using System;
using System.Xml.Linq;
using UnityEngine;

namespace Data
{
    public enum Orientation
    {
        Down,
        Left,
        Right,
        Up
    }

    public enum EntityState
    {
        Idle,
        Walking,
        MeleeAttack,
        RangedAttack,
        Death,
    }

    public class DrawingOrderDef : Define
    {
        public DrawNodeDef idle_down;
        public DrawNodeDef idle_up;
        public DrawNodeDef idle_left;
        public DrawNodeDef idle_right;

        public DrawNodeDef walk_down;
        public DrawNodeDef walk_up;
        public DrawNodeDef walk_left;
        public DrawNodeDef walk_right;

        public DrawNodeDef meleeAttack_down;
        public DrawNodeDef meleeAttack_up;
        public DrawNodeDef meleeAttack_left;
        public DrawNodeDef meleeAttack_right;

        public DrawNodeDef rangedAttack_down;
        public DrawNodeDef rangedAttack_up;
        public DrawNodeDef rangedAttack_left;
        public DrawNodeDef rangedAttack_right;
        
        public DrawNodeDef death_down;
        public DrawNodeDef death_up;
        public DrawNodeDef death_left;
        public DrawNodeDef death_right;

        public DrawNodeDef GetDrawNodeDef(EntityState state, Orientation orientation,
            out Orientation? fallbackOrientation)
        {
            fallbackOrientation = null;

            // 根据状态和方向获取对应的DrawNodeDef
            var result = GetDrawNodeDefInternal(state, orientation);

            if (result != null)
            {
                return result;
            }

            // 如果找不到，按照规则查找替补
            switch (orientation)
            {
                case Orientation.Up:
                    // 上方向优先找下方向
                    result = GetDrawNodeDefInternal(state, Orientation.Down);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Down;
                        return result;
                    }

                    // 其次找左右方向
                    result = GetDrawNodeDefInternal(state, Orientation.Left);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Left;
                        return result;
                    }

                    result = GetDrawNodeDefInternal(state, Orientation.Right);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Right;
                        return result;
                    }

                    break;

                case Orientation.Down:
                    // 下方向优先找上方向
                    result = GetDrawNodeDefInternal(state, Orientation.Up);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Up;
                        return result;
                    }

                    // 其次找左右方向
                    result = GetDrawNodeDefInternal(state, Orientation.Left);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Left;
                        return result;
                    }

                    result = GetDrawNodeDefInternal(state, Orientation.Right);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Right;
                        return result;
                    }

                    break;

                case Orientation.Left:
                    // 左方向优先找右方向
                    result = GetDrawNodeDefInternal(state, Orientation.Right);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Right;
                        return result;
                    }

                    // 其次找上下方向
                    result = GetDrawNodeDefInternal(state, Orientation.Up);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Up;
                        return result;
                    }

                    result = GetDrawNodeDefInternal(state, Orientation.Down);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Down;
                        return result;
                    }

                    break;

                case Orientation.Right:
                    // 右方向优先找左方向
                    result = GetDrawNodeDefInternal(state, Orientation.Left);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Left;
                        return result;
                    }

                    // 其次找上下方向
                    result = GetDrawNodeDefInternal(state, Orientation.Up);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Up;
                        return result;
                    }

                    result = GetDrawNodeDefInternal(state, Orientation.Down);
                    if (result != null)
                    {
                        fallbackOrientation = Orientation.Down;
                        return result;
                    }

                    break;
                default:
                    throw new ArgumentOutOfRangeException(nameof(orientation), orientation, null);
            }

            // 如果所有替补都找不到，返回null
            return null;
        }

        private DrawNodeDef GetDrawNodeDefInternal(EntityState state, Orientation orientation)
        {
            // 根据状态和方向获取对应的DrawNodeDef
            switch (state)
            {
                case EntityState.Idle:
                    switch (orientation)
                    {
                        case Orientation.Down: return idle_down;
                        case Orientation.Up: return idle_up;
                        case Orientation.Left: return idle_left;
                        case Orientation.Right: return idle_right;
                    }

                    break;

                case EntityState.Walking:
                    switch (orientation)
                    {
                        case Orientation.Down: return walk_down;
                        case Orientation.Up: return walk_up;
                        case Orientation.Left: return walk_left;
                        case Orientation.Right: return walk_right;
                    }

                    break;

                case EntityState.MeleeAttack:
                    switch (orientation)
                    {
                        case Orientation.Down: return meleeAttack_down;
                        case Orientation.Up: return meleeAttack_up;
                        case Orientation.Left: return meleeAttack_left;
                        case Orientation.Right: return meleeAttack_right;
                    }

                    break;

                case EntityState.RangedAttack:
                    switch (orientation)
                    {
                        case Orientation.Down: return rangedAttack_down;
                        case Orientation.Up: return rangedAttack_up;
                        case Orientation.Left: return rangedAttack_left;
                        case Orientation.Right: return rangedAttack_right;
                    }

                    break;
                case EntityState.Death:
                    switch (orientation)
                    {
                        case Orientation.Down: return death_down;
                        case Orientation.Up: return death_up;
                        case Orientation.Left: return death_left;
                        case Orientation.Right: return death_right;
                    }

                    break;
            }

            return null;
        }
    }

    public class DrawNodeDef : Define
    {
        public string[] textures;
        public DrawNodeDef[] nodes;
        public string nodeName;
        public Vector2 position = new(0, 0);
        public float FPS = 5f;

        public override bool Init(XElement xmlDef)
        {
            base.Init(xmlDef);

            nodeName = xmlDef.Attribute("name")?.Value ?? "noName";
            position = Utils.StringUtils.StringToVector2(xmlDef.Attribute("position")?.Value ?? "0,0");
            FPS = float.TryParse(xmlDef.Attribute("FPS")?.Value, out var result) ? result : 5.0f;
            return false;
        }

        /// <summary>
        /// 获取播放一遍动画所需的最小时间（取当前节点动画与所有子集动画的最大值）。
        /// </summary>
        /// <returns>播放一遍动画所需的最小时间（秒），如果无动画则为0。</returns>
        public float GetMinAnimationDuration()
        {
            var maxDuration = 0f;
            // 计算当前节点自身的动画时间
            if (textures != null && textures.Length > 0)
            {
                // 只有当FPS大于0时，才计算有效的动画时间。
                // 如果FPS <= 0，表示该部分动画无法播放，其时长贡献为0，不参与最大值计算。
                if (FPS > 0)
                {
                    maxDuration = Math.Max(maxDuration, textures.Length / FPS);
                }
            }

            // 递归计算子节点的动画时间，并更新最大值
            if (nodes != null && nodes.Length > 0)
            {
                foreach (var node in nodes)
                {
                    if (node != null)
                    {
                        maxDuration = Math.Max(maxDuration, node.GetMinAnimationDuration());
                    }
                }
            }

            return maxDuration;
        }
    }

}