using System;
using System.Collections;
using System.Collections.Generic;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

namespace AppUI.Util
{
    [Serializable]
    public class UIBlinkTextItem
    {
        [Tooltip("留空则忽略")]
        public TMP_Text text;

        [Tooltip("勾选后使用下方颜色，否则用组件全局文字颜色")]
        public bool useCustomColors;

        public Color colorA = Color.white;
        public Color colorB = Color.red;
    }

    public enum UIBlinkImageMode
    {
        /// <summary>在 spriteA / spriteB 之间切换。</summary>
        Sprite,
        /// <summary>在 colorA / colorB 之间切换（不改 Sprite）。</summary>
        Color,
    }

    [Serializable]
    public class UIBlinkImageItem
    {
        [Tooltip("留空则忽略")]
        public Image image;

        public UIBlinkImageMode mode = UIBlinkImageMode.Sprite;

        [Tooltip("勾选后使用本项 Sprite，否则用组件全局图片")]
        public bool useCustomSprites;

        public Sprite spriteA;
        public Sprite spriteB;

        [Tooltip("Color 模式：勾选后用本项颜色，否则用组件全局图片颜色")]
        public bool useCustomColors;

        public Color colorA = Color.white;
        public Color colorB = new Color(1f, 1f, 1f, 0.35f);
    }

    /// <summary>
    /// 文字（TMP）闪烁：切换颜色；图片闪烁：切换 Sprite 或颜色。
    /// 可选平滑渐变过渡（颜色插值；Sprite 模式在过渡中点切换贴图并插值 Tint）。
    /// </summary>
    [DisallowMultipleComponent]
    public class UIBlinkEffect : MonoBehaviour
    {
        [Header("播放")]
        [Tooltip("每个状态保持时长（秒）；开启渐变时指到达目标状态后的停留时间")]
        [SerializeField]
        [Min(0.02f)]
        float stateInterval = 0.5f;

        [SerializeField]
        bool loop = true;

        [SerializeField]
        bool playOnEnable = true;

        [Tooltip("停止时是否恢复到状态 A")]
        [SerializeField]
        bool restoreStateOnStop = true;

        [Tooltip("启用后延迟多久开始（秒）")]
        [SerializeField]
        [Min(0f)]
        float startDelay;

        [Header("渐变过渡（可选）")]
        [Tooltip("开启后 A↔B 之间颜色/透明度平滑插值，而非瞬间切换")]
        [SerializeField]
        bool useSmoothTransition;

        [Tooltip("单次 A→B 或 B→A 的过渡时长（秒）")]
        [SerializeField]
        [Min(0f)]
        float transitionDuration = 0.2f;

        [SerializeField]
        AnimationCurve transitionCurve = AnimationCurve.EaseInOut(0f, 0f, 1f, 1f);

        [Tooltip("勾选后过渡不受 Time.timeScale 影响")]
        [SerializeField]
        bool useUnscaledTime;

        [Header("文字（全局默认颜色）")]
        [SerializeField]
        Color textColorA = Color.white;

        [SerializeField]
        Color textColorB = Color.red;

        [SerializeField]
        List<UIBlinkTextItem> textItems = new List<UIBlinkTextItem>();

        [Header("图片")]
        [SerializeField]
        UIBlinkImageMode defaultImageMode = UIBlinkImageMode.Sprite;

        [SerializeField]
        Sprite imageSpriteA;

        [SerializeField]
        Sprite imageSpriteB;

        [SerializeField]
        Color imageColorA = Color.white;

        [SerializeField]
        Color imageColorB = new Color(1f, 1f, 1f, 0.35f);

        [SerializeField]
        List<UIBlinkImageItem> imageItems = new List<UIBlinkImageItem>();

        Coroutine _blinkRoutine;
        bool _showingStateA = true;
        bool _isPlaying;

        public bool IsPlaying => _isPlaying;

        public bool UseSmoothTransition
        {
            get => useSmoothTransition;
            set => useSmoothTransition = value;
        }

        public float TransitionDuration
        {
            get => transitionDuration;
            set => transitionDuration = Mathf.Max(0f, value);
        }

        public float StateInterval
        {
            get => stateInterval;
            set => stateInterval = Mathf.Max(0.02f, value);
        }

        public bool Loop
        {
            get => loop;
            set => loop = value;
        }

        void OnEnable()
        {
            if (playOnEnable)
                Play();
        }

        void OnDisable()
        {
            Stop(restoreStateOnStop);
        }

        public void Play()
        {
            Stop(false);
            _showingStateA = true;
            ApplyStateLerp(0f);
            _blinkRoutine = StartCoroutine(BlinkRoutine());
            _isPlaying = true;
        }

        public void Stop() => Stop(restoreStateOnStop);

        public void Stop(bool restore)
        {
            if (_blinkRoutine != null)
            {
                StopCoroutine(_blinkRoutine);
                _blinkRoutine = null;
            }

