function rotatePoints(points, center, degrees) {
    if (points && points.length) {
        const [cx, cy] = center;
        const angle = (Math.PI / 180) * degrees;
        const cos = Math.cos(angle);
        const sin = Math.sin(angle);
        for (const p of points) {
            const [x, y] = p;
            p[0] = ((x - cx) * cos) - ((y - cy) * sin) + cx;
            p[1] = ((x - cx) * sin) + ((y - cy) * cos) + cy;
        }
    }
}
function rotateLines(lines, center, degrees) {
    const points = [];
    lines.forEach((line) => points.push(...line));
    rotatePoints(points, center, degrees);
}
function areSamePoints(p1, p2) {
    return p1[0] === p2[0] && p1[1] === p2[1];
}
export function hachureLines(polygons, hachureGap, hachureAngle, hachureStepOffset = 1) {
    const angle = hachureAngle;
    const gap = Math.max(hachureGap, 0.1);
    const polygonList = (polygons[0] && polygons[0][0] && (typeof polygons[0][0] === 'number')) ? [polygons] : polygons;
    const rotationCenter = [0, 0];
    if (angle) {
        for (const polygon of polygonList) {
            rotatePoints(polygon, rotationCenter, angle);
        }
    }
    const lines = straightHachureLines(polygonList, gap, hachureStepOffset);
    if (angle) {
        for (const polygon of polygonList) {
            rotatePoints(polygon, rotationCenter, -angle);
        }
        rotateLines(lines, rotationCenter, -angle);
    }
    return lines;
}
function straightHachureLines(polygons, gap, hachureStepOffset) {
    const vertexArray = [];
    for (const polygon of polygons) {
        const vertices = [...polygon];
        if (!areSamePoints(vertices[0], vertices[vertices.length - 1])) {
            vertices.push([vertices[0][0], vertices[0][1]]);
        }
        if (vertices.length > 2) {
            vertexArray.push(vertices);
        }
    }
    const lines = [];
    gap = Math.max(gap, 0.1);
    // Create sorted edges table
    const edges = [];
    for (const vertices of vertexArray) {
        for (let i = 0; i < vertices.length - 1; i++) {
            const p1 = vertices[i];
            const p2 = vertices[i + 1];
            if (p1[1] !== p2[1]) {
                const ymin = Math.min(p1[1], p2[1]);
                edges.push({
                    ymin,
                    ymax: Math.max(p1[1], p2[1]),
                    x: ymin === p1[1] ? p1[0] : p2[0],
                    islope: (p2[0] - p1[0]) / (p2[1] - p1[1]),
                });
            }
        }
    }
    edges.sort((e1, e2) => {
        if (e1.ymin < e2.ymin) {
            return -1;
        }
        if (e1.ymin > e2.ymin) {
            return 1;
        }
        if (e1.x < e2.x) {
            return -1;
        }
        if (e1.x > e2.x) {
            return 1;
        }
        if (e1.ymax === e2.ymax) {
            return 0;
        }
        return (e1.ymax - e2.ymax) / Math.abs((e1.ymax - e2.ymax));
    });
    if (!edges.length) {
        return lines;
    }
    // Start scanning
    let activeEdges = [];
    let y = edges[0].ymin;
    let iteration = 0;
    while (activeEdges.length || edges.length) {
        if (edges.length) {
            let ix = -1;
            for (let i = 0; i < edges.length; i++) {
                if (edges[i].ymin > y) {
                    break;
                }
                ix = i;
            }
            const removed = edges.splice(0, ix + 1);
            removed.forEach((edge) => {
                activeEdges.push({ s: y, edge });
            });
        }
        activeEdges = activeEdges.filter((ae) => {
            if (ae.edge.ymax <= y) {
                return false;
            }
            return true;
        });
        activeEdges.sort((ae1, ae2) => {
            if (ae1.edge.x === ae2.edge.x) {
                return 0;
            }
            return (ae1.edge.x - ae2.edge.x) / Math.abs((ae1.edge.x - ae2.edge.x));
        });
        // fill between the edges
        if ((hachureStepOffset !== 1) || (iteration % gap === 0)) {
            if (activeEdges.length > 1) {
                for (let i = 0; i < activeEdges.length; i = i + 2) {
                    const nexti = i + 1;
                    if (nexti >= activeEdges.length) {
                        break;
                    }
                    const ce = activeEdges[i].edge;
                    const ne = activeEdges[nexti].edge;
                    lines.push([
                        [Math.round(ce.x), y],
                        [Math.round(ne.x), y],
                    ]);
                }
            }
        }
        y += hachureStepOffset;
        activeEdges.forEach((ae) => {
            ae.edge.x = ae.edge.x + (hachureStepOffset * ae.edge.islope);
        });
        iteration++;
    }
    return lines;
}