/**
 * Determine whether two geometries of the same type have identical X,Y coordinate values.
 * See http://edndoc.esri.com/arcsde/9.0/general_topics/understand_spatial_relations.htm
 *
 * @name booleanEqual
 * @param {Geometry|Feature} feature1 GeoJSON input
 * @param {Geometry|Feature} feature2 GeoJSON input
 * @returns {boolean} true if the objects are equal, false otherwise
 * @example
 * var pt1 = turf.point([0, 0]);
 * var pt2 = turf.point([0, 0]);
 * var pt3 = turf.point([1, 1]);
 *
 * turf.booleanEqual(pt1, pt2);
 * //= true
 * turf.booleanEqual(pt2, pt3);
 * //= false
 */
function booleanEqual<G1 extends Geometry, G2 extends Geometry>(feature1: Feature<G1> | G1, feature2: Feature<G2> | G2): boolean {
    // validation
    if (!feature1) throw new Error('feature1 is required');
    if (!feature2) throw new Error('feature2 is required');
    var type1 = getType(feature1);
    var type2 = getType(feature2);
    if (type1 !== type2) return false;

    var equality = new GeojsonEquality({precision: 6});
    return equality.compare(cleanCoords(feature1), cleanCoords(feature2));
}

/**
 * Boolean-contains returns True if the second geometry is completely contained by the first geometry.
 * The interiors of both geometries must intersect and, the interior and boundary of the secondary (geometry b)
 * must not intersect the exterior of the primary (geometry a).
 * Boolean-contains returns the exact opposite result of the `@turf/boolean-within`.
 *
 * @name booleanContains
 * @param {Geometry|Feature<any>} feature1 GeoJSON Feature or Geometry
 * @param {Geometry|Feature<any>} feature2 GeoJSON Feature or Geometry
 * @returns {boolean} true/false
 * @example
 * var line = turf.lineString([[1, 1], [1, 2], [1, 3], [1, 4]]);
 * var point = turf.point([1, 2]);
 *
 * turf.booleanContains(line, point);
 * //=true
 */
export default function booleanContains(feature1: Feature<any> | Geometry, feature2: Feature<any> | Geometry) {
    const geom1 = getGeom(feature1);
    const geom2 = getGeom(feature2);
    const type1 = getType(feature1);
    const type2 = getType(feature2);
    const coords1 = getCoords(feature1);
    const coords2 = getCoords(feature2);

    switch (type1) {
    case 'Point':
        switch (type2) {
        case 'Point':
            return compareCoords(coords1, coords2);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    case 'MultiPoint':
        switch (type2) {
        case 'Point':
            return isPointInMultiPoint(geom1, geom2);
        case 'MultiPoint':
            return isMultiPointInMultiPoint(geom1, geom2);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    case 'LineString':
        switch (type2) {
        case 'Point':
            return isPointOnLine(geom2, geom1, {ignoreEndVertices: true});
        case 'LineString':
            return isLineOnLine(geom1, geom2);
        case 'MultiPoint':
            return isMultiPointOnLine(geom1, geom2);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    case 'Polygon':
        switch (type2) {
        case 'Point':
            return booleanPointInPolygon(geom2, geom1, {ignoreBoundary: true});
        case 'LineString':
            return isLineInPoly(geom1, geom2);
        case 'Polygon':
            return isPolyInPoly(geom1, geom2);
        case 'MultiPoint':
            return isMultiPointInPoly(geom1, geom2);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    default:
        throw new Error('feature1 ' + type1 + ' geometry not supported');
    }
}

