using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Windows.Forms;
using IsoFilePatcher.Iso9660;

namespace IsoFilePatcher
{
    internal static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        private static void Main(string[] args)
        {
            try
            {
                MainInternal(args);
            }
            catch (Exception ex)
            {

                Console.WriteLine();
                Console.WriteLine("----ERROR BEGIN----");
                Console.WriteLine(ex);
                Console.WriteLine("-----ERROR END-----");
            }

            Console.WriteLine();
            Console.Write("Press ENTER to exit...");
            Console.ReadLine();
        }

        private static void MainInternal(string[] args)
        {
            if (args.Length != 3)
            {
                Console.WriteLine($"Useage: {Path.GetFileName(Application.ExecutablePath)} <IsoFile> <Path> <DataToReplaceFrom>");
                Console.WriteLine($"Example: {Path.GetFileName(Application.ExecutablePath)} C:\\PS3.ISO PS3_GAME\\USRDIR\\EBOOT.BIN C:\\RESIGNED_EBOOT.BIN");
                return;
            }

            var isoFile = args[0];
            var path = args[1];
            var dataToReplaceFrom = args[2];

            Console.WriteLine($"Opening {isoFile} ...");

            using (var isoStream = new FileStream(isoFile, FileMode.Open, FileAccess.ReadWrite))
            {
                Console.WriteLine("Skipping system area...");
                isoStream.Position = 16 * Constants.SectorSize;

                Console.WriteLine("Parsing VolumeDescriptor...");
                var descriptors = new List<VolumeDescriptor>();
                do
                {
                    var item = VolumeDescriptor.Parse(isoStream);
                    if (item.IsVolumeDescriptorSetTerminator) break;
                    descriptors.Add(item);
                } while (true);

                Console.WriteLine("Parsing path entries...");
                var root = (descriptors.FirstOrDefault(p => p.Type == 2) ?? descriptors[0]).RootPathEntry;
                root.ScanChilds(isoStream);

                Console.WriteLine("Locating file...");
                var pathEntries = path.Split(Path.DirectorySeparatorChar);
                var currentPath = root;
                foreach (var item in pathEntries)
                {
                    var target = currentPath.ChildPathEntries.FirstOrDefault(p => 0 == string.Compare(p.Name, item, StringComparison.OrdinalIgnoreCase));
                    if (target == null)
                        throw new ArgumentException("Path not found");
                    currentPath = target;
                }

                if (currentPath.IsDirectory)
                    throw new ArgumentException("Path is a directory");

                Console.WriteLine("Feasibility checking...");
                var dataFile = new FileInfo(dataToReplaceFrom);
                if (false == dataFile.Exists)
                    throw new FileNotFoundException("File not found", dataToReplaceFrom);
                if (dataFile.Length > currentPath.DataLength)
                    throw new ArgumentException("File large than orignal, can not continue");

                Console.WriteLine("Operation in progress...");
                isoStream.Position = currentPath.ExtentLba * currentPath.VolumeDescriptor.LogicalBlockSize;
                using (var stream = dataFile.OpenRead())
                {
                    stream.CopyTo(isoStream);
                }
                Console.WriteLine("Flushing file...");
                isoStream.Flush();
                Console.WriteLine("Closing file...");
                isoStream.Close();
                isoStream.Dispose();

                Console.WriteLine("Operation completed successfully.");
            }
        }
    }
}