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

namespace Axiom.Interpreter
{
  public class Emitter
  {
    private bool emitting = true;
    private int lastSymbol;
    private BinaryReader inputStream;
    private BinaryWriter outputStream;    // the assigned output stream
    private BinaryWriter activeStream;    // the active stream
    private Stack<BinaryWriter> writeStack = new Stack<BinaryWriter>();
    private Stack<CapturedCode> captureStack = new Stack<CapturedCode>();
    private bool isCapturing = false;
    private bool debug = true;

    public Emitter(BinaryReader inputStream, BinaryWriter outputStream)
    {
      this.inputStream = inputStream;
      this.outputStream = outputStream;
      this.activeStream = outputStream;
    }

    public bool Debug
    {
      get { return debug; }
      set { debug = value; }
    }

    public void BeginCapture()
    {
        writeStack.Push(activeStream);
        activeStream = new BinaryWriter(new MemoryStream());
        isCapturing = true;
    }

    public void EndCapture()
    {
        if (!isCapturing)throw new InvalidOperationException("EndCapture called without a matching BeginCapture.");
        activeStream.Flush();
        MemoryStream memoryStream = (MemoryStream)activeStream.BaseStream;
        byte[] capturedBytes = memoryStream.ToArray();
        activeStream.Close();
        activeStream.Dispose();       
        activeStream = writeStack.Pop();
        isCapturing = writeStack.Count > 0;
        captureStack.Push(new CapturedCode(capturedBytes));
    }

    /// <summary>
    /// EmitCapture - Later, for CONTINUE semantics, we can Peek() at the top of the captureStack to get the increment code without popping it.
    /// </summary>
    public void EmitCapture()
    {
      if(0==captureStack.Count)throw new InvalidOperationException("The CaptureList is empty.");
      CapturedCode code = captureStack.Pop();
      activeStream.Write(code.Bytes,0,code.Length);
    }

    public void Emit(String literalValue)
    {
      if (!emitting) return;
      activeStream.Write(literalValue.Length);
      activeStream.Write(literalValue);
    }

    public void Emit(Scanner.ScanSymbols code)
    {
      if (!emitting) return;
      activeStream.Write((int)code);
      if (Debug) MDTrace.WriteLine(LogLevel.DEBUG, Scanner.SymbolToString(code));
    }

    public void Emit(Scanner.ScanSymbols code,int value)
    {
      if (!emitting) return;
      activeStream.Write((int)code);
      activeStream.Write(value);
      if (Debug) MDTrace.WriteLine(LogLevel.DEBUG, Scanner.SymbolToString(code) + "," + value.ToString());
    }

    public void Emit(Scanner.ScanSymbols code,double value)
    {
      if (!emitting) return;
      activeStream.Write((int)code);
      activeStream.Write(value);
      if (Debug) MDTrace.WriteLine(LogLevel.DEBUG, Scanner.SymbolToString(code) + "," + value.ToString());
    }

    public void Emit(Scanner.ScanSymbols code,String value)
    {
      if (!emitting) return;
      activeStream.Write((int)code);
      activeStream.Write(value);
      if (Debug) MDTrace.WriteLine(LogLevel.DEBUG, Scanner.SymbolToString(code) + "," + value.ToString());
    }

    public long CodePointer() 
    { 
      return activeStream.BaseStream.Position; 
    }

    public void Seek(long position) 
    { 
      activeStream.BaseStream.Seek(position, SeekOrigin.Begin); 
    }

    public void Emit(Parser.ParserSymbols code)
    {
      if (!emitting) return;
      long positionBefore = activeStream.BaseStream.Position;
      activeStream.Write((int)code);
      long positionAfter = activeStream.BaseStream.Position;
      if (Debug) MDTrace.WriteLine(LogLevel.DEBUG, Parser.SymbolToString(code) + "[" + positionBefore + "," + positionAfter + "]");
    }

