using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace Games.Common.IO
{
    /// <inheritdoc />
    /// <summary>
    /// Implements <see cref="IReadWrite" /> with input read from a <see cref="TextReader" /> and output written to a
    /// <see cref="TextWriter" />.
    /// </summary>
    public class TextIO : IReadWrite
    {
        private readonly TextReader _input;
        private readonly TextWriter _output;
        private readonly TokenReader _stringTokenReader;
        private readonly TokenReader _numberTokenReader;

        public TextIO(TextReader input, TextWriter output)
        {
            _input = input ?? throw new ArgumentNullException(nameof(input));
            _output = output ?? throw new ArgumentNullException(nameof(output));
            _stringTokenReader = TokenReader.ForStrings(this);
            _numberTokenReader = TokenReader.ForNumbers(this);
        }

        public float ReadNumber(string prompt) => ReadNumbers(prompt, 1)[0];

        public (float, float) Read2Numbers(string prompt)
        {
            var numbers = ReadNumbers(prompt, 2);
            return (numbers[0], numbers[1]);
        }

        public (float, float, float) Read3Numbers(string prompt)
        {
            var numbers = ReadNumbers(prompt, 3);
            return (numbers[0], numbers[1], numbers[2]);
        }

        public (float, float, float, float) Read4Numbers(string prompt)
        {
            var numbers = ReadNumbers(prompt, 4);
            return (numbers[0], numbers[1], numbers[2], numbers[3]);
        }

        public void ReadNumbers(string prompt, float[] values)
        {
            if (values.Length == 0)
            {
                throw new ArgumentException($"'{nameof(values)}' must have a non-zero length.", nameof(values));
            }

            var numbers = _numberTokenReader.ReadTokens(prompt, (uint)values.Length).Select(t => t.Number).ToArray();
            numbers.CopyTo(values.AsSpan());
        }

        private IReadOnlyList<float> ReadNumbers(string prompt, uint quantity) =>
            (quantity > 0)
                ? _numberTokenReader.ReadTokens(prompt, quantity).Select(t => t.Number).ToList()
                : throw new ArgumentOutOfRangeException(
                    nameof(quantity),
                    $"'{nameof(quantity)}' must be greater than zero.");

        public void Write(string value) => _output.Write(value);

        public void WriteLine(string value) => _output.WriteLine(value);

        public string ReadString(string prompt)
        {
            return ReadStrings(prompt, 1)[0];
        }

        public (string, string) Read2Strings(string prompt)
        {
            var values = ReadStrings(prompt, 2);
            return (values[0], values[1]);
        }

        private IReadOnlyList<string> ReadStrings(string prompt, uint quantityRequired) =>
            _stringTokenReader.ReadTokens(prompt, quantityRequired).Select(t => t.String).ToList();

        internal string ReadLine(string prompt)
        {
            Write(prompt + "? ");
            return _input.ReadLine();
        }
    }
}