using OpenMacroBoard.SDK.Helper;
using System;
using System.Collections;
using System.Collections.Generic;

namespace OpenMacroBoard.SDK
{
    /// <summary>
    /// Represents a grid-like keyboard layout for macro boards.
    /// </summary>
    public class GridKeyLayout : IKeyLayout
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="GridKeyLayout"/> class.
        /// </summary>
        /// <param name="countX">Number of keys in the x-coordinate (horizontal)</param>
        /// <param name="countY">Number of keys in the y-coordinate (vertical)</param>
        /// <param name="keySize">Square key size (pixels)</param>
        /// <param name="gapSize">Distance between keys (pixels)</param>
        public GridKeyLayout(int countX, int countY, int keySize, int gapSize)
        {
#pragma warning disable SA1503, IDE0011 // Braces should not be omitted
            if (countX <= 0) throw new ArgumentOutOfRangeException(nameof(countX));
            if (countY <= 0) throw new ArgumentOutOfRangeException(nameof(countY));
            if (keySize <= 0) throw new ArgumentOutOfRangeException(nameof(keySize));
            if (gapSize <= 0) throw new ArgumentOutOfRangeException(nameof(gapSize));
#pragma warning restore SA1503, IDE0011

            CountX = countX;
            CountY = countY;
            KeySize = keySize;
            GapSize = gapSize;
            Count = countX * countY;

            Area = this.GetFullArea();
        }

        /// <summary>
        /// Gets the number of keys on this layout.
        /// </summary>
        public int Count { get; }

        /// <inheritdoc />
        public int KeySize { get; }

        /// <inheritdoc />
        public int GapSize { get; }

        /// <inheritdoc />
        public OmbRectangle Area { get; }

        /// <inheritdoc />
        public int CountX { get; }

        /// <inheritdoc />
        public int CountY { get; }

        /// <summary>
        /// Gets the dimensions of the key with a given <paramref name="keyIndex"/>.
        /// </summary>
        /// <param name="keyIndex">The index of the key.</param>
        /// <returns>The dimensions of the requested key.</returns>
        /// <exception cref="ArgumentOutOfRangeException">Is thrown if the <paramref name="keyIndex"/> is out of range.</exception>
        public OmbRectangle this[int keyIndex]
        {
            get
            {
                if (keyIndex < 0 || keyIndex >= Count)
                {
                    throw new ArgumentOutOfRangeException(nameof(keyIndex));
                }

                // split id into x and y component
                var y = keyIndex / CountX;
                var x = keyIndex % CountX;

                var fullSize = KeySize + GapSize;
                return new OmbRectangle(fullSize * x, fullSize * y, KeySize, KeySize);
            }
        }

        /// <inheritdoc />
        public IEnumerator<OmbRectangle> GetEnumerator()
        {
            for (int i = 0; i < Count; i++)
            {
                yield return this[i];
            }
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }
    }
}