using Godot;
using JevOverlay.Core;

namespace JevOverlay.UI;

/// <summary>Godot controls only. This view cannot read files or call the game API.</summary>
public sealed class OverlayView
{
    private readonly CanvasLayer layer = new() { Name = "JevDecisionOverlay", Layer = 100 };
    private readonly PanelContainer panel = new() { MouseFilter = Control.MouseFilterEnum.Stop };
    private readonly VBoxContainer body = new();
    private readonly Label status = new() { AutowrapMode = TextServer.AutowrapMode.WordSmart };
    private readonly RichTextLabel summary = TextArea();
    private readonly RichTextLabel evidence = TextArea();
    private readonly ItemList history = new()
    {
        CustomMinimumSize = new(0, 110),
        FocusMode = Control.FocusModeEnum.None,
        SizeFlagsVertical = Control.SizeFlags.ExpandFill,
    };
    private readonly Button collapse = Button("−", "Collapse panel (F8)");
    private readonly Button details = Button("Show questions and answers");
    private readonly Button follow = Button("Follow latest");
    private IReadOnlyList<DecisionEntry> entries = [];
    private DecisionKey? selected;
    private bool following = true;
    private bool collapsed;
    private bool expanded;

    public OverlayView(SceneTree tree)
    {
        var root = new Control { MouseFilter = Control.MouseFilterEnum.Ignore };
        layer.AddChild(root);
        tree.Root.AddChild(layer);
        root.SetAnchorsAndOffsetsPreset(Control.LayoutPreset.FullRect);
        root.AddChild(panel);
        panel.SetAnchorsAndOffsetsPreset(Control.LayoutPreset.TopRight);
        var style = new StyleBoxFlat
        {
            BgColor = new Color(0.055f, 0.065f, 0.085f, 0.96f),
            BorderColor = new Color(0.3f, 0.4f, 0.5f),
            BorderWidthLeft = 1, BorderWidthRight = 1, BorderWidthTop = 1, BorderWidthBottom = 1,
            CornerRadiusTopLeft = 8, CornerRadiusTopRight = 8,
            CornerRadiusBottomLeft = 8, CornerRadiusBottomRight = 8,
            ContentMarginLeft = 12, ContentMarginRight = 12,
            ContentMarginTop = 10, ContentMarginBottom = 10,
        };
        panel.AddThemeStyleboxOverride("panel", style);
        panel.Theme = new Theme { DefaultFontSize = 16 };
        panel.AddThemeColorOverride("font_color", new Color(0.92f, 0.94f, 0.96f));
        var layout = new VBoxContainer();
        layout.AddThemeConstantOverride("separation", 8);
        panel.AddChild(layout);
        var header = new HBoxContainer();
        layout.AddChild(header);
        header.AddChild(new Label
        {
            Text = "Jev decisions · read only",
            SizeFlagsHorizontal = Control.SizeFlags.ExpandFill,
            MouseFilter = Control.MouseFilterEnum.Ignore,
        });
        header.AddChild(collapse);
        collapse.Pressed += ToggleCollapsed;
        layout.AddChild(body);
        body.SizeFlagsVertical = Control.SizeFlags.ExpandFill;
        body.AddThemeConstantOverride("separation", 8);
        body.AddChild(status);
        body.AddChild(summary);
        body.AddChild(details);
        body.AddChild(evidence);
        evidence.Visible = false;
        details.Pressed += () =>
        {
            expanded = !expanded;
            evidence.Visible = expanded;
            details.Text = expanded ? "Hide questions and answers" : "Show questions and answers";
        };
        body.AddChild(new Label { Text = "Recent decisions · select to inspect" });
        body.AddChild(history);
        body.AddChild(follow);
        follow.ToggleMode = true;
        follow.ButtonPressed = true;
        follow.Toggled += enabled =>
        {
            following = enabled;
            if (enabled) SelectLatest();
        };
        history.ItemSelected += index =>
        {
            if (index < 0 || index >= entries.Count) return;
            following = false;
            follow.SetPressedNoSignal(false);
            selected = entries[(int)index].Key;
            RenderSelection();
        };
        summary.Text = "Waiting for decision records.\nF8 collapses or expands this panel.";
    }

    public void ToggleCollapsed()
    {
        collapsed = !collapsed;
        body.Visible = !collapsed;
        collapse.Text = collapsed ? "+" : "−";
        collapse.TooltipText = collapsed ? "Expand panel (F8)" : "Collapse panel (F8)";
    }

    public void Resize(Vector2 viewport)
    {
        panel.OffsetLeft = -Math.Min(440, Math.Max(280, viewport.X - 32));
        panel.OffsetRight = -16;
        panel.OffsetTop = 64;
        panel.OffsetBottom = collapsed ? 112 : Math.Min(viewport.Y - 16, expanded ? 764 : 584);
    }

    public void SetStatus(string text, string? tooltip = null)
    {
        status.Text = text;
        status.TooltipText = tooltip ?? text;
    }

    public void Render(DecisionHistory model)
    {
        // Copy the list; selection must refer to the same ordering as the visible rows.
        entries = model.Entries.ToArray();
        history.Clear();
        foreach (var entry in entries)
        {
            int index = history.AddItem($"#{entry.Key.Step}  {entry.Source.ToUpperInvariant()}  {entry.Action}");
            history.SetItemTooltip(index, $"Session: {entry.Key.Session}\n{entry.Status}");
            history.SetItemCustomFgColor(index, entry.Source switch
            {
                "jev" => new Color(0.55f, 0.8f, 1f),
                "fallback" => new Color(1f, 0.75f, 0.4f),
                _ => new Color(0.8f, 0.85f, 0.85f),
            });
        }
        if (following) SelectLatest();
        else RenderSelection();
    }

    private void SelectLatest()
    {
        selected = entries.Count == 0 ? null : entries[0].Key;
        RenderSelection();
        if (entries.Count > 0) history.EnsureCurrentIsVisible();
    }

    private void RenderSelection()
    {
        int index = -1;
        for (int i = 0; i < entries.Count; i++)
            if (entries[i].Key == selected) { index = i; break; }
        if (index < 0)
        {
            summary.Text = selected is null ? "Waiting for decision records."
                : "This decision is no longer in the recent history. Select Follow latest.";
            evidence.Text = "No decision selected.";
        }
        else
        {
            history.Select(index);
            // Do not reset text selection or scroll when another decision arrives.
            string nextSummary = entries[index].Summary();
            string nextEvidence = entries[index].Evidence();
            if (summary.Text != nextSummary) summary.Text = nextSummary;
            if (evidence.Text != nextEvidence) evidence.Text = nextEvidence;
        }
    }

    public void Dispose() => layer.QueueFree();

    private static Button Button(string text, string tooltip = "") => new()
    {
        Text = text, TooltipText = tooltip, FocusMode = Control.FocusModeEnum.None,
    };

    private static RichTextLabel TextArea() => new()
    {
        BbcodeEnabled = false,
        SelectionEnabled = true,
        ScrollActive = true,
        CustomMinimumSize = new(0, 90),
        SizeFlagsVertical = Control.SizeFlags.ExpandFill,
        SizeFlagsHorizontal = Control.SizeFlags.ExpandFill,
        FocusMode = Control.FocusModeEnum.None,
    };
}