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


namespace Duplicati.Library.Main.Database
{
    internal class LocalBackupDatabase : LocalDatabase
    {
        private class PathEntryKeeper
        {
            public DateTime Lastmodified;
            public long FileID;
            public long Filesize;
            public string Metahash;
            public long Metasize;
            
            private SortedList<KeyValuePair<long, long>, long> m_versions;
            
            public PathEntryKeeper(long fileId, DateTime lastmodified, long filesize, string metahash, long metasize)
            {
                this.FileID = fileId;
                this.Lastmodified = lastmodified;
                this.Filesize = filesize;
                this.Metahash = metahash;
                this.Metasize = metasize;
                this.m_versions = null;
            }
            
            public long GetFilesetID(long blocksetId, long metadataId)
            {
                if (m_versions == null)
                    return -1;

                long r;
                if (!m_versions.TryGetValue(new KeyValuePair<long, long>(blocksetId, metadataId), out r))
                    return -1;
                else
                    return r;
            }
            
            public void AddFilesetID(long blocksetId, long metadataId, long filesetId)
            {
                if (m_versions == null)
                    m_versions = new SortedList<KeyValuePair<long, long>, long>(1, new KeyValueComparer());
                m_versions.Add(new KeyValuePair<long, long>(blocksetId, metadataId), filesetId);
            }
            
            private struct KeyValueComparer : IComparer<KeyValuePair<long, long>>
            {
                public int Compare(KeyValuePair<long, long> x, KeyValuePair<long, long> y)
                {
                    return x.Key == y.Key ? 
                            (x.Value == y.Value ? 
                                0 
                                : (x.Value < y.Value ? -1 : 1)) 
                            : (x.Key < y.Key ? -1 : 1);
                }
            }
        }
    
        private readonly System.Data.IDbCommand m_findblockCommand;
        private readonly System.Data.IDbCommand m_findblocksetCommand;
        private readonly System.Data.IDbCommand m_findfilesetCommand;
        private readonly System.Data.IDbCommand m_findmetadatasetCommand;

        private readonly System.Data.IDbCommand m_insertblockCommand;

        private readonly System.Data.IDbCommand m_insertfileCommand;

        private readonly System.Data.IDbCommand m_insertblocksetCommand;
        private readonly System.Data.IDbCommand m_insertblocksetentryFastCommand;
        private readonly System.Data.IDbCommand m_insertblocksetentryCommand;
        private readonly System.Data.IDbCommand m_insertblocklistHashesCommand;

        private readonly System.Data.IDbCommand m_insertmetadatasetCommand;

        private readonly System.Data.IDbCommand m_findfileCommand;
        private readonly System.Data.IDbCommand m_selectfilelastmodifiedCommand;
        private readonly System.Data.IDbCommand m_selectfileHashCommand;
        private readonly System.Data.IDbCommand m_selectblocklistHashesCommand;

        private readonly System.Data.IDbCommand m_insertfileOperationCommand;
        
        private PathLookupHelper<PathEntryKeeper> m_pathLookup;
        
        private long m_missingBlockHashes;
        
        private long m_filesetId;

        public LocalBackupDatabase(string path, Options options)
            : this(new LocalDatabase(path, "Backup", false), options)
        {
            this.ShouldCloseConnection = true;
        }
           
        public LocalBackupDatabase(LocalDatabase db, Options options)
            : base(db)
        {
            m_findblockCommand = m_connection.CreateCommand();
            m_insertblockCommand = m_connection.CreateCommand();
            m_insertfileCommand = m_connection.CreateCommand();
            m_insertblocksetCommand = m_connection.CreateCommand();
            m_insertmetadatasetCommand = m_connection.CreateCommand();
            m_findblocksetCommand = m_connection.CreateCommand();
            m_findmetadatasetCommand = m_connection.CreateCommand();
            m_findfilesetCommand = m_connection.CreateCommand();
            m_insertblocksetentryCommand = m_connection.CreateCommand();
            m_insertblocklistHashesCommand = m_connection.CreateCommand();
            m_selectblocklistHashesCommand = m_connection.CreateCommand();
            m_insertfileOperationCommand = m_connection.CreateCommand();
            m_findfileCommand = m_connection.CreateCommand();
            m_selectfilelastmodifiedCommand = m_connection.CreateCommand();
            m_selectfileHashCommand = m_connection.CreateCommand();
            m_insertblocksetentryFastCommand = m_connection.CreateCommand();
                
            m_findblockCommand.CommandText = @"SELECT ""ID"" FROM ""Block"" WHERE ""Hash"" = ? AND ""Size"" = ?";
            m_findblockCommand.AddParameters(2);

            m_findblocksetCommand.CommandText = @"SELECT ""ID"" FROM ""Blockset"" WHERE ""Fullhash"" = ? AND ""Length"" = ?";
            m_findblocksetCommand.AddParameters(2);

            m_findmetadatasetCommand.CommandText = @"SELECT ""A"".""ID"" FROM ""Metadataset"" A, ""BlocksetEntry"" B, ""Block"" C WHERE ""A"".""BlocksetID"" = ""B"".""BlocksetID"" AND ""B"".""BlockID"" = ""C"".""ID"" AND ""C"".""Hash"" = ? AND ""C"".""Size"" = ?";
            m_findmetadatasetCommand.AddParameters(2);

