///////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  Note:
//


using FileSystem.Utils;
using Microsoft.Contracts;
using Microsoft.SingSharp.Reflection;
using Microsoft.Singularity.Applications;
using Microsoft.Singularity.Channels;
using Microsoft.Singularity.Configuration;
using Microsoft.Singularity.Directory;
using Microsoft.Singularity.FileSystem;
using Microsoft.Singularity.Io;
using Microsoft.Singularity.V1.Services;
using Microsoft.Singularity;
using System.Text;
using System.Threading;
using System;

[assembly: Transform(typeof(ApplicationResourceTransform))]

namespace Microsoft.Singularity.Applications
{
    [ConsoleCategory(HelpMessage="create a new file", DefaultAction=true)]
    internal class Parameters
    {
        [InputEndpoint("data")]
        public readonly TRef<UnicodePipeContract.Exp:READY> Stdin;

        [OutputEndpoint("data")]
        public readonly TRef<UnicodePipeContract.Imp:READY> Stdout;

        [Endpoint]
        public readonly TRef<DirectoryServiceContract.Imp:Start> nsRef;

        [StringParameter("filename", Mandatory=true, Position=0, HelpMessage="Name of file to create")]
        internal string fileName;

        [ BoolParameter("o", Default = false, Mandatory = false, HelpMessage = "Overwrite existing file") ]
        internal bool overwrite;

        [StringParameter("c", Default=null, Mandatory=false, HelpMessage="Initial contents of file as a text string")]
        internal string contentsString;

        [StringParameter("x", Default=null, Mandatory=false, HelpMessage="Initial contents of file as a sequence of hexadecimal bytes, such as 000FA8")]
        internal string contentsHexString;

        [StringParameter("s", Default=null, Mandatory=false,
         HelpMessage="Size of file. Specified contents will be repeated to fill it, or all zero bits will be used if no pattern is specified.")]
        internal string fileSize;

        reflective internal Parameters();

        internal int AppMain() {
            return FsCreateFile.AppMain(this);
        }
    }

    public class FsCreateFile
    {
        private const int WriteChunkBytes = 128 * 1024;

        internal static bool CreateFile(string! fileName, DirectoryServiceContract.Imp! ds)
        {
            ErrorCode error;
            FileUtils.CreateFile(fileName, ds, out error);
            bool ok = (error == ErrorCode.NoError);
            if (!ok) {
                Console.WriteLine("File ({0}) create failed. Reason: {1}",
                                  fileName, SdsUtils.ErrorCodeToString(error));
            }
            return ok;
        }

        private static bool
        WritePattern(FileContract.Imp! fileClient, byte[]! pattern, int size)
        {
            // Create a buffer to write out data and fill it with
            // repeated copies of pattern.
            int writeBufferBytes = size;
            if (writeBufferBytes > WriteChunkBytes) {
                writeBufferBytes = WriteChunkBytes;
            }
            writeBufferBytes -= (writeBufferBytes % pattern.Length);

            byte []! writeBuffer = new byte[writeBufferBytes];
            for (int i = 0; i < writeBuffer.Length; i += pattern.Length) {
                Array.Copy(pattern, 0, writeBuffer, i, pattern.Length);
            }

            int end = size - (size % pattern.Length);
            for (int i = 0; i < end; i += writeBuffer.Length) {
                if (FileUtils.Write(fileClient, i, writeBuffer) !=
                    writeBuffer.Length) {
                    Console.WriteLine("Truncated write.");
                    return false;
                }
            }

            if (end != size &&
                FileUtils.Write((!)fileClient, 0, (int)(size - end), end,
                                writeBuffer) != (size - end)) {
                Console.WriteLine("Truncated write.");
                return false;
            }
            return true;
        }

        internal static bool
        WriteToFile(string! fileName, byte[]! pattern, int size)
        {
            FileContract.Imp:Ready fileClient = null;
            try {
                ErrorCode error;
                fileClient = FileUtils.OpenFile(fileName, out error);

                if (fileClient != null) {
                    assert error == ErrorCode.NoError;
                    return WritePattern(fileClient, pattern, (int)size);
                }
                return false;
            }
            finally {
                delete fileClient;
            }
        }

        private static byte HexUpperCharToByte(char hexChar)
        {
            if (Char.IsDigit(hexChar)) {
                return (byte)(int.Parse(new String(hexChar, 1)));
            }
            else {
                switch (hexChar) {
                    case 'A': return 10;
                    case 'B': return 11;
                    case 'C': return 12;
                    case 'D': return 13;
                    case 'E': return 14;
                    case 'F': return 15;
                }
                throw new FormatException(String.Format("Invalid hex character '{0}'", hexChar));
            }
        }

        private static byte[]! HexStringToBytes(string! hex)
        {
            foreach (char c in " \t\r\n") {
                hex = hex.Replace(new String(c,1), "");
            }
            hex = hex.ToUpper();
            if (hex.Length == 0) {
                throw new FormatException("Hex byte string should not be empty.");
            }
            if ((hex.Length % 2) != 0) {
                throw new FormatException("Hex byte string should contain an even number of digits.");
            }

            byte[]! result = new byte[hex.Length / 2];
            for (int i = 0; i < result.Length; i++) {
                result[i] = (byte)(HexUpperCharToByte(hex[2*i]) * 16  +
                                   HexUpperCharToByte(hex[2*i + 1]));
            }
            return result;
        }

        internal static int AppMain(Parameters! config)
        {
            if (config.contentsString != null && config.contentsHexString != null) {
                Console.WriteLine("Can only specify at most one of the options -c or -x.");
                return -1;
            }

            DirectoryServiceContract.Imp ds = config.nsRef.Acquire();
            if (ds == null) {
                Console.WriteLine("Unable to acquire handle to the Directory Service root");
                return -1;
            }
            ds.RecvSuccess();

            // Check if the file already exists
            ErrorCode error;
            FileAttributesRecord fileAttributes;
            SdsUtils.GetAttributes((!)config.fileName, ds, out fileAttributes, out error);
            if (config.overwrite) {
                if (error == ErrorCode.NotFound) {
                    Console.WriteLine("Cannot overwrite file. File does not exist.");
                    delete ds;
                    return -1;
                }
            }
            else if (error != ErrorCode.NotFound) {
                Console.WriteLine("Cannot create file. File already exists.");
                delete ds;
                return -1;
            }

            try {
                byte[]! data = new byte[0];
                if (config.contentsString != null) {
                    data = Encoding.UTF8.GetBytes(config.contentsString);
                }
                else if (config.contentsHexString != null) {
                    data = HexStringToBytes(config.contentsHexString);
                }

                int fileSize = 0;
                if (config.fileSize != null) {
                    ulong userFileSize = DiskSizeUtils.ParsePrettySizeString(config.fileSize);
                    if (userFileSize > (ulong)Int32.MaxValue) {
                        Console.WriteLine("File size not supported.");
                        return -1;
                    }
                    fileSize = (int)userFileSize;
                }
                else {
                    fileSize = data.Length;
                }

                if (fileSize > 0 && data.Length == 0) {
                    // Fill in with zero bits
                    data = new byte[1];
                    data[0] = 0;
                }

                if (config.overwrite == false &&
                    !CreateFile(config.fileName, ds)) {
                    return -1;
                }
                if (fileSize != 0 &&
                    !WriteToFile(config.fileName, data, fileSize)) {
                    return -1;
                }
            }
            catch (FormatException ex) {
                Console.WriteLine("Invalid parameter format: " + ex.Message + ".");
                return -1;
            }
            finally {
                delete ds;
            }
            return 0;
        }
    } // class Test
}