/**********************************************************************************************
    Shape to Circle v.1.1
    Copyright (c) 2017 Tomas Šinkūnas. All rights reserved.
    www.rendertom.com

    Description:
    	Morpth any shape into a circle.

	Change log:
		v1.1 - 2017 05 14
			- Center of the circle is calculated from shapes bounding box.
			- Adds more radius selection options: "Bounding Box Height" and "Bounding Box Width"

		v1.0 - 2017 05 10
			- Initial release

	Released as open-source under the MIT license:

		The MIT License (MIT)
		Copyright (c) 2017 Tomas Šinkūnas www.renderTom.com
		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.

**********************************************************************************************/

(function(thisObj) {

	scriptBuildUI(thisObj)

	function scriptBuildUI(thisObj) {
		var win = (thisObj instanceof Panel) ? thisObj : new Window("palette", "Shape to Circle", undefined, {
			resizeable: true
		});
		win.alignChildren = ["fill", "top"];
		win.spacing = 5;
		var grpCustomRadius = win.add("group");
		var checkCustomRadius = grpCustomRadius.add("checkbox", undefined, "Custom Radius");
		checkCustomRadius.value = true;
		checkCustomRadius.onClick = function() {
			etCustomRadius.enabled = this.value;
			ddRadius.enabled = !this.value;
		}
		var etCustomRadius = grpCustomRadius.add("edittext", undefined, "200");
		etCustomRadius.alignment = ["fill", "top"];

		var ddRadius = win.add("dropdownlist", undefined, ["Average from Center", "Bounding Box Height", "Bounding Box Width", "Maximum from Center", "Minimum from Center"]);
		ddRadius.selection = 0;

		var button = win.add("button", undefined, "Do It!");
		button.onClick = function() {
			if (etCustomRadius.enabled) {
				if (isNaN(etCustomRadius.text) || parseInt(etCustomRadius.text) < 0) {
					etCustomRadius.active = true;
					return alert("Please enter vadid radius value.");
				} else {
					main(parseInt(etCustomRadius.text));
				}
			} else {
				main(ddRadius.selection.text);
			}
		};

		win.onShow = function() {
			checkCustomRadius.onClick();
		};

		win.onResizing = win.onResize = function() {
			this.layout.resize();
		};

		win instanceof Window
			? (win.center(), win.show())
			: (win.layout.layout(true), win.layout.resize());
	}

	function main(radiusFromUI) {
		try {
			var radius = radiusFromUI;
			var distanceArray = [];

			var composition = getActiveComposition();
			var selectedLayers = getSelectedLayers(composition);
			var allShapeProperties = getAllShapeProperties(selectedLayers);
			if (allShapeProperties.length === 0)
				throw new Error("Please select Path property.");

			var pathValue, circleShape,
				boundingBox = [],
				centerCoordinates = [],
				circlePoints = [];

			app.beginUndoGroup("Shape to Circle");

			for (var j = 0, jl = allShapeProperties.length; j < jl; j++) {
				pathValue = allShapeProperties[j].value;
				boundingBox = getBoundingBox(pathValue);
				centerCoordinates = averageInArray(boundingBox);

				if (isNaN(radiusFromUI)) {
					distanceArray = getDistanceFromCenter(centerCoordinates, pathValue.vertices);
					if (radiusFromUI.match("Average")) radius = averageInArray(distanceArray);
					else if (radiusFromUI.match("Width")) radius = (boundingBox[1][0] - boundingBox[0][0]) / 2;
					else if (radiusFromUI.match("Height")) radius = (boundingBox[1][1] - boundingBox[0][1]) / 2;
					else if (radiusFromUI.match("Maximum")) radius = Math.max.apply(null, distanceArray);
					else if (radiusFromUI.match("Minimum")) radius = Math.min.apply(null, distanceArray);
				}

				circlePoints = pointsToCircle(centerCoordinates, radius, pathValue);

				circleShape = new Shape();
				circleShape.vertices = circlePoints.vertices;
				circleShape.inTangents = circlePoints.inTangents;
				circleShape.outTangents = circlePoints.outTangents;
				circleShape.closed = pathValue.closed;

				allShapeProperties[j].numKeys === 0
					? allShapeProperties[j].setValue(circleShape)
					: allShapeProperties[j].setValueAtTime(composition.time, circleShape);

