/**
 * Minimal scale + tick helpers. No d3 — just the bits dashboards need.
 */

/** "Nice" rounded domain max so axis ticks land on clean numbers. */
export function niceMax(max: number, ticks = 4): number {
	if (max <= 0) return ticks
	const rough = max / ticks
	const mag = 10 ** Math.floor(Math.log10(rough))
	const norm = rough / mag
	const step = norm >= 5 ? 10 : norm >= 2 ? 5 : norm >= 1 ? 2 : 1
	const niceStep = step * mag
	return Math.ceil(max / niceStep) * niceStep
}

/** Evenly spaced tick values from min..max (inclusive). */
export function ticks(min: number, max: number, count = 4): number[] {
	const out: number[] = []
	const step = (max - min) / count
	for (let i = 0; i <= count; i++) out.push(min + step * i)
	return out
}

/** Linear scale factory: maps a value in [d0,d1] → pixel in [r0,r1]. */
export function linear(d0: number, d1: number, r0: number, r1: number) {
	const span = d1 - d0 || 1
	return (v: number) => r0 + ((v - d0) / span) * (r1 - r0)
}

/** Band scale for categorical x: returns center x + band width. */
export function band(count: number, range: number, padding = 0.2) {
	const step = range / Math.max(1, count)
	const bandWidth = step * (1 - padding)
	return {
		bandWidth,
		center: (i: number) => step * i + step / 2,
		start: (i: number) => step * i + (step - bandWidth) / 2,
	}
}