArgumentNullException(nameof(uiLock));
        _chatOpacity = chatOpacity ?? NullRuntimeChatOpacityTarget.Instance;
        _commands = commands ?? throw new ArgumentNullException(nameof(commands));
        _log = log ?? Console.WriteLine;
        _audio = audio;
        _cameras = cameras;
    }

    public void ApplyDisplayWindowState(DisplaySettings display)
    {
        _displayWindow.Apply(display);
        // #389 blast MUST-FIX 2 (see the ctor's cameras doc): the Field of
        // View applies live on Save, from the update-phase save handler —
        // deliberately NOT from the render-phase preview seam
        // (WorldRenderFrameBuilder.Apply), whose mid-frame camera mutation
        // is the review's WATCH-3 cull-vs-raster landmine.
        if (_cameras is not null)
            RuntimeSettingsStartupTargets.ApplyFieldOfView(_cameras, display.FieldOfView);
    }

    /// <summary>Campaign OP slice OP6: reuses the SAME static helper the
    /// startup path (<see cref="RuntimeSettingsStartupTargets.ApplyAudio"/>)
    /// already runs — one mixer-apply implementation, two call sites (once
    /// at process start, now also on every <c>RuntimeSettingsController.
    /// SaveAudio</c>). <see langword="null"/> engine (a headless/no-audio
    /// host) is a silent no-op, matching every other optional target in
    /// this class.</summary>
    public void ApplyAudio(AudioSettings audio) =>
        RuntimeSettingsStartupTargets.ApplyAudio(_audio, audio);

    public void ApplyQuality(QualitySettings quality)
    {
        _quality.SetAlphaToCoverage(quality.AlphaToCoverage);
        _quality.SetAnisotropic(quality.AnisotropicLevel);
        _quality.PublishRenderRange(quality.NearRadius, quality.FarRadius);
        _quality.ReconfigureStreamingRadii(quality.NearRadius, quality.FarRadius);
        _quality.SetCompletionBudget(quality.MaxCompletionsPerFrame);
        _log(
            $"[QUALITY] Streaming reconciled: nearRadius={quality.NearRadius}, " +
            $"farRadius={quality.FarRadius}, " +
            $"maxCompletions={quality.MaxCompletionsPerFrame}");
    }

    public void ApplyUiLock(bool locked) => _uiLock.Apply(locked);

    /// <summary>
    /// CH3 (2026-08-09): publishes through the SAME
    /// <see cref="LiveSessionCommandRouter"/> generation-gated route every
    /// other outbound Settings/chat command uses — a no-op when no route is
    /// currently attached (disconnected / reconnecting), exactly like every
    /// other <c>ICommandBus.Publish</c> call site. N6 (CH3 Opus review,
    /// 2026-08-09): this silent drop is safe because
    /// <c>RuntimeSettingsController.SaveChat</c> already wrote the toggle to
    /// settings.json BEFORE calling here — the local preference is never
    /// lost — and the next successful connect's PlayerDescription re-runs
    /// <c>SyncChatFromServerOptions</c>, reconciling the draft/persisted
    /// snapshot back to whatever the server actually has (which may or may
    /// not match the dropped toggle, since the wire send never landed).
    /// </summary>
    public void SetSingleCharacterOption(uint optionId, bool value) =>
        _commands.Publish(new SetSingleCharacterOptionRuntimeCmd(optionId, value));

    public void SetChatOpacity(float defaultOpacity, float activeOpacity) =>
        _chatOpacity.Apply(defaultOpacity, activeOpacity);
}