            m_findfilesetCommand.CommandText = @"SELECT ""ID"" FROM ""File"" WHERE ""BlocksetID"" = ? AND ""MetadataID"" = ? AND ""Path"" = ?";
            m_findfilesetCommand.AddParameters(3);

            m_insertblockCommand.CommandText = @"INSERT INTO ""Block"" (""Hash"", ""VolumeID"", ""Size"") VALUES (?, ?, ?); SELECT last_insert_rowid();";
            m_insertblockCommand.AddParameters(3);

            m_insertfileOperationCommand.CommandText = @"INSERT INTO ""FilesetEntry"" (""FilesetID"", ""FileID"", ""Lastmodified"") VALUES (?, ?, ?)";
            m_insertfileOperationCommand.AddParameters(3);

            m_insertfileCommand.CommandText = @"INSERT INTO ""File"" (""Path"",""BlocksetID"", ""MetadataID"") VALUES (?, ? ,?); SELECT last_insert_rowid();";
            m_insertfileCommand.AddParameters(3);

            m_insertblocksetCommand.CommandText = @"INSERT INTO ""Blockset"" (""Length"", ""FullHash"") VALUES (?, ?); SELECT last_insert_rowid();";
            m_insertblocksetCommand.AddParameters(2);

            m_insertblocksetentryFastCommand.CommandText = @"INSERT INTO ""BlocksetEntry"" (""BlocksetID"", ""Index"", ""BlockID"") VALUES (?,?,?)";
            m_insertblocksetentryFastCommand.AddParameters(3);

            m_insertblocksetentryCommand.CommandText = @"INSERT INTO ""BlocksetEntry"" (""BlocksetID"", ""Index"", ""BlockID"") SELECT ? AS A, ? AS B, ""ID"" FROM ""Block"" WHERE ""Hash"" = ? AND ""Size"" = ?";
            m_insertblocksetentryCommand.AddParameters(4);

            m_insertblocklistHashesCommand.CommandText = @"INSERT INTO ""BlocklistHash"" (""BlocksetID"", ""Index"", ""Hash"") VALUES (?, ?, ?)";
            m_insertblocklistHashesCommand.AddParameters(3);

            m_insertmetadatasetCommand.CommandText = @"INSERT INTO ""Metadataset"" (""BlocksetID"") VALUES (?); SELECT last_insert_rowid();";
            m_insertmetadatasetCommand.AddParameter();

            m_selectfilelastmodifiedCommand.CommandText = @"SELECT ""File"".""ID"", ""FilesetEntry"".""LastModified"" FROM ""File"", ""FilesetEntry"" WHERE ""Path"" = ? AND ""File"".""ID"" = ""FilesetEntry"".""FileID"" AND ""FilesetEntry"".""FilesetID"" = ? LIMIT 1";
            m_selectfilelastmodifiedCommand.AddParameters(2);

            //Need a temporary table with path/lastmodified lookups
            m_findfileCommand.CommandText =
                @" SELECT ""File"".""ID"" AS ""FileID"", ""FilesetEntry"".""Lastmodified"", ""FileBlockset"".""Length"", ""MetaBlockset"".""Fullhash"" AS ""Metahash"", ""MetaBlockset"".""Length"" AS ""Metasize"" " +
                @"   FROM ""File"", ""FilesetEntry"", ""Fileset"", ""Blockset"" ""FileBlockset"", ""Metadataset"", ""Blockset"" ""MetaBlockset"" " +
                @"  WHERE ""File"".""Path"" = ? " +
                @"    AND ""FilesetEntry"".""FileID"" = ""File"".""ID"" AND ""Fileset"".""ID"" = ""FilesetEntry"".""FilesetID"" " +
                @"    AND ""FileBlockset"".""ID"" = ""File"".""BlocksetID"" " +
                @"    AND ""Metadataset"".""ID"" = ""File"".""MetadataID"" AND ""MetaBlockset"".""ID"" = ""Metadataset"".""BlocksetID"" " +
                @"  ORDER BY ""Fileset"".""Timestamp"" DESC " +
                @"  LIMIT 1 ";
            m_findfileCommand.AddParameters(1);

            m_selectfileHashCommand.CommandText = @"SELECT ""Blockset"".""Fullhash"" FROM ""Blockset"", ""File"" WHERE ""Blockset"".""ID"" = ""File"".""BlocksetID"" AND ""File"".""ID"" = ?  ";
            m_selectfileHashCommand.AddParameters(1);

            m_selectblocklistHashesCommand.CommandText = @"SELECT ""Hash"" FROM ""BlocklistHash"" WHERE ""BlocksetID"" = ? ORDER BY ""Index"" ASC ";
            m_selectblocklistHashesCommand.AddParameters(1);
        }
        
        /// <summary>
        /// Builds the lookup tables. Call this method after deleting items, and before processing items
        /// </summary>
        /// <param name="options">The option settings</param>
        public void BuildLookupTable(Options options)
        {
            if (options.UseFilepathCache)
                m_pathLookup = new PathLookupHelper<PathEntryKeeper>(true);


