/******************************************************************************
 * Spine Runtimes License Agreement
 * Last updated January 1, 2020. Replaces all prior versions.
 *
 * Copyright (c) 2013-2020, Esoteric Software LLC
 *
 * Integration of the Spine Runtimes into software or otherwise creating
 * derivative works of the Spine Runtimes is permitted under the terms and
 * conditions of Section 2 of the Spine Editor License Agreement:
 * http://esotericsoftware.com/spine-editor-license
 *
 * Otherwise, it is permitted to integrate the Spine Runtimes into software
 * or otherwise create derivative works of the Spine Runtimes (collectively,
 * "Products"), provided that each user of the Products must obtain their own
 * Spine Editor license and redistribution of the Products in any form must
 * include this license and copyright notice.
 *
 * THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL ESOTERIC SOFTWARE LLC BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES,
 * BUSINESS INTERRUPTION, OR LOSS OF USE, DATA, OR PROFITS) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *****************************************************************************/

module spine {
	export class SkeletonClipping {
		private triangulator = new Triangulator();
		private clippingPolygon = new Array<number>();
		private clipOutput = new Array<number>();
		clippedVertices = new Array<number>();
		clippedTriangles = new Array<number>();
		private scratch = new Array<number>();

		private clipAttachment: ClippingAttachment;
		private clippingPolygons: Array<Array<number>>;

		clipStart (slot: Slot, clip: ClippingAttachment): number {
			if (this.clipAttachment != null) return 0;
			this.clipAttachment = clip;

			let n = clip.worldVerticesLength;
			let vertices = Utils.setArraySize(this.clippingPolygon, n);
			clip.computeWorldVertices(slot, 0, n, vertices, 0, 2);
			let clippingPolygon = this.clippingPolygon;
			SkeletonClipping.makeClockwise(clippingPolygon);
			let clippingPolygons = this.clippingPolygons = this.triangulator.decompose(clippingPolygon, this.triangulator.triangulate(clippingPolygon));
			for (let i = 0, n = clippingPolygons.length; i < n; i++) {
				let polygon = clippingPolygons[i];
				SkeletonClipping.makeClockwise(polygon);
				polygon.push(polygon[0]);
				polygon.push(polygon[1]);
			}

			return clippingPolygons.length;
		}

		clipEndWithSlot (slot: Slot) {
			if (this.clipAttachment != null && this.clipAttachment.endSlot == slot.data) this.clipEnd();
		}

		clipEnd () {
			if (this.clipAttachment == null) return;
			this.clipAttachment = null;
			this.clippingPolygons = null;
			this.clippedVertices.length = 0;
			this.clippedTriangles.length = 0;
			this.clippingPolygon.length = 0;
		}

		isClipping (): boolean {
			return this.clipAttachment != null;
		}

		clipTriangles (vertices: ArrayLike<number>, verticesLength: number, triangles: ArrayLike<number>, trianglesLength: number, uvs: ArrayLike<number>,
			light: Color, dark: Color, twoColor: boolean) {

			let clipOutput = this.clipOutput, clippedVertices = this.clippedVertices;
			let clippedTriangles = this.clippedTriangles;
			let polygons = this.clippingPolygons;
			let polygonsCount = this.clippingPolygons.length;
			let vertexSize = twoColor ? 12 : 8;

			let index = 0;
			clippedVertices.length = 0;
			clippedTriangles.length = 0;
			outer:
			for (let i = 0; i < trianglesLength; i += 3) {
				let vertexOffset = triangles[i] << 1;
				let x1 = vertices[vertexOffset], y1 = vertices[vertexOffset + 1];
				let u1 = uvs[vertexOffset], v1 = uvs[vertexOffset + 1];

				vertexOffset = triangles[i + 1] << 1;
				let x2 = vertices[vertexOffset], y2 = vertices[vertexOffset + 1];
				let u2 = uvs[vertexOffset], v2 = uvs[vertexOffset + 1];

				vertexOffset = triangles[i + 2] << 1;
				let x3 = vertices[vertexOffset], y3 = vertices[vertexOffset + 1];
				let u3 = uvs[vertexOffset], v3 = uvs[vertexOffset + 1];

				for (let p = 0; p < polygonsCount; p++) {
					let s = clippedVertices.length;
					if (this.clip(x1, y1, x2, y2, x3, y3, polygons[p], clipOutput)) {
						let clipOutputLength = clipOutput.length;
						if (clipOutputLength == 0) continue;
						let d0 = y2 - y3, d1 = x3 - x2, d2 = x1 - x3, d4 = y3 - y1;
						let d = 1 / (d0 * d2 + d1 * (y1 - y3));

