using System;
using System.Collections;
using AibisDream.Framework;
using AibisDream.Kit;
using AibisDream.SaveSystem;
using AibisDream.Utility;
using DG.Tweening;
using UnityEngine;
using UnityEngine.ResourceManagement.AsyncOperations;

namespace AibisDream
{
    /// <summary>
    /// 梦境场景通用图片展示器。只负责普通小图、大图与背景遮罩；
    /// 场景专属动态表现通过 <see cref="PresentationChanging"/> 与本组件解耦。
    /// </summary>
    public class SpriteShowcase : Singleton<SpriteShowcase>
    {
        private const string DreamSpritePath = "Sprite/梦境/{0}.png";

        [SerializeField] private SpriteRenderer _spriteRenderer;
        [SerializeField] private SpriteRenderer _backgroundSpriteRenderer;
        [SerializeField] private SpriteRenderer _largeSpriteRenderer;

        private string _currentSmallPicName;
        private string _currentLargePicName;

        public event Action PresentationChanging;

        private bool IsSmallShowing => _spriteRenderer != null && _spriteRenderer.gameObject.activeSelf;
        private bool IsLargeShowing => _largeSpriteRenderer != null && _largeSpriteRenderer.gameObject.activeSelf;

        public override void OnSingletonInit()
        {
            ClearSmallImmediate();
            ClearLargeImmediate();
        }

        private void OnDisable()
        {
            ClearSmallImmediate();
            ClearLargeImmediate();
        }

        private static string NormalizeDreamPicName(string picName)
        {
            if (string.IsNullOrEmpty(picName)) return picName;
            return picName.EndsWith(".png", StringComparison.OrdinalIgnoreCase)
                ? picName.Substring(0, picName.Length - 4)
                : picName;
        }

        private IEnumerator LoadDreamSpriteInto(
            SpriteRenderer target,
            string picName,
            Action<bool> completed = null,
            Action<string> warning = null)
        {
            if (target == null)
            {
                completed?.Invoke(false);
                yield break;
            }

            var key = string.Format(DreamSpritePath, NormalizeDreamPicName(picName));
            var handle = ResourceSystem.LoadAsync<Sprite>(key);
            yield return handle;
            if (handle.Status == AsyncOperationStatus.Succeeded && handle.Result != null)
            {
                target.sprite = handle.Result;
                completed?.Invoke(true);
            }
            else
            {
                var message = $"[SpriteShowcase] Failed to load sprite: {key}";
                Debug.LogError(message, this);
                warning?.Invoke(message);
                completed?.Invoke(false);
            }
        }

        public IEnumerator ShowObj(string picName, float duration = 1f)
        {
            NotifyPresentationChanging();

            if (IsLargeShowing)
                yield return HideLargeInternal(duration);

            if (_spriteRenderer == null) yield break;
            _spriteRenderer.DOKill();
            _spriteRenderer.gameObject.SetActive(true);

            var loaded = false;
            yield return LoadDreamSpriteInto(_spriteRenderer, picName, value => loaded = value);
            if (!loaded)
            {
                ClearSmallImmediate();
                yield break;
            }

            _currentSmallPicName = NormalizeDreamPicName(picName);
            if (duration <= 0f)
                _spriteRenderer.SetAlpha(1f);
            else
                yield return _spriteRenderer.DOFade(1f, duration).WaitForCompletion();
        }

        public IEnumerator ShowLargeObj(string picName, float duration = 1f)
        {
            NotifyPresentationChanging();

            if (IsSmallShowing)
                yield return HideSmallInternal(0f);

            if (_largeSpriteRenderer == null) yield break;
            _largeSpriteRenderer.DOKill();
            _largeSpriteRenderer.gameObject.SetActive(true);
            _largeSpriteRenderer.SetAlpha(0f);

            var loaded = false;
            yield return LoadDreamSpriteInto(_largeSpriteRenderer, picName, value => loaded = value);
            if (!loaded)
            {
                ClearLargeImmediate();
                yield break;
            }

            _currentLargePicName = NormalizeDreamPicName(picName);
            if (duration <= 0f)
                _largeSpriteRenderer.SetAlpha(1f);
            else
                yield return _largeSpriteRenderer.DOFade(1f, duration).WaitForCompletion();
        }

        public IEnumerator HideObj(float duration = 1f)
        {
            yield return HideObj(false, duration);
        }

        public IEnumerator HideObj(bool force, float duration = 1f)
        {
            NotifyPresentationChanging();
            if (!force && !IsSmallShowing) yield break;
            yield return HideSmallInternal(duration);
        }

        public IEnumerator HideLargeObj(float duration = 1f)
        {
            NotifyPresentationChanging();
            if (!IsLargeShowing) yield break;
            yield return HideLargeInternal(duration);
        }