			}
			app.endUndoGroup();
		} catch (e) {
			alert(e.message);
		}
	}

// -----------------------------------------------
	function getActiveComposition() {
		var composition = app.project.activeItem;
		if (!composition || !(composition instanceof CompItem))
			throw new Error("Please select composition first.");
		return composition;
	};

	function getAllShapeProperties(selectedLayers) {
		var allShapeProperties = [];
		var layerShapeProperties = [];
		for (var i = 0, il = selectedLayers.length; i < il; i++) {
			layerShapeProperties = getLayerShapeProperties(selectedLayers[i]);
			if (layerShapeProperties.length > 0) {
				allShapeProperties = allShapeProperties.concat(layerShapeProperties);
			}
		}
		return allShapeProperties;
	};

	function getLayerShapeProperties(layer) {
		var shapeProperties = [];
		var prop;
		var selectedProperties = layer.selectedProperties;
		for (var i = 0, il = selectedProperties.length; i < il; i++) {
			prop = selectedProperties[i];

			if (prop.matchName === "ADBE Vector Shape - Group") {
				if (prop.property("ADBE Vector Shape").selected === true) {
					continue
				} else {
					shapeProperties.push(prop.property("ADBE Vector Shape"))
				}
			} else if (prop.matchName === "ADBE Mask Atom") {
				if (prop.property("ADBE Mask Shape").selected === true) {
					continue
				} else {
					shapeProperties.push(prop.property("ADBE Mask Shape"))
				}
			} else if (prop.matchName.match("ADBE Vector Shape|ADBE Mask Shape")) {
				shapeProperties.push(prop)
			}
		}
		return shapeProperties;
	};

	function getSelectedLayers(composition) {
		var selectedLayers = composition.selectedLayers;
		if (selectedLayers.length === 0)
			throw new Error("Please select layer first.");
		return selectedLayers;
	};

// -----------------------------------------------
	function averageInArray(verticesArray) {
		return sumArray(verticesArray) / verticesArray.length;
	};

	function clockwiseDirection(vertices) {
		// http://stackoverflow.com/questions/14505565/detect-if-a-set-of-points-in-an-array-that-are-the-vertices-of-a-complex-polygon
		var polygonArea = getPoligonArea(vertices);
		return polygonArea > 0;
	};

	function distanceBetweenPoints(point1, point2) {
		var deltaX = point1[0] - point2[0];
		var deltaY = point1[1] - point2[1];
		var distance = Math.sqrt(deltaX * deltaX + deltaY * deltaY);
		return distance;
	};

	function getAngle(point1, point2) {
		var distanceX = point2[0] - point1[0];
		var distanceY = point2[1] - point1[1];
		var theta = Math.atan2(distanceY, distanceX);
		return theta;
	};

	function getBoundingBox(pathValue) {
		var bezierPoints = toBezierPoints(pathValue),
			xValues = [],
			yValues = [],
			segmentBoundingBox = {};

		for (var i = 0, il = bezierPoints.length; i < il; i++) {
			segmentBoundingBox = getBoundsOfCurve(bezierPoints[i][0], bezierPoints[i][1], bezierPoints[i][2], bezierPoints[i][3]);
			xValues.push(segmentBoundingBox.left);
			xValues.push(segmentBoundingBox.right);
			yValues.push(segmentBoundingBox.top);
			yValues.push(segmentBoundingBox.bottom);
		}

		return [
			[Math.min.apply(null, xValues), Math.min.apply(null, yValues)],
			[Math.max.apply(null, xValues), Math.max.apply(null, yValues)]
		];
	};

	function getBoundsOfCurve(p1, p2, p3, p4) {
		// http://stackoverflow.com/questions/2587751/an-algorithm-to-find-bounding-box-of-closed-bezier-curves
		var tvalues = [],
			xvalues = [],
			yvalues = [],
			a, b, c, t, roots;

		for (var i = 0; i < 2; ++i) {
			if (i === 0) {
				b = 6 * p1[0] - 12 * p2[0] + 6 * p3[0];
				a = -3 * p1[0] + 9 * p2[0] - 9 * p3[0] + 3 * p4[0];
				c = 3 * p2[0] - 3 * p1[0];
			} else {
				b = 6 * p1[1] - 12 * p2[1] + 6 * p3[1];
				a = -3 * p1[1] + 9 * p2[1] - 9 * p3[1] + 3 * p4[1];
				c = 3 * p2[1] - 3 * p1[1];
			}

			if (Math.abs(a) < 1e-12) { // Numerical robustness
				if (Math.abs(b) < 1e-12) continue; // Numerical robustness

				t = -c / b;
				if (0 < t && t < 1) tvalues.push(t);
				continue;
			}

			// Solve Quadratic Equation
			roots = quadraticEquation(a, b, c);
			if (!roots) continue;
			if (0 < roots.root1 && roots.root1 < 1) tvalues.push(roots.root1);
			if (0 < roots.root2 && roots.root2 < 1) tvalues.push(roots.root2);