    public void Emit(Parser.ParserSymbols code,Object value)
    {
      if (!emitting) return;
      long positionBefore = activeStream.BaseStream.Position;
      activeStream.Write((int)code);
      Type type = value.GetType();
      activeStream.Write(type.ToString());
      activeStream.Write(value.ToString());
      long positionAfter = activeStream.BaseStream.Position;
      if (Debug) MDTrace.WriteLine(LogLevel.DEBUG, Parser.SymbolToString(code) + "," + type.ToString() + "," + value.ToString() + "[" + positionBefore + "," + positionAfter + "]");
    }

    public void Emit(Parser.ParserSymbols code,Object value,int intValue)
    {
      if (!emitting) return;
      long positionBefore = activeStream.BaseStream.Position;
      activeStream.Write((int)code);
      Type type = value.GetType();
      activeStream.Write(type.ToString());
      activeStream.Write(value.ToString());
      activeStream.Write(intValue);
      long positionAfter = activeStream.BaseStream.Position;
      if (Debug) MDTrace.WriteLine(LogLevel.DEBUG, Parser.SymbolToString(code) + "," + type.ToString() + "," + value.ToString() + "," + intValue + "[" + positionBefore + "," + positionAfter + "]");
    }

    public void Emit(Parser.ParserSymbols code,long value)
    {
      if (!emitting) return;
      long positionBefore = activeStream.BaseStream.Position;
      activeStream.Write((int)code);
      activeStream.Write(value);
      long positionAfter = activeStream.BaseStream.Position;
      if (Debug) MDTrace.WriteLine(LogLevel.DEBUG, Parser.SymbolToString(code) + "," + value.ToString() + "," + value.ToString() + "[" + positionBefore + "," + positionAfter + "]");
    }

    public void EmitAsNull(Parser.ParserSymbols code)
    {
      if (!emitting) return;
      long positionBefore = activeStream.BaseStream.Position;
      activeStream.Write((int)code);
      Type type = typeof(System.Nullable);
      activeStream.Write(type.ToString());
      activeStream.Write("null".ToString());
      long positionAfter = activeStream.BaseStream.Position;
      if (Debug) MDTrace.WriteLine(LogLevel.DEBUG, Parser.SymbolToString(code) + "," + type.ToString() + "," + "null" + "[" + positionBefore + "," + positionAfter + "]");
    }

    public void Emit(int code,int op)
    {
      if (!emitting) return;
      activeStream.Write(code);
      activeStream.Write(op);
    }

    public void Emit(int identifier)
    {
      if (!emitting) return;
      activeStream.Write(identifier);
    }

    public void Emit(byte value)
    {
      if (!emitting) return;
      activeStream.Write(value);
    }

    public int Peek(ref int value)
    {
      value = inputStream.PeekChar();
      return value;
    }

    public int Peek()
    {
      int value = inputStream.PeekChar();
      return value;
    }

    public int PeekIgnore(ref int value,int[] ignoreChars)
    {
      long streamPosition = inputStream.BaseStream.Position;
      while (true)
      {
        int readValue = (int)inputStream.ReadChar();
        value = readValue;
        if (!ignoreChars.Any(x => x.Equals(readValue))) break;
      }
      inputStream.BaseStream.Seek(streamPosition, SeekOrigin.Begin);
      return value;
    }

    public int Read()
    {
      lastSymbol = inputStream.Read();
      return lastSymbol;
    }

    public int Read(ref String literal)
    {
      literal = inputStream.ReadString();
      return 0;
    }

    public int Read(ref byte value)
    {
      try { value = inputStream.ReadByte(); return 0; }
      catch (EndOfStreamException) { return 0xFFFF; }
    }

    public int Read(ref int value)
    {
      try { value = inputStream.ReadInt32(); return 0; }
      catch (EndOfStreamException) { return 0xFFFF; }
    }

    public int Read(ref double value)
    {
      try { value = inputStream.ReadDouble(); return 0; }
      catch (EndOfStreamException) { return 0xFFFF; }
    }

    public bool Emitting
    {
      get { return emitting; }
      set { emitting = value; }
    }
  }
}