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import { formatCotacol, formatSpeed, ticks } from "./analytics-logic.js";
import type { AnalyticsPoint } from "./types.js";
interface Plot {
left: number;
right: number;
top: number;
bottom: number;
}
interface AnalyticsColors {
surface: string;
grid: string;
subtle: string;
forest: string;
accent: string;
mutedText: string;
}
const POINT_RADIUS = 4;
const HOVER_RADIUS = 7;
const HIT_RADIUS = 12;
export class AnalyticsScatter {
private readonly canvas: HTMLCanvasElement;
private readonly points: AnalyticsPoint[];
private readonly colors: AnalyticsColors;
private readonly output: HTMLElement | null;
private readonly context: CanvasRenderingContext2D;
private plot: Plot | null;
private hoveredIndex: number;
private readonly minSpeed: number;
private readonly maxSpeed: number;
private readonly minCotacol: number;
private readonly maxCotacol: number;
constructor(canvas: HTMLCanvasElement, points: AnalyticsPoint[], colors: AnalyticsColors) {
this.canvas = canvas;
this.points = points;
this.colors = colors;
this.output = document.getElementById("analytics-hover");
const context = canvas.getContext("2d");
if (!context) throw new Error("Analytics canvas is unavailable");
this.context = context;
this.plot = null;
this.hoveredIndex = -1;
let maxSpeed = 0;
let maxCotacol = 0;
for (const point of points) {
maxSpeed = Math.max(maxSpeed, point.speedKmh);
maxCotacol = Math.max(maxCotacol, point.cotacolPer100Km);
}
this.minSpeed = 0;
this.minCotacol = 0;
this.maxSpeed = maxSpeed * 1.08 || 1;
this.maxCotacol = maxCotacol * 1.08 || 1;
this.bindEvents();
}
redraw(): void {
this.draw();
}
private draw(): void {
const rect = this.canvas.getBoundingClientRect();
if (rect.width === 0 || rect.height === 0) return;
const ratio = window.devicePixelRatio || 1;
this.canvas.width = Math.floor(rect.width * ratio);
this.canvas.height = Math.floor(rect.height * ratio);
this.context.setTransform(ratio, 0, 0, ratio, 0, 0);
const plot: Plot = { left: 44, right: rect.width - 16, top: 16, bottom: rect.height - 30 };
this.plot = plot;
this.context.clearRect(0, 0, rect.width, rect.height);
this.context.fillStyle = this.colors.surface;
this.context.fillRect(0, 0, rect.width, rect.height);
this.drawGrid(plot);
this.drawPoints(plot);
if (this.hoveredIndex >= 0) this.drawHover(plot);
}
private drawGrid(plot: Plot): void {
this.context.font = "11px system-ui, sans-serif";
const xTicks = ticks(this.minSpeed, this.maxSpeed);
for (const tick of xTicks) {
const x = this.xForSpeed(tick, plot);
this.context.strokeStyle = this.colors.grid;
this.context.lineWidth = 1;
this.context.beginPath();
this.context.moveTo(x, plot.top);
this.context.lineTo(x, plot.bottom);
this.context.stroke();
this.context.fillStyle = this.colors.subtle;
this.context.textAlign = "center";
this.context.textBaseline = "top";
this.context.fillText(formatSpeed(tick), x, plot.bottom + 8);
}
this.context.fillStyle = this.colors.mutedText;
this.context.textAlign = "right";
this.context.fillText("km/h", plot.right, plot.bottom + 8);
const yTicks = ticks(this.minCotacol, this.maxCotacol);
for (const tick of yTicks) {
const y = this.yForCotacol(tick, plot);
this.context.strokeStyle = this.colors.grid;
this.context.lineWidth = 1;
this.context.beginPath();
this.context.moveTo(plot.left, y);
this.context.lineTo(plot.right, y);
this.context.stroke();
this.context.fillStyle = this.colors.subtle;
this.context.textAlign = "right";
this.context.textBaseline = "middle";
this.context.fillText(formatCotacol(tick), plot.left - 8, y);
}
}
private drawPoints(plot: Plot): void {
for (let index = 0; index < this.points.length; index++) {
const point = this.points[index];
