using System.Windows;
using System.Windows.Media;

namespace ytLive.Models;

/// <summary>
/// A scene's usage of the app-wide webcam — conceptually `webcam.{scene}.config`.
/// The identity lives once on the <see cref="Webcam"/> entity; this object is that
/// scene's placement, clip/mirror, border, and visibility for it. Exists only in
/// scenes where the creator added the webcam.
/// </summary>
public class WebcamSceneConfig : SceneElement
{
    public string WebcamId { get; init; } = string.Empty;
    public override bool IsWebcam => true;
    public override bool IsDraggable => true;
    public override ElementKind Kind => ElementKind.Dynamic;
    public override ImageSource? DisplaySource => VideoImageSource;

    private BackgroundEffect _backgroundEffect = BackgroundEffect.None;
    /// <summary>TASK 51: this scene's background effect for the webcam (persisted).</summary>
    public BackgroundEffect BackgroundEffect
    {
        get => _backgroundEffect;
        set
        {
            if (!Set(ref _backgroundEffect, value)) return;
            Raise(nameof(RemoveBackground));
            Raise(nameof(BlurBackground));
            Raise(nameof(HasBackgroundEffect));
        }
    }

    /// <summary>True while Remove or Blur is on — shows the strength slider.</summary>
    public bool HasBackgroundEffect => BackgroundEffect != BackgroundEffect.None;

    private double _backgroundStrength = 0.5;
    /// <summary>TASK 51: 0..1 — Blur amount, or Remove's edge softness (persisted).</summary>
    public double BackgroundStrength
    {
        get => _backgroundStrength;
        set => Set(ref _backgroundStrength, Math.Clamp(value, 0, 1));
    }

    /// <summary>Pill-switch surface: Remove and Blur behave like radio buttons — turning one
    /// on turns the other off; turning the active one off means <see cref="BackgroundEffect.None"/>.</summary>
    public bool RemoveBackground
    {
        get => BackgroundEffect == BackgroundEffect.Remove;
        set => BackgroundEffect = value ? BackgroundEffect.Remove
            : BackgroundEffect == BackgroundEffect.Remove ? BackgroundEffect.None : BackgroundEffect;
    }

    /// <inheritdoc cref="RemoveBackground"/>
    public bool BlurBackground
    {
        get => BackgroundEffect == BackgroundEffect.Blur;
        set => BackgroundEffect = value ? BackgroundEffect.Blur
            : BackgroundEffect == BackgroundEffect.Blur ? BackgroundEffect.None : BackgroundEffect;
    }

    // ─── Vertical (9:16) tier placement (TASK 57, the "vv" feature) ────────
    // The vertical tier is a centred band crop of the same master frame, so the
    // 16:9 placement lands outside the cropped window and the camera vanishes
    // from the vertical output. The vertical tier therefore keeps its OWN
    // position, size and shape per scene, stored here and resolved when the
    // tier changes; switching back to 16:9 restores the desktop layout exactly.

    /// <summary>The vertical placement's X (null until the scene has one).</summary>
    public double? VerticalX { get; set; }

    /// <summary>The vertical placement's Y (null until the scene has one).</summary>
    public double? VerticalY { get; set; }

    /// <summary>The vertical placement's width (null until the scene has one).</summary>
    public double? VerticalWidth { get; set; }

    /// <summary>The vertical placement's height (null until the scene has one).</summary>
    public double? VerticalHeight { get; set; }

    /// <summary>The vertical placement's clip shape (circle or rect) — the
    /// creator's own choice per scene, independent of the 16:9 shape.</summary>
    public ClipShape? VerticalClipShape { get; set; }

    /// <summary>The vertical placement's pre-Round rect (so a Round tile
    /// restores its aspect on toggle-back, like the 16:9 one does).</summary>
    public double? VerticalRectWidth { get; set; }

    /// <inheritdoc cref="VerticalRectWidth"/>
    public double? VerticalRectHeight { get; set; }

    /// <summary>True once this scene has a vertical placement of its own.</summary>
    public bool HasVerticalLayout => VerticalX is not null;

    /// <summary>True while the vertical placement is the LIVE geometry (the
    /// element's own X/Y/W/H). The 16:9 layout is parked in
    /// <see cref="LandscapeX"/> and friends until the tier switches back.</summary>
    public bool VerticalLayoutLive { get; private set; }

    /// <summary>True while the vertical placement must stay RECT — the Chat
    /// scene's vertical layout (the creator's table: "vv · Chat = rect only, no
    /// circle option"). The circle is not offered there, so the shape cannot
    /// become Round by any writer.</summary>
    public bool VerticalShapeLocked { get; internal set; }

