require("ol/ol.css");

const { Map, View } = require("ol");

const GeoJSON = require("ol/format/GeoJSON").default;
const reader = new GeoJSON({ featureProjection: "EPSG:3857" });

const TileLayer = require("ol/layer/Tile").default;
const XYZSource = require("ol/source/XYZ").default;

const VectorLayer = require("ol/layer/Vector").default;
const VectorSource = require("ol/source/Vector").default;
const { getVectorContext } = require("ol/render");

const Point = require("ol/geom/Point").default;

const proj = require("ol/proj");

const { Style, Fill, Stroke, Circle, Icon } = require("ol/style");
const colorModule = require("color");

const mapboxToken = "pk.eyJ1IjoibWF0dGVvZGVsYWJyZSIsImEiOiJja2NxaTUyMmUwcmFhMn\
h0NmFsdzQ3emxqIn0.cyxF0h36emIMTk3cc4VqUw";

const simulation = require("../tam/simulation");
const network = require("../tam/network.json");

const lineFeaturesOrder = (feature1, feature2) => {
    const lines1 = feature1.get("lines");

    if (lines1.length === 0) {
        return -1;
    }

    const lines2 = feature2.get("lines");

    if (lines2.length === 0) {
        return 1;
    }

    return Math.min(...lines1) - Math.min(...lines2);
};

const makeDataSources = () => {
    const segmentsSource = new VectorSource();
    const stopsSource = new VectorSource();

    const readFeatures = hash => Object.values(hash).map(json => {
        json.properties.lines = json.properties.routes.filter(

            // Only consider normal routes (excluding alternate routes)
            ([lineRef, routeRef]) =>
                network.lines[lineRef].routes[routeRef].state === "normal"
        ).map(([lineRef]) => lineRef);

        if (json.properties.lines.length >= 1) {
            json.properties.colors = json.properties.lines.map(
                lineRef => network.lines[lineRef].color
            );
        } else {
            json.properties.colors = ["#FFFFFF"];
        }

        return reader.readFeature(json);
    });

    segmentsSource.addFeatures(readFeatures(network.segments));
    stopsSource.addFeatures(readFeatures(network.stops));
    return { segmentsSource, stopsSource };
};

const makeBorderColor = mainColor => {
    const hsl = colorModule(mainColor).hsl();

    hsl.color = Math.max(0, hsl.color[2] -= 20);
    return hsl.hex();
};

const makeCourseColor = mainColor => {
    const hsl = colorModule(mainColor).hsl();

    hsl.color = Math.max(0, hsl.color[2] += 10);
    return hsl.hex();
};

const sizes = {
    segmentOuter: 8,
    segmentInner: 6,
    stopRadius: 6,
    stopBorder: 1.5,
    courseSize: 15,
    courseOuterBorder: 13,
    courseBorder: 10,
    courseInnerBorder: 7
};

const segmentBorderStyle = feature => new Style({
    stroke: new Stroke({
        color: makeBorderColor(feature.get("colors")[0]),
        width: sizes.segmentOuter
    })
});

const segmentInnerStyle = feature => new Style({
    stroke: new Stroke({
        color: feature.get("colors")[0],
        width: sizes.segmentInner
    })
});

const stopStyle = feature => new Style({
    image: new Circle({
        fill: new Fill({
            color: feature.get("colors")[0]
        }),
        stroke: new Stroke({
            color: makeBorderColor(feature.get("colors")[0]),
            width: sizes.stopBorder
        }),
        radius: sizes.stopRadius
    })
});

const courseStyles = {};

const getCourseStyle = lineColor => {
    if (!(lineColor in courseStyles)) {
        const icon = window.document.createElement("canvas");

        const shapeSize = sizes.courseSize;
        const iconSize = sizes.courseSize + sizes.courseOuterBorder;

        icon.width = iconSize;
        icon.height = iconSize;

        const cx = icon.width / 2;
        const cy = icon.height / 2;

        const iconCtx = icon.getContext("2d");

        for (const [color, size] of [
            [makeBorderColor(lineColor), sizes.courseOuterBorder],
            [lineColor, sizes.courseBorder],
            [makeCourseColor(lineColor), sizes.courseInnerBorder]
        ]) {
            iconCtx.fillStyle = color;
            iconCtx.strokeStyle = color;
            iconCtx.lineWidth = size;
            iconCtx.lineJoin = "round";
            iconCtx.miterLimit = 200000;

