import * as turf from '@turf/turf'
import {BBox} from "./BBox";
import togpx from "togpx"
import Constants from "../Models/Constants";
import LayerConfig from "../Models/ThemeConfig/LayerConfig";

export class GeoOperations {

    private static readonly _earthRadius = 6378137;
    private static readonly _originShift = 2 * Math.PI * GeoOperations._earthRadius / 2;

    static surfaceAreaInSqMeters(feature: any) {
        return turf.area(feature);
    }

    /**
     * Converts a GeoJson feature to a point GeoJson feature
     * @param feature
     */
    static centerpoint(feature: any) {
        const newFeature = turf.center(feature);
        newFeature.properties = feature.properties;
        newFeature.id = feature.id;
        return newFeature;
    }

    static centerpointCoordinates(feature: any): [number, number] {
        return <[number, number]>turf.center(feature).geometry.coordinates;
    }

    /**
     * Returns the distance between the two points in meters
     * @param lonlat0
     * @param lonlat1
     */
    static distanceBetween(lonlat0: [number, number], lonlat1: [number, number]) {
        return turf.distance(lonlat0, lonlat1, {units: "meters"})
    }

    static convexHull(featureCollection, options: { concavity?: number }) {
        return turf.convex(featureCollection, options)
    }

    /**
     * Calculates the overlap of 'feature' with every other specified feature.
     * The features with which 'feature' overlaps, are returned together with their overlap area in m²
     *
     * If 'feature' is a LineString, the features in which this feature is (partly) embedded is returned, the overlap length in meter is given
     * If 'feature' is a Polygon, overlapping points and points within the polygon will be returned
     *
     * If 'feature' is a point, it will return every feature the point is embedded in. Overlap will be undefined
     *
     */
    static calculateOverlap(feature: any, otherFeatures: any[]): { feat: any, overlap: number }[] {

        const featureBBox = BBox.get(feature);
        const result: { feat: any, overlap: number }[] = [];
        if (feature.geometry.type === "Point") {
            const coor = feature.geometry.coordinates;
            for (const otherFeature of otherFeatures) {

                if (feature.properties.id !== undefined && feature.properties.id === otherFeature.properties.id) {
                    continue;
                }

                if (otherFeature.geometry === undefined) {
                    console.error("No geometry for feature ", feature)
                    throw "List of other features contains a feature without geometry an undefined"
                }

                if (GeoOperations.inside(coor, otherFeature)) {
                    result.push({feat: otherFeature, overlap: undefined})
                }
            }
            return result;
        }

        if (feature.geometry.type === "LineString") {

            for (const otherFeature of otherFeatures) {

                if (feature.properties.id !== undefined && feature.properties.id === otherFeature.properties.id) {
                    continue;
                }

                const intersection = GeoOperations.calculateInstersection(feature, otherFeature, featureBBox)
                if (intersection === null) {
                    continue
                }
                result.push({feat: otherFeature, overlap: intersection})

            }
            return result;
        }

        if (feature.geometry.type === "Polygon" || feature.geometry.type === "MultiPolygon") {

            for (const otherFeature of otherFeatures) {

                if (feature.properties.id !== undefined && feature.properties.id === otherFeature.properties.id) {
                    continue;
                }

                if (otherFeature.geometry.type === "Point") {
                    if (this.inside(otherFeature, feature)) {
                        result.push({feat: otherFeature, overlap: undefined})
                    }
                    continue;
                }


                // Calculate the surface area of the intersection

                const intersection = this.calculateInstersection(feature, otherFeature, featureBBox)
                if (intersection === null) {
                    continue;
                }
                result.push({feat: otherFeature, overlap: intersection})

