using Godot;
using Theriapolis.Core.Data;
using Theriapolis.GodotHost.Scenes.Widgets;
using Theriapolis.GodotHost.UI;

namespace Theriapolis.GodotHost.Scenes.Steps;

/// <summary>
/// Step V — History. Direct port of <c>StepBackground</c> in
/// <c>src/steps.jsx</c>: card per background showing flavor, granted
/// skill / tool proficiencies, and a unique feature with a description
/// popover.
/// </summary>
public partial class StepBackground : VBoxContainer, IStep
{
    private CharacterDraft _draft = null!;
    private GridContainer _grid = null!;

    public void Bind(CharacterDraft draft)
    {
        _draft = draft;
        _draft.Changed += () => Callable.From(Refresh).CallDeferred();
        Build();
    }

    public string? Validate() =>
        string.IsNullOrEmpty(_draft?.BackgroundId) ? "Pick a history." : null;

    private void Build()
    {
        AddThemeConstantOverride("separation", 16);

        var intro = new VBoxContainer();
        intro.AddThemeConstantOverride("separation", 6);
        AddChild(intro);
        intro.AddChild(new Label { Text = "FOLIO V · HISTORY" });
        intro.AddChild(new Label { Text = "Choose a History" });
        intro.AddChild(new Label
        {
            Text = "Where your character came from before the wandering began. "
                 + "History grants extra skill and tool proficiencies and a unique "
                 + "feature that resolves in-fiction more often than in combat.",
            AutowrapMode = TextServer.AutowrapMode.WordSmart,
        });

        _grid = new GridContainer { Columns = 3, SizeFlagsHorizontal = SizeFlags.ExpandFill };
        _grid.AddThemeConstantOverride("h_separation", 16);
        _grid.AddThemeConstantOverride("v_separation", 16);
        AddChild(_grid);

        Refresh();
    }

    /// <summary>
    /// Background-availability rules. The backgrounds.json schema doesn't
    /// carry restriction fields — the gating lives in flavor text only —
    /// so they're hardcoded here. Each predicate returns true when the
    /// background is available to the given draft; missing entries are
    /// universally available.
    ///
    /// If backgrounds.json ever gains structured restriction fields,
    /// swap these out for a property-driven check.
    /// </summary>
    private static readonly System.Collections.Generic.Dictionary<string, System.Func<UI.CharacterDraft, bool>> AvailabilityRules = new()
    {
        // Hybrid-only backgrounds — flavor text explicitly hybrid.
        { "passer",             d => d.IsHybrid },
        { "hybrid_underground", d => d.IsHybrid },
        { "former_chattel",     d => d.IsHybrid },

        // Clade-restricted backgrounds.
        { "warren_runner",      d => d.HasClade("leporidae") },
        { "pack_raised",        d => d.HasClade("canidae") },
        { "herd_city_born",     d => d.HasAnyCladeOfKind("prey") },
    };

    private void Refresh()
    {
        if (_grid is null) return;
        foreach (var c in _grid.GetChildren()) c.QueueFree();
        foreach (var bg in CodexContent.Backgrounds)
        {
            if (AvailabilityRules.TryGetValue(bg.Id, out var rule) && !rule(_draft))
                continue;
            _grid.AddChild(BuildCard(bg));
        }
    }

    private Control BuildCard(BackgroundDef bg)
    {
        bool selected = _draft.BackgroundId == bg.Id;

        var card = new PanelContainer
        {
            CustomMinimumSize = new Vector2(200, 0),
            MouseFilter = MouseFilterEnum.Stop,
        };
        if (selected) card.Modulate = new Color(1f, 0.95f, 0.85f);

        card.GuiInput += (InputEvent e) =>
        {
            if (e is InputEventMouseButton mb && mb.Pressed && mb.ButtonIndex == MouseButton.Left)
                _draft.Patch(new Godot.Collections.Dictionary { { "background_id", bg.Id } });
        };

        var box = new VBoxContainer { MouseFilter = MouseFilterEnum.Pass };
        box.AddThemeConstantOverride("separation", 6);
        card.AddChild(box);

        box.AddChild(new Label { Text = bg.Name });
        if (!string.IsNullOrEmpty(bg.Flavor))
        {
            box.AddChild(new Label
            {
                Text = bg.Flavor,
                AutowrapMode = TextServer.AutowrapMode.WordSmart,
            });
        }

        // Skill + tool prof chips.
        if (bg.SkillProficiencies.Length > 0 || bg.ToolProficiencies.Length > 0)
        {
            var profs = new HFlowContainer { MouseFilter = MouseFilterEnum.Pass };
            profs.AddThemeConstantOverride("h_separation", 6);
            profs.AddThemeConstantOverride("v_separation", 4);
            box.AddChild(profs);

            foreach (var s in bg.SkillProficiencies)
                profs.AddChild(new TraitChip { TraitName = s, Description = "Skill proficiency", Tag = "skill" });
            foreach (var t in bg.ToolProficiencies)
                profs.AddChild(new TraitChip { TraitName = t, Description = "Tool proficiency", Tag = "tool" });
        }

        // Background feature — chip whose popover shows the description.
        if (!string.IsNullOrEmpty(bg.FeatureName))
        {
            var featRow = new HBoxContainer();
            featRow.AddThemeConstantOverride("separation", 6);
            box.AddChild(featRow);
            featRow.AddChild(new Label { Text = "FEATURE" });
            featRow.AddChild(new TraitChip
            {
                TraitName = bg.FeatureName,
                Description = bg.FeatureDescription,
            });
        }

        return card;
    }
}