            //Populate the lookup tables
            using (var cmd = m_connection.CreateCommand())
            {
                //Need a temporary table with path/lastmodified lookups
                var scantableDefinition =
                    @"SELECT ""A1"".""ID"" AS ""FileID"", ""A1"".""Lastmodified"" AS ""Lastmodified"", ""A1"".""Path"" AS ""Path"", ""C"".""Length"" AS ""Length"", ""F"".""Fullhash"" AS ""Metahash"", ""F"".""Length"" AS ""Metasize"", ""A1"".""BlocksetID"" " +
                    @"  FROM (SELECT ""File"".""ID"", ""File"".""BlocksetID"", ""File"".""MetadataID"", ""FilesetEntry"".""Lastmodified"", ""File"".""Path"", ""Fileset"".""Timestamp"" " +
                    @"          FROM ""FilesetEntry"", ""Fileset"", ""File"" WHERE ""Fileset"".""ID"" = ""FilesetEntry"".""FilesetID"" AND ""File"".""ID"" = ""FilesetEntry"".""FileID"" " +
                    @"       ) ""A1"" LEFT JOIN " +
                    @"       (SELECT ""File"".""Path"", ""Fileset"".""Timestamp"" " +
                    @"           FROM ""FilesetEntry"", ""Fileset"", ""File"" WHERE ""Fileset"".""ID"" = ""FilesetEntry"".""FilesetID"" AND ""File"".""ID"" = ""FilesetEntry"".""FileID"" " +
                    @"       ) ""A2"" ON ""A1"".""Path"" = ""A2"".""Path"" AND ""A1"".""Timestamp"" < ""A2"".""Timestamp"" " +
                    @"       , ""Blockset"" ""C"", ""Metadataset"" ""E"", ""Blockset"" ""F"" " +
                    @" WHERE ""A2"".""Path"" IS NULL " +
                    @"   AND ""C"".""ID"" = ""A1"".""BlocksetID"" " +
                    @"   AND ""A1"".""MetadataID"" = ""E"".""ID"" " +
                    @"   AND ""F"".""ID"" = ""E"".""BlocksetID"" ";

                if (m_pathLookup != null)
                    using(new Logging.Timer("Build path lastmodified lookup table"))
                    using (var rd = cmd.ExecuteReader(string.Format(@" SELECT ""FileID"", ""Lastmodified"", ""Length"", ""Path"", ""Metahash"", ""Metasize"" FROM ({0}) WHERE ""BlocksetID"" >= 0 ", scantableDefinition)))
                        while (rd.Read())
                        {
                            var id = rd.GetInt64(0);
                            var lastmodified = new DateTime(rd.GetInt64(1), DateTimeKind.Utc);
                            var filesize = rd.GetInt64(2);
                            var path = rd.GetString(3);
                            var metahash = rd.GetString(4);
                            var metasize = rd.GetInt64(5);
                            m_pathLookup.Insert(path, new PathEntryKeeper(id, lastmodified, filesize, metahash, metasize));
                        }

                if (m_pathLookup != null)
                    try
                    {
                        using(new Logging.Timer("Build path lookup table"))
                        using (var rd = cmd.ExecuteReader(string.Format(@" SELECT ""Path"", ""BlocksetID"", ""MetadataID"", ""ID"" FROM ""File"" ")))
                            while (rd.Read())
                            {
                                var path = rd.GetValue(0).ToString();
                                var blocksetid = rd.GetInt64(1);
                                var metadataid = rd.GetInt64(2);
                                var filesetid = rd.GetInt64(3);

                                PathEntryKeeper r;
                                if (!m_pathLookup.TryFind(path, out r))
                                {
                                    r = new PathEntryKeeper(-1, new DateTime(0, DateTimeKind.Utc), -1, null, -1);
                                    r.AddFilesetID(blocksetid, metadataid, filesetid);
                                    m_pathLookup.Insert(path, r);
                                }
                                else
                                    r.AddFilesetID(blocksetid, metadataid, filesetid);
                            }
                    }
                    catch (Exception ex)
                    {
                        throw new InvalidDataException("Duplicate file entries detected, run repair to fix it", ex);
                    }
                                                        
                m_missingBlockHashes = cmd.ExecuteScalarInt64(@"SELECT COUNT (*) FROM (SELECT DISTINCT ""Block"".""Hash"", ""Block"".""Size"" FROM ""Block"", ""RemoteVolume"" WHERE ""RemoteVolume"".""ID"" = ""Block"".""VolumeID"" AND ""RemoteVolume"".""State"" NOT IN (?,?,?,?))", 0, RemoteVolumeState.Temporary.ToString(), RemoteVolumeState.Uploading.ToString(), RemoteVolumeState.Uploaded.ToString(), RemoteVolumeState.Verified.ToString());

                var tc = cmd.ExecuteScalarInt64(@"SELECT COUNT(*) FROM ""Remotevolume"" WHERE ""ID"" IN (SELECT DISTINCT ""VolumeID"" FROM ""Block"") AND ""State"" NOT IN (?, ?, ?, ?);", 0, RemoteVolumeState.Temporary.ToString(), RemoteVolumeState.Uploading.ToString(), RemoteVolumeState.Uploaded.ToString(), RemoteVolumeState.Verified.ToString());
                if (tc > 0)
                    throw new InvalidDataException("Detected blocks that are not reachable in the block table");

