using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;
using System.Collections;

public class SongButton : MonoBehaviour
{
    [Header("thisSong_so")]
    public ScriptableObject thisSong_so;
    [Header("展示的信息")]
    public Text songNameText;
    public Text multiNameText;
    public Text joinTime_and_dlcName_Text;
    public Text songOverallDescriptionText;
    public Text highestScoreText;
    public Text difficultyIDText;
    public Text songIDText;
    public Image buttonImage;
    [Header("头图")]
    public Image profileImage;
    public int song_songSerialID;
    [Header("select mark")]
    public Image selected_boarder;
    public Image fade_image;

    [Header("Fade Image Settings")]
    public float minAlpha = 0f;
    public float maxAlpha = 1f;
    public float blinkDuration = 0.5f;

    private static SongButton currentSelected;
    private Coroutine fadeCoroutine;
    private Coroutine blinkCoroutine;

    public void Start()
    {
        if (selected_boarder != null)
        {
            Color c = selected_boarder.color;
            c.a = 0f;
            selected_boarder.color = c;
        }
        if (fade_image != null)
        {
            Color c = fade_image.color;
            c.a = 0f;
            fade_image.color = c;
        }
    }

    public void SetButtonData(string songName, int highestScore, int difficultyID, Sprite songSprite, int songID)
    {
        Debug.Log("SetButtonData 被调用, songID 参数: " + songID);

        var sd = SongDataLibrary.Instance != null ? SongDataLibrary.Instance.GetSongDataByID(songID) : null;
        if (sd != null)
        {
            if (songNameText != null) songNameText.text = sd.songName;

            if (multiNameText != null)
                multiNameText.text = "音乐：" + sd.artistName + "  |  曲绘：" + sd.painter + "  |  制谱：" + sd.level_creator;

            if (joinTime_and_dlcName_Text != null)
            {
                string join = string.IsNullOrEmpty(sd.thisLevel_addDateString) ? "未知" : sd.thisLevel_addDateString;
                string dlc = string.IsNullOrEmpty(sd.belongsTo_whichDLC) ? "未归档DLC" : sd.belongsTo_whichDLC;
                joinTime_and_dlcName_Text.text = "歌曲收录时间：" + join + "   |   " + "所属DLC：" + dlc;
            }

            if (songOverallDescriptionText != null)
            {
                songOverallDescriptionText.text = string.IsNullOrEmpty(sd.thisLevel_overallDescription) ? "暂无歌曲简介。" : sd.thisLevel_overallDescription;
            }

            int bestTotal = 0;
            int bestDiff = -1;
            if (sd.personalRecordMap != null)
            {
                foreach (var kvp in sd.personalRecordMap)
                {
                    int diff = kvp.Key;
                    int p = kvp.Value;
                    int i = sd.GetIdolRecord(diff);
                    int combined = p + i;
                    if (combined > bestTotal)
                    {
                        bestTotal = combined;
                        bestDiff = diff;
                    }
                }
            }

            if (bestDiff == -1)
            {
                bestTotal = sd.personalRecord;
                bestDiff = sd.thisLevel_selectedDifficultyID;
            }

            if (highestScoreText != null) highestScoreText.text = bestTotal.ToString();

            string diffDisplay = bestDiff.ToString();
            if (sd.chartFiles != null)
            {
                foreach (var entry in sd.chartFiles)
                {
                    if (entry != null && entry.difficulty == bestDiff)
                    {
                        diffDisplay = entry.difficultyLEVEL.ToString();
                        break;
                    }
                }
            }
            if (difficultyIDText != null) difficultyIDText.text = diffDisplay;

            if (buttonImage != null) buttonImage.sprite = sd.backgroudPIC;

            if (profileImage != null)
            {
                profileImage.sprite = sd.card_profileImage;
                if (sd.card_profileImage != null)
                {
                    profileImage.color = new Color(profileImage.color.r, profileImage.color.g, profileImage.color.b, 1f);
                    profileImage.enabled = true;
                }
                else
                {
                    profileImage.enabled = false;
                }
            }

            song_songSerialID = songID;
            if (songIDText != null) songIDText.text = "数据库索引号：" + song_songSerialID.ToString();
        }
        else
        {
            if (songNameText != null) songNameText.text = songName;
            if (highestScoreText != null) highestScoreText.text = "PR: " + highestScore.ToString();
            if (difficultyIDText != null) difficultyIDText.text = difficultyID.ToString();
            if (buttonImage != null) buttonImage.sprite = songSprite;
            song_songSerialID = songID;
            if (songIDText != null) songIDText.text = "Song ID: " + song_songSerialID.ToString();
        }
    }

