///////////////////////////////////////////////////////////////////////////////
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//

//
// Ported from SpecWeb99 source code by Mark Aiken
//

using FileSystem.Utils;
using Microsoft.SingSharp;
using Microsoft.SingSharp.Runtime;
using Microsoft.Singularity;
using Microsoft.Singularity.Channels;
using Microsoft.Singularity.Directory;
using System;
using System.Diagnostics;
using System.IO;
using System.Text;

///////////////////////////////////////
// Quick and dirty abstraction of file operations
//////////////////////////////////////
using Microsoft.Contracts;
using Microsoft.SingSharp.Reflection;
using Microsoft.Singularity.Applications;
using Microsoft.Singularity.Io;
using Microsoft.Singularity.Configuration;
[assembly: Transform(typeof(ApplicationResourceTransform))]

namespace Microsoft.Singularity.Applications
{
    [ConsoleCategory(HelpMessage="Generate files for Specweb", 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;

        [BoolParameter( "v", Default=false, HelpMessage="verbose")]
        internal bool doVerbose;

        [BoolParameter( "V", Default=false, HelpMessage="validate only")]
        internal bool doValidateOnly;

        [BoolParameter( "t", Default=false, HelpMessage="test mode")]
        internal bool doTestMode;

        [BoolParameter( "p", Default=false, HelpMessage="Purge files on exit")]
        internal bool doCleanup;

        [LongParameter( "n",  Default=9, HelpMessage="Files per class")]
        internal long filesPerClass;

        [LongParameter( "c", Default=10, HelpMessage="Number of connections")]
        internal long connections;

        [StringParameter( "directory", Mandatory=true, Position=0, HelpMessage="directory.")]
        internal string directory;


        reflective internal Parameters();

        internal int AppMain() {
            WafGen99.AppMain(this);
            return 0;
        }
    }

    public class FILE
    {
        static private VContainer<byte>! workBuffer;

        private TRef<FileContract.Imp:Ready>! connRef;
        private long filePos;
        private string! path;

        public static FILE CreateFile(string! path)
        {
            if (FileUtils.CreateFile(path) != 0) {
                return null;
            }

            return OpenFile(path);
        }

        public static FILE OpenFile(string! path)
        {
            FileContract.Imp conn = FileUtils.OpenFile(path);

            if (conn != null) {
                return new FILE(conn, path);
            }
            else {
                return null;
            }
        }

        static FILE()
        {
            workBuffer  = new VContainer<byte>(new [ExHeap] byte[2 * 1024 * 1024]);
        }

        private FILE([Claims] FileContract.Imp:Ready! conn, string! thePath)
        {
            connRef     = new TRef<FileContract.Imp:Ready>(conn);
            filePos     = 0;
            path        = thePath;
            base();
        }

        public int Write(string! str)
        {
            byte[] bytes = Encoding.ASCII.GetBytes(str);
            return Write(bytes, 0, bytes.Length);
        }

        public int Write(byte[]! buf, int offset, int length)
        {
            FileContract.Imp conn = connRef.Acquire();
            byte[]! in ExHeap wbuf = workBuffer.Acquire();
            if (length > wbuf.Length) {
                DebugStub.Print("workbuf resize {0} -> {1} (write)\n",
                                __arglist(wbuf.Length, length));
                delete wbuf;
                wbuf = new [ExHeap] byte [length];
            }
            Bitter.FromByteArray(wbuf, 0, length, buf, offset);

            try {
                long bytesWritten;
                int error;
                conn.SendWrite(wbuf, 0, filePos, length);
                conn.RecvAckWrite(out wbuf, out bytesWritten, out error);
                workBuffer.Release(wbuf);

                filePos += bytesWritten;
                if (error == 0) {
                    return (int)bytesWritten;
                }
                else {
                    throw new Exception("Write failed");
                }
            }
            finally {
                connRef.Release(conn);
            }
            return 0;
        }

        public int Read(byte[]! buf, int offset, int length)
        {
            FileContract.Imp conn = connRef.Acquire();
            byte[]! in ExHeap bytes = workBuffer.Acquire();

            if (length > bytes.Length) {
                DebugStub.Print("workbuf resize {0} -> {1} (read)\n",
                                __arglist(bytes.Length, length));
                delete bytes;
                bytes = new [ExHeap] byte [length];
            }

            try {
                long bytesRead;
                int error;
                conn.SendRead(bytes, 0, filePos, length);
                conn.RecvAckRead(out bytes, out bytesRead, out error);

                filePos += bytesRead;

                if (error == 0) {
                    Bitter.ToByteArray(bytes, 0, length, buf, offset);
                    workBuffer.Release(bytes);
                    return (int)bytesRead;
                }
                else {
                    workBuffer.Release(bytes);
                    throw new Exception("Read failed");
                    return 0;
                }
            }
            finally {
                connRef.Release(conn);
            }
        }

        public int Size
        {
            // TODO
            get {
                long size;
                NodeType nodeType;
                ErrorCode error;