            }
        }

        /// <summary>
        /// Adds a block to the local database, returning a value indicating if the value presents a new block
        /// </summary>
        /// <param name="key">The block key</param>
        /// <param name="archivename">The name of the archive that holds the data</param>
        /// <returns>True if the block should be added to the current output</returns>
        public bool AddBlock (string key, long size, long volumeid, System.Data.IDbTransaction transaction = null)
        {
            m_findblockCommand.Transaction = transaction;
            m_findblockCommand.SetParameterValue(0, key);
            m_findblockCommand.SetParameterValue(1, size);
            var r = m_findblockCommand.ExecuteScalarInt64(-1);

            if (r == -1L)
            {
                m_insertblockCommand.Transaction = transaction;
                m_insertblockCommand.SetParameterValue(0, key);
                m_insertblockCommand.SetParameterValue(1, volumeid);
                m_insertblockCommand.SetParameterValue(2, size);
                r = m_insertblockCommand.ExecuteScalarInt64();
                return true;
            }
            else
            {
                //Update lookup cache if required
                return false;
            }
        }


        /// <summary>
        /// Adds a blockset to the database, returns a value indicating if the blockset is new
        /// </summary>
        /// <param name="filehash">The hash of the blockset</param>
        /// <param name="size">The size of the blockset</param>
        /// <param name="fragmentoffset">The fragmentoffset for the last block</param>
        /// <param name="fragmenthash">The hash of the fragment</param>
        /// <param name="hashes">The list of hashes</param>
        /// <param name="blocksetid">The id of the blockset, new or old</param>
        /// <returns>True if the blockset was created, false otherwise</returns>
        public bool AddBlockset(string filehash, long size, int blocksize, IEnumerable<string> hashes, IEnumerable<string> blocklistHashes, out long blocksetid, System.Data.IDbTransaction transaction = null)
        {
            m_findblocksetCommand.Transaction = transaction;
            blocksetid = m_findblocksetCommand.ExecuteScalarInt64(null, -1, filehash, size);
            if (blocksetid != -1)
                return false; //Found it

            using(var tr = new TemporaryTransactionWrapper(m_connection, transaction))
            {
                m_insertblocksetCommand.Transaction = tr.Parent;
                m_insertblocksetCommand.SetParameterValue(0, size);
                m_insertblocksetCommand.SetParameterValue(1, filehash);
                blocksetid = m_insertblocksetCommand.ExecuteScalarInt64();

                long ix = 0;
                if (blocklistHashes != null)
                {
                    m_insertblocklistHashesCommand.SetParameterValue(0, blocksetid);
                    m_insertblocklistHashesCommand.Transaction = tr.Parent;
                    foreach(var bh in blocklistHashes)
                    {
                        m_insertblocklistHashesCommand.SetParameterValue(1, ix);
                        m_insertblocklistHashesCommand.SetParameterValue(2, bh);
                        m_insertblocklistHashesCommand.ExecuteNonQuery();
                        ix++;
                    }
                }

                m_insertblocksetentryCommand.SetParameterValue(0, blocksetid);
                m_insertblocksetentryCommand.Transaction = tr.Parent;

                m_insertblocksetentryFastCommand.SetParameterValue(0, blocksetid);
                m_insertblocksetentryFastCommand.Transaction = tr.Parent;

                ix = 0;
                long remainsize = size;
                foreach(var h in hashes)
                {
                    var exsize = remainsize < blocksize ? remainsize : blocksize;
                    m_insertblocksetentryCommand.SetParameterValue(1, ix);
                    m_insertblocksetentryCommand.SetParameterValue(2, h);
                    m_insertblocksetentryCommand.SetParameterValue(3, exsize);
                    var c = m_insertblocksetentryCommand.ExecuteNonQuery();
                    if (c != 1)
                    {
                        m_result.AddError(string.Format("Checking errors, related to #1400. Unexpected result count: {0}, expected {1}, hash: {2}, size: {3}, blocksetid: {4}, ix: {5}, fullhash: {6}, fullsize: {7}", c, 1, h, exsize, blocksetid, ix, filehash, size), null);
                        using (var cmd = m_connection.CreateCommand(tr.Parent))
                        {
                            var bid = cmd.ExecuteScalarInt64(@"SELECT ""ID"" FROM ""Block"" WHERE ""Hash"" = ?", -1, h);
                            if (bid == -1)
                                throw new Exception(string.Format("Could not find any blocks with the given hash: {0}", h));
                            foreach(var rd in cmd.ExecuteReaderEnumerable(@"SELECT ""Size"" FROM ""Block"" WHERE ""Hash"" = ?", h))
                                m_result.AddError(string.Format("Found block with ID {0} and hash {1} and size {2}", bid, h, rd.ConvertValueToInt64(0, -1)), null);
                        }

                        throw new Exception(string.Format("Unexpected result count: {0}, expected {1}, check log for more messages", c, 1));
                    }
                    
                    ix++;
                    remainsize -= blocksize;
                }

                tr.Commit();
            }

            return true;