/**
 * Boolean-within returns true if the first geometry is completely within the second geometry.
 * The interiors of both geometries must intersect and, the interior and boundary of the primary (geometry a)
 * must not intersect the exterior of the secondary (geometry b).
 * Boolean-within returns the exact opposite result of the `@turf/boolean-contains`.
 *
 * @name booleanWithin
 * @param {Geometry|Feature<any>} feature1 GeoJSON Feature or Geometry
 * @param {Geometry|Feature<any>} feature2 GeoJSON Feature or Geometry
 * @returns {boolean} true/false
 * @example
 * var line = turf.lineString([[1, 1], [1, 2], [1, 3], [1, 4]]);
 * var point = turf.point([1, 2]);
 *
 * turf.booleanWithin(point, line);
 * //=true
 */
function booleanWithin(feature1: Feature<any> | Geometry, feature2: Feature<any> | Geometry): boolean {
    var type1 = getType(feature1);
    var type2 = getType(feature2);
    var geom1 = getGeom(feature1);
    var geom2 = getGeom(feature2);

    switch (type1) {
    case 'Point':
        switch (type2) {
        case 'MultiPoint':
            return isPointInMultiPoint(geom1, geom2);
        case 'LineString':
            return booleanPointOnLine(geom1, geom2, {ignoreEndVertices: true});
        case 'Polygon':
        case 'MultiPolygon':
            return booleanPointInPolygon(geom1, geom2, {ignoreBoundary: true});
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    case 'MultiPoint':
        switch (type2) {
        case 'MultiPoint':
            return isMultiPointInMultiPoint(geom1, geom2);
        case 'LineString':
            return isMultiPointOnLine(geom1, geom2);
        case 'Polygon':
        case 'MultiPolygon':
            return isMultiPointInPoly(geom1, geom2);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    case 'LineString':
        switch (type2) {
        case 'LineString':
            return isLineOnLine(geom1, geom2);
        case 'Polygon':
        case 'MultiPolygon':
            return isLineInPoly(geom1, geom2);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    case 'Polygon':
        switch (type2) {
        case 'Polygon':
        case 'MultiPolygon':
            return isPolyInPoly(geom1, geom2);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    default:
        throw new Error('feature1 ' + type1 + ' geometry not supported');
    }
}

/**
 * Transform function: attempts to dissolve geojson objects where possible
 * [GeoJSON] -> GeoJSON geometry
 *
 * @private
 * @param {FeatureCollection<LineString|MultiLineString|Polygon|MultiPolygon>} geojson Features to dissolved
 * @param {Object} [options={}] Optional parameters
 * @param {boolean} [options.mutate=false] Prevent input mutation
 * @returns {Feature<MultiLineString|MultiPolygon>} Dissolved Features
 */
function dissolve(geojson: FeatureCollection<LineString|MultiLineString|Polygon|MultiPolygon>, options: {
    mutate?: boolean,
} = {}): Feature<LineString|MultiLineString|Polygon|MultiPolygon> | null {
    // Optional parameters
    options = options || {};
    if (!isObject(options)) { throw new Error("options is invalid"); }
    const mutate = options.mutate;

    // Validation
    if (getType(geojson) !== "FeatureCollection") { throw new Error("geojson must be a FeatureCollection"); }
    if (!geojson.features.length) { throw new Error("geojson is empty"); }

    // Clone geojson to avoid side effects
    // Topojson modifies in place, so we need to deep clone first
    if (mutate === false || mutate === undefined) { geojson = clone(geojson); }

    // Assert homogenity
    const type = getHomogenousType(geojson);
    if (!type) { throw new Error("geojson must be homogenous"); }

    // Data => Typescript hack
    const data: any = geojson;

    switch (type) {
    case "LineString":
        return lineDissolve(data, options);
    case "Polygon":
        return polygonDissolve(data, options);
    default:
        throw new Error(type + " is not supported");
    }
}

/**
 * Compares two geometries of the same dimension and returns true if their intersection set results in a geometry
 * different from both but of the same dimension. It applies to Polygon/Polygon, LineString/LineString,
 * Multipoint/Multipoint, MultiLineString/MultiLineString and MultiPolygon/MultiPolygon.
 *
 * @name booleanOverlap
 * @param  {Geometry|Feature<LineString|MultiLineString|Polygon|MultiPolygon>} feature1 input
 * @param  {Geometry|Feature<LineString|MultiLineString|Polygon|MultiPolygon>} feature2 input
 * @returns {boolean} true/false
 * @example
 * var poly1 = turf.polygon([[[0,0],[0,5],[5,5],[5,0],[0,0]]]);
 * var poly2 = turf.polygon([[[1,1],[1,6],[6,6],[6,1],[1,1]]]);
 * var poly3 = turf.polygon([[[10,10],[10,15],[15,15],[15,10],[10,10]]]);
 *
 * turf.booleanOverlap(poly1, poly2)
 * //=true
 * turf.booleanOverlap(poly2, poly3)
 * //=false
 */
function booleanOverlap(feature1: Feature<any> | Geometry, feature2: Feature<any> | Geometry): boolean {
    // validation
    if (!feature1) throw new Error('feature1 is required');
    if (!feature2) throw new Error('feature2 is required');
    var type1 = getType(feature1);
    var type2 = getType(feature2);
    if (type1 !== type2) throw new Error('features must be of the same type');
    if (type1 === 'Point') throw new Error('Point geometry not supported');