    /// <summary>The vertical tier's band over the master frame (transient — the
    /// VM sets it when the tier changes). While the vertical placement is live
    /// the camera's geometry is clamped to it: outside the band is invisible.</summary>
    public Rect VerticalBand { get; set; } = Rect.Empty;

    // The parked 16:9 layout — meaningful only while the vertical placement is
    // live (it is the 16:9 geometry the tier switch restores).
    public double LandscapeX { get; private set; }
    public double LandscapeY { get; private set; }
    public double LandscapeWidth { get; private set; }
    public double LandscapeHeight { get; private set; }
    public ClipShape LandscapeClipShape { get; private set; }
    public double? LandscapeRectWidth { get; private set; }
    public double? LandscapeRectHeight { get; private set; }

    /// <summary>Parks the live (16:9) layout and brings a vertical placement
    /// in. The vertical placement becomes the live geometry from here on.</summary>
    public void BeginVerticalLayout(double x, double y, double width, double height, ClipShape clipShape)
    {
        LandscapeX = X;
        LandscapeY = Y;
        LandscapeWidth = Width;
        LandscapeHeight = Height;
        LandscapeClipShape = ClipShape;
        LandscapeRectWidth = RectWidth;
        LandscapeRectHeight = RectHeight;

        VerticalLayoutLive = true;
        Width = width;
        Height = height;
        X = x;
        Y = y;
        ClipShape = clipShape;
        RectWidth = VerticalRectWidth;
        RectHeight = VerticalRectHeight;
    }

    /// <summary>Restores the parked 16:9 layout — the tier switched back.</summary>
    public void EndVerticalLayout()
    {
        if (!VerticalLayoutLive) return;

        // The vertical placement is the creator's own — keep it, so switching
        // back and forth does not lose where they put it.
        CommitLiveLayoutToVertical();

        VerticalLayoutLive = false;
        Width = LandscapeWidth;
        Height = LandscapeHeight;
        X = LandscapeX;
        Y = LandscapeY;
        ClipShape = LandscapeClipShape;
        RectWidth = LandscapeRectWidth;
        RectHeight = LandscapeRectHeight;
    }

    /// <summary>Copies the live geometry into the stored vertical placement, so
    /// the stored copy never lags the live one (the save path calls this).</summary>
    public void CommitLiveLayoutToVertical()
    {
        VerticalX = X;
        VerticalY = Y;
        VerticalWidth = Width;
        VerticalHeight = Height;
        VerticalClipShape = ClipShape;
        VerticalRectWidth = RectWidth;
        VerticalRectHeight = RectHeight;
    }

    // The Chat scene's vertical layout is rect-only (the creator's table, the
    // circle option is not offered there). Locking the SHAPE property — not
    // just the toggle — means no writer can slip a Round camera in: the
    // toggle, the shape button and the placement swap all go through here.
    public override ClipShape ClipShape
    {
        get => base.ClipShape;
        set => base.ClipShape = VerticalShapeLocked ? ClipShape.Traditional : value;
    }

    public override void ToggleClipShape()
    {
        if (VerticalShapeLocked)
        {
            ClipShape = ClipShape.Traditional;
            return;
        }
        base.ToggleClipShape();
    }

    // The geometry is clamped into the band while the vertical placement is
    // live — a camera outside the cropped window is a camera the viewers never
    // see, and every writer (drag, resize handle, the properties fields) goes
    // through these setters.
    public override double X
    {
        get => base.X;
        set => base.X = ClampToBand(value, base.Width, vertical: true);
    }

    public override double Y
    {
        get => base.Y;
        set => base.Y = ClampToBand(value, base.Height, vertical: false);
    }

    public override double Width
    {
        get => base.Width;
        set => base.Width = VerticalLayoutLive && !VerticalBand.IsEmpty
            ? Math.Min(value, VerticalBand.Width)
            : value;
    }

    public override double Height
    {
        get => base.Height;
        set => base.Height = VerticalLayoutLive && !VerticalBand.IsEmpty
            ? Math.Min(value, VerticalBand.Height / 2)
            : value;
    }

    private double ClampToBand(double value, double size, bool vertical)
    {
        if (!VerticalLayoutLive || VerticalBand.IsEmpty) return value;
        var band = VerticalBand;
        var min = vertical ? band.Left : band.Top;
        var max = vertical ? band.Right - size : band.Bottom - size;
        if (max < min) return min;
        return Math.Clamp(value, min, max);
    }
}