//////////////////////////////////////////////////////////////////////////////
// Project: Ob51
// License: Apache License, Version 2.0; for details see LICENSE file
// Copyright: see NOTICE file
//
// Last file commit: $Revision: 143 $   Made by: $Author: avek $
//////////////////////////////////////////////////////////////////////////////  
using System;
using System.Collections.Generic;
using System.Text;

namespace Ob51.Compiler
{
    /// <summary>
    /// Represents an error or warning encountered by some module of Ob51 compiler.
    /// </summary>
    public class Issue
    {
        /// <summary>
        /// Codes for importance of this <see cref="Issue"/>.
        /// </summary>
        public enum Severities
        {
            /// <summary>
            /// Fatal error. The compiler can't proceed and must stop
            /// immediately.
            /// </summary>
            FatalError,
            /// <summary>
            /// Error. The compiler may not produce output, but will check
            /// for more errors.
            /// </summary>
            Error,
            /// <summary>
            /// Warning. The compiler will produce output program, but it can
            /// behave unexpectedly in some way.
            /// </summary>
            Warning,
            /// <summary>
            /// Note. The compiler will produce a normal program.
            /// </summary>
            Note
        };

        /// <summary>
        /// An exception class thrown when parser has no <see cref="IssueList"/>
        /// to record exceptions in.
        /// </summary>
        public class UnableToRecordIssueException : ApplicationException
        {
            /// <summary>
            /// <see cref="Issue"/> that caused this exception.
            /// </summary>
            public readonly Issue IssueNotRecorded;

            /// <summary>
            /// Constructor for <see cref="UnableToRecordIssueException"/> exception.
            /// </summary>
            /// <param name="issue"><see cref="Issue"/> that caused exception</param>
            public UnableToRecordIssueException(Issue issue): base()
            {
                IssueNotRecorded = issue;
            }
        }

        /// <summary>
        /// The default <see cref="Code"/> value that specifies unknown
        /// internal error that happened for unrecognizable reason.
        /// </summary>
        public const uint UnknownInternalError = 100;

        /// <summary>
        /// The default <see cref="Message"/> value that describes
        /// <see cref="UnknownInternalError"/> to the user.
        /// </summary>
        public const string UnknownInternalErrorMessage = "internal compiler error";

        /// <summary>
        /// Creates an error object with specified file location and extra info.
        /// </summary>
        public Issue(Severities severity,
                     uint code,
                     string message,
                     string fileName,
                     uint line,
                     uint column,
                     object extraInfo):
            this(severity, code, message, fileName, line, column)
        {
            this.ExtraInfo = extraInfo;
        }

        /// <summary>
        /// Creates an error object with specified file name and position.
        /// </summary>
        public Issue(Severities severity,
                     uint Code,
                     string message,
                     string fileName,
                     uint line,
                     uint column)
        {
            this.Severity = severity;
            this.Code = Code;
            this.Message = message;
            this.FileName = fileName;
            this.Line = line;
            this.Column = column;
        }

        /// <summary>
        /// Creates an error object with file location as in
        /// <see cref="InternalTree.ProgramNode"/>.
        /// </summary>
        public Issue(Severities severity,
                     uint code,
                     string message,
                     InternalTree.ProgramNode src):
            this(severity, code, message, src.SourceFileName, src.SourceLineNumber,
            src.SourceColumnNumber, src)
        {
        }

        /// <summary>
        /// Creates an error object with unspecified file name and position.
        /// </summary>
        public Issue(Severities severity, uint code, string message):
            this(severity, code, message, string.Empty, uint.MaxValue, uint.MaxValue)
        {
        }

        /// <summary>
        /// Default constructor for <see cref="Issue"/> class. Creates an instance
        /// of "internal compiler error".
        /// </summary>
        public Issue():
            this(Severities.FatalError,
                UnknownInternalError, UnknownInternalErrorMessage)
        {
        }

        /// <summary>
        /// Importance of this <see cref="Issue"/>.
        /// </summary>
        public readonly Severities Severity;

        /// <summary>
        /// A value that determines exact kind of this <see cref="Issue"/>.
        /// </summary>
        public readonly uint Code;

        /// <summary>
        /// Error or warning description in human-readable form.
        /// </summary>
        public readonly string Message;
        
        /// <summary>
        /// File in which the error occured.
        /// </summary>
        public readonly string FileName;

        /// <summary>
        /// Line in which the error occured.
        /// </summary>
        public readonly uint Line;

        /// <summary>
        /// Column in which the error occured.
        /// </summary>
        public readonly uint Column;

        /// <summary>
        /// Extra information field (its content depends on <see cref="Code"/>).
        /// </summary>
        public readonly object ExtraInfo = null;
    }
}