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);
}

internal sealed class SilkRuntimeDisplayWindowTarget : IRuntimeDisplayWindowTarget
{
    private readonly IWindow _window;

    public SilkRuntimeDisplayWindowTarget(IWindow window)
    {
        _window = window ?? throw new ArgumentNullException(nameof(window));
    }

    public void Apply(DisplaySettings display)
    {
        ArgumentNullException.ThrowIfNull(display);
        bool haveResolution =
            TryParseResolution(display.Resolution, out int width, out int height);
        if (haveResolution && (_window.Size.X != width || _window.Size.Y != height))
        {
            // #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);
        }

        WindowState desired = display.Fullscreen
            ? WindowState.Fullscreen
            : WindowState.Normal;

        // #374 investigation note: while FULLSCREEN, the visible resolution
        // is the display's video mode, and Silk's abstract windowing API
        // cannot change it (IViewProperties.VideoMode is read-only; Silk
        // fullscreen is desktop-mode borderless). The Size write above is
        // therefore only visible in windowed mode — a resolution pick while
        // fullscreen changes what a later return to windowed restores, not
        // the fullscreen mode itself. Retail's own fullscreen resolution
        // switch (Device::ForceDisplayResolution) needs a native
        // glfwSetWindowMonitor port — issue #376.
        if (_window.WindowState != desired)
            _window.WindowState = desired;
    }

    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;

    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)
        : 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)
    {
    }

    internal RuntimeSettingsTargets(
        IRuntimeDisplayWindowTarget displayWindow,
        IRuntimeQualityApplicationTarget quality,
        IRuntimeUiLockTarget uiLock,
        ICommandBus commands,
        Action<string>? log = null,
        IRuntimeChatOpacityTarget? chatOpacity = null,
        OpenAlAudioEngine? audio = 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;
    }

    public void ApplyDisplayWindowState(DisplaySettings display) =>
        _displayWindow.Apply(display);

    /// <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);
}