        }

        /// <summary>
        /// Adds a metadata set to the database, and returns a value indicating if the record was new
        /// </summary>
        /// <param name="hash">The metadata hash</param>
        /// <param name="metadataid">The id of the metadata set</param>
        /// <returns>True if the set was added to the database, false otherwise</returns>
        public bool AddMetadataset(string filehash, long size, int blocksize, IEnumerable<string> blockhashes, IEnumerable<string> blocklisthashes, out long metadataid, System.Data.IDbTransaction transaction = null)
        {
            if (size > 0)
            {
                m_findmetadatasetCommand.Transaction = transaction;
                metadataid = m_findmetadatasetCommand.ExecuteScalarInt64(null, -1, filehash, size);
                if (metadataid != -1)
                    return false;
            

                long blocksetid;
                AddBlockset(filehash, size, blocksize, blockhashes, blocklisthashes, out blocksetid, transaction);

                using (var tr = new TemporaryTransactionWrapper(m_connection, transaction))
                {
                    m_insertmetadatasetCommand.Transaction = tr.Parent;
                    m_insertmetadatasetCommand.SetParameterValue(0, blocksetid);
                    metadataid = m_insertmetadatasetCommand.ExecuteScalarInt64();
                    tr.Commit();
                }

                return true;
            }

            metadataid = -2;
            return false;

        }

        /// <summary>
        /// Adds a file record to the database
        /// </summary>
        /// <param name="filename">The path to the file</param>
        /// <param name="lastmodified">The time the file was modified</param>
        /// <param name="blocksetID">The ID of the hashkey for the file</param>
        /// <param name="metadataID">The ID for the metadata</param>
        /// <param name="transaction">The transaction to use for insertion, or null for no transaction</param>
        /// <param name="operationId">The operationId to use, or -1 to use the current operation</param>
        public void AddFile(string filename, DateTime lastmodified, long blocksetID, long metadataID, System.Data.IDbTransaction transaction)
        {            
            var fileidobj = -1L;
            PathEntryKeeper entry = null;
            var entryFound = false;
            
            if (m_pathLookup != null)
            {
                if (entryFound = (m_pathLookup.TryFind(filename, out entry) && entry != null))
                {
                    var fid = entry.GetFilesetID(blocksetID, metadataID);
                    if (fid >= 0)
                        fileidobj = fid;
                }
            }
            else
            {
                m_findfilesetCommand.Transaction = transaction;
                m_findfilesetCommand.SetParameterValue(0, blocksetID);
                m_findfilesetCommand.SetParameterValue(1, metadataID);
                m_findfilesetCommand.SetParameterValue(2, filename);
                fileidobj = m_findfilesetCommand.ExecuteScalarInt64();
            }
            
            if (fileidobj == -1)
            {
                using(var tr = new TemporaryTransactionWrapper(m_connection, transaction))
                {
                    m_insertfileCommand.Transaction = tr.Parent;
                    m_insertfileCommand.SetParameterValue(0, filename);
                    m_insertfileCommand.SetParameterValue(1, blocksetID);
                    m_insertfileCommand.SetParameterValue(2, metadataID);
                    fileidobj = m_insertfileCommand.ExecuteScalarInt64();
                    tr.Commit();                    

                    // We do not need to update this, because we will not ask for the same file twice
                    if (m_pathLookup != null)
                    {
                        if (!entryFound)
                        {
                            entry = new PathEntryKeeper(-1, new DateTime(0, DateTimeKind.Utc), -1, null, -1);
                            entry.AddFilesetID(blocksetID, metadataID, fileidobj);
                            m_pathLookup.Insert(filename, entry);
                        }
                        else
                            entry.AddFilesetID(blocksetID, metadataID, fileidobj);
                    }
                }
            }
            
            m_insertfileOperationCommand.Transaction = transaction;
            m_insertfileOperationCommand.SetParameterValue(0, m_filesetId);
            m_insertfileOperationCommand.SetParameterValue(1, fileidobj);
            m_insertfileOperationCommand.SetParameterValue(2, lastmodified.ToUniversalTime().Ticks);
            m_insertfileOperationCommand.ExecuteNonQuery();

        }

        public void AddUnmodifiedFile(long fileid, DateTime lastmodified, System.Data.IDbTransaction transaction = null)
        {
            m_insertfileOperationCommand.Transaction = transaction;
            m_insertfileOperationCommand.SetParameterValue(0, m_filesetId);
            m_insertfileOperationCommand.SetParameterValue(1, fileid);
            m_insertfileOperationCommand.SetParameterValue(2, lastmodified.ToUniversalTime().Ticks);
            m_insertfileOperationCommand.ExecuteNonQuery();
        }

        public void AddDirectoryEntry(string path, long metadataID, DateTime lastmodified, System.Data.IDbTransaction transaction = null)
        {
            AddFile(path, lastmodified, FOLDER_BLOCKSET_ID, metadataID, transaction);
        }
        
        public void AddSymlinkEntry(string path, long metadataID, DateTime lastmodified, System.Data.IDbTransaction transaction = null)
        {
            AddFile(path, lastmodified, SYMLINK_BLOCKSET_ID, metadataID, transaction);
        }

        public long GetFileLastModified(string path, long filesetid, out DateTime oldModified)
        {
            m_selectfilelastmodifiedCommand.SetParameterValue(0, path);
            m_selectfilelastmodifiedCommand.SetParameterValue(1, filesetid);
            using (var rd = m_selectfilelastmodifiedCommand.ExecuteReader())
                if (rd.Read())
                {
                    oldModified = new DateTime(rd.ConvertValueToInt64(1), DateTimeKind.Utc);
                    return rd.ConvertValueToInt64(0);    
                }