            _isPlaying = false;
            if (restore)
                ApplyStateLerp(0f);
        }

        public void SetState(bool stateA)
        {
            _showingStateA = stateA;
            ApplyStateLerp(stateA ? 0f : 1f);
        }

        IEnumerator BlinkRoutine()
        {
            if (startDelay > 0f)
                yield return WaitSeconds(startDelay);

            _showingStateA = true;
            ApplyStateLerp(0f);

            while (true)
            {
                yield return WaitSeconds(stateInterval);

                var targetA = !_showingStateA;
                yield return TransitionToState(targetA);
                _showingStateA = targetA;

                if (!loop)
                {
                    if (!_showingStateA)
                    {
                        yield return WaitSeconds(stateInterval);
                        yield return TransitionToState(true);
                        _showingStateA = true;
                    }

                    _isPlaying = false;
                    _blinkRoutine = null;
                    yield break;
                }
            }
        }

        IEnumerator TransitionToState(bool targetStateA)
        {
            if (!useSmoothTransition || transitionDuration <= 0f)
            {
                ApplyStateLerp(targetStateA ? 0f : 1f);
                yield break;
            }

            var startT = _showingStateA ? 0f : 1f;
            var endT = targetStateA ? 0f : 1f;
            var elapsed = 0f;

            while (elapsed < transitionDuration)
            {
                elapsed += useUnscaledTime ? Time.unscaledDeltaTime : Time.deltaTime;
                var normalized = Mathf.Clamp01(elapsed / transitionDuration);
                var curveT = transitionCurve != null && transitionCurve.length > 0
                    ? transitionCurve.Evaluate(normalized)
                    : normalized;
                ApplyStateLerp(Mathf.Lerp(startT, endT, curveT));
                yield return null;
            }

            ApplyStateLerp(endT);
        }

        IEnumerator WaitSeconds(float seconds)
        {
            if (seconds <= 0f)
                yield break;
            if (useUnscaledTime)
            {
                var end = Time.unscaledTime + seconds;
                while (Time.unscaledTime < end)
                    yield return null;
            }
            else
            {
                yield return new WaitForSeconds(seconds);
            }
        }

        /// <param name="t">0 = 状态 A，1 = 状态 B</param>
        void ApplyStateLerp(float t)
        {
            t = Mathf.Clamp01(t);
            ApplyTextStateLerp(t);
            ApplyImageStateLerp(t);
        }

        void ApplyTextStateLerp(float t)
        {
            if (textItems == null)
                return;

            foreach (var item in textItems)
            {
                if (item?.text == null)
                    continue;
                var a = item.useCustomColors ? item.colorA : textColorA;
                var b = item.useCustomColors ? item.colorB : textColorB;
                item.text.color = Color.Lerp(a, b, t);
            }
        }

        void ApplyImageStateLerp(float t)
        {
            if (imageItems == null)
                return;

            foreach (var item in imageItems)
            {
                if (item?.image == null)
                    continue;

                var mode = item.mode;
                if (mode == UIBlinkImageMode.Sprite && item.image.sprite == null && defaultImageMode == UIBlinkImageMode.Color)
                    mode = UIBlinkImageMode.Color;

                var ca = item.useCustomColors ? item.colorA : imageColorA;
                var cb = item.useCustomColors ? item.colorB : imageColorB;

                if (mode == UIBlinkImageMode.Color)
                {
                    item.image.color = Color.Lerp(ca, cb, t);
                    continue;
                }

                var spA = item.useCustomSprites ? item.spriteA : imageSpriteA;
                var spB = item.useCustomSprites ? item.spriteB : imageSpriteB;

                if (useSmoothTransition && transitionDuration > 0f)
                {
                    var sp = t < 0.5f ? spA : spB;
                    if (sp != null)
                        item.image.sprite = sp;
                    item.image.color = Color.Lerp(ca, cb, t);
                }
                else
                {
                    var sp = t < 0.5f ? spA : spB;
                    if (sp != null)
                        item.image.sprite = sp;
                    item.image.color = Color.Lerp(ca, cb, t);
                }
            }
        }

#if UNITY_EDITOR
        [ContextMenu("Preview State A")]
        void EditorPreviewA()
        {
            ApplyStateLerp(0f);
        }

        [ContextMenu("Preview State B")]
        void EditorPreviewB()
        {
            ApplyStateLerp(1f);
        }

        [ContextMenu("Preview Transition 50%")]
        void EditorPreviewMid()
        {
            ApplyStateLerp(0.5f);
        }
#endif
    }
}