            }
            return result;
        }
        console.error("Could not correctly calculate the overlap of ", feature, ": unsupported type")
        return result;
    }

    public static inside(pointCoordinate, feature): boolean {
        // ray-casting algorithm based on
        // http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html

        if (feature.geometry.type === "Point") {
            return false;
        }

        if (pointCoordinate.geometry !== undefined) {
            pointCoordinate = pointCoordinate.geometry.coordinates
        }

        if (feature.geometry.type === "MultiPolygon") {
            const coordinates = feature.geometry.coordinates[0];
            const outerPolygon = coordinates[0];
            const inside = GeoOperations.inside(pointCoordinate, {
                geometry: {
                    type: 'Polygon',
                    coordinates: [outerPolygon]
                }
            })
            if (!inside) {
                return false;
            }
            for (let i = 1; i < coordinates.length; i++) {
                const inHole = GeoOperations.inside(pointCoordinate, {
                    geometry: {
                        type: 'Polygon',
                        coordinates: [coordinates[i]]
                    }
                })
                if (inHole) {
                    return false;
                }
            }
            return true;
        }


        const x: number = pointCoordinate[0];
        const y: number = pointCoordinate[1];

        for (let i = 0; i < feature.geometry.coordinates.length; i++) {
            let poly = feature.geometry.coordinates[i];

            let inside = false;
            for (let i = 0, j = poly.length - 1; i < poly.length; j = i++) {
                const coori = poly[i];
                const coorj = poly[j];

                const xi = coori[0];
                const yi = coori[1];
                const xj = coorj[0];
                const yj = coorj[1];

                const intersect = ((yi > y) != (yj > y))
                    && (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
                if (intersect) {
                    inside = !inside;
                }
            }
            if (inside) {
                return true;
            }
        }

        return false;
    };

    static lengthInMeters(feature: any) {
        return turf.length(feature) * 1000
    }

    static buffer(feature: any, bufferSizeInMeter: number) {
        return turf.buffer(feature, bufferSizeInMeter / 1000, {
            units: 'kilometers'
        })
    }

    static bbox(feature: any) {
        const [lon, lat, lon0, lat0] = turf.bbox(feature)
        return {
            "type": "Feature",
            "geometry": {
                "type": "LineString",
                "coordinates": [
                    [
                        lon,
                        lat
                    ],
                    [
                        lon0,
                        lat
                    ],
                    [
                        lon0,
                        lat0
                    ],
                    [
                        lon,
                        lat0
                    ],
                    [
                        lon,
                        lat
                    ],
                ]
            }
        }
    }

    /**
     * Generates the closest point on a way from a given point
     *
     *  The properties object will contain three values:
     // - `index`: closest point was found on nth line part,
     // - `dist`: distance between pt and the closest point (in kilometer),
     // `location`: distance along the line between start (of the line) and the closest point.
     * @param way The road on which you want to find a point
     * @param point Point defined as [lon, lat]
     */
    public static nearestPoint(way, point: [number, number]) {
        if (way.geometry.type === "Polygon") {
            way = {...way}
            way.geometry = {...way.geometry}
            way.geometry.type = "LineString"
            way.geometry.coordinates = way.geometry.coordinates[0]
        }

        return turf.nearestPointOnLine(way, point, {units: "kilometers"});
    }

    public static toCSV(features: any[]): string {

        const headerValuesSeen = new Set<string>();
        const headerValuesOrdered: string[] = []

        function addH(key) {
            if (!headerValuesSeen.has(key)) {
                headerValuesSeen.add(key)
                headerValuesOrdered.push(key)
            }
        }

        addH("_lat")
        addH("_lon")

        const lines: string[] = []

        for (const feature of features) {
            const properties = feature.properties;
            for (const key in properties) {
                if (!properties.hasOwnProperty(key)) {
                    continue;
                }
                addH(key)

            }
        }
        headerValuesOrdered.sort()
        for (const feature of features) {
            const properties = feature.properties;
            let line = ""
            for (const key of headerValuesOrdered) {
                const value = properties[key]
                if (value === undefined) {
                    line += ","
                } else {
                    line += JSON.stringify(value) + ","
                }
            }
            lines.push(line)
        }

        return headerValuesOrdered.map(v => JSON.stringify(v)).join(",") + "\n" + lines.join("\n")
    }

