using System;
using System.Collections.Generic;

namespace Spectre.Console.Testing
{
    /// <summary>
    /// Represents a testable console input mechanism.
    /// </summary>
    public sealed class TestConsoleInput : IAnsiConsoleInput
    {
        private readonly Queue<ConsoleKeyInfo> _input;

        /// <summary>
        /// Initializes a new instance of the <see cref="TestConsoleInput"/> class.
        /// </summary>
        public TestConsoleInput()
        {
            _input = new Queue<ConsoleKeyInfo>();
        }

        /// <summary>
        /// Pushes the specified text to the input queue.
        /// </summary>
        /// <param name="input">The input string.</param>
        public void PushText(string input)
        {
            if (input is null)
            {
                throw new ArgumentNullException(nameof(input));
            }

            foreach (var character in input)
            {
                PushCharacter(character);
            }
        }

        /// <summary>
        /// Pushes the specified text followed by 'Enter' to the input queue.
        /// </summary>
        /// <param name="input">The input.</param>
        public void PushTextWithEnter(string input)
        {
            PushText(input);
            PushKey(ConsoleKey.Enter);
        }

        /// <summary>
        /// Pushes the specified character to the input queue.
        /// </summary>
        /// <param name="input">The input.</param>
        public void PushCharacter(char input)
        {
            var control = char.IsUpper(input);
            _input.Enqueue(new ConsoleKeyInfo(input, (ConsoleKey)input, false, false, control));
        }

        /// <summary>
        /// Pushes the specified key to the input queue.
        /// </summary>
        /// <param name="input">The input.</param>
        public void PushKey(ConsoleKey input)
        {
            _input.Enqueue(new ConsoleKeyInfo((char)input, input, false, false, false));
        }

        /// <inheritdoc/>
        public ConsoleKeyInfo ReadKey(bool intercept)
        {
            if (_input.Count == 0)
            {
                throw new InvalidOperationException("No input available.");
            }

            return _input.Dequeue();
        }
    }
}