using Nexus.Core;

namespace Nexus.Data;

/// <summary>
/// Classifies entities from path + component data into EntityCategory.
/// Single source of truth for entity classification in the Data layer.
/// </summary>
public static class EntityClassifier
{
    public static EntityCategory Classify(string? path, HashSet<string>? components)
    {
        var baseCategory = ClassifyFromPath(path);
        if (components is { Count: > 0 })
            return ReclassifyFromComponents(baseCategory, components);
        return baseCategory;
    }

    private static EntityCategory ClassifyFromPath(string? path)
    {
        if (path is null) return EntityCategory.Unknown;

        var firstSlash = path.IndexOf('/');
        if (firstSlash < 0) return EntityCategory.Unknown;

        var secondSlash = path.IndexOf('/', firstSlash + 1);
        var segment = secondSlash > 0
            ? path[(firstSlash + 1)..secondSlash]
            : path[(firstSlash + 1)..];

        switch (segment)
        {
            case "Characters":
                return EntityCategory.Player;

            case "Monsters":
                if (path.Contains("/Critters/", StringComparison.OrdinalIgnoreCase))
                    return EntityCategory.Critter;
                if (path.Contains("/NPC/", StringComparison.OrdinalIgnoreCase) ||
                    path.Contains("/TownNPC/", StringComparison.OrdinalIgnoreCase))
                    return EntityCategory.Npc;
                return EntityCategory.Monster;

            case "NPC":
                return EntityCategory.Npc;

            case "Effects":
                return EntityCategory.Effect;

            case "MiscellaneousObjects":
                if (path.Contains("Doodad", StringComparison.OrdinalIgnoreCase))
                    return EntityCategory.Doodad;
                if (path.Contains("/Chest", StringComparison.OrdinalIgnoreCase) ||
                    path.Contains("/Stash", StringComparison.OrdinalIgnoreCase))
                    return EntityCategory.Chest;
                if (path.Contains("/Shrine", StringComparison.OrdinalIgnoreCase))
                    return EntityCategory.Shrine;
                if (path.Contains("/Portal", StringComparison.OrdinalIgnoreCase))
                    return EntityCategory.Portal;
                return EntityCategory.MiscObject;

            case "Terrain":
                if (path.Contains("/Doodad", StringComparison.OrdinalIgnoreCase))
                    return EntityCategory.Doodad;
                return EntityCategory.Terrain;

            case "Items":
                return EntityCategory.WorldItem;

            default:
                return EntityCategory.Unknown;
        }
    }

    private static EntityCategory ReclassifyFromComponents(EntityCategory baseCategory, HashSet<string> components)
    {
        // Priority order matching ExileCore's ParseType logic
        if (components.Contains("Monster")) return EntityCategory.Monster;
        if (components.Contains("Chest")) return EntityCategory.Chest;
        if (components.Contains("Shrine")) return EntityCategory.Shrine;
        if (components.Contains("Waypoint")) return EntityCategory.Waypoint;
        if (components.Contains("AreaTransition")) return EntityCategory.AreaTransition;
        if (components.Contains("Portal")) return EntityCategory.Portal;
        if (components.Contains("TownPortal")) return EntityCategory.TownPortal;
        if (components.Contains("NPC")) return EntityCategory.Npc;
        if (components.Contains("Player")) return EntityCategory.Player;
        // Don't override path-based classification for Effects/Terrain/etc.
        return baseCategory;
    }
}