using System;
using System.CodeDom.Compiler;
using System.Runtime.Serialization;
using System.Text;

namespace Chernobyl.Plugin.Exceptions
{
    /// <summary>
    /// An exception that is thrown when the compilation of scripts or other 
    /// resources produces an error.
    /// </summary>
    public class CompileErrorException : Exception
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="CompileErrorException"/> 
        /// class which uses the <see cref="DefaultMessage"/>.
        /// </summary>
        /// <param name="errors">The <see cref="CompilerResults"/> that contain
        /// information about the compilation in question.</param>
        public CompileErrorException(CompilerResults errors)
            : this(DefaultMessage, errors)
        { }

        /// <summary>
        /// Initializes a new instance of the <see cref="CompileErrorException"/> 
        /// class.
        /// </summary>
        /// <param name="message">The error message that explains the reason for 
        /// the exception.</param>
        /// <param name="results">The <see cref="CompilerResults"/> that contain
        /// information about the compilation in question.</param>
        public CompileErrorException(string message, CompilerResults results)
            : base(message)
        {
            Results = results;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="CompileErrorException"/> class.
        /// </summary>
        /// <param name="message">The error message that explains the reason for 
        /// the exception.</param>
        /// <param name="results">The <see cref="CompilerResults"/> that contain
        /// information about the compilation in question.</param>
        /// <param name="innerException">The exception that is the cause of the 
        /// current exception, or a null reference (Nothing in Visual Basic) if 
        /// no inner exception is specified.</param>
        public CompileErrorException(string message, CompilerResults results, Exception innerException)
            : base(message, innerException)
        {
            Results = results;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="CompileErrorException"/> class.
        /// </summary>
        /// <param name="info">The <see cref="SerializationInfo"/> that holds 
        /// the serialized object data about the exception being thrown.</param>
        /// <param name="context">The <see cref="StreamingContext"/> that contains 
        /// contextual information about the source or destination.</param>
        /// <exception cref="ArgumentNullException">The <paramref name="info"/> 
        /// parameter is null.</exception>
        /// <exception cref="SerializationException">The class name is null or 
        /// <see cref="Exception.HResult"/> is zero (0).</exception>
        public CompileErrorException(SerializationInfo info, StreamingContext context)
            : base(info, context)
        { }

        /// <summary>
        /// The <see cref="CompilerResults"/> that contain information about the
        /// compilation in question.
        /// </summary>
        public CompilerResults Results { get; private set; }

        /// <summary>
        /// Gets a message that describes the current exception.
        /// </summary>
        /// <value></value>
        /// <returns>
        /// The error message that explains the reason for the exception, or an
        /// empty string("").
        /// </returns>
        public override string Message
        {
            get
            {
                if(_message == null)
                {
                    // add the errors to the exception message.

                    StringBuilder errorBuilder = new StringBuilder(base.Message);
                    errorBuilder.Append(" The following errors occurred during compilation:");
                    errorBuilder.AppendLine();

                    foreach (CompilerError error in Results.Errors)
                        errorBuilder.AppendLine(error.ToString());

                    _message = errorBuilder.ToString();
                }

                return _message;
            }
        }

        /// <summary>
        /// The default message of this exception. This message is used if a 
        /// message isn't provided to a constructor of this class.
        /// </summary>
        public const string DefaultMessage = "Failed to compile the resource, " + 
            "errors were found during its compilation.";

        /// <summary>
        /// The <see cref="String"/> that contains the formatted message
        /// returned by <see cref="Exception.Message"/>, stored for optimization
        /// purposes.
        /// </summary>
        string _message;
    }
}