require('ol/ol.css');

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

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 Feature = require('ol/Feature').default;
const Point = require('ol/geom/Point').default;
const LineString = require('ol/geom/LineString').default;

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

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

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

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

const getRouteColors = routes =>
{
    const colors = routes.filter(
        // Only consider normal routes (excluding alternate routes)
        ([lineRef, routeRef]) =>
        network.lines[lineRef].routes[routeRef].state === 'normal'
    ).map(([lineRef]) => network.lines[lineRef].color);

    if (colors.length >= 1)
    {
        return colors;
    }

    return ['#FFFFFF'];
};

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

    segmentsSource.addFeatures(
        Object.values(network.segments).map(({routes, points}) =>
            new Feature({
                colors: getRouteColors(routes),
                geometry: new LineString(points.map(
                    ({lat, lon}) => proj.fromLonLat([lon, lat])
                )),
            })
        )
    );

    stopsSource.addFeatures(
        Object.values(network.stops).map(({routes, lon, lat}) =>
            new Feature({
                colors: getRouteColors(routes),
                geometry: new Point(proj.fromLonLat([lon, lat])),
            })
        )
    );

    return {segmentsSource, stopsSource};
};

const makeBorderColor = mainColor =>
{
    const hsl = color(mainColor).hsl();
    hsl.color = Math.max(0, hsl.color[2] -= 20);
    return hsl.hex();
};

const makeCourseColor = mainColor =>
{
    const hsl = color(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 = color =>
{
    if (!(color in courseStyles))
    {
        const icon = 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 (let [color, size] of [
            [makeBorderColor(color), sizes.courseOuterBorder],
            [color, sizes.courseBorder],
            [makeCourseColor(color), 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[color] = new Style({
            image: new Icon({
                img: icon,
                imgSize: [icon.width, icon.height],
            }),
        });
    }

    return courseStyles[color];
};

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,
        style: segmentBorderStyle,

        updateWhileInteracting: true,
        updateWhileAnimating: true,
    });

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

        updateWhileInteracting: true,
        updateWhileAnimating: true,
    });

    const stopsLayer = new VectorLayer({
        source: stopsSource,
        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 focusZoom = 17;

    const startFocus = courseId =>
    {
        if (courseId in simulInstance.courses)
        {
            const course = simulInstance.courses[courseId];
            view.animate({
                center: course.position,
                zoom: focusZoom,
                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
        if (stopsLayer.renderer_)
        {
            ev.context = stopsLayer.renderer_.context;
            ev.inversePixelTransform
                = stopsLayer.renderer_.inversePixelTransform;

            const ctx = getVectorContext(ev);
            let rotation = 0;

            for (let 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);
                    // view.setZoom(focus);
                }
            }
        }

        map.render();
    });

    map.render();

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

        for (let 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;