    // features must be not equal
    var equality = new GeojsonEquality({precision: 6});
    if (equality.compare(feature1, feature2)) return false;

    var overlap = 0;

    switch (type1) {
    case 'MultiPoint':
        var coords1 = coordAll(feature1);
        var coords2 = coordAll(feature2);
        coords1.forEach(function (coord1) {
            coords2.forEach(function (coord2) {
                if (coord1[0] === coord2[0] && coord1[1] === coord2[1]) overlap++;
            });
        });
        break;

    case 'LineString':
    case 'MultiLineString':
        segmentEach(feature1, function (segment1) {
            segmentEach(feature2, function (segment2) {
                if (lineOverlap(segment1, segment2).features.length) overlap++;
            });
        });
        break;

    case 'Polygon':
    case 'MultiPolygon':
        segmentEach(feature1, function (segment1) {
            segmentEach(feature2, function (segment2) {
                if (lineIntersect(segment1, segment2).features.length) overlap++;
            });
        });
        break;
    }

    return overlap > 0;
}

/**
 * Boolean-Crosses returns True if the intersection results in a geometry whose dimension is one less than
 * the maximum dimension of the two source geometries and the intersection set is interior to
 * both source geometries.
 *
 * Boolean-Crosses returns t (TRUE) for only multipoint/polygon, multipoint/linestring, linestring/linestring, linestring/polygon, and linestring/multipolygon comparisons.
 *
 * @name booleanCrosses
 * @param {Geometry|Feature<any>} feature1 GeoJSON Feature or Geometry
 * @param {Geometry|Feature<any>} feature2 GeoJSON Feature or Geometry
 * @returns {boolean} true/false
 * @example
 * var line1 = turf.lineString([[-2, 2], [4, 2]]);
 * var line2 = turf.lineString([[1, 1], [1, 2], [1, 3], [1, 4]]);
 *
 * var cross = turf.booleanCrosses(line1, line2);
 * //=true
 */
function booleanCrosses(feature1: Feature<any> | Geometry, feature2: Feature<any> | Geometry): boolean {
    var type1 = getType(feature1);
    var type2 = getType(feature2);
    var geom1 = getGeom(feature1);
    var geom2 = getGeom(feature2);

    switch (type1) {
    case 'MultiPoint':
        switch (type2) {
        case 'LineString':
            return doMultiPointAndLineStringCross(geom1, geom2);
        case 'Polygon':
            return doesMultiPointCrossPoly(geom1, geom2);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    case 'LineString':
        switch (type2) {
        case 'MultiPoint': // An inverse operation
            return doMultiPointAndLineStringCross(geom2, geom1);
        case 'LineString':
            return doLineStringsCross(geom1, geom2);
        case 'Polygon':
            return doLineStringAndPolygonCross(geom1, geom2);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    case 'Polygon':
        switch (type2) {
        case 'MultiPoint': // An inverse operation
            return doesMultiPointCrossPoly(geom2, geom1);
        case 'LineString': // An inverse operation
            return doLineStringAndPolygonCross(geom2, geom1);
        default:
            throw new Error('feature2 ' + type2 + ' geometry not supported');
        }
    default:
        throw new Error('feature1 ' + type1 + ' geometry not supported');
    }
}

