import { getVectorContext } from "ol/render";
import Point from "ol/geom/Point";
import { fromExtent } from 'ol/geom/Polygon';
import { Style, Icon } from "ol/style";
import { sizes, cacheStyle, makeBorderColor, makeCourseColor } from "./common";
import network from "../../data/network.json";

const courseStyle = cacheStyle(
    lineColor => {
        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();
        }

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

export const setupCoursesAnimation = (
    map, coursesSimulation, stopsLayer, onClick
) => {
    const view = map.getView();

    // Draw courses directly on the map
    map.on("postcompose", ev => {
        coursesSimulation.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);
            const bbox = fromExtent(map.getView().calculateExtent());
            bbox.scale(1.05);

            for (const course of Object.values(coursesSimulation.courses)) {
                if (!bbox.intersectsCoordinate(course.position)) {
                    continue;
                }

                const point = new Point(course.position);
                const color = network.lines[course.line].color;
                const style = courseStyle(color);

                style.getImage().setRotation(
                    view.getRotation() +
                    course.angle
                );

                ctx.setStyle(style);
                ctx.drawGeometry(point);
            }
        }

        map.render();
    });

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

        for (const course of Object.values(coursesSimulation.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) {
                clicked.push(course.id);
            }
        }

        // Sort selected courses in increasing departing/arrival time
        clicked.sort((id1, id2) => {
            const course1 = coursesSimulation.courses[id1];
            const course2 = coursesSimulation.courses[id2];

            const time1 = (
                course1.state === "moving"
                ? course1.arrivalTime
                : course1.departureTime
            );

            const time2 = (
                course2.state === "moving"
                ? course2.arrivalTime
                : course2.departureTime
            );

            return time1 - time2;
        });

        onClick(clicked);
    });
};