/*
 * REFERENCES:
 * https://www.joe0.com/2019/01/27/how-create-a-custom-browser-uri-scheme-and-c-protocol-handler-client-that-supports-opening-and-editing-of-remotely-hosted-documents-through-webdav/
 * https://stackoverflow.com/questions/44675085/minimize-console-at-app-startup-c-sharp
 * 
 */
using System;
using System.Collections.Specialized;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;

namespace LocalExplorer
{
    class Program
    {
        [DllImport("User32.dll", CallingConvention = CallingConvention.StdCall, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool ShowWindow([In] IntPtr hWnd, [In] int nCmdShow);

        [DllImport("shell32.dll", EntryPoint = "FindExecutable")]
        private static extern long FindExecutable(string lpFile, string lpDirectory, StringBuilder lpResult);

        static void Main(string[] args)
        {
            bool bDirectoryExists = false;
            bool bFileExists = false;

            //Start this process hidden
            IntPtr handle = Process.GetCurrentProcess().MainWindowHandle;
            ShowWindow(handle, 0);

            //Check to make sure a path was passed in as an argument to the program.
            if (args.Length == 0)
            {
                Console.WriteLine("usage: LocalExplorer.exe <path to open with Explorer.exe>");
                WriteOutputFile("no args passed to program");
                Environment.Exit(1);
            }

            //Collect up the path
            //the replace function is here to trim out the arg as it
            //comes in from the url protocol handler
            string path = args[0].Replace("saolocalexplorer:", "").Replace("%5C", "\\");

            //If there is a space in the path as it comes from the URL
            //protocol handler, replace it with an actual space.
            path = path.Replace("%20", " ");

            //Replace / with \ to support proper unc
            path = path.Replace("/", "\\");

            //If the URL contains a #,
            //Trim out everything after # including the # 
            if(path.Contains("#"))
                { path = path.Substring(0, path.IndexOf("#")); }

            WriteOutputFile($"arg passed: {path}");

            //Determine if file or directory.

            //Check to see if the directory or file exists.
            if (Directory.Exists(path))
                { bDirectoryExists = true; }

            if (!bDirectoryExists && File.Exists(path))
                { bFileExists = true; }

            //if the directory exists pop it open.
            if (bDirectoryExists)
            {
                OpenDirectory(path);
            }
            else if (bFileExists)
            {
                OpenFile(path);
            }
            else //The directory or file does not exist.
            {
                MessageBox.Show($"Directory or File does not exist: {path}");

                WriteOutputFile($"Directory or File does not exist: {path}");
                Console.WriteLine($"Directory or File does not exist: {path}");
            }
        } //end main

        private static void OpenDirectory(string path)
        {
            ProcessStartInfo startInfo = new ProcessStartInfo
            {
                Arguments = path,
                FileName = "explorer.exe"
            };

            //put this inside try/catch block just in case 
            //explorer.exe has a permission issue or something.
            try
            {
                Process.Start(startInfo);
            }
            catch
            {
                Console.WriteLine($"Could not proc explorer.exe to open {path}");
                WriteOutputFile($"Could not proc explorer.exe to open {path}");
            }
        }

        private static void OpenFile(string pathToFile)
        {
            string PATH_PREFIX = Properties.Settings.Default.PREFIX;
            StringCollection ALLOWED_EXTENSIONS = Properties.Settings.Default.ALLOWED_EXTENSIONS;
            string commandToRun;

            //Perform sanity checks.
            //Check for ssv.wa.lcl prefix.
            if (!pathToFile.Contains(PATH_PREFIX))
            {
                MessageBox.Show($"Not permitted to open file because path does not contain {PATH_PREFIX} : {pathToFile}");
                return;
            }
            //Check for allowed file extensions. List of allowed extensions is above.
            //GetExtension returns .docx as example, strip out to match allowed extensions
            string extension = Path.GetExtension(pathToFile);

            if (!ALLOWED_EXTENSIONS.Contains(extension))
            {
                MessageBox.Show($"Not an allowed extension: {pathToFile} ; extension: {extension}");
                return;
            }

            string path = $"{Path.GetTempFileName()}{Path.GetExtension(pathToFile)}";

            //Need to create the new temp file.
            if (!File.Exists(path))
            {
                using (StreamWriter sw = File.CreateText(path)) { }
            }

            if (HasExecutable(path))
            {
                commandToRun = $"\"{FindExecutable(path)}\" \"{pathToFile}\"";
            }
            else
            {
                commandToRun = $"\"{pathToFile}\"";
                WriteOutputFile($"This file does not have an assigned executable: {pathToFile}");
            }

            WriteOutputFile($"opening file with command: {commandToRun}");

            //LOOKS LIKE YOUR COMMAND LINE JUST GOT EXECUTED
            try
            {
                Process cmd = new Process();
                cmd.StartInfo.FileName = "cmd.exe";
                cmd.StartInfo.RedirectStandardInput = true;
                cmd.StartInfo.RedirectStandardOutput = true;
                cmd.StartInfo.CreateNoWindow = true;
                cmd.StartInfo.UseShellExecute = false;

                cmd.Start();
                cmd.StandardInput.WriteLine(commandToRun);
                cmd.StandardInput.Flush();
                cmd.StandardInput.Close();
            }
            catch
            {
                MessageBox.Show($"Unable to execute command: {commandToRun}");
                return;
            }
        }
        private static void WriteOutputFile(string debugLine)
        {
            if (!Properties.Settings.Default.DEBUG)
                { return; }

            StreamWriter outFile = new StreamWriter(@"C:\LocalExplorer\OUTPUT.txt", true);
            outFile.WriteLine(debugLine);
            outFile.Close();
        }

        public static bool HasExecutable(string path)
        {
            var executable = FindExecutable(path);
            return !string.IsNullOrEmpty(executable);
        }
        private static string FindExecutable(string path)
        {
            var executable = new StringBuilder(1024);
            FindExecutable(path, string.Empty, executable);
            return executable.ToString();
        }
    }
}