    //Converts given lat/lon in WGS84 Datum to XY in Spherical Mercator EPSG:900913
    public static ConvertWgs84To900913(lonLat: [number, number]): [number, number] {
        const lon = lonLat[0];
        const lat = lonLat[1];
        const x = lon * GeoOperations._originShift / 180;
        let y = Math.log(Math.tan((90 + lat) * Math.PI / 360)) / (Math.PI / 180);
        y = y * GeoOperations._originShift / 180;
        return [x, y];
    }

    //Converts XY point from (Spherical) Web Mercator EPSG:3785 (unofficially EPSG:900913) to lat/lon in WGS84 Datum
    public static Convert900913ToWgs84(lonLat: [number, number]): [number, number] {
        const lon = lonLat[0]
        const lat = lonLat[1]
        const x = 180 * lon / GeoOperations._originShift;
        let y = 180 * lat / GeoOperations._originShift;
        y = 180 / Math.PI * (2 * Math.atan(Math.exp(y * Math.PI / 180)) - Math.PI / 2);
        return [x, y];
    }

    public static GeoJsonToWGS84(geojson) {
        return turf.toWgs84(geojson)
    }

    /**
     * Tries to remove points which do not contribute much to the general outline.
     * Points for which the angle is ~ 180° are removed
     * @param coordinates
     * @constructor
     */
    public static SimplifyCoordinates(coordinates: [number, number][]) {
        const newCoordinates = []
        for (let i = 1; i < coordinates.length - 1; i++) {
            const coordinate = coordinates[i];
            const prev = coordinates[i - 1]
            const next = coordinates[i + 1]
            const b0 = turf.bearing(prev, coordinate, {final: true})
            const b1 = turf.bearing(coordinate, next)

            const diff = Math.abs(b1 - b0)
            if (diff < 2) {
                continue
            }
            newCoordinates.push(coordinate)
        }
        return newCoordinates

    }

    /**
     * Calculates line intersection between two features.
     */
    public static LineIntersections(feature, otherFeature): [number, number][] {
        return turf.lineIntersect(feature, otherFeature).features.map(p => <[number, number]>p.geometry.coordinates)
    }

    public static AsGpx(feature, generatedWithLayer?: LayerConfig) {

        const metadata = {}
        const tags = feature.properties

        if (generatedWithLayer !== undefined) {

            metadata["name"] = generatedWithLayer.title?.GetRenderValue(tags)?.Subs(tags)?.txt
            metadata["desc"] = "Generated with MapComplete layer " + generatedWithLayer.id
            if (tags._backend?.contains("openstreetmap")) {
                metadata["copyright"] = "Data copyrighted by OpenStreetMap-contributors, freely available under ODbL. See https://www.openstreetmap.org/copyright"
                metadata["author"] = tags["_last_edit:contributor"]
                metadata["link"] = "https://www.openstreetmap.org/" + tags.id
                metadata["time"] = tags["_last_edit:timestamp"]
            } else {
                metadata["time"] = new Date().toISOString()
            }
        }

        return togpx(feature, {
            creator: "MapComplete " + Constants.vNumber,
            metadata
        })
    }

    public static IdentifieCommonSegments(coordinatess: [number, number][][]): {
        originalIndex: number,
        segmentShardWith: number[],
        coordinates: []
    }[] {

        // An edge. Note that the edge might be reversed to fix the sorting condition:  start[0] < end[0] && (start[0] != end[0] || start[0] < end[1])
        type edge = { start: [number, number], end: [number, number], intermediate: [number, number][], members: { index: number, isReversed: boolean }[] }

