using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Text;
using UnityEngine;

public class Texture2PDF : MonoBehaviour
{
    /// <summary>
    /// 插件默认路径
    /// </summary>
    private static string pluginPath = string.Format("{0}\\LGUtilityCore\\Texture2PDF-Plugins\\Image2PDF.exe", Application.streamingAssetsPath.Replace("/", "\\"));

    /// <summary>
    /// 测试导出的Texture2D
    /// </summary>
    public Texture2D[] textureArray;
    /// <summary>
    /// 测试输出PDF路径
    /// </summary>
    public string outPutPdfPath;

    // Start is called before the first frame update
    void Start()
    {
        //图片至少2个，最后1个参数必须是pdf文件路径
        //Texture2PDF.Convert2PDF(new string[] { "D:\\temp\\pdf-test\\1.jpg", "D:\\temp\\pdf-test\\2.jpg", "D:\\temp\\pdf-test\\3.jpg", "D:\\temp\\pdf-test\\4.jpg" }, "d:\\test_output.pdf");

        //Convert2PDF(textureArray, outPutPdfPath);
    }

    /// <summary>
    /// 执行转换PDF
    /// </summary>
    /// <param name="image_paths">图片路径集合，至少2个</param>
    /// <param name="pdf_path">输出PDF文件路径</param>
    /// /// <param name="callBack">回调函数(bool,string)</param>
    public static void Convert2PDF(string[] image_paths, string pdf_path, Action<bool, string> callBack = null)
    {
        if (image_paths.Length < 2)
            return;

        StringBuilder args = new StringBuilder();
        foreach (var path in image_paths)
            args.AppendFormat("{0} ", path);
        args.Append(pdf_path);
        RunExternalProcess(pluginPath, args.ToString(), callBack);
    }

    /// <summary>
    /// 执行转换PDF
    /// </summary>
    /// <param name="textures">Texture2D数组</param>
    /// <param name="pdf_path">输出PDF文件路径</param>
    /// <param name="callBack">回调函数(bool,string)</param>
    public static void Convert2PDF(Texture2D[] textures, string pdf_path, Action<bool, string> callBack = null)
    {
        if (textures.Length < 2)
            return;

        List<string> image_paths = new List<string>();

        // Get the path to the temporary directory
        string tempPath = Path.GetTempPath();
        foreach (var tex in textures)
        {
            string filePath = Path.Combine(tempPath, string.Format("{0}.jpg", Guid.NewGuid().ToString()));
            SaveTextureAsJPG(tex, filePath);
            image_paths.Add(filePath);
        }

        Convert2PDF(image_paths.ToArray(), pdf_path, (bool status,string result) => 
        {
            //删除临时图片文件
            image_paths.ForEach(x => 
            { 
                try 
                { 
                    System.IO.File.Delete(x); 
                } 
                catch (Exception e) 
                { 
                    Debug.LogError(e.Message); 
                } 
            });

            if(callBack!=null)
                callBack(status, result);
        });
    }

    /// <summary>
    /// 保存Texture2D为jpg文件
    /// </summary>
    /// <param name="texture">Texture2D</param>
    /// <param name="filePath">jpg保存路径</param>
    private static void SaveTextureAsJPG(Texture2D texture, string filePath)
    {
        // Encode texture to JPG format
        byte[] bytes = DeCompress(texture).EncodeToJPG();
        // Write the bytes to a file
        File.WriteAllBytes(filePath, bytes);
    }

    /// <summary>
    /// 转换，避免Read/Write读取不到等异常
    /// </summary>
    /// <param name="source">原始Texture2D</param>
    /// <returns>临时Texture2D</returns>
    public static Texture2D DeCompress(Texture2D source)
    {
        RenderTexture renderTex = RenderTexture.GetTemporary(
                    source.width,
                    source.height,
                    0,
                    RenderTextureFormat.Default,
                    RenderTextureReadWrite.Linear);

        Graphics.Blit(source, renderTex);
        RenderTexture previous = RenderTexture.active;
        RenderTexture.active = renderTex;
        Texture2D readableText = new Texture2D(source.width, source.height);
        readableText.ReadPixels(new Rect(0, 0, renderTex.width, renderTex.height), 0, 0);
        readableText.Apply();
        RenderTexture.active = previous;
        RenderTexture.ReleaseTemporary(renderTex);
        return readableText;
    }


    /// <summary>
    /// 执行插件程序
    /// </summary>
    /// <param name="exePath">插件路径</param>
    /// <param name="arguments">插件参数，图片至少2个，最后1个参数必须是pdf文件路径</param>
    /// <returns></returns>
    private static void RunExternalProcess(string exePath, string arguments, Action<bool, string> callBack = null)
    {
        System.Diagnostics.Process process = new System.Diagnostics.Process();
        process.StartInfo.FileName = exePath;
        process.StartInfo.Arguments = arguments;
        process.StartInfo.UseShellExecute = false;
        process.StartInfo.RedirectStandardOutput = true;
        process.StartInfo.RedirectStandardError = true;
        process.StartInfo.CreateNoWindow = true;

        process.Start();

        bool callBackStatus = true;
        string output = "", error = "";

        while (!process.HasExited)
        {
            output = process.StandardOutput.ReadToEnd();
            error = process.StandardError.ReadToEnd();

            if (!string.IsNullOrEmpty(error))
            {
                callBackStatus = false;
            }
        }

        process.WaitForExit();
        if (null != callBack)
            callBack(callBackStatus, callBackStatus ? output : error);
    }
}