						let clipOutputCount = clipOutputLength >> 1;
						let clipOutputItems = this.clipOutput;
						let clippedVerticesItems = Utils.setArraySize(clippedVertices, s + clipOutputCount * vertexSize);
						for (let ii = 0; ii < clipOutputLength; ii += 2) {
							let x = clipOutputItems[ii], y = clipOutputItems[ii + 1];
							clippedVerticesItems[s] = x;
							clippedVerticesItems[s + 1] = y;
							clippedVerticesItems[s + 2] = light.r;
							clippedVerticesItems[s + 3] = light.g;
							clippedVerticesItems[s + 4] = light.b;
							clippedVerticesItems[s + 5] = light.a;
							let c0 = x - x3, c1 = y - y3;
							let a = (d0 * c0 + d1 * c1) * d;
							let b = (d4 * c0 + d2 * c1) * d;
							let c = 1 - a - b;
							clippedVerticesItems[s + 6] = u1 * a + u2 * b + u3 * c;
							clippedVerticesItems[s + 7] = v1 * a + v2 * b + v3 * c;
							if (twoColor) {
								clippedVerticesItems[s + 8] = dark.r;
								clippedVerticesItems[s + 9] = dark.g;
								clippedVerticesItems[s + 10] = dark.b;
								clippedVerticesItems[s + 11] = dark.a;
							}
							s += vertexSize;
						}

						s = clippedTriangles.length;
						let clippedTrianglesItems = Utils.setArraySize(clippedTriangles, s + 3 * (clipOutputCount - 2));
						clipOutputCount--;
						for (let ii = 1; ii < clipOutputCount; ii++) {
							clippedTrianglesItems[s] = index;
							clippedTrianglesItems[s + 1] = (index + ii);
							clippedTrianglesItems[s + 2] = (index + ii + 1);
							s += 3;
						}
						index += clipOutputCount + 1;

					} else {
						let clippedVerticesItems = Utils.setArraySize(clippedVertices, s + 3 * vertexSize);
						clippedVerticesItems[s] = x1;
						clippedVerticesItems[s + 1] = y1;
						clippedVerticesItems[s + 2] = light.r;
						clippedVerticesItems[s + 3] = light.g;
						clippedVerticesItems[s + 4] = light.b;
						clippedVerticesItems[s + 5] = light.a;
						if (!twoColor) {
							clippedVerticesItems[s + 6] = u1;
							clippedVerticesItems[s + 7] = v1;

							clippedVerticesItems[s + 8] = x2;
							clippedVerticesItems[s + 9] = y2;
							clippedVerticesItems[s + 10] = light.r;
							clippedVerticesItems[s + 11] = light.g;
							clippedVerticesItems[s + 12] = light.b;
							clippedVerticesItems[s + 13] = light.a;
							clippedVerticesItems[s + 14] = u2;
							clippedVerticesItems[s + 15] = v2;

							clippedVerticesItems[s + 16] = x3;
							clippedVerticesItems[s + 17] = y3;
							clippedVerticesItems[s + 18] = light.r;
							clippedVerticesItems[s + 19] = light.g;
							clippedVerticesItems[s + 20] = light.b;
							clippedVerticesItems[s + 21] = light.a;
							clippedVerticesItems[s + 22] = u3;
							clippedVerticesItems[s + 23] = v3;
						} else {
							clippedVerticesItems[s + 6] = u1;
							clippedVerticesItems[s + 7] = v1;
							clippedVerticesItems[s + 8] = dark.r;
							clippedVerticesItems[s + 9] = dark.g;
							clippedVerticesItems[s + 10] = dark.b;
							clippedVerticesItems[s + 11] = dark.a;

							clippedVerticesItems[s + 12] = x2;
							clippedVerticesItems[s + 13] = y2;
							clippedVerticesItems[s + 14] = light.r;
							clippedVerticesItems[s + 15] = light.g;
							clippedVerticesItems[s + 16] = light.b;
							clippedVerticesItems[s + 17] = light.a;
							clippedVerticesItems[s + 18] = u2;
							clippedVerticesItems[s + 19] = v2;
							clippedVerticesItems[s + 20] = dark.r;
							clippedVerticesItems[s + 21] = dark.g;
							clippedVerticesItems[s + 22] = dark.b;
							clippedVerticesItems[s + 23] = dark.a;

							clippedVerticesItems[s + 24] = x3;
							clippedVerticesItems[s + 25] = y3;
							clippedVerticesItems[s + 26] = light.r;
							clippedVerticesItems[s + 27] = light.g;
							clippedVerticesItems[s + 28] = light.b;
							clippedVerticesItems[s + 29] = light.a;
							clippedVerticesItems[s + 30] = u3;
							clippedVerticesItems[s + 31] = v3;
							clippedVerticesItems[s + 32] = dark.r;
							clippedVerticesItems[s + 33] = dark.g;
							clippedVerticesItems[s + 34] = dark.b;
							clippedVerticesItems[s + 35] = dark.a;
						}

						s = clippedTriangles.length;
						let clippedTrianglesItems = Utils.setArraySize(clippedTriangles, s + 3);
						clippedTrianglesItems[s] = index;
						clippedTrianglesItems[s + 1] = (index + 1);
						clippedTrianglesItems[s + 2] = (index + 2);
						index += 3;
						continue outer;
					}
				}
			}
		}