                DirectoryServiceContract.Imp! rootNS = DirectoryService.NewClientEndpoint();
                bool ok  = FileUtils.GetAttributes(path, rootNS, out size, out nodeType, out  error);
                delete rootNS;

                if (!ok) {
                    throw new Exception("Failed to get attributes");
                } else {
                    return unchecked((int)size);
                }
            }
        }

        public void Close()
        {
            FileContract.Imp conn = connRef.Acquire();

            try {
                conn.SendClose();
            }
            finally {
                connRef.Release(conn);
            }
        }
    }

    ///////////////////////////////////////
    // The content generator / verifier
    //////////////////////////////////////

    public class WafGen99
    {
        //////////////////////////////////
        // Constants
        private const int    MAX_PATH              = 256;
        private const int    LINESIZE              = 64;
        private const int    MARKER_FREQ           = 4096;
        private const int    BUF_SIZE              = 1024*1024; /* 1MB */
        private const string topDirName            = "file_set";

        //////////////////////////////////
        // Pseudo-constants
        private static readonly int[]!  CLASS_BASE_SIZE = {1024, 10240, 102400, 1024000};
        private static readonly int MAX_CLASS_COUNT = CLASS_BASE_SIZE.Length;

        //////////////////////////////////
        // Instance variables
        private bool verbose = false;
        private bool testMode = false;
        private byte[]! buf;
        private string baseDir;
        private readonly int filesPerClass;

        public WafGen99(bool   verb,
                        bool   test,
                        string theBase,
                        int    filesPerClass)
        {
            buf = new byte[BUF_SIZE];
            base();
            verbose = verb;
            testMode = test;
            this.filesPerClass = filesPerClass;
            baseDir = theBase;
        }

        private static byte GetTestValue(int index)
        {
            string pattern = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
            return (byte) pattern[index % pattern.Length];
        }

        // Returns false on error
        private bool CreateFile(int classNum, int num, int size, string! name, string! path)
        {
            FILE fp;

            int initialSize = size;

            int[] incLocations = new int[MAX_CLASS_COUNT * filesPerClass * 10];
            int markerCt;
            int includes;
            int includeCt;
            int markersPerInclude;

            if (verbose) {
                Console.WriteLine("Creating  {0} [ {1} bytes ]", name, size);
            }

            // Try to open the file
            fp = FILE.CreateFile(path);

            if (fp == null) {
                Console.WriteLine("Can't open file '" + path + "'");
                return false;
            }

            // Write a header line
            size -= fp.Write(String.Format("{0,9:d} {1}\n", size, name));

            markerCt = size / MARKER_FREQ + 1;
            includeCt = size / (4096*4) + 1;

            if (classNum == 0) {
                includeCt = 0;
            }
            else if (classNum == 1) {
                includeCt = 1;
            }
            else if (classNum == 2) {
                includeCt = 2;
            }
            else {
                includeCt = 0;
            }

            Random rand = new Random();

            if (includeCt > 0) {
                markersPerInclude = markerCt / includeCt;

                for (int i = 0; i < includeCt; i++) {
                    /* The replacements can't cover up the implanted validation
                    characters -- they will always just after a marker*/
                    incLocations[i] = rand.Next(markersPerInclude * i, markersPerInclude * (i+1) - 1);

                    if (incLocations[i] > markerCt) {
                        incLocations[i] = markerCt;
                    }
                }
            }

            includes = 0;
            markerCt = 0;

            int pos = 0;
            int nameOffset = 0;

            for (int i = 0; i < size; i++) {
                if (!testMode && (i % MARKER_FREQ == 0)) {
                    buf[pos++] = ((byte)name[nameOffset++]);

                    if ((includes < includeCt) && (incLocations[includes] == markerCt)) {
                        includes++;
                        string markerStr = String.Format("<!WEB99CAD><IMG SRC=\"/file_set/dirNNNNN/classX_Y\"><!/WEB99CAD>\n");
                        int encodedBytes = Encoding.ASCII.GetBytes(markerStr, 0, markerStr.Length, buf, pos);
                        i += encodedBytes;
                        pos += encodedBytes;
                    }

                    markerCt++;

