using System.Collections.Generic;
using System.Text;
using LibMMD.Model;

namespace LibMMD.Motion
{
    internal sealed class MmdMotionBindingMap
    {
        internal readonly List<KeyValuePair<string, int>> Bones = new List<KeyValuePair<string, int>>();
        internal readonly List<KeyValuePair<string, int>> Ik = new List<KeyValuePair<string, int>>();
        internal readonly List<KeyValuePair<string, int>> Morphs = new List<KeyValuePair<string, int>>();
        internal int GrooveFallbackCenterIndex { get; private set; } = -1;

        internal MmdMotionBindingMap(MmdMotion motion, MmdModel model)
        {
            var groove = -1;
            var center = -1;
            var lowerBody = -1;
            for (var i = 0; i < model.Bones.Length; ++i)
            {
                var bone = model.Bones[i];
                var name = Normalize(bone.Name);
                var nameEn = Normalize(bone.NameEn);
                if (groove < 0 && (name == "グルーブ" || nameEn == "groove")) groove = i;
                if (center < 0 && (name == "センター" || nameEn == "center")) center = i;
                if (lowerBody < 0 && (name == "下半身" || nameEn == "lowerbody")) lowerBody = i;
                if (motion.IsBoneRegistered(bone.Name))
                    Bones.Add(new KeyValuePair<string, int>(bone.Name, i));
                if (bone.HasIk && motion.IsIkRegistered(bone.Name))
                    Ik.Add(new KeyValuePair<string, int>(bone.Name, i));
            }

            var hasUsableGroove = groove >= 0 && lowerBody >= 0 && IsAncestor(model, groove, lowerBody);
            if (!hasUsableGroove && center >= 0 && motion.IsBoneRegistered("グルーブ"))
                GrooveFallbackCenterIndex = center;

            for (var i = 0; i < model.Morphs.Length; ++i)
                if (motion.IsMorphRegistered(model.Morphs[i].Name))
                    Morphs.Add(new KeyValuePair<string, int>(model.Morphs[i].Name, i));
        }

        private static string Normalize(string name) =>
            string.IsNullOrWhiteSpace(name)
                ? string.Empty
                : name.Normalize(NormalizationForm.FormKC).Replace(" ", string.Empty).ToLowerInvariant();

        private static bool IsAncestor(MmdModel model, int ancestor, int bone)
        {
            var remaining = model.Bones.Length;
            while (bone >= 0 && bone < model.Bones.Length && remaining-- > 0)
            {
                if (bone == ancestor) return true;
                bone = model.Bones[bone].ParentIndex;
            }
            return false;
        }
    }
}