        // The strategy:
        // 1. Index _all_ edges from _every_ linestring. Index them by starting key, gather which relations run over them
        // 2. Join these edges back together - as long as their membership groups are the same
        // 3. Convert to results

        const allEdgesByKey = new Map<string, edge>()

        for (let index = 0; index < coordinatess.length; index++) {
            const coordinates = coordinatess[index];
            for (let i = 0; i < coordinates.length - 1; i++) {

                const c0 = coordinates[i];
                const c1 = coordinates[i + 1]
                const isReversed = (c0[0] > c1[0]) || (c0[0] == c1[0] && c0[1] > c1[1])

                let key: string
                if (isReversed) {
                    key = "" + c1 + ";" + c0
                } else {
                    key = "" + c0 + ";" + c1
                }
                const member = {index, isReversed}
                if (allEdgesByKey.has(key)) {
                    allEdgesByKey.get(key).members.push(member)
                    continue
                }

                let edge: edge;
                if (!isReversed) {
                    edge = {
                        start: c0,
                        end: c1,
                        members: [member],
                        intermediate: []
                    }
                } else {
                    edge = {
                        start: c1,
                        end: c0,
                        members: [member],
                        intermediate: []
                    }
                }
                allEdgesByKey.set(key, edge)

            }
        }

        // Lets merge them back together!

        let didMergeSomething = false;
        let allMergedEdges = Array.from(allEdgesByKey.values())
        const allEdgesByStartPoint = new Map<string, edge[]>()
        for (const edge of allMergedEdges) {

            edge.members.sort((m0, m1) => m0.index - m1.index)

            const kstart = edge.start + ""
            if (!allEdgesByStartPoint.has(kstart)) {
                allEdgesByStartPoint.set(kstart, [])
            }
            allEdgesByStartPoint.get(kstart).push(edge)
        }


        function membersAreCompatible(first: edge, second: edge): boolean {
            // There must be an exact match between the members
            if (first.members === second.members) {
                return true
            }

            if (first.members.length !== second.members.length) {
                return false
            }

            // Members are sorted and have the same length, so we can check quickly
            for (let i = 0; i < first.members.length; i++) {
                const m0 = first.members[i]
                const m1 = second.members[i]
                if (m0.index !== m1.index || m0.isReversed !== m1.isReversed) {
                    return false
                }
            }

            // Allrigth, they are the same, lets mark this permanently
            second.members = first.members
            return true

        }

        do {
            didMergeSomething = false
            // We use 'allMergedEdges' as our running list
            const consumed = new Set<edge>()
            for (const edge of allMergedEdges) {
                // Can we make this edge longer at the end?
                if (consumed.has(edge)) {
                    continue
                }

                console.log("Considering edge", edge)
                const matchingEndEdges = allEdgesByStartPoint.get(edge.end + "")
                console.log("Matchign endpoints:", matchingEndEdges)
                if (matchingEndEdges === undefined) {
                    continue
                }


                for (let i = 0; i < matchingEndEdges.length; i++) {
                    const endEdge = matchingEndEdges[i];

                    if (consumed.has(endEdge)) {
                        continue
                    }

                    if (!membersAreCompatible(edge, endEdge)) {
                        continue
                    }

                    // We can make the segment longer!
                    didMergeSomething = true
                    console.log("Merging ", edge, "with ", endEdge)
                    edge.intermediate.push(edge.end)
                    edge.end = endEdge.end
                    consumed.add(endEdge)
                    matchingEndEdges.splice(i, 1)
                    break;
                }
            }

            allMergedEdges = allMergedEdges.filter(edge => !consumed.has(edge));

        } while (didMergeSomething)

        return []
    }

    /**
     * Removes points that do not contribute to the geometry from linestrings and the outer ring of polygons.
     * Returs a new copy of the feature
     * @param feature
     */
    static removeOvernoding(feature: any) {
        if (feature.geometry.type !== "LineString" && feature.geometry.type !== "Polygon") {
            throw "Overnode removal is only supported on linestrings and polygons"
        }

        const copy = {
            ...feature,
            geometry: {...feature.geometry}
        }
        let coordinates: [number, number][]
        if (feature.geometry.type === "LineString") {
            coordinates = [...feature.geometry.coordinates]
            copy.geometry.coordinates = coordinates
        } else {
            coordinates = [...feature.geometry.coordinates[0]]
            copy.geometry.coordinates[0] = coordinates
        }