    public void OnSongButtonClick()
    {
        Debug.Log("点击按钮的 song_songSerialID: " + song_songSerialID);
        SongData selectedSong = SongDataLibrary.Instance.GetSongDataByID(song_songSerialID);
        if (selectedSong != null)
        {
            if (currentSelected != null && currentSelected != this)
            {
                currentSelected.FadeOutSelectedBorder();
            }
            currentSelected = this;
            FadeInSelectedBorder();

            SongDataHolder.SelectedSongData = selectedSong;
            var selectedInfo = FindObjectOfType<selected_songInfo>();
            if (selectedInfo != null)
            {
                selectedInfo.UpdateSelectedSongDisplay();
            }

            // Save per-DLC selected song index to PlayerPrefs
            string dlcKey = SongSelectUI.CurrentDlcKey;
            if (string.IsNullOrEmpty(dlcKey)) dlcKey = "default_0";
            string prefsKey = "song_selected_" + dlcKey;
            int index = GetIndexAmongSongButtons();
            PlayerPrefs.SetInt(prefsKey, index);
            PlayerPrefs.Save();
            Debug.Log($"SongButton: saved selected song index {index} for key {prefsKey}");
        }
        else
        {
            Debug.LogError("未找到对应的 SongData, songID: " + song_songSerialID);
        }
    }

    private int GetIndexAmongSongButtons()
    {
        // Use parent traversal to find only SongButton siblings, to avoid mismatch when other UI children exist.
        var parent = transform.parent;
        if (parent == null) return 0;
        int idx = 0;
        for (int i = 0; i < parent.childCount; i++)
        {
            var child = parent.GetChild(i);
            var sb = child != null ? child.GetComponent<SongButton>() : null;
            if (sb == null) continue;
            if (sb == this) return idx;
            idx++;
        }
        return 0;
    }

    private void FadeInSelectedBorder()
    {
        if (selected_boarder != null)
        {
            if (fadeCoroutine != null) StopCoroutine(fadeCoroutine);
            fadeCoroutine = StartCoroutine(FadeImage(selected_boarder, selected_boarder.color.a, 1f, 0.3f));
        }
        if (fade_image != null)
        {
            if (blinkCoroutine != null) StopCoroutine(blinkCoroutine);
            blinkCoroutine = StartCoroutine(BlinkFadeImage());
        }
    }

    private void FadeOutSelectedBorder()
    {
        if (selected_boarder != null)
        {
            if (fadeCoroutine != null) StopCoroutine(fadeCoroutine);
            fadeCoroutine = StartCoroutine(FadeImage(selected_boarder, selected_boarder.color.a, 0f, 0.3f));
        }
        if (fade_image != null)
        {
            if (blinkCoroutine != null) StopCoroutine(blinkCoroutine);
            fadeCoroutine = StartCoroutine(FadeImage(fade_image, fade_image.color.a, 0f, 0.3f));
        }
    }

    private IEnumerator FadeImage(Image img, float startAlpha, float endAlpha, float duration)
    {
        if (img == null) yield break;
        float time = 0f;
        Color color = img.color;
        while (time < duration)
        {
            time += Time.deltaTime;
            float alpha = Mathf.Lerp(startAlpha, endAlpha, time / duration);
            color.a = alpha;
            img.color = color;
            yield return null;
        }
        color.a = endAlpha;
        img.color = color;
    }

    private IEnumerator BlinkFadeImage()
    {
        if (fade_image == null) yield break;
        Color color = fade_image.color;
        while (true)
        {
            float time = 0f;
            while (time < blinkDuration / 2f)
            {
                time += Time.deltaTime;
                float alpha = Mathf.Lerp(minAlpha, maxAlpha, time / (blinkDuration / 2f));
                color.a = alpha;
                fade_image.color = color;
                yield return null;
            }
            time = 0f;
            while (time < blinkDuration / 2f)
            {
                time += Time.deltaTime;
                float alpha = Mathf.Lerp(maxAlpha, minAlpha, time / (blinkDuration / 2f));
                color.a = alpha;
                fade_image.color = color;
                yield return null;
            }
        }
    }
}