#pragma warning disable SA1402

namespace FluentTest.Commanding
{
    using System;
    using System.Diagnostics;
    using System.Windows.Input;

    public class RelayCommand : IRelayCommand
    {
        private readonly Action action;
        private readonly Func<bool> canExecute;

        protected RelayCommand()
        {
        }

        public RelayCommand(Action execute)
        {
            this.action = execute;
        }

        public RelayCommand(Action execute, Func<bool> canExecute)
            : this(execute)
        {
            this.canExecute = canExecute;
        }

        #region IRelayCommand Members

        [DebuggerStepThrough]
        public virtual bool CanExecute(object parameter)
        {
            return this.canExecute is null
                || this.canExecute();
        }

        /// <inheritdoc />
        public event EventHandler CanExecuteChanged
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }

        public event EventHandler Executed;

        public event EventHandler Executing;

        protected void OnExecuted()
        {
            this.Executed?.Invoke(this, null);
        }

        protected void OnExecuting()
        {
            this.Executing?.Invoke(this, null);
        }

        public void Execute(object parameter)
        {
            this.OnExecuting();

            this.InvokeAction(parameter);

            this.OnExecuted();
        }

        protected virtual void InvokeAction(object parameter)
        {
            this.action();
        }

        #endregion // IRelayCommand Members
    }

    /// <summary>
    /// A command whose sole purpose is to
    /// relay its functionality to other
    /// objects by invoking delegates. The
    /// default return value for the CanExecute
    /// method is 'true'.
    /// </summary>
    public class RelayCommand<T> : RelayCommand
    {
        private readonly Action<T> action;
        private readonly Func<T, bool> canExecute;

        protected RelayCommand()
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="RelayCommand{T}"/> class.
        /// </summary>
        /// <param name="action">The execution logic.</param>
        public RelayCommand(Action<T> action)
            : this(action, null)
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="RelayCommand{T}"/> class.
        /// </summary>
        /// <param name="action">The execution logic.</param>
        /// <param name="canExecute">The execution status logic.</param>
        public RelayCommand(Action<T> action, Func<T, bool> canExecute)
        {
            this.action = action;
            this.canExecute = canExecute;
        }

        /// <summary>
        /// Defines the method that determines whether the command can execute in its current state.
        /// </summary>
        /// <returns>
        /// true if this command can be executed; otherwise, false.
        /// </returns>
        /// <param name="parameter">Data used by the command.  If the command does not require data to be passed, this object can be set to null.</param>
        public override bool CanExecute(object parameter)
        {
            return this.canExecute is null
                   || this.canExecute((T)parameter);
        }

        protected override void InvokeAction(object parameter)
        {
            this.action((T)parameter);
        }
    }
}