		/** Clips the input triangle against the convex, clockwise clipping area. If the triangle lies entirely within the clipping
		 * area, false is returned. The clipping area must duplicate the first vertex at the end of the vertices list. */
		clip (x1: number, y1: number, x2: number, y2: number, x3: number, y3: number, clippingArea: Array<number>, output: Array<number>) {
			let originalOutput = output;
			let clipped = false;

			// Avoid copy at the end.
			let input: Array<number> = null;
			if (clippingArea.length % 4 >= 2) {
				input = output;
				output = this.scratch;
			} else
				input = this.scratch;

			input.length = 0;
			input.push(x1);
			input.push(y1);
			input.push(x2);
			input.push(y2);
			input.push(x3);
			input.push(y3);
			input.push(x1);
			input.push(y1);
			output.length = 0;

			let clippingVertices = clippingArea;
			let clippingVerticesLast = clippingArea.length - 4;
			for (let i = 0;; i += 2) {
				let edgeX = clippingVertices[i], edgeY = clippingVertices[i + 1];
				let edgeX2 = clippingVertices[i + 2], edgeY2 = clippingVertices[i + 3];
				let deltaX = edgeX - edgeX2, deltaY = edgeY - edgeY2;

				let inputVertices = input;
				let inputVerticesLength = input.length - 2, outputStart = output.length;
				for (let ii = 0; ii < inputVerticesLength; ii += 2) {
					let inputX = inputVertices[ii], inputY = inputVertices[ii + 1];
					let inputX2 = inputVertices[ii + 2], inputY2 = inputVertices[ii + 3];
					let side2 = deltaX * (inputY2 - edgeY2) - deltaY * (inputX2 - edgeX2) > 0;
					if (deltaX * (inputY - edgeY2) - deltaY * (inputX - edgeX2) > 0) {
						if (side2) { // v1 inside, v2 inside
							output.push(inputX2);
							output.push(inputY2);
							continue;
						}
						// v1 inside, v2 outside
						let c0 = inputY2 - inputY, c2 = inputX2 - inputX;
						let s = c0 * (edgeX2 - edgeX) - c2 * (edgeY2 - edgeY);
						if (Math.abs(s) > 0.000001) {
							let ua = (c2 * (edgeY - inputY) - c0 * (edgeX - inputX)) / s;
							output.push(edgeX + (edgeX2 - edgeX) * ua);
							output.push(edgeY + (edgeY2 - edgeY) * ua);
						} else {
							output.push(edgeX);
							output.push(edgeY);
						}
					} else if (side2) { // v1 outside, v2 inside
						let c0 = inputY2 - inputY, c2 = inputX2 - inputX;
						let s = c0 * (edgeX2 - edgeX) - c2 * (edgeY2 - edgeY);
						if (Math.abs(s) > 0.000001) {
							let ua = (c2 * (edgeY - inputY) - c0 * (edgeX - inputX)) / s;
							output.push(edgeX + (edgeX2 - edgeX) * ua);
							output.push(edgeY + (edgeY2 - edgeY) * ua);
						} else {
							output.push(edgeX);
							output.push(edgeY);
						}
						output.push(inputX2);
						output.push(inputY2);
					}
					clipped = true;
				}

				if (outputStart == output.length) { // All edges outside.
					originalOutput.length = 0;
					return true;
				}

				output.push(output[0]);
				output.push(output[1]);

				if (i == clippingVerticesLast) break;
				let temp = output;
				output = input;
				output.length = 0;
				input = temp;
			}

			if (originalOutput != output) {
				originalOutput.length = 0;
				for (let i = 0, n = output.length - 2; i < n; i++)
					originalOutput[i] = output[i];
			} else
				originalOutput.length = originalOutput.length - 2;

			return clipped;
		}

		public static makeClockwise (polygon: ArrayLike<number>) {
			let vertices = polygon;
			let verticeslength = polygon.length;

			let area = vertices[verticeslength - 2] * vertices[1] - vertices[0] * vertices[verticeslength - 1], p1x = 0, p1y = 0, p2x = 0, p2y = 0;
			for (let i = 0, n = verticeslength - 3; i < n; i += 2) {
				p1x = vertices[i];
				p1y = vertices[i + 1];
				p2x = vertices[i + 2];
				p2y = vertices[i + 3];
				area += p1x * p2y - p2x * p1y;
			}
			if (area < 0) return;

			for (let i = 0, lastX = verticeslength - 2, n = verticeslength >> 1; i < n; i += 2) {
				let x = vertices[i], y = vertices[i + 1];
				let other = lastX - i;
				vertices[i] = vertices[other];
				vertices[i + 1] = vertices[other + 1];
				vertices[other] = x;
				vertices[other + 1] = y;
			}
		}
	}
}