            oldModified = new DateTime(0, DateTimeKind.Utc);
            return -1;
        }

        public long GetFileEntry(string path, long filesetid, out DateTime oldModified, out long lastFileSize, out string oldMetahash, out long oldMetasize)
        {
            if (m_pathLookup != null)
            {            
                PathEntryKeeper tmp;
                if (m_pathLookup.TryFind(path, out tmp) && tmp != null && tmp.FileID >= 0)
                {
                    oldModified = tmp.Lastmodified;
                    lastFileSize = tmp.Filesize;
                    oldMetahash = tmp.Metahash;
                    oldMetasize = tmp.Metasize;
                    return tmp.FileID;
                }
                else
                {
                    oldModified = new DateTime(0, DateTimeKind.Utc);
                    lastFileSize = -1;
                    oldMetahash = null;
                    oldMetasize = -1;
                    return -1;
                }
            }
            else
            {
                m_findfileCommand.SetParameterValue(0, path);

                using(var rd = m_findfileCommand.ExecuteReader())
                    if (rd.Read())
                    {
                        oldModified = new DateTime(rd.ConvertValueToInt64(1), DateTimeKind.Utc);
                        lastFileSize = rd.GetInt64(2);
                        oldMetahash = rd.GetString(3);
                        oldMetasize = rd.GetInt64(4);
                        return rd.ConvertValueToInt64(0);
                    }
                    else
                    {
                        oldModified = new DateTime(0, DateTimeKind.Utc);
                        lastFileSize = -1;
                        oldMetahash = null;
                        oldMetasize = -1;
                        return -1;
                    }
            }
        }

        public string GetFileHash(long fileid)
        {
            m_selectfileHashCommand.SetParameterValue(0, fileid);
            var r = m_selectfileHashCommand.ExecuteScalar();
            if (r == null || r == DBNull.Value)
                return null;
                
            return r.ToString();
        }
        
        public void WriteFileset(Volumes.FilesetVolumeWriter filesetvolume, System.Data.IDbTransaction transaction)
        {
            WriteFileset(filesetvolume, transaction, m_filesetId);
        }        

        public override void Dispose ()
        {
            m_pathLookup = null;

            base.Dispose();
        }

        private long GetPreviousFilesetID(System.Data.IDbCommand cmd)
        {
            return GetPreviousFilesetID(cmd, OperationTimestamp, m_filesetId);
        }
        
        private long GetPreviousFilesetID(System.Data.IDbCommand cmd, DateTime timestamp, long filesetid)
        {
            var lastFilesetId = cmd.ExecuteScalarInt64(@"SELECT ""ID"" FROM ""Fileset"" WHERE ""Timestamp"" < ? AND ""ID"" != ? ORDER BY ""Timestamp"" DESC ", -1, NormalizeDateTimeToEpochSeconds(timestamp), filesetid);                
            return lastFilesetId;
        }

        internal void UpdateChangeStatistics(BackupResults results)
        {
            using(var cmd = m_connection.CreateCommand())
            {
                var lastFilesetId = GetPreviousFilesetID(cmd);
                results.AddedFolders = cmd.ExecuteScalarInt64(@"SELECT COUNT(*) FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ? AND ""File"".""BlocksetID"" = ? AND NOT ""File"".""Path"" IN (SELECT ""Path"" FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ?)", 0, m_filesetId, FOLDER_BLOCKSET_ID, lastFilesetId);
                results.AddedSymlinks = cmd.ExecuteScalarInt64(@"SELECT COUNT(*) FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ? AND ""File"".""BlocksetID"" = ? AND NOT ""File"".""Path"" IN (SELECT ""Path"" FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ?)", 0, m_filesetId, SYMLINK_BLOCKSET_ID, lastFilesetId);

                results.DeletedFolders = cmd.ExecuteScalarInt64(@"SELECT COUNT(*) FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ? AND ""File"".""BlocksetID"" = ? AND NOT ""File"".""Path"" IN (SELECT ""Path"" FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ?)", 0, lastFilesetId, FOLDER_BLOCKSET_ID, m_filesetId);
                results.DeletedSymlinks = cmd.ExecuteScalarInt64(@"SELECT COUNT(*) FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ? AND ""File"".""BlocksetID"" = ? AND NOT ""File"".""Path"" IN (SELECT ""Path"" FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ?)", 0, lastFilesetId, SYMLINK_BLOCKSET_ID, m_filesetId);

                var subqueryNonFiles = @"SELECT ""File"".""Path"", ""Blockset"".""Fullhash"" FROM ""File"", ""FilesetEntry"", ""Metadataset"", ""Blockset"" WHERE ""File"".""ID"" = ""FilesetEntry"".""FileID"" AND ""Metadataset"".""ID"" = ""File"".""MetadataID"" AND ""File"".""BlocksetID"" = ? AND ""Metadataset"".""BlocksetID"" = ""Blockset"".""ID"" AND ""FilesetEntry"".""FilesetID"" = ? ";
                results.ModifiedFolders = cmd.ExecuteScalarInt64(@"SELECT COUNT(*) FROM (" + subqueryNonFiles + @") A, (" + subqueryNonFiles + @") B WHERE ""A"".""Path"" = ""B"".""Path"" AND ""A"".""Fullhash"" != ""B"".""Fullhash"" ", 0, lastFilesetId, FOLDER_BLOCKSET_ID, m_filesetId, FOLDER_BLOCKSET_ID);
                results.ModifiedSymlinks = cmd.ExecuteScalarInt64(@"SELECT COUNT(*) FROM (" + subqueryNonFiles + @") A, (" + subqueryNonFiles + @") B WHERE ""A"".""Path"" = ""B"".""Path"" AND ""A"".""Fullhash"" != ""B"".""Fullhash"" ", 0, lastFilesetId, SYMLINK_BLOCKSET_ID, m_filesetId, SYMLINK_BLOCKSET_ID);
                