/**
 * Merges all connected (non-forking, non-junctioning) line strings into single lineStrings.
 * [LineString] -> LineString|MultiLineString
 *
 * @param {FeatureCollection<LineString|MultiLineString>} geojson Lines to dissolve
 * @param {Object} [options={}] Optional parameters
 * @param {boolean} [options.mutate=false] Prevent input mutation
 * @returns {Feature<LineString|MultiLineString>} Dissolved lines
 */
function lineDissolve(
    geojson: FeatureCollection<LineString|MultiLineString>,
    options: {mutate?: boolean} = {},
): Feature<LineString|MultiLineString> | null {
    // Optional parameters
    options = options || {};
    if (!isObject(options)) { throw new Error("options is invalid"); }
    const mutate = options.mutate;

    // Validation
    if (getType(geojson) !== "FeatureCollection") { throw new Error("geojson must be a FeatureCollection"); }
    if (!geojson.features.length) { throw new Error("geojson is empty"); }

    // Clone geojson to avoid side effects
    if (mutate === false || mutate === undefined) { geojson = clone(geojson); }

    const result: any[] = [];
    const lastLine = lineReduce(geojson, (previousLine: any, currentLine: any) => {
        // Attempt to merge this LineString with the other LineStrings, updating
        // the reference as it is merged with others and grows.
        const merged = mergeLineStrings(previousLine, currentLine);

        // Accumulate the merged LineString
        if (merged) { return merged;
        // Put the unmerged LineString back into the list
        } else {
            result.push(previousLine);
            return currentLine;
        }
    });
    // Append the last line
    if (lastLine) { result.push(lastLine); }

    // Return null if no lines were dissolved
    if (!result.length) {
        return null;
    // Return LineString if only 1 line was dissolved
    } else if (result.length === 1) {
        return result[0];
    // Return MultiLineString if multiple lines were dissolved with gaps
    } else { return multiLineString(result.map((line) => {
        return line.coordinates;
    })); }
}

/**
 * Dissolves all overlapping (Multi)Polygon
 *
 * @param {FeatureCollection<Polygon|MultiPolygon>} geojson Polygons to dissolve
 * @param {Object} [options={}] Optional parameters
 * @param {boolean} [options.mutate=false] Prevent input mutation
 * @returns {Feature<Polygon|MultiPolygon>} Dissolved Polygons
 */
export default function polygonDissolve(
    geojson: FeatureCollection<Polygon|MultiPolygon>,
    options: {mutate?: boolean} = {},
): Feature<Polygon|MultiPolygon> | null {
    // Validation
    if (getType(geojson) !== "FeatureCollection") { throw new Error("geojson must be a FeatureCollection"); }
    if (!geojson.features.length) { throw new Error("geojson is empty"); }

    // Clone geojson to avoid side effects
    // Topojson modifies in place, so we need to deep clone first
    if (options.mutate === false || options.mutate === undefined) { geojson = clone(geojson); }

    const geoms: any[] = [];
    flattenEach(geojson, (feature) => {
        geoms.push(feature.geometry);
    });
    const topo: any = topology({geoms: geometryCollection(geoms).geometry});
    const merged: any = merge(topo, topo.objects.geoms.geometries);
    return merged;
}

/**
 * Returns the closest {@link Point|point}, of a {@link FeatureCollection|collection} of points,
 * to a {@link LineString|line}. The returned point has a `dist` property indicating its distance to the line.
 *
 * @name nearestPointToLine
 * @param {FeatureCollection|GeometryCollection<Point>} points Point Collection
 * @param {Feature|Geometry<LineString>} line Line Feature
 * @param {Object} [options] Optional parameters
 * @param {string} [options.units='kilometers'] unit of the output distance property
 * (eg: degrees, radians, miles, or kilometers)
 * @param {Object} [options.properties={}] Translate Properties to Point
 * @returns {Feature<Point>} the closest point
 * @example
 * var pt1 = turf.point([0, 0]);
 * var pt2 = turf.point([0.5, 0.5]);
 * var points = turf.featureCollection([pt1, pt2]);
 * var line = turf.lineString([[1,1], [-1,1]]);
 *
 * var nearest = turf.nearestPointToLine(points, line);
 *
 * //addToMap
 * var addToMap = [nearest, line];
 */
function nearestPointToLine<P = {dist: number, [key: string]: any}>(
    points: FeatureCollection<Point> | Feature<GeometryCollection> | GeometryCollection,
    line: Feature<LineString> | LineString,
    options: {
        units?: Units,
        properties?: Properties,
    } = {},
): Feature<Point, P> {
    const units = options.units;
    const properties = options.properties || {};

