using Godot;
using Mr.BrickAdventures.Autoloads;
using Mr.BrickAdventures.Progression;
using Mr.BrickAdventures.scripts.Resources;

namespace Mr.BrickAdventures.scripts.UI;

/// <summary>
/// One buy/upgrade button in the marketplace.
/// </summary>
/// <remarks>
/// Reads the owned level from the Playthrough and the costs from the authored upgrade table — the split
/// <c>SkillData.Level</c> used to blur. It also listens to <see cref="EventBus.SkillSetChanged"/> rather
/// than to a signal on a component it had to locate by node path on the player.
/// </remarks>
public partial class MarketplaceButton : Button
{
    [Export] public SkillData Data { get; set; }
    [Export] public Texture2D UnlockedSkillIcon { get; set; }
    [Export] public Texture2D LockedSkillIcon { get; set; }
    [Export] public Container SkillLevelContainer { get; set; }

    private static ProgressionRoot Progression => ProgressionRoot.Instance;

    public override void _Ready()
    {
        if (EventBus.Instance != null)
        {
            EventBus.Instance.SkillSetChanged += UpdateButtonState;
            EventBus.Instance.CoinsChanged += OnCoinsChanged;
        }

        UpdateButtonState();
    }

    public override void _ExitTree()
    {
        if (EventBus.Instance != null)
        {
            EventBus.Instance.SkillSetChanged -= UpdateButtonState;
            EventBus.Instance.CoinsChanged -= OnCoinsChanged;
        }
    }

    private void OnCoinsChanged(int totalCoins) => UpdateButtonState();

    /// <summary>The level the player owns this skill at, or 0 when they do not own it.</summary>
    private int OwnedLevel()
    {
        if (Data == null || Progression == null || string.IsNullOrWhiteSpace(Data.Name)) return 0;

        return Progression.LevelOf(SkillId.Of(Data.Name))?.Value ?? 0;
    }

    private void UpdateButtonState()
    {
        if (Data == null || Data.Upgrades.Count == 0)
        {
            // No authored upgrades means it cannot be bought at any price.
            Visible = false;
            return;
        }

        var owned = OwnedLevel();

        for (var i = 0; i < SkillLevelContainer.GetChildCount(); i++)
            SkillLevelContainer.GetChild(i).QueueFree();

        for (var i = 0; i < Data.MaxLevel; i++)
        {
            SkillLevelContainer.AddChild(new TextureRect
            {
                Texture = i < owned ? UnlockedSkillIcon : LockedSkillIcon,
                ExpandMode = TextureRect.ExpandModeEnum.FitWidthProportional,
            });
        }

        if (owned >= Data.MaxLevel)
        {
            Text = $"{Tr(Data.Name)} (MAX)";
            Disabled = true;
            return;
        }

        // Upgrades[n] is the cost to reach level n + 1, so the next level costs Upgrades[owned].
        Text = $"{Tr(Data.Name)} ({Data.Upgrades[owned].Cost})";
        Disabled = false;
    }
}