                var tmpName1 = "TmpFileList-" + Library.Utility.Utility.ByteArrayAsHexString(Guid.NewGuid().ToByteArray());
                var tmpName2 = "TmpFileList-" + Library.Utility.Utility.ByteArrayAsHexString(Guid.NewGuid().ToByteArray());
                try
                {
                    var subqueryFiles = @"SELECT ""File"".""Path"", ""A"".""Fullhash"" AS ""Filehash"", ""B"".""Fullhash"" AS ""Metahash"" FROM ""File"", ""FilesetEntry"", ""Blockset"" A, ""Blockset"" B, ""Metadataset""  WHERE ""File"".""ID"" = ""FilesetEntry"".""FileID"" AND ""A"".""ID"" = ""File"".""BlocksetID"" AND ""FilesetEntry"".""FilesetID"" = ? AND ""File"".""MetadataID"" = ""Metadataset"".""ID"" AND ""Metadataset"".""BlocksetID"" = ""B"".""ID"" ";
                
                    cmd.ExecuteNonQuery(string.Format(@"CREATE TEMPORARY TABLE ""{0}"" AS " + subqueryFiles, tmpName1), lastFilesetId);
                    cmd.ExecuteNonQuery(string.Format(@"CREATE TEMPORARY TABLE ""{0}"" AS " + subqueryFiles, tmpName2), m_filesetId);
                
                    results.AddedFiles = cmd.ExecuteScalarInt64(string.Format(@"SELECT COUNT(*) FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ? AND ""File"".""BlocksetID"" != ? AND ""File"".""BlocksetID"" != ? AND NOT ""File"".""Path"" IN (SELECT ""Path"" FROM ""{0}"")", tmpName1), 0, m_filesetId, FOLDER_BLOCKSET_ID, SYMLINK_BLOCKSET_ID);
                    results.DeletedFiles = cmd.ExecuteScalarInt64(string.Format(@"SELECT COUNT(*) FROM ""{0}"" WHERE ""{0}"".""Path"" NOT IN (SELECT ""Path"" FROM ""File"" INNER JOIN ""FilesetEntry"" ON ""File"".""ID"" = ""FilesetEntry"".""FileID"" WHERE ""FilesetEntry"".""FilesetID"" = ?)", tmpName1), 0, m_filesetId);
                    results.ModifiedFiles = cmd.ExecuteScalarInt64(string.Format(@"SELECT COUNT(*) FROM ""{0}"" A, ""{1}"" B WHERE ""A"".""Path"" = ""B"".""Path"" AND (""A"".""Filehash"" != ""B"".""Filehash"" OR ""A"".""Metahash"" != ""B"".""Metahash"")", tmpName1, tmpName2), 0);
                    
                }
                finally
                {
                    try { cmd.ExecuteNonQuery(string.Format(@"DROP TABLE IF EXISTS ""{0}"";", tmpName1)); }
                    catch (Exception ex) { m_result.AddWarning("Dispose temp table error", ex); }
                    try { cmd.ExecuteNonQuery(string.Format(@"DROP TABLE IF EXISTS ""{0}"";", tmpName2)); }
                    catch (Exception ex) { m_result.AddWarning("Dispose temp table error", ex); }
                }
            }
        }

        public void AppendFilesFromPreviousSet(System.Data.IDbTransaction transaction, IEnumerable<string> deleted)
        {
            AppendFilesFromPreviousSet(transaction, deleted, m_filesetId, -1, OperationTimestamp);
        }

        public void AppendFilesFromPreviousSet(System.Data.IDbTransaction transaction, IEnumerable<string> deleted, long filesetid, long prevId, DateTime timestamp)
        {
            using(var cmd = m_connection.CreateCommand())
            using (var tr = new TemporaryTransactionWrapper(m_connection, transaction))
            {
                long lastFilesetId = prevId < 0 ? GetPreviousFilesetID(cmd, timestamp, filesetid) : prevId;

                cmd.Transaction = tr.Parent;
                cmd.ExecuteNonQuery( @"INSERT INTO ""FilesetEntry"" (""FilesetID"", ""FileID"", ""Lastmodified"") SELECT ? AS ""FilesetID"", ""FileID"", ""Lastmodified"" FROM (SELECT DISTINCT ""FilesetID"", ""FileID"", ""Lastmodified"" FROM ""FilesetEntry"" WHERE ""FilesetID"" = ? AND ""FileID"" NOT IN (SELECT ""FileID"" FROM ""FilesetEntry"" WHERE ""FilesetID"" = ?)) ", filesetid, lastFilesetId, filesetid);

