using System;
using System.Reflection.Emit;

namespace BLToolkit.Reflection.Emit
{
    /// <summary>
    /// A wrapper around the <see cref="ConstructorBuilder"/> class.
    /// </summary>
    public class ConstructorBuilderHelper : MethodBuilderBase
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="ConstructorBuilder"/> class
        /// with the specified parameters.
        /// </summary>
        /// <param name="typeBuilder">Associated <see cref="TypeBuilderHelper"/>.</param>
        /// <param name="constructorBuilder">A <see cref="ConstructorBuilder"/></param>
        public ConstructorBuilderHelper(TypeBuilderHelper typeBuilder, ConstructorBuilder constructorBuilder)
            : base(typeBuilder)
        {
            if (constructorBuilder == null) throw new ArgumentNullException("constructorBuilder");

            _constructorBuilder = constructorBuilder;
            _constructorBuilder.SetCustomAttribute(Type.Assembly.BLToolkitAttribute);
        }

        private readonly ConstructorBuilder _constructorBuilder;
        /// <summary>
        /// Gets ConstructorBuilder.
        /// </summary>
        public           ConstructorBuilder  ConstructorBuilder
        {
            get { return _constructorBuilder; }
        }

        /// <summary>
        /// Converts the supplied <see cref="ConstructorBuilderHelper"/> to a <see cref="MethodBuilder"/>.
        /// </summary>
        /// <param name="constructorBuilder">The <see cref="ConstructorBuilder"/>.</param>
        /// <returns>A <see cref="ConstructorBuilder"/>.</returns>
        public static implicit operator ConstructorBuilder(ConstructorBuilderHelper constructorBuilder)
        {
            if (constructorBuilder == null) throw new ArgumentNullException("constructorBuilder");

            return constructorBuilder.ConstructorBuilder;
        }

        private EmitHelper _emitter;
        /// <summary>
        /// Gets <see cref="EmitHelper"/>.
        /// </summary>
        public override EmitHelper Emitter
        {
            get
            {
                if (_emitter == null)
                    _emitter = new EmitHelper(this, _constructorBuilder.GetILGenerator());

                return _emitter;
            }
        }
    }
}