using UnityEngine;
using UnityEngine.UI;
#if UNITY_EDITOR
using UnityEditor;
#endif

[ExecuteAlways]
public class BgmSpectrumVisualizer : MonoBehaviour
{
    [Header("Audio")]
    public AudioSource source;
    public FFTWindow fftWindow = FFTWindow.BlackmanHarris;

    [Header("Bars")]
    public RectTransform barPrefab;
    public int bars = 64;
    public float barWidth = 4.8f;
    public float barSpacing = 2f;
    public float maxHeight = 100f;

    [Header("Spectrum")]
    public int spectrumSize = 512;
    public float amplitude = 60f;
    public float smooth = 12f;
    public float noiseFloor = 0.002f;

    [Header("Wave")]
    public float waveAmplitude = 6f;
    public float waveSpeed = 1.6f;
    public float waveFrequency = 0.45f;
    [Tooltip("If true, bars expand upward from baseline only.")]
    public bool growUpOnly = true;

    [Header("Edit Preview")]
    public bool previewInEditMode = true;
    public float previewAmplitude = 0.6f;
    public float previewNoiseSpeed = 0.25f;

    private float[] spectrum;
    private RectTransform[] barRects;
    private float[] barHeights;
    private Vector2[] barBasePos;
    private bool rebuildQueued;

    private void Awake()
    {
        if (Application.isPlaying)
        {
            Init();
        }
        else
        {
            ScheduleRebuild();
        }
    }

    private void OnEnable()
    {
        if (barRects == null || barRects.Length == 0)
        {
            if (Application.isPlaying) Init();
            else ScheduleRebuild();
        }
    }

    private void OnValidate()
    {
        if (bars < 1) bars = 1;
        if (barWidth < 1f) barWidth = 1f;
        if (barSpacing < 0f) barSpacing = 0f;
        if (maxHeight < 1f) maxHeight = 1f;

        ScheduleRebuild();
    }

    private void Init()
    {
        RebuildBars();
    }

    private void ScheduleRebuild()
    {
        if (rebuildQueued) return;
        rebuildQueued = true;
#if UNITY_EDITOR
        EditorApplication.delayCall -= RebuildIfQueued;
        EditorApplication.delayCall += RebuildIfQueued;
#endif
    }

#if UNITY_EDITOR
    private void RebuildIfQueued()
    {
        if (!rebuildQueued) return;
        rebuildQueued = false;
        if (this == null) return;

        RebuildBars();
        if (!Application.isPlaying && previewInEditMode)
            UpdateBarsPreview();
    }
#endif

    private void Update()
    {
        if (!Application.isPlaying)
        {
            if (previewInEditMode)
                UpdateBarsPreview();
            return;
        }

        if (source == null)
        {
            var mgr = BgmPlaybackManager.Instance;
            if (mgr != null) source = mgr.audioSource;
        }

        if (source == null || source.clip == null)
            return;

        if (spectrum == null || spectrum.Length != spectrumSize)
            spectrum = new float[spectrumSize];

        source.GetSpectrumData(spectrum, 0, fftWindow);

        for (int i = 0; i < bars; i++)
        {
            float t = (float)i / (bars - 1);
            int idx = Mathf.Clamp(Mathf.RoundToInt(Mathf.Lerp(1, spectrumSize - 1, t * t)), 1, spectrumSize - 1);

            float v = Mathf.Max(0f, spectrum[idx] - noiseFloor) * amplitude;
            float baseHeight = Mathf.Clamp01(v) * maxHeight;

            float wave = Mathf.Sin(Time.time * waveSpeed + i * waveFrequency) * waveAmplitude;
            float target = Mathf.Clamp(baseHeight + wave, 0f, maxHeight);

            barHeights[i] = Mathf.Lerp(barHeights[i], target, Time.deltaTime * smooth);

