using o0.Geometry2D.Float;
using System;

namespace o0.Project
{
    internal class o0Extension
    {
        public static void DrawLine(Matrix matrix, Line line, Func<int, int, float> setValue, Vector size = default, bool dashedLine = false)
        {
            if (line == null || matrix == null)
                return;
            if (size == default)
                size = new Vector(0, 1);
            if (size.x != 0)
            {
                var halfExtLength = size.x / 2;
                var offset = new Vector(halfExtLength / line.Length * (line.B.x - line.A.x), halfExtLength / line.Length * (line.B.y - line.A.y));
                line = new Line(line.A - offset, line.B + offset);
            }

            void _draw(int x, int y)
            {
                try
                {
                    if (dashedLine)
                    {
                        var d = (new Vector(x, y) - line.A).Length;
                        if (d % 75 < 35)
                            matrix[x, y] = setValue(x, y);
                    }
                    else
                        matrix[x, y] = setValue(x, y);
                }
                catch { }
            }

            var halfWidth = size.y / 2;
            if (line.A.y == line.B.y)
            {
                var xRange = ((int)Math.Round(line.A.x), (int)Math.Round(line.B.x) + 1);
                foreach (var y in ((int)Math.Round(line.A.y - halfWidth)).Range((int)Math.Round(line.A.y + halfWidth) + 1))
                    foreach (var x in xRange.Item1.Range(xRange.Item2))
                        _draw(x, y);
                return;
            }
            else if (line.A.x == line.B.x)
            {
                var yRange = ((int)Math.Round(line.A.y), (int)Math.Round(line.B.y) + 1);
                foreach (var x in ((int)Math.Round(line.A.x - halfWidth)).Range((int)Math.Round(line.A.x + halfWidth) + 1))
                    foreach (var y in yRange.Item1.Range(yRange.Item2))
                        _draw(x, y);
                return;
            }
            var upOffset = new Vector(halfWidth / line.Length * (line.A.y - line.B.y), halfWidth / line.Length * (line.B.x - line.A.x));
            if (upOffset.y < 0)
                upOffset = -upOffset;
            Vector up, down, left, right;
            if (upOffset.x < 0)//0-90度
            {
                up = line.B + upOffset;
                down = line.A - upOffset;
                left = line.A + upOffset;
                right = line.B - upOffset;
            }
            else
            {
                up = line.A + upOffset;
                down = line.B - upOffset;
                left = line.A - upOffset;
                right = line.B + upOffset;
            }
            var topLeft = new Line(left, up);
            var bottomLeft = new Line(left, down);
            var topRight = new Line(up, right);
            var bottomRight = new Line(down, right);

            var topLeftXToYRate = topLeft.XToYRate;
            var bottomLeftXToYRate = bottomLeft.XToYRate;
            var topRightXToYRate = topRight.XToYRate;
            var bottomRightXToYRate = bottomRight.XToYRate;
            foreach (var y in ((int)Math.Round(down.y)).Range((int)Math.Round(up.y) + 1))
                foreach (var x in ((int)Math.Max(topLeft.YToX(y, topLeftXToYRate), bottomLeft.YToX(y, bottomLeftXToYRate)))
                    .Range((int)Math.Min(topRight.YToX(y, topRightXToYRate), bottomRight.YToX(y, bottomRightXToYRate)) + 1))
                    _draw(x, y);
        }

        /// <summary>计算点到直线的垂足，垂足坐标可能在Line的延长线上，可通过inLineSegment判断垂足是否在线段上</summary>
        public static Vector PointPedal(Line l, in Vector v, out bool inLineSegment)
        {
            Vector d = l.B - l.A;
            float dotD = d.Dot(d);
            if (dotD == 0)
                throw new DivideByZeroException();
            float dotL = (v - l.A).Dot(d);
            var factor = dotL / dotD;
            Vector proj = d * factor;
            inLineSegment = factor >= 0 && factor <= 1;
            return l.A + proj;
        }


    }
}