#region MigraDoc - Creating Documents on the Fly
//
// Authors:
//   Klaus Potzesny
//
// Copyright (c) 2001-2017 empira Software GmbH, Cologne Area (Germany)
//
// http://www.pdfsharp.com
// http://www.migradoc.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using PdfSharp.Drawing;

namespace MigraDoc.Rendering
{
    /// <summary>
    /// Abstract base class for all areas to render in.
    /// </summary>
    public abstract class Area
    {
        /// <summary>
        /// Gets the left boundary of the area.
        /// </summary>
        public abstract XUnit X { get; set; }

        /// <summary>
        /// Gets the top boundary of the area.
        /// </summary>
        public abstract XUnit Y { get; set; }

        /// <summary>
        /// Gets the largest fitting rect with the given y position and height.
        /// </summary>
        /// <param name="yPosition">Top bound of the searched rectangle.</param>
        /// <param name="height">Height of the searched rectangle.</param>
        /// <returns>
        /// The largest fitting rect with the given y position and height.
        /// Null if yPosition exceeds the area.
        /// </returns>
        public abstract Rectangle GetFittingRect(XUnit yPosition, XUnit height);

        /// <summary>
        /// Gets or sets the height of the smallest rectangle containing the area. 
        /// </summary>
        public abstract XUnit Height { get; set; }

        /// <summary>
        /// Gets or sets the width of the smallest rectangle containing the area. 
        /// </summary>
        public abstract XUnit Width { get; set; }

        /// <summary>
        /// Returns the union of this area snd the given one.
        /// </summary>
        /// <param name="area">The area to unite with.</param>
        /// <returns>The union of the two areas.</returns>
        public abstract Area Unite(Area area);

        /// <summary>
        /// Lowers the area and makes it smaller.
        /// </summary>
        /// <param name="verticalOffset">The measure of lowering.</param>
        /// <returns>The lowered Area.</returns>
        public abstract Area Lower(XUnit verticalOffset);
    }

    public class Rectangle : Area
    {
        /// <summary>
        /// Initializes a new rectangle object.
        /// </summary>
        /// <param name="x">Left bound of the rectangle.</param>
        /// <param name="y">Upper bound of the rectangle.</param>
        /// <param name="width">Width of the rectangle.</param>
        /// <param name="height">Height of the rectangle.</param>
        public Rectangle(XUnit x, XUnit y, XUnit width, XUnit height)
        {
            _x = x;
            _y = y;
            _width = width;
            _height = height;
        }

        /// <summary>
        /// Initializes a new Rectangle by copying its values.
        /// </summary>
        /// <param name="rect">The rectangle to copy.</param>
        public Rectangle(Rectangle rect)
        {
            _x = rect._x;
            _y = rect._y;
            _width = rect._width;
            _height = rect._height;
        }

        /// <summary>
        /// Gets the largest fitting rect with the given y position and height.
        /// </summary>
        /// <param name="yPosition">Top boundary of the requested rectangle.</param>
        /// <param name="height">Height of the requested rectangle.</param>
        /// <returns>The largest fitting rect with the given y position and height or NULL if the requested height does not fit.</returns>
        public override Rectangle GetFittingRect(XUnit yPosition, XUnit height)
        {
            if (yPosition + height > _y + _height + Renderer.Tolerance)
                return null;

            return new Rectangle(_x, yPosition, _width, height);
        }

        /// <summary>
        /// Gets or sets the left boundary of the rectangle. 
        /// </summary>
        public override XUnit X
        {
            get { return _x; }
            set { _x = value; }
        }
        XUnit _x;

        /// <summary>
        /// Gets or sets the top boundary of the rectangle. 
        /// </summary>
        public override XUnit Y
        {
            get { return _y; }
            set { _y = value; }
        }
        XUnit _y;

        /// <summary>
        /// Gets or sets the width of the rectangle. 
        /// </summary>
        public override XUnit Width
        {
            get { return _width; }
            set { _width = value; }
        }
        XUnit _width;

        /// <summary>
        /// Gets or sets the height of the rectangle. 
        /// </summary>
        public override XUnit Height
        {
            get { return _height; }
            set { _height = value; }
        }
        XUnit _height;

        /// <summary>
        /// Returns the union of the rectangle and the given area.
        /// </summary>
        /// <param name="area">The area to unite with.</param>
        /// <returns>The union of the two areas.</returns>
        public override Area Unite(Area area)
        {
            if (area == null)
                return this;
            // This implementation is of course not correct, but it works for our purposes.
            XUnit minTop = Math.Min(_y, area.Y);
            XUnit minLeft = Math.Min(_x, area.X);
            XUnit maxRight = Math.Max(_x + _width, area.X + area.Width);
            XUnit maxBottom = Math.Max(_y + _height, area.Y + area.Height);
            return new Rectangle(minLeft, minTop, maxRight - minLeft, maxBottom - minTop);
        }

        public override Area Lower(XUnit verticalOffset)
        {
            return new Rectangle(_x, _y + verticalOffset, _width, _height - verticalOffset);
        }
    }
}