                if (deleted != null)
                {
                    cmd.CommandText = @"DELETE FROM ""FilesetEntry"" WHERE ""FilesetID"" = ? AND ""FileID"" IN (SELECT ""ID"" FROM ""File"" WHERE ""Path"" = ?) ";
                    cmd.AddParameter(filesetid);
                    cmd.AddParameter();

                    foreach (string s in deleted)
                    {
                        cmd.SetParameterValue(1, s);
                        cmd.ExecuteNonQuery();
                    }
                }

                tr.Commit();
            }
        }
    
        /// <summary>
        /// Creates a timestamped backup operation to correctly associate the fileset with the time it was created.
        /// </summary>
        /// <param name="volumeid">The ID of the fileset volume to update</param>
        /// <param name="timestamp">The timestamp of the operation to create</param>
        /// <param name="transaction">An optional external transaction</param>
        public override long CreateFileset(long volumeid, DateTime timestamp, System.Data.IDbTransaction transaction = null)
        {
            return m_filesetId = base.CreateFileset(volumeid, timestamp, transaction);
        }
                                
        public IEnumerable<KeyValuePair<long, DateTime>> GetIncompleteFilesets(System.Data.IDbTransaction transaction)
        {
            using(var cmd = m_connection.CreateCommand())
            {
                cmd.Transaction = transaction;
                using(var rd = cmd.ExecuteReader(@"SELECT DISTINCT ""Fileset"".""ID"", ""Fileset"".""Timestamp"" FROM ""Fileset"", ""RemoteVolume"" WHERE ""RemoteVolume"".""ID"" = ""Fileset"".""VolumeID"" AND ""Fileset"".""ID"" IN (SELECT ""FilesetID"" FROM ""FilesetEntry"")  AND (""RemoteVolume"".""State"" = ""Uploading"" OR ""RemoteVolume"".""State"" = ""Temporary"")"))
                    while(rd.Read())
                    {
                        yield return new KeyValuePair<long, DateTime>(
                            rd.GetInt64(0),
                            ParseFromEpochSeconds(rd.GetInt64(1)).ToLocalTime()
                        );
                    }
            }
        }

        public IRemoteVolume GetRemoteVolumeFromName(string name)
        {
            using(var cmd = m_connection.CreateCommand())
            using(var rd = cmd.ExecuteReader(@"SELECT ""Name"", ""Hash"", ""Size"" FROM ""RemoteVolume"" WHERE ""Name"" = ?", name))
                if (rd.Read())
                    return new RemoteVolume(rd.GetValue(0).ToString(), rd.GetValue(1).ToString(), rd.ConvertValueToInt64(2));
                else
                    return null;
        }

        public RemoteVolumeEntry GetRemoteVolumeFromID(long id)
        {
            using (var cmd = m_connection.CreateCommand())
            using (var rd = cmd.ExecuteReader(@"SELECT ""Name"", ""Type"", ""Size"", ""Hash"", ""State"", ""DeleteGraceTime"" FROM ""RemoteVolume"" WHERE ""ID"" = ?", id))
                if (rd.Read())
                    return new RemoteVolumeEntry(
                        rd.GetValue(0).ToString(),
                        (rd.GetValue(3) == null || rd.GetValue(3) == DBNull.Value) ? null : rd.GetValue(3).ToString(),
                        rd.ConvertValueToInt64(2, -1),
                        (RemoteVolumeType)Enum.Parse(typeof(RemoteVolumeType), rd.GetValue(1).ToString()),
                        (RemoteVolumeState)Enum.Parse(typeof(RemoteVolumeState), rd.GetValue(4).ToString()),
                        new DateTime(rd.ConvertValueToInt64(5, 0), DateTimeKind.Utc)
                    );
                else
                    return default(RemoteVolumeEntry);
        }

        public IEnumerable<string> GetMissingIndexFiles()
        {
            using(var cmd = m_connection.CreateCommand())
            using(var rd = cmd.ExecuteReader(@"SELECT ""Name"" FROM ""RemoteVolume"" WHERE ""Type"" = ? AND NOT ""ID"" IN (SELECT ""BlockVolumeID"" FROM ""IndexBlockLink"") AND ""State"" IN (?,?)", RemoteVolumeType.Blocks.ToString(), RemoteVolumeState.Uploaded.ToString(), RemoteVolumeState.Verified.ToString()))
                while (rd.Read())
                    yield return rd.GetValue(0).ToString();
        }
        
        public void LinkFilesetToVolume(long filesetid, long volumeid, System.Data.IDbTransaction transaction)
        {
            using(var cmd = m_connection.CreateCommand())
            {
                cmd.Transaction = transaction;
                var c = cmd.ExecuteNonQuery(@"UPDATE ""Fileset"" SET ""VolumeID"" = ? WHERE ""ID"" = ?", volumeid, filesetid);
                if (c != 1)
                    throw new Exception(string.Format("Failed to link filesetid {0} to volumeid {1}", filesetid, volumeid));
            }            
        }

        public string GetFirstPath()
        {
            using (var cmd = m_connection.CreateCommand())
            {
                cmd.CommandText = string.Format(@"SELECT ""Path"" FROM ""File"" ORDER BY LENGTH(""Path"") DESC LIMIT 1");
                var v0 = cmd.ExecuteScalar();
                if (v0 == null || v0 == DBNull.Value)
                    return null;

                return v0.ToString();
            }
        }

    }
}