            var rt = barRects[i];
            float h = Mathf.Max(1f, barHeights[i]);
            var sd = rt.sizeDelta;
            if (sd.x != barWidth || sd.y != h)
                rt.sizeDelta = new Vector2(barWidth, h);
            if (growUpOnly && barBasePos != null && i < barBasePos.Length)
            {
                var ap = rt.anchoredPosition;
                float nx = barBasePos[i].x;
                float ny = barBasePos[i].y + h * 0.5f;
                if (ap.x != nx || ap.y != ny)
                    rt.anchoredPosition = new Vector2(nx, ny);
            }
        }
    }

    private void RebuildBars()
    {
        if (barPrefab == null)
        {
            var go = new GameObject("Bar", typeof(RectTransform), typeof(Image), typeof(Outline));
            var img = go.GetComponent<Image>();
            img.color = Color.white;
            var outline = go.GetComponent<Outline>();
            outline.effectColor = new Color(0f, 0f, 0f, 1f);
            outline.effectDistance = new Vector2(1f, 1f);
            outline.useGraphicAlpha = true;
            barPrefab = go.GetComponent<RectTransform>();
            barPrefab.sizeDelta = new Vector2(barWidth, 10f);
            go.SetActive(false);
        }

        // destroy existing bars
        for (int i = transform.childCount - 1; i >= 0; i--)
        {
            var child = transform.GetChild(i);
            if (Application.isPlaying)
                Destroy(child.gameObject);
            else
                DestroyImmediate(child.gameObject);
        }

        spectrum = new float[Mathf.Max(64, spectrumSize)];
        barRects = new RectTransform[bars];
        barHeights = new float[bars];
        barBasePos = new Vector2[bars];

        for (int i = 0; i < bars; i++)
        {
            var bar = Instantiate(barPrefab, transform);
            bar.gameObject.SetActive(true);
            barRects[i] = bar;
            var outline = bar.GetComponent<Outline>();
            if (outline == null)
            {
                outline = bar.gameObject.AddComponent<Outline>();
                outline.effectColor = new Color(0f, 0f, 0f, 1f);
                outline.effectDistance = new Vector2(1f, 1f);
                outline.useGraphicAlpha = true;
            }
            barRects[i].sizeDelta = new Vector2(barWidth, 1f);
            var basePos = new Vector2(i * (barWidth + barSpacing), 0f);
            barRects[i].anchoredPosition = basePos;
            barBasePos[i] = basePos;
        }
    }

    private void UpdateBarsPreview()
    {
        if (barRects == null || barRects.Length == 0)
            return;

        float time = GetEditorTime();
        for (int i = 0; i < bars; i++)
        {
            float t = (float)i / (bars - 1);
            float noise = Mathf.PerlinNoise(t * 2.5f, time * previewNoiseSpeed);
            float baseHeight = Mathf.Lerp(0.2f, 1f, noise) * maxHeight * previewAmplitude;
            float wave = Mathf.Sin(time * waveSpeed + i * waveFrequency) * waveAmplitude;
            float target = Mathf.Clamp(baseHeight + wave, 0f, maxHeight);
            barHeights[i] = Mathf.Lerp(barHeights[i], target, 0.2f);
            var rt = barRects[i];
            float h = Mathf.Max(1f, barHeights[i]);
            var sd = rt.sizeDelta;
            if (sd.x != barWidth || sd.y != h)
                rt.sizeDelta = new Vector2(barWidth, h);
            if (growUpOnly && barBasePos != null && i < barBasePos.Length)
            {
                var ap = rt.anchoredPosition;
                float nx = barBasePos[i].x;
                float ny = barBasePos[i].y + h * 0.5f;
                if (ap.x != nx || ap.y != ny)
                    rt.anchoredPosition = new Vector2(nx, ny);
            }
        }
    }

    private float GetEditorTime()
    {
#if UNITY_EDITOR
        return (float)EditorApplication.timeSinceStartup;
#else
        return Time.realtimeSinceStartup;
#endif
    }
}