    // validation
    const pts = normalize(points);
    if (!pts.features.length) { throw new Error("points must contain features"); }

    if (!line) { throw new Error("line is required"); }
    if (getType(line) !== "LineString") { throw new Error("line must be a LineString"); }

    let dist = Infinity;
    let pt: any = null;

    featureEach(pts, (point) => {
        const d = pointToLineDistance(point, line, { units });
        if (d < dist) {
            dist = d;
            pt = point;
        }
    });
    /**
     * Translate Properties to final Point, priorities:
     * 1. options.properties
     * 2. inherent Point properties
     * 3. dist custom properties created by NearestPointToLine
     */
    if (pt) { pt.properties = objectAssign({dist}, pt.properties, properties); }
    // if (pt) { pt.properties = objectAssign({dist}, pt.properties, properties); }
    return pt;
}

/**
 * Takes any {@link Feature} or a {@link FeatureCollection} and returns its [center of mass](https://en.wikipedia.org/wiki/Center_of_mass) using this formula: [Centroid of Polygon](https://en.wikipedia.org/wiki/Centroid#Centroid_of_polygon).
 *
 * @name centerOfMass
 * @param {GeoJSON} geojson GeoJSON to be centered
 * @param {Object} [options={}] Optional Parameters
 * @param {Object} [options.properties={}] Translate Properties to Feature
 * @returns {Feature<Point>} the center of mass
 * @example
 * var polygon = turf.polygon([[[-81, 41], [-88, 36], [-84, 31], [-80, 33], [-77, 39], [-81, 41]]]);
 *
 * var center = turf.centerOfMass(polygon);
 *
 * //addToMap
 * var addToMap = [polygon, center]
 */
function centerOfMass<P = Properties>(geojson: any, options: {
    properties?: P,
} = {}): Feature<Point, P> {
    switch (getType(geojson)) {
    case 'Point':
        return point(getCoord(geojson), options.properties);
    case 'Polygon':
        var coords = [];
        coordEach(geojson, function (coord) {
            coords.push(coord);
        });

        // First, we neutralize the feature (set it around coordinates [0,0]) to prevent rounding errors
        // We take any point to translate all the points around 0
        var centre = centroid(geojson, {properties: options.properties});
        var translation = centre.geometry.coordinates;
        var sx = 0;
        var sy = 0;
        var sArea = 0;
        var i, pi, pj, xi, xj, yi, yj, a;

        var neutralizedPoints = coords.map(function (point) {
            return [
                point[0] - translation[0],
                point[1] - translation[1]
            ];
        });

        for (i = 0; i < coords.length - 1; i++) {
            // pi is the current point
            pi = neutralizedPoints[i];
            xi = pi[0];
            yi = pi[1];

            // pj is the next point (pi+1)
            pj = neutralizedPoints[i + 1];
            xj = pj[0];
            yj = pj[1];

            // a is the common factor to compute the signed area and the final coordinates
            a = xi * yj - xj * yi;

            // sArea is the sum used to compute the signed area
            sArea += a;

            // sx and sy are the sums used to compute the final coordinates
            sx += (xi + xj) * a;
            sy += (yi + yj) * a;
        }

        // Shape has no area: fallback on turf.centroid
        if (sArea === 0) {
            return centre;
        } else {
            // Compute the signed area, and factorize 1/6A
            var area = sArea * 0.5;
            var areaFactor = 1 / (6 * area);

            // Compute the final coordinates, adding back the values that have been neutralized
            return point([
                translation[0] + areaFactor * sx,
                translation[1] + areaFactor * sy
            ], options.properties);
        }
    default:
        // Not a polygon: Compute the convex hull and work with that
        var hull = convex(geojson);

        if (hull) return centerOfMass(hull, {properties: options.properties});
        // Hull is empty: fallback on the centroid
        else return centroid(geojson, {properties: options.properties});
    }
}