		}

		var u, j = tvalues.length;
		while (j--) {
			t = tvalues[j];
			u = 1 - t;
			xvalues[j] = (u * u * u * p1[0]) + (3 * u * u * t * p2[0]) + (3 * u * t * t * p3[0]) + (t * t * t * p4[0]);
			yvalues[j] = (u * u * u * p1[1]) + (3 * u * u * t * p2[1]) + (3 * u * t * t * p3[1]) + (t * t * t * p4[1]);
		}

		xvalues.push(p1[0], p4[0]);
		yvalues.push(p1[1], p4[1]);

		return {
			left: Math.min.apply(null, xvalues),
			top: Math.min.apply(null, yvalues),
			right: Math.max.apply(null, xvalues),
			bottom: Math.max.apply(null, yvalues),
		};
	};

	function getDistanceFromCenter(center, vertices) {
		var distanceFromCenter;
		var distanceArray = [];
		for (var i = 0, il = vertices.length; i < il; i++) {
			distanceFromCenter = distanceBetweenPoints(center, vertices[i]);
			distanceArray.push(distanceFromCenter);
		}
		return distanceArray;
	};

	function getHandleLength(numPoints, radius) {
		return radius * getMagicNumber() * 4 / numPoints;
	};

	function getMagicNumber() {
		// http://stackoverflow.com/questions/1734745/how-to-create-circle-with-bézier-curves
		// https://people-mozilla.org/~jmuizelaar/Riskus354.pdf
		return (4 / 3) * Math.tan(Math.PI / (2 * 4));
	}

	function getPointCoordinates(center, radius, angle) {
		return [
			center[0] + radius * Math.cos(angle),
			center[1] + radius * Math.sin(angle)
		]
	};

	function getPoligonArea(vertices) {
		var area = j = 0;
		for (var i = 0, il = vertices.length; i < il; i++) {
			j = (i + 1) % vertices.length;
			area += vertices[i][0] * vertices[j][1];
			area -= vertices[j][0] * vertices[i][1];
		}
		return area / 2;
	};

	function pointsToCircle(center, radius, pathValue) {
		var angle, anchor, handle;
		var vertices = pathValue.vertices;
		var numPoints = vertices.length;
		var slice = 2 * Math.PI / numPoints;
		var handleLength = getHandleLength(numPoints, radius);
		var angleOffset = getAngle(center, vertices[0]);

		var newCoordinates = {
			vertices: [],
			inTangents: [],
			outTangents: []
		};

		if (clockwiseDirection(vertices)) {
			for (var i = 0; i < numPoints; i++) {
				angle = slice * i + angleOffset;

				anchor = getPointCoordinates(center, radius, angle);
				handle = getPointCoordinates(anchor, handleLength, angle + Math.PI / 2);

				newCoordinates.vertices.push(anchor);
				newCoordinates.inTangents.push(anchor - handle);
				newCoordinates.outTangents.push(handle - anchor);
			}
		} else {
			for (var i = numPoints; i > 0; i--) {
				angle = slice * i + angleOffset;

				anchor = getPointCoordinates(center, radius, angle);
				handle = getPointCoordinates(anchor, handleLength, angle + Math.PI / 2);

				newCoordinates.vertices.push(anchor);
				newCoordinates.inTangents.push(handle - anchor);
				newCoordinates.outTangents.push(anchor - handle);
			}

		}

		// Add additional point to close the circle
		if (!pathValue.closed) {
			newCoordinates.vertices.push(newCoordinates.vertices[0]);
			newCoordinates.inTangents.push(newCoordinates.inTangents[0]);
			newCoordinates.outTangents.push(newCoordinates.outTangents[0]);
		}

		return newCoordinates;
	};

	function quadraticEquation(a, b, c) {
		var D = b * b - 4 * a * c; // D is the discriminant of the quadratic equation
		if (D < 0) return null; // If the discriminant is negative, then there are no real roots
		var sqrtD = Math.sqrt(D); // If the discriminant is positive, then there are two distinct roots

		return {
			root1: (-b + sqrtD) / (2 * a),
			root2: (-b - sqrtD) / (2 * a)
		}
	};

	function sumArray(array) {
		var totalSum = array[0];
		for (var i = 1, il = array.length; i < il; i++)
			totalSum += array[i];
		return totalSum;
	};

	function toBezierPoints(pathValue) {
		var valuesArray = [],
			p1, p2, p3, p4;

		for (var i = 0, il = pathValue.vertices.length - 1; i < il; i++) {
			p1 = pathValue.vertices[i];
			p2 = pathValue.vertices[i] + pathValue.outTangents[i];
			p3 = pathValue.inTangents[i + 1] + pathValue.vertices[i + 1]
			p4 = pathValue.vertices[i + 1];

			valuesArray.push([p1, p2, p3, p4]);
		}

		if (pathValue.closed) {
			p1 = pathValue.vertices[pathValue.vertices.length - 1];
			p2 = pathValue.vertices[pathValue.vertices.length - 1] + pathValue.outTangents[pathValue.outTangents.length - 1];
			p3 = pathValue.inTangents[0] + pathValue.vertices[0]
			p4 = pathValue.vertices[0];

			valuesArray.push([p1, p2, p3, p4]);
		}

		return valuesArray;
	};
})(this);