// /*
//  * Licensed to the Apache Software Foundation (ASF) under one or more
//  * contributor license agreements.  See the NOTICE file distributed with
//  * this work for additional information regarding copyright ownership.
//  * The ASF licenses this file to You under the Apache License, Version 2.0
//  * (the "License"); you may not use this file except in compliance with
//  * the License.  You may obtain a copy of the License at
//  *
//  *     http://www.apache.org/licenses/LICENSE-2.0
//  *
//  * Unless required by applicable law or agreed to in writing, software
//  * distributed under the License is distributed on an "AS IS" BASIS,
//  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  * See the License for the specific language governing permissions and
//  * limitations under the License.
//  */
// 

using System;
using System.Collections;
using System.IO;
using System.Text;

namespace Apache.NMS.Stomp.Protocol
{
    public class StompFrame
    {
        /// Used to terminate a header line or end of a headers section of the Frame.
        public const String NEWLINE = "\n";
        /// Used to seperate the Key / Value pairing in Frame Headers
        public const String SEPARATOR = ":";
        /// Used to mark the End of the Frame.
        public const byte FRAME_TERMINUS = (byte) 0;
        
        private string command;
        private IDictionary properties = new Hashtable();
        private byte[] content;

        private readonly Encoding encoding = new UTF8Encoding();
        
        public StompFrame()
        {
        }

        public StompFrame(string command)
        {
            this.command = command;
        }
        
        public byte[] Content
        {
            get { return this.content; }
            set { this.content = value; }
        }

        public string Command
        {
            get { return this.command; }
            set { this.command = value; }
        }

        public IDictionary Properties
        {
            get { return this.properties; }
            set { this.properties = value; }
        }

        public bool HasProperty(string name)
        {
            return this.properties.Contains(name);
        }

        public void SetProperty(string name, Object value)
        {
            if(value == null)
            {
                return;
            }
            
            this.Properties[name] = value.ToString();
        }

        public string GetProperty(string name)
        {
            return GetProperty(name, null);
        }

        public string GetProperty(string name, string fallback)
        {
            if(this.properties.Contains(name))
            {
                return this.properties[name] as string;
            }

            return fallback;
        }

        public string RemoveProperty(string name)
        {
            string result = null;
            
            if(this.properties.Contains(name))
            {
                result = this.properties[name] as string;
                this.properties.Remove(name);
            }

            return result;
        }

        public void ClearProperties()
        {
            this.properties.Clear();
        }

        public void ToStream(BinaryWriter dataOut)
        {
            StringBuilder builder = new StringBuilder();
            
            builder.Append(this.Command);
            builder.Append(NEWLINE);

            foreach(String key in this.Properties.Keys)
            {
                builder.Append(key);
                builder.Append(SEPARATOR);
                builder.Append(this.Properties[key] as string);
                builder.Append(NEWLINE);
            }

            builder.Append(NEWLINE);
            dataOut.Write(this.encoding.GetBytes(builder.ToString()));
            
            if(this.Content != null)
            {
                dataOut.Write(this.Content);
            }

            dataOut.Write(FRAME_TERMINUS);
        }

        public void FromStream(BinaryReader dataIn)
        {
            this.ReadCommandHeader(dataIn);
            this.ReadHeaders(dataIn);
            this.ReadContent(dataIn);
        }

        private void ReadCommandHeader(BinaryReader dataIn)
        {
            do 
            {
                this.command = ReadLine(dataIn);
            }
            while(this.command == "");            
        }

        private void ReadHeaders(BinaryReader dataIn)
        {
            string line;
            while((line = ReadLine(dataIn)) != "")
            {
                int idx = line.IndexOf(':');
                
                if(idx > 0)
                {
                    string key = line.Substring(0, idx);
                    string value = line.Substring(idx + 1);
                    
                    this.properties[key] = value;
                }
                else
                {
                    Tracer.Debug("StompFrame - Read Malformed Header: " + line);
                }
            }            
        }

        private void ReadContent(BinaryReader dataIn)
        {
            if(this.properties.Contains("content-length"))
            {
                int size = Int32.Parse(this.properties["content-length"] as string);
                this.content = dataIn.ReadBytes(size);
                
                // Read the terminating NULL byte for this frame.                
                if(dataIn.Read() != 0)
                {
                    Tracer.Debug("StompFrame - Error Invalid Frame, no trailing Null.");
                }
            }
            else
            {
                MemoryStream ms = new MemoryStream();
                int nextChar;
                while((nextChar = dataIn.Read()) != 0)
                {
                    // The first Null in this case marks the end of data.
                    if(nextChar < 0)
                    {
                        break;
                    }
                    
                    ms.WriteByte((byte)nextChar);
                }
                
                this.content = ms.ToArray();
            }            
        }

        private String ReadLine(BinaryReader dataIn)
        {
            MemoryStream ms = new MemoryStream();
            
            while(true)
            {
                int nextChar = dataIn.Read();
                if(nextChar < 0)
                {
                    throw new IOException("Peer closed the stream.");
                }
                if(nextChar == 10)
                {
                    break;
                }
                ms.WriteByte((byte)nextChar);
            }
            
            byte[] data = ms.ToArray();
            return encoding.GetString(data, 0, data.Length);
        }        
    }
}