                    if (nameOffset == name.Length) {
                        nameOffset = 0;
                    }
                }
                else if (i % LINESIZE == LINESIZE - 1) {
                    buf[pos++] = (byte)'\n';
                }
                else if (testMode) {
                    buf[pos++] = GetTestValue(i);
                }
                else {
                    buf[pos++] = (byte)rand.Next(33,125);
                }

                if (pos >= BUF_SIZE) {
                    fp.Write(buf, 0, pos);
                    pos = 0;
                }
            }

            if (pos > 0) {
                fp.Write(buf, 0, pos);
            }

            fp.Close();

            if (!ValidateFile(classNum, num, initialSize, name, path)) {
                DebugStub.Break();
                ValidateFile(classNum, num, initialSize, name, path);
                return false;
            }

            return true;
        }

        // returns false on failure
        bool ValidateFile(int classNum, int fileNum, int size, string! name, string! path)
        {
            FILE fp;

            if (verbose) {
                Console.WriteLine("Verifying {0} [ {1} bytes ]", name, size);
            }

            fp = FILE.OpenFile(path);

            if (fp == null) {
                Console.WriteLine("Couldn't open file '" + path + "'");
                return false;
            }

            if (fp.Size != size) {
                Console.WriteLine("{0}: Incorrect file size (expected {1} bytes, have {2} bytes).", name, size, fp.Size);
                return false;
            }

            string valString = String.Format("{0,9:d} {1}\n", size, name);
            int headerSize = valString.Length;

            // Read the file header
            fp.Read(buf, 0, headerSize);
            string readString = Encoding.ASCII.GetString(buf, 0, headerSize);

            if (valString != readString) {
                Console.WriteLine("{0}: Header for file is incorrect", name);
                return false;
            }

            int curBufSize = fp.Read(buf, 0, BUF_SIZE);
            int offset = 0, nameOffset = 0;

            // Examine every byte in the file in this loop
            for (int i = 0; i < size - headerSize; i++) {
                if (!testMode && (i % MARKER_FREQ == 0)) {
                    if (buf[i - offset] != name[nameOffset++]) {
                        Console.WriteLine("{0}:Validation data incorrect at offset {1}", name, headerSize + offset + i);
                        fp.Close();
                        return false;
                    }

                    if (nameOffset == name.Length) {
                        nameOffset = 0;
                    }
                }
                else if (i % LINESIZE == LINESIZE - 1) {
                    if (buf[i - offset] != '\n') {
                        Console.WriteLine("{0}:Missing newline at offset {1}", name, headerSize + offset + i);
                        fp.Close();
                        return false;
                    }
                }
                else if (testMode) {
                    byte expected = GetTestValue(i);
                    if (buf[i - offset] != expected) {
                        Console.WriteLine("{0}:Bad byte value at offset {1} ({2} != {3})", name, headerSize + offset + i, buf[i - offset], expected);
                        fp.Close();
                        return false;
                    }
                }

                if (i >= curBufSize) {
                    offset += curBufSize;
                    curBufSize = fp.Read(buf, 0, BUF_SIZE);

                    if (curBufSize <= 0) {
                        Console.WriteLine("{0}: Error reading from file", path);
                        fp.Close();
                        return false;
                    }
                }
            }

            fp.Close();
            return true;
        }

        private struct FileSpec
        {
            public string name, fullPath;
            public int size, classNum, fileNum;
        }

        private string[]! MakeDirList(int startDir, int endDir)
        {
            int numDirs = endDir - startDir;
            string[] retval = new string[numDirs];

            for(int dir = startDir; dir < endDir; dir++) {
                retval[dir - startDir] = String.Format("{0}/dir{1}", topDirName, dir.ToString("d05"));
            }

            return retval;
        }

        private FileSpec[]! MakeFileList(string[]! dirs)
        {
            FileSpec[] retval = new FileSpec[MAX_CLASS_COUNT * filesPerClass * dirs.Length];
            int idx = 0;

            foreach (string dirName in dirs) {
                for (int classNum = 0; classNum < MAX_CLASS_COUNT; classNum++) {
                    for (int num = 0; num < filesPerClass; num++) {
                        int size = (CLASS_BASE_SIZE[classNum] * (num+1)) / 10;

