using System;
using System.Reflection;
using System.Collections.Concurrent;

namespace Unosquare.Swan.Reflection {
  /// <summary>
  /// Represents a Method Info Cache.
  /// </summary>
  public class MethodInfoCache : ConcurrentDictionary<String, MethodInfo> {
    /// <summary>
    /// Retrieves the properties stored for the specified type.
    /// If the properties are not available, it calls the factory method to retrieve them
    /// and returns them as an array of PropertyInfo.
    /// </summary>
    /// <typeparam name="T">The type of type.</typeparam>
    /// <param name="name">The name.</param>
    /// <param name="alias">The alias.</param>
    /// <param name="types">The types.</param>
    /// <returns>
    /// The cached MethodInfo.
    /// </returns>
    /// <exception cref="ArgumentNullException">name
    /// or
    /// factory.</exception>
    /// <exception cref="System.ArgumentNullException">type.</exception>
    public MethodInfo Retrieve<T>(String name, String alias, params Type[] types)
        => this.Retrieve(typeof(T), name, alias, types);

    /// <summary>
    /// Retrieves the specified name.
    /// </summary>
    /// <typeparam name="T">The type of type.</typeparam>
    /// <param name="name">The name.</param>
    /// <param name="types">The types.</param>
    /// <returns>
    /// The cached MethodInfo.
    /// </returns>
    public MethodInfo Retrieve<T>(String name, params Type[] types)
        => this.Retrieve(typeof(T), name, name, types);

    /// <summary>
    /// Retrieves the specified type.
    /// </summary>
    /// <param name="type">The type.</param>
    /// <param name="name">The name.</param>
    /// <param name="types">The types.</param>
    /// <returns>
    /// An array of the properties stored for the specified type.
    /// </returns>
    public MethodInfo Retrieve(Type type, String name, params Type[] types)
        => this.Retrieve(type, name, name, types);

    /// <summary>
    /// Retrieves the specified type.
    /// </summary>
    /// <param name="type">The type.</param>
    /// <param name="name">The name.</param>
    /// <param name="alias">The alias.</param>
    /// <param name="types">The types.</param>
    /// <returns>
    /// The cached MethodInfo.
    /// </returns>
    public MethodInfo Retrieve(Type type, String name, String alias, params Type[] types) {
      if(type == null) {
        throw new ArgumentNullException(nameof(type));
      }

      if(alias == null) {
        throw new ArgumentNullException(nameof(alias));
      }

      if(name == null) {
        throw new ArgumentNullException(nameof(name));
      }

      return this.GetOrAdd(
                alias,
                x => type.GetMethod(name, types ?? new Type[0]));
    }

    /// <summary>
    /// Retrieves the specified name.
    /// </summary>
    /// <typeparam name="T">The type of type.</typeparam>
    /// <param name="name">The name.</param>
    /// <returns>
    /// The cached MethodInfo.
    /// </returns>
    public MethodInfo Retrieve<T>(String name)
        => this.Retrieve(typeof(T), name);

    /// <summary>
    /// Retrieves the specified type.
    /// </summary>
    /// <param name="type">The type.</param>
    /// <param name="name">The name.</param>
    /// <returns>
    /// The cached MethodInfo.
    /// </returns>
    /// <exception cref="ArgumentNullException">
    /// type
    /// or
    /// name.
    /// </exception>
    public MethodInfo Retrieve(Type type, String name) {
      if(type == null) {
        throw new ArgumentNullException(nameof(type));
      }

      if(name == null) {
        throw new ArgumentNullException(nameof(name));
      }

      return this.GetOrAdd(
                name,
                type.GetMethod);
    }
  }
}