            iconCtx.beginPath();
            iconCtx.moveTo(cx - 0.5 * shapeSize, cy - 0.3 * shapeSize);
            iconCtx.lineTo(cx + 0.5 * shapeSize, cy);
            iconCtx.lineTo(cx - 0.5 * shapeSize, cy + 0.3 * shapeSize);
            iconCtx.closePath();
            iconCtx.stroke();
            iconCtx.fill();
        }

        courseStyles[lineColor] = new Style({
            image: new Icon({
                img: icon,
                imgSize: [icon.width, icon.height]
            })
        });
    }

    return courseStyles[lineColor];
};

const createMap = target => {

    // Map background
    const backgroundSource = new XYZSource({
        url: `https://api.mapbox.com/${[
            "styles", "v1", "mapbox", "streets-v11",
            "tiles", "512", "{z}", "{x}", "{y}"
        ].join("/")}?access_token=${mapboxToken}`,
        tileSize: [512, 512]
    });

    const backgroundLayer = new TileLayer({
        source: backgroundSource
    });

    // Static data overlay
    const { segmentsSource, stopsSource } = makeDataSources();

    const segmentsBorderLayer = new VectorLayer({
        source: segmentsSource,
        renderOrder: lineFeaturesOrder,
        style: segmentBorderStyle,

        updateWhileInteracting: true,
        updateWhileAnimating: true
    });

    const segmentsInnerLayer = new VectorLayer({
        source: segmentsSource,
        renderOrder: lineFeaturesOrder,
        style: segmentInnerStyle,

        updateWhileInteracting: true,
        updateWhileAnimating: true
    });

    const stopsLayer = new VectorLayer({
        source: stopsSource,
        renderOrder: lineFeaturesOrder,
        style: stopStyle,

        minZoom: 13,
        updateWhileInteracting: true,
        updateWhileAnimating: true
    });

    // Setup map
    const view = new View({
        center: proj.fromLonLat([3.88, 43.605]),
        zoom: 14,
        maxZoom: 22,
        constrainResolution: true
    });

    const map = new Map({
        target,
        layers: [
            backgroundLayer,
            segmentsBorderLayer,
            segmentsInnerLayer,
            stopsLayer
        ],
        view
    });

    // Run courses simulation
    const simulInstance = simulation.start();

    // Course on which the view is currently focused
    let focusedCourse = null;

    const startFocus = courseId => {
        if (courseId in simulInstance.courses) {
            const course = simulInstance.courses[courseId];

            view.animate({
                center: course.position,
                duration: 500
            }, () => {
                focusedCourse = courseId;
            });
        }
    };

    const stopFocus = () => {
        focusedCourse = null;
    };

    // Draw courses directly on the map
    map.on("postcompose", ev => {
        simulInstance.update();

        // The normal way to access a layer’s vector context is through the
        // `postrender` event of that layer. However, `postrender` is not
        // triggered when no feature of the layer is inside the current
        // bounding box, but we want to draw vehicles in between stops even
        // if no stop is visible. This hack listens to the global `postcompose`
        // event, which is always triggered at every frame, and reconstructs
        // the stops layer’s vector context from internal variables
        /* eslint-disable no-underscore-dangle */
        if (stopsLayer.renderer_) {
            ev.context = stopsLayer.renderer_.context;
            ev.inversePixelTransform =
                stopsLayer.renderer_.inversePixelTransform;
            /* eslint-enable no-underscore-dangle */

            const ctx = getVectorContext(ev);

            for (const course of Object.values(simulInstance.courses)) {
                const color = network.lines[course.line].color;
                const style = getCourseStyle(color);

                style.getImage().setRotation(course.angle);
                ctx.setStyle(style);

                const point = new Point(course.position);

                ctx.drawGeometry(point);

                if (course.id === focusedCourse) {
                    view.setCenter(course.position);
                }
            }
        }

        map.render();
    });

    map.render();

    map.on("singleclick", ev => {
        const mousePixel = map.getPixelFromCoordinate(ev.coordinate);
        const maxDistance = sizes.courseSize + sizes.courseOuterBorder;

        for (const course of Object.values(simulInstance.courses)) {
            const coursePixel = map.getPixelFromCoordinate(course.position);
            const dx = mousePixel[0] - coursePixel[0];
            const dy = mousePixel[1] - coursePixel[1];
            const distance = dx * dx + dy * dy;

            if (distance <= maxDistance * maxDistance) {
                startFocus(course.id);
                return;
            }
        }

        // Clicking anywhere else resets focus
        stopFocus();
    });

    return map;
};

exports.createMap = createMap;