                        retval[idx] = new FileSpec();
                        retval[idx].name = String.Format("{0}/class{1,1:d}_{2,1:d}", dirName, classNum, num);
                        retval[idx].fullPath = String.Format("{0}/{1}", baseDir, retval[idx].name);
                        retval[idx].classNum = classNum;
                        retval[idx].fileNum = num;
                        retval[idx].size = size;
                        idx++;
                    }
                }
            }

            return retval;
        }

        // Returns false on failure
        private bool CreateFiles(int startDir, int endDir)
        {
            string topDirectory = String.Format("{0}/{1}", baseDir, topDirName);

            if (DirectoryUtils.CreateDirectory(topDirectory) != 0) {
                Console.WriteLine("Couldn't mkdir '" + topDirectory + "'");
                return false;
            }

            string[]! dirs = MakeDirList(startDir, endDir);

            foreach (string relPath in dirs) {
                string fullPath = String.Format("{0}/{1}", baseDir, relPath);
                if (DirectoryUtils.CreateDirectory(fullPath) != 0) {
                    Console.WriteLine("Couldn't mkdir '" + fullPath + "'");
                    return false;
                }
            }

            FileSpec[]! files = MakeFileList(dirs);

            foreach (FileSpec spec in files) {
                if (!CreateFile(spec.classNum, spec.fileNum, spec.size, (!)spec.name, (!)spec.fullPath)) {
                    Console.WriteLine("Couldn't make file '" + spec.fullPath + "'");
                    return false;
                }
            }

            return true;
        }

        // Returns false on failure
        private bool ValidateFiles(int startDir, int endDir)
        {
            string[]! dirs = MakeDirList(startDir, endDir);
            FileSpec[]! files = MakeFileList(dirs);

            foreach (FileSpec spec in files) {
                if (!ValidateFile(spec.classNum, spec.fileNum, spec.size, (!)spec.name, (!)spec.fullPath)) {
                    Console.WriteLine("Validation failed for file '" + spec.fullPath + "'");
                    return false;
                }
            }

            return true;
        }

        private bool Cleanup(int startDir, int endDir)
        {
            bool success = true;
            string[]! dirs = MakeDirList(startDir, endDir);

            FileSpec[]! files = MakeFileList(dirs);
            foreach (FileSpec spec in files) {
                int error = FileUtils.DeleteFile((!)spec.fullPath);
                if (error != 0) {
                    Console.WriteLine("Failed to delete {0} (error {1})",
                                      spec.fullPath, error);
                    success = false;
                }
            }

            foreach (string! relPath in dirs) {
                string fullPath = baseDir + "/" + relPath;
                int error = DirectoryUtils.DeleteDirectory(fullPath);
                if (error != 0) {
                    Console.WriteLine("Failed to delete {0} (error {1})",
                                      fullPath, error);
                    success = false;
                }
            }

            do {
                string topDirectory = String.Format("{0}/{1}", baseDir, topDirName);
                int error = DirectoryUtils.DeleteDirectory(topDirectory);
                if (error != 0) {
                    Console.WriteLine("Failed to delete {0} (error {1})",
                                      topDirectory, error);
                    success = false;
                }
            } while (false);

            return success;
        }

        private static int ConnectionsToDirectories(int conns)
        {
            return ((int) (25 + (((400000.0 / 122000.0) * conns)/5.0)));
        }

        private static void Usage()
        {
            Console.WriteLine("wafgen99: A static-content fileset generator for SpecWEB99");
            Console.WriteLine("          ported by Mark Aiken");
            Console.WriteLine("");
            Console.WriteLine("wafgen99 [-v] [-V] [-t] [connectionCount] targetDir");
            Console.WriteLine("  -v : Verbose output");
            Console.WriteLine("  -V : Validate files only (no generation)");
            Console.WriteLine("  -t : Test mode; no random characters in generated files");
            Console.WriteLine("  targetDir : Location to hold the fileset");
        }

        internal static void AppMain(Parameters! config)
        {

            bool verbose = config.doVerbose;
            bool testmode = config.doTestMode;
            bool validateOnly = config.doValidateOnly;
            string basePath = config.directory;

            int connectionCount = (int)config.connections;
            int filesPerClass   = (int)config.filesPerClass;

            if (testmode && validateOnly) {
                Console.WriteLine("Test mode is incompatible with validate-only mode");
                Usage();
                return;
            }

            if (basePath == null) {
                Console.WriteLine("No target path specified");
                Usage();
                return;
            }

            WafGen99 waf =
                new WafGen99(verbose, testmode, basePath, filesPerClass);

            int directoryCount = ConnectionsToDirectories(connectionCount);
            if (!validateOnly) {
                if (!waf.CreateFiles(0, directoryCount)) {
                    Console.WriteLine("Failed to create all files.");
                    return;
                }
            }

            if (!waf.ValidateFiles(0, directoryCount)) {
                Console.WriteLine("Validation failed.");
                return;
            }

            if (config.doCleanup && !waf.Cleanup(0, directoryCount)) {
                Console.WriteLine("Clean up failed.");
                return;
            }

            Console.WriteLine("Success.");
        }
    }
}