using System.IO;
using UnityEditor;
using UnityEngine;

[CustomEditor(typeof(T4MSwap))]
public class T4MSwapEditor : Editor
{
    private Shader _t4MNormalShader;
    private Shader _t4MShader;
    private T4MSwap _target;

    private void OnEnable()
    {
        _target = (T4MSwap) target;
        _t4MShader = Shader.Find("Zhanyou/Scene/T4M 4 Textures");
        _t4MNormalShader = Shader.Find("Zhanyou/Scene/T4M 4 Textures Bump");
    }

    public override void OnInspectorGUI()
    {
        base.OnInspectorGUI();
        if (GUILayout.Button("Fix Channel"))
        {
            var channelTex = GetChannelTexture();
            if (channelTex != null)
            {
                var temp = new Texture2D(channelTex.width, channelTex.height, TextureFormat.ARGB32, false);
                for (var i = 0; i < channelTex.width; i++)
                for (var j = 0; j < channelTex.height; j++)
                {
                    var color = channelTex.GetPixel(i, j);
                    var r = Mathf.Clamp01(color.r);
                    var g = Mathf.Clamp01(color.g);
                    var b = Mathf.Clamp01(color.b);
                    var a = Mathf.Clamp01(color.a);
                    var total = r + g + b + a;
                    if (total > 0)
                    {
                        var modifier = 1f / total;
                        color = new Color(r, g, b, a) * modifier;
                    }
                    else
                    {
                        color.r = color.g = color.b = color.a = 0.25f;
                    }

                    temp.SetPixel(i, j, color);
                }

                temp.Apply();
                SaveTexture(temp, channelTex);
            }
        }

        GUILayout.Space(5f);
        if (GUILayout.Button("Execute"))
        {
            if (_target.source != _target.target &&
                ValidChannel(_target.source) &&
                ValidChannel(_target.target))
            {
                var channelTex = GetChannelTexture();
                if (channelTex != null)
                {
                    var material = _target.targetMaterial;
                    var sourceChannel = _target.source - 1;
                    var targetChannel = _target.target - 1;
                    var sourceName = GetColorTexName(sourceChannel);
                    var targetName = GetColorTexName(targetChannel);
                    var sourceTex = material.GetTexture(sourceName);
                    var targetTex = material.GetTexture(targetName);
                    var sourceScale = material.GetTextureScale(sourceName);
                    var targetScale = material.GetTextureScale(targetName);
                    var sourceOffset = material.GetTextureOffset(sourceName);
                    var targetOffset = material.GetTextureOffset(targetName);
                    material.SetTexture(sourceName, targetTex);
                    material.SetTexture(targetName, sourceTex);
                    material.SetTextureScale(sourceName, targetScale);
                    material.SetTextureScale(targetName, sourceScale);
                    material.SetTextureOffset(sourceName, targetOffset);
                    material.SetTextureOffset(targetName, sourceOffset);
                    if (material.shader == _t4MNormalShader)
                    {
                        sourceName = GetNormalTexName(sourceChannel);
                        targetName = GetNormalTexName(targetChannel);
                        sourceTex = material.GetTexture(sourceName);
                        targetTex = material.GetTexture(targetName);
                        material.SetTexture(sourceName, targetTex);
                        material.SetTexture(targetName, sourceTex);
                        const string bumpVectorName = "_BumpVector";
                        const string glossName = "_Gloss";
                        var bumpStrength = material.GetColor(bumpVectorName);
                        var gloss = material.GetColor(glossName);
                        var sourceBump = GetChannelColor(bumpStrength, sourceChannel);
                        var targetBump = GetChannelColor(bumpStrength, targetChannel);
                        var sourceGloss = GetChannelColor(gloss, sourceChannel);
                        var targetGloss = GetChannelColor(gloss, targetChannel);
                        SetChannelColor(ref bumpStrength, sourceChannel, targetBump);
                        SetChannelColor(ref bumpStrength, targetChannel, sourceBump);
                        SetChannelColor(ref gloss, sourceChannel, targetGloss);
                        SetChannelColor(ref gloss, targetChannel, sourceGloss);
                        material.SetColor(bumpVectorName, bumpStrength);
                        material.SetColor(glossName, gloss);
                    }

                    var temp = new Texture2D(channelTex.width, channelTex.height, TextureFormat.ARGB32, false);
                    for (var i = 0; i < channelTex.width; i++)
                    for (var j = 0; j < channelTex.height; j++)
                    {
                        var color = channelTex.GetPixel(i, j);
                        var sourcePixel = GetChannelColor(color, sourceChannel);
                        var targetPixel = GetChannelColor(color, targetChannel);
                        SetChannelColor(ref color, targetChannel, sourcePixel);
                        SetChannelColor(ref color, sourceChannel, targetPixel);
                        temp.SetPixel(i, j, color);
                    }

                    temp.Apply();
                    SaveTexture(temp, channelTex);
                }
            }
            else
            {
                Debug.LogError("通道设定错误");
            }
        }
    }

    private Texture2D GetChannelTexture()
    {
        Texture2D result = null;
        var material = _target.targetMaterial;
        if (material != null)
            if (material.shader == _t4MShader || material.shader == _t4MNormalShader)
            {
                var channelTex = _target.targetMaterial.GetTexture("_Control") as Texture2D;
                if (channelTex != null)
                {
                    // 强制替换文件编码格式为ARGB32，防止异常
                    var assetPath = AssetDatabase.GetAssetPath(channelTex);
                    var importer = AssetImporter.GetAtPath(assetPath) as TextureImporter;
                    if (importer == null)
                    {
                        Debug.LogError(string.Format("无法获得贴图{0}的TextureImporter！", assetPath));
                    }
                    else
                    {
                        // 暂时没有必要使用GetPlatformTextureSettings
                        importer.textureFormat = TextureImporterFormat.ARGB32;
                        importer.textureCompression = TextureImporterCompression.Uncompressed;
                        importer.SaveAndReimport();
                        result = channelTex;
                    }
                }
            }

        return result;
    }

    private void SaveTexture(Texture2D temp, Texture2D channelTex)
    {
        var assetPath = AssetDatabase.GetAssetPath(channelTex);
        assetPath = Application.dataPath + Path.DirectorySeparatorChar +
                    assetPath.Substring("Assets/".Length);
        var bytes = temp.EncodeToPNG();
        DestroyImmediate(temp);
        File.WriteAllBytes(assetPath, bytes);
        EditorUtility.SetDirty(_target.targetMaterial);
        AssetDatabase.SaveAssets();
        AssetDatabase.Refresh();
    }

    private bool ValidChannel(int channel)
    {
        return channel > 0 && channel < 5;
    }

    private float GetChannelColor(Color color, int channel)
    {
        var result = 0f;
        switch (channel)
        {
            case 0:
                result = color.r;
                break;
            case 1:
                result = color.g;
                break;
            case 2:
                result = color.b;
                break;
            case 3:
                result = color.a;
                break;
        }

        return result;
    }

    private void SetChannelColor(ref Color color, int channel, float value)
    {
        switch (channel)
        {
            case 0:
                color.r = value;
                break;
            case 1:
                color.g = value;
                break;
            case 2:
                color.b = value;
                break;
            case 3:
                color.a = value;
                break;
        }
    }

    private string GetColorTexName(int channel)
    {
        return "_Splat" + channel;
    }

    private string GetNormalTexName(int channel)
    {
        return "_BumpSplat" + channel;
    }
}