        // inline replacement in the coordinates list
        for (let i = coordinates.length - 2; i >= 1; i--) {
            const coordinate = coordinates[i];
            const nextCoordinate = coordinates[i + 1]
            const prevCoordinate = coordinates[i - 1]

            const distP = GeoOperations.distanceBetween(coordinate, prevCoordinate)
            if (distP < 0.1) {
                coordinates.splice(i, 1)
                continue
            }

            if (i == coordinates.length - 2) {
                const distN = GeoOperations.distanceBetween(coordinate, nextCoordinate)
                if (distN < 0.1) {
                    coordinates.splice(i, 1)
                    continue
                }
            }

            const bearingN = turf.bearing(coordinate, nextCoordinate)
            const bearingP = turf.bearing(prevCoordinate, coordinate)
            const diff = Math.abs(bearingN - bearingP)
            if (diff < 4) {
                // If the diff is low, this point is hardly relevant
                coordinates.splice(i, 1)
            } else if (360 - diff < 4) {
                // In case that the line is going south, e.g. bearingN = 179, bearingP = -179
                coordinates.splice(i, 1)
            }

        }
        return copy;

    }

    /**
     * Calculates the intersection between two features.
     * Returns the length if intersecting a linestring and a (multi)polygon (in meters), returns a surface area (in m²) if intersecting two (multi)polygons
     * Returns 0 if both are linestrings
     * Returns null if the features are not intersecting
     */
    private static calculateInstersection(feature, otherFeature, featureBBox: BBox, otherFeatureBBox?: BBox): number {
        if (feature.geometry.type === "LineString") {


            otherFeatureBBox = otherFeatureBBox ?? BBox.get(otherFeature);
            const overlaps = featureBBox.overlapsWith(otherFeatureBBox)
            if (!overlaps) {
                return null;
            }

            // Calculate the length of the intersection


            let intersectionPoints = turf.lineIntersect(feature, otherFeature);
            if (intersectionPoints.features.length == 0) {
                // No intersections.
                // If one point is inside of the polygon, all points are


                const coors = feature.geometry.coordinates;
                const startCoor = coors[0]
                if (this.inside(startCoor, otherFeature)) {
                    return this.lengthInMeters(feature)
                }

                return null;
            }
            let intersectionPointsArray = intersectionPoints.features.map(d => {
                return d.geometry.coordinates
            });

            if (otherFeature.geometry.type === "LineString") {
                if (intersectionPointsArray.length > 0) {
                    return 0
                }
                return null;
            }
            if (intersectionPointsArray.length == 1) {
                // We need to add the start- or endpoint of the current feature, depending on which one is embedded
                const coors = feature.geometry.coordinates;
                const startCoor = coors[0]
                if (this.inside(startCoor, otherFeature)) {
                    // The startpoint is embedded
                    intersectionPointsArray.push(startCoor)
                } else {
                    intersectionPointsArray.push(coors[coors.length - 1])
                }
            }

            let intersection = turf.lineSlice(turf.point(intersectionPointsArray[0]), turf.point(intersectionPointsArray[1]), feature);

            if (intersection == null) {
                return null;
            }
            const intersectionSize = turf.length(intersection); // in km
            return intersectionSize * 1000


        }

        if (feature.geometry.type === "Polygon" || feature.geometry.type === "MultiPolygon") {
            const otherFeatureBBox = BBox.get(otherFeature);
            const overlaps = featureBBox.overlapsWith(otherFeatureBBox)
            if (!overlaps) {
                return null;
            }
            if (otherFeature.geometry.type === "LineString") {
                return this.calculateInstersection(otherFeature, feature, otherFeatureBBox, featureBBox)
            }

            try {

                const intersection = turf.intersect(feature, otherFeature);
                if (intersection == null) {
                    return null;
                }
                return turf.area(intersection); // in m²
            } catch (e) {
                if (e.message === "Each LinearRing of a Polygon must have 4 or more Positions.") {
                    // WORKAROUND TIME!
                    // See https://github.com/Turfjs/turf/pull/2238
                    return null;
                }
                throw e;
            }

        }
        throw "CalculateIntersection fallthrough: can not calculate an intersection between features"

    }


}