// ==++==
//
//   
//    Copyright (c) 2002 Microsoft Corporation.  All rights reserved.
//   
//    The use and distribution terms for this software are contained in the file
//    named license.txt, which can be found in the root of this distribution.
//    By using this software in any fashion, you are agreeing to be bound by the
//    terms of this license.
//   
//    You must not remove this notice, or any other, from this software.
//   
//
// ==--==
namespace Microsoft.JScript 
{
    
  using System;
  using System.Reflection;
  using System.Reflection.Emit;

  public class Context{
    internal DocumentContext document;
    internal String source_string;
    internal int lineNumber;
    internal int startLinePos;
    internal int startPos;
    internal int endLineNumber;
    internal int endLinePos;
    internal int endPos;
    internal JSToken token;
    internal int errorReported;
  
    internal Context(DocumentContext document, String source_string){
      this.document = document;
      this.source_string = source_string;
      this.lineNumber = 1;
      this.startLinePos = 0;
      this.startPos = 0;
      this.endLineNumber = 1;
      this.endLinePos = 0;
      this.endPos = (source_string == null) ? -1 : source_string.Length;
      this.token = JSToken.None;
      this.errorReported = 1000000;
    }
    
    internal Context(DocumentContext document, String source_string, int lineNumber, int startLinePos, int startPos, int endLineNumber,
                     int endLinePos, int endPos, JSToken token){
      this.document = document;
      this.source_string = source_string;
      this.lineNumber = lineNumber;
      this.startLinePos = startLinePos;
      this.startPos = startPos;
      this.endLineNumber = endLineNumber;
      this.endLinePos = endLinePos;
      this.endPos = endPos;
      this.token = token;
      this.errorReported = 1000000;
    }
    
    internal Context Clone(){
      Context context = new Context(this.document, this.source_string, this.lineNumber, this.startLinePos, this.startPos, 
                         this.endLineNumber, this.endLinePos, this.endPos, this.token);
      context.errorReported = this.errorReported;
      return context;
    }
    
    internal Context CombineWith(Context other){
      return new Context(this.document, this.source_string, this.lineNumber, this.startLinePos, this.startPos, 
                         other.endLineNumber, other.endLinePos, other.endPos, this.token);
    }
    
    internal void EmitLineInfo(ILGenerator ilgen){
      this.document.EmitLineInfo(ilgen, this.StartLine, this.StartColumn, this.EndLine, this.EndColumn);
    }

    internal void EmitFirstLineInfo(ILGenerator ilgen){
      this.document.EmitFirstLineInfo(ilgen, this.StartLine, this.StartColumn, this.EndLine, this.EndColumn);
    }
    
    public int EndColumn {
      get {
        return this.endPos - this.endLinePos;
      }
    }

    public int EndLine {
      get {
        return this.endLineNumber;
      }
    }

    public int EndPosition {
      get {
        return this.endPos;
      }
    }

    internal bool Equals(String str){
      int len = endPos - startPos;
      return (len == str.Length && String.CompareOrdinal(source_string, startPos, str, 0, len) == 0);
    }
    
    internal bool Equals(Context ctx){
      return (this.source_string == ctx.source_string &&
              this.lineNumber == ctx.lineNumber &&
              this.startLinePos == ctx.startLinePos &&
              this.startPos == ctx.startPos &&
              this.endLineNumber == ctx.endLineNumber &&
              this.endLinePos == ctx.endLinePos &&
              this.endPos == ctx.endPos &&
              this.token == ctx.token);
    }
    
    public String GetCode() {
      if (this.endPos > this.startPos && this.endPos <= this.source_string.Length){
        return this.source_string.Substring(this.startPos, this.endPos - this.startPos);
      }
      return null; 
    }

    public JSToken GetToken() {
      return this.token; 
    }

    internal void HandleError(JSError errorId) {
      this.HandleError(errorId, null, false);
    }

    internal void HandleError(JSError errorId, bool treatAsError) {
      this.HandleError(errorId, null, treatAsError);
    }

    internal void HandleError(JSError errorId, String message) {
      this.HandleError(errorId, message, false);
    }

    internal void HandleError(JSError errorId, String message, bool treatAsError) {
      if (errorId == JSError.UndeclaredVariable && this.document.HasAlreadySeenErrorFor(this.GetCode()))
        return;
      JScriptException error = new JScriptException(errorId, this);
      if (message != null)
        error.value = message;
      if (treatAsError)
        error.isError = treatAsError;
      int sev = error.Severity;
      if (sev < this.errorReported){
        this.document.HandleError(error);
        this.errorReported = sev;
      }
    }

    internal void SetSourceContext(DocumentContext document, String source) {
      this.source_string = source;
      this.endPos = source.Length;
      this.document = document;      
    }
      
    public int StartColumn {
      get {
        return this.startPos - this.startLinePos;
      }
    } 

    public int StartLine {
      get {
        return this.lineNumber;
      }
    }

    public int StartPosition {
      get {
        return this.startPos;
      }
    }

    internal void UpdateWith(Context other){
      this.endPos = other.endPos;
      this.endLineNumber = other.endLineNumber;
      this.endLinePos = other.endLinePos;
    }
    
  }

}