#if LIVE2D_AVAILABLE

using Live2D.Cubism.Core;
using Live2D.Cubism.Framework;
using System.Collections.Generic;
using System.Linq;
using UnityCommon;
using UnityEngine;

namespace Naninovel
{
    [RequireComponent(typeof(CubismModel))]
    public class Live2DAppearanceController : MonoBehaviour
    {
        [System.Serializable]
        public class ParametersMap : SerializableMap<string, float> { }

        [System.Serializable]
        public class AppearanceData
        {
            [Tooltip("Appearance to bind parameters for.")]
            public string Appearance = string.Empty;
            [Tooltip("List of parameters' name and value to bind.")]
            public ParametersMap Params = default;
        }

        private struct ModifyRequest
        {
            public float SmoothedValue => Mathf.SmoothStep(startValue, targetValue, (Time.time - startTime) / normalizedDuration);

            private readonly float targetValue;
            private readonly float startValue;
            private readonly float startTime;
            private readonly float normalizedDuration;

            public ModifyRequest (CubismParameter param, float targetValue, float duration)
            {
                this.targetValue = targetValue;
                startValue = param.Value;
                startTime = Time.time;

                // In case we're starting the animation when the param is not at default value: reduce the duration accordingly.
                var curValueProgress = 1f - ((targetValue - param.Value) / (targetValue - param.DefaultValue));
                var curTimeProgress = InversedSmoothStep(curValueProgress);
                normalizedDuration = duration * (1f - curTimeProgress);
                print(normalizedDuration);
            }

            private static float InversedSmoothStep (float v) => v + (v - (v * v * (3f - 2f * v)));
        }

        [SerializeField] private List<AppearanceData> appearanceMap = default;
        [SerializeField] private CubismParameterBlendMode blendMode = CubismParameterBlendMode.Override;
        [SerializeField] private string headXAngleParamId = "PARAM_ANGLE_X";

        private const float headXAngleDelta = 30f;
        private static CubismParameter headXParam;
        private CubismModel cubismModel;
        private Dictionary<string, ModifyRequest> appearanceRequests = new Dictionary<string, ModifyRequest>();
        private ModifyRequest lookDirRequest;

        public void SetAppearance (string appearance, float duration)
        {
            appearanceRequests.Clear();
            var appearanceData = appearanceMap?.FirstOrDefault(a => a.Appearance == appearance);
            if (appearanceData is null) return;
            foreach (var kv in appearanceData.Params)
                appearanceRequests[kv.Key] = new ModifyRequest(cubismModel.Parameters.FindById(kv.Key), kv.Value, duration);
        }

        public void SetLookDirection (CharacterLookDirection lookDirection, float duration)
        {
            if (headXParam is null) return;

            var targetValue = default(float);
            switch (lookDirection)
            {
                case CharacterLookDirection.Center:
                    targetValue = 0f;
                    break;
                case CharacterLookDirection.Left:
                    targetValue = -headXAngleDelta;
                    break;
                case CharacterLookDirection.Right:
                    targetValue = headXAngleDelta;
                    break;
            }
            lookDirRequest = new ModifyRequest(headXParam, targetValue, duration);
        }

        private void Start ()
        {
            cubismModel = this.FindCubismModel();
            headXParam = cubismModel.Parameters.FindById(headXAngleParamId);
        }

        private void LateUpdate ()
        {
            for (int i = 0; i < cubismModel.Parameters.Length; i++)
            {
                var param = cubismModel.Parameters[i];

                var value = !appearanceRequests.ContainsKey(param.Id) ? param.DefaultValue : appearanceRequests[param.Id].SmoothedValue;
                if (Mathf.Approximately(param.Value, value)) continue;

                param.BlendToValue(blendMode, value);
            }

            if (headXParam != null) headXParam.BlendToValue(blendMode, lookDirRequest.SmoothedValue);
        }
    }
}

#endif