this.context.fillStyle = this.colors.accent;
this.context.beginPath();
this.context.arc(this.xForSpeed(point.speedKmh, plot), this.yForCotacol(point.cotacolPer100Km, plot), POINT_RADIUS, 0, 2 * Math.PI);
this.context.fill();
}
}
private drawHover(plot: Plot): void {
const point = this.points[this.hoveredIndex];
const x = this.xForSpeed(point.speedKmh, plot);
const y = this.yForCotacol(point.cotacolPer100Km, plot);
this.context.strokeStyle = this.colors.forest;
this.context.lineWidth = 2;
this.context.beginPath();
this.context.arc(x, y, HOVER_RADIUS, 0, 2 * Math.PI);
this.context.stroke();
}
private xForSpeed(speed: number, plot: Plot): number {
const span = Math.max(this.maxSpeed - this.minSpeed, 1);
return plot.left + ((speed - this.minSpeed) / span) * (plot.right - plot.left);
}
private yForCotacol(cotacol: number, plot: Plot): number {
const span = Math.max(this.maxCotacol - this.minCotacol, 1);
return plot.bottom - ((cotacol - this.minCotacol) / span) * (plot.bottom - plot.top);
}
private nearestPoint(x: number, y: number): number {
if (!this.plot) return -1;
let nearest = -1;
let best = Infinity;
for (let index = 0; index < this.points.length; index++) {
const point = this.points[index];
const dx = this.xForSpeed(point.speedKmh, this.plot) - x;
const dy = this.yForCotacol(point.cotacolPer100Km, this.plot) - y;
const distance = Math.hypot(dx, dy);
if (distance < best) {
best = distance;
nearest = index;
}
}
return best <= HIT_RADIUS ? nearest : -1;
}
private bindEvents(): void {
this.canvas.addEventListener("pointermove", (event: PointerEvent) => {
const rect = this.canvas.getBoundingClientRect();
const index = this.nearestPoint(event.clientX - rect.left, event.clientY - rect.top);
this.canvas.style.cursor = index >= 0 ? "pointer" : "default";
this.setHovered(index);
});
this.canvas.addEventListener("pointerleave", () => {
this.canvas.style.cursor = "default";
this.setHovered(-1);
});
this.canvas.addEventListener("pointercancel", () => this.setHovered(-1));
this.canvas.addEventListener("click", () => {
if (this.hoveredIndex < 0) return;
window.location.href = this.points[this.hoveredIndex].url;
});
}
private setHovered(index: number): void {
if (index === this.hoveredIndex) return;
this.hoveredIndex = index;
if (this.output) {
if (index < 0) {
this.output.textContent = "Hover a point to inspect a ride.";
} else {
const point = this.points[index];
this.output.textContent = `${point.name} · ${formatSpeed(point.speedKmh)} km/h · ${formatCotacol(point.cotacolPer100Km)} Cotacol/100km · click for details`;
}
}
this.draw();
}
}
export const mountAnalytics = (): void => {
const canvas = document.getElementById("analytics-chart");
const pointsScript = document.getElementById("analytics-points");
if (!canvas || !pointsScript) return;
const data = JSON.parse(pointsScript.textContent ?? "") as AnalyticsPoint[];
if (data.length === 0) return;
const colorProbe = document.createElement("span");
colorProbe.hidden = true;
document.body.append(colorProbe);
const resolveColor = (name: string): string => {
colorProbe.style.color = `var(${name})`;
return getComputedStyle(colorProbe).color;
};
const colors: AnalyticsColors = {
surface: resolveColor("--color-plot-surface"),
grid: resolveColor("--color-plot-grid"),
subtle: resolveColor("--color-subtle"),
forest: resolveColor("--color-forest"),
accent: resolveColor("--color-accent"),
mutedText: resolveColor("--color-muted"),
};
colorProbe.remove();
const scatter = new AnalyticsScatter(canvas as HTMLCanvasElement, data, colors);
window.addEventListener("resize", () => scatter.redraw());
scatter.redraw();
};
mountAnalytics();
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