// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

﻿

namespace Standard
{
    using System;
    using System.Diagnostics.CodeAnalysis;
    using System.Windows;
    using System.Windows.Media;

    internal static class DpiHelper
    {
        [ThreadStatic]
        private static Matrix _transformToDevice;
        [ThreadStatic]
        private static Matrix _transformToDip;

        /// <summary>
        /// Convert a point in device independent pixels (1/96") to a point in the system coordinates.
        /// </summary>
        /// <param name="logicalPoint">A point in the logical coordinate system.</param>
        /// <returns>Returns the parameter converted to the system's coordinates.</returns>
        public static Point LogicalPixelsToDevice(Point logicalPoint, double dpiScaleX, double dpiScaleY)
        {
            _transformToDevice = Matrix.Identity;
            _transformToDevice.Scale(dpiScaleX, dpiScaleY);
            return _transformToDevice.Transform(logicalPoint);
        }

        /// <summary>
        /// Convert a point in system coordinates to a point in device independent pixels (1/96").
        /// </summary>
        /// <param name="devicePoint">A point in the physical coordinate system.</param>
        /// <returns>Returns the parameter converted to the device independent coordinate system.</returns>
        public static Point DevicePixelsToLogical(Point devicePoint, double dpiScaleX, double dpiScaleY)
        {
            _transformToDip = Matrix.Identity;
            _transformToDip.Scale(1d / dpiScaleX, 1d / dpiScaleY);
            return _transformToDip.Transform(devicePoint);
        }

        [SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
        public static Rect LogicalRectToDevice(Rect logicalRectangle, double dpiScaleX, double dpiScaleY)
        {
            Point topLeft = LogicalPixelsToDevice(new Point(logicalRectangle.Left, logicalRectangle.Top), dpiScaleX, dpiScaleY);
            Point bottomRight = LogicalPixelsToDevice(new Point(logicalRectangle.Right, logicalRectangle.Bottom), dpiScaleX, dpiScaleY);

            return new Rect(topLeft, bottomRight);
        }

        public static Rect DeviceRectToLogical(Rect deviceRectangle, double dpiScaleX, double dpiScaleY)
        {
            Point topLeft = DevicePixelsToLogical(new Point(deviceRectangle.Left, deviceRectangle.Top), dpiScaleX, dpiScaleY);
            Point bottomRight = DevicePixelsToLogical(new Point(deviceRectangle.Right, deviceRectangle.Bottom), dpiScaleX, dpiScaleY);

            return new Rect(topLeft, bottomRight);
        }

        [SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
        public static Size LogicalSizeToDevice(Size logicalSize, double dpiScaleX, double dpiScaleY)
        {
            Point pt = LogicalPixelsToDevice(new Point(logicalSize.Width, logicalSize.Height), dpiScaleX, dpiScaleY);

            return new Size { Width = pt.X, Height = pt.Y };
        }

        public static Size DeviceSizeToLogical(Size deviceSize, double dpiScaleX, double dpiScaleY)
        {
            Point pt = DevicePixelsToLogical(new Point(deviceSize.Width, deviceSize.Height), dpiScaleX, dpiScaleY);

            return new Size(pt.X, pt.Y);
        }

        public static Thickness LogicalThicknessToDevice(Thickness logicalThickness, double dpiScaleX, double dpiScaleY)
        {
            Point topLeft = LogicalPixelsToDevice(new Point(logicalThickness.Left, logicalThickness.Top), dpiScaleX, dpiScaleY);
            Point bottomRight = LogicalPixelsToDevice(new Point(logicalThickness.Right, logicalThickness.Bottom), dpiScaleX, dpiScaleY);

            return new Thickness(topLeft.X, topLeft.Y, bottomRight.X, bottomRight.Y);
        }
    }
}