        public IEnumerator HideAll(float duration = 1f)
        {
            NotifyPresentationChanging();
            if (IsSmallShowing)
                yield return HideSmallInternal(duration);
            if (IsLargeShowing)
                yield return HideLargeInternal(duration);
        }

        private IEnumerator HideSmallInternal(float duration)
        {
            if (_spriteRenderer == null) yield break;
            _spriteRenderer.DOKill();
            if (duration > 0f)
                yield return _spriteRenderer.DOFade(0f, duration).WaitForCompletion();
            ClearSmallImmediate();
        }

        private IEnumerator HideLargeInternal(float duration)
        {
            if (_largeSpriteRenderer == null) yield break;
            _largeSpriteRenderer.DOKill();
            if (duration > 0f)
                yield return _largeSpriteRenderer.DOFade(0f, duration).WaitForCompletion();
            ClearLargeImmediate();
        }

        public IEnumerator FadeInAsync(float duration = 1f)
        {
            if (_backgroundSpriteRenderer == null) yield break;
            _backgroundSpriteRenderer.gameObject.SetActive(true);
            if (duration <= 0f)
                _backgroundSpriteRenderer.SetAlpha(1f);
            else
                yield return _backgroundSpriteRenderer.DOFade(1f, duration).WaitForCompletion();
        }

        public IEnumerator FadeOutAsync(float duration = 1f)
        {
            if (_backgroundSpriteRenderer == null) yield break;
            _backgroundSpriteRenderer.gameObject.SetActive(true);
            if (duration > 0f)
                yield return _backgroundSpriteRenderer.DOFade(0f, duration).WaitForCompletion();
            SetBackgroundImmediate(false);
        }

        public void FadeInSync(float duration = 1f)
        {
            StartCoroutine(FadeInAsync(duration));
        }

        public void FadeOutSync(float duration = 1f)
        {
            StartCoroutine(FadeOutAsync(duration));
        }

        public void ClearPresentationEffects()
        {
            NotifyPresentationChanging();
            ClearSmallImmediate();
            ClearLargeImmediate();
            SetBackgroundImmediate(false);
        }

        public ShowcaseSnapshotDto CaptureSnapshot()
        {
            var mode = ShowcaseDisplayMode.None;
            var picName = string.Empty;
            if (IsSmallShowing && !string.IsNullOrEmpty(_currentSmallPicName))
            {
                mode = ShowcaseDisplayMode.Small;
                picName = _currentSmallPicName;
            }
            else if (IsLargeShowing && !string.IsNullOrEmpty(_currentLargePicName))
            {
                mode = ShowcaseDisplayMode.Large;
                picName = _currentLargePicName;
            }

            return new ShowcaseSnapshotDto
            {
                displayMode = mode.ToString(),
                picName = picName,
                isBackgroundVisible = _backgroundSpriteRenderer != null
                                      && _backgroundSpriteRenderer.gameObject.activeSelf
                                      && _backgroundSpriteRenderer.color.a > 0.001f
            };
        }

        public IEnumerator RestoreSnapshotAsync(ShowcaseSnapshotDto snapshot, Action<string> warning = null)
        {
            ClearPresentationEffects();
            if (snapshot == null) yield break;

            if (!Enum.TryParse(snapshot.displayMode, true, out ShowcaseDisplayMode mode))
            {
                warning?.Invoke($"[SpriteShowcase] Unknown display mode: {snapshot.displayMode}");
                mode = ShowcaseDisplayMode.None;
            }

            switch (mode)
            {
                case ShowcaseDisplayMode.Small when !string.IsNullOrWhiteSpace(snapshot.picName):
                    yield return ShowObj(snapshot.picName, 0f);
                    break;
                case ShowcaseDisplayMode.Large when !string.IsNullOrWhiteSpace(snapshot.picName):
                    yield return ShowLargeObj(snapshot.picName, 0f);
                    break;
            }

            SetBackgroundImmediate(snapshot.isBackgroundVisible);
        }

        private void NotifyPresentationChanging()
        {
            PresentationChanging?.Invoke();
        }

        private void ClearSmallImmediate()
        {
            if (_spriteRenderer != null)
            {
                _spriteRenderer.DOKill();
                _spriteRenderer.SetAlpha(0f);
                _spriteRenderer.gameObject.SetActive(false);
            }
            _currentSmallPicName = null;
        }

        private void ClearLargeImmediate()
        {
            if (_largeSpriteRenderer != null)
            {
                _largeSpriteRenderer.DOKill();
                _largeSpriteRenderer.SetAlpha(0f);
                _largeSpriteRenderer.gameObject.SetActive(false);
            }
            _currentLargePicName = null;
        }

        private void SetBackgroundImmediate(bool visible)
        {
            if (_backgroundSpriteRenderer == null) return;
            _backgroundSpriteRenderer.DOKill();
            _backgroundSpriteRenderer.SetAlpha(visible ? 1f : 0f);
            _backgroundSpriteRenderer.gameObject.SetActive(visible);
        }
    }
}