export type ChartRangeValue = number | "all";

export interface ChartRangeOption {
	value: ChartRangeValue;
	label: string;
}

interface FiniteChartRange extends ChartRangeOption {
	key: string;
	value: number;
}

/** Canonical finite windows for chart configuration and display filtering. */
const FINITE_CHART_RANGES: readonly FiniteChartRange[] = [
	{ key: "5m", value: 300, label: "5 minutes" },
	{ key: "15m", value: 900, label: "15 minutes" },
	{ key: "30m", value: 1800, label: "30 minutes" },
	{ key: "1h", value: 3600, label: "1 hour" },
	{ key: "3h", value: 10800, label: "3 hours" },
	{ key: "6h", value: 21600, label: "6 hours" },
	{ key: "12h", value: 43200, label: "12 hours" },
	{ key: "24h", value: 86400, label: "24 hours" },
	{ key: "2d", value: 172800, label: "2 days" },
	{ key: "7d", value: 604800, label: "7 days" },
	{ key: "14d", value: 1209600, label: "14 days" },
	{ key: "30d", value: 2592000, label: "30 days" },
];

/** Shared range choices used by every time-series chart. */
export const DEFAULT_CHART_RANGES: readonly ChartRangeOption[] =
	FINITE_CHART_RANGES;

/** Symbolic range values persisted by Prometheus chart and mean widgets. */
export const PROMETHEUS_WINDOW_VALUES = FINITE_CHART_RANGES.map(
	(range) => range.key,
);

export const ALL_VALUES_CHART_RANGE: ChartRangeOption = {
	value: "all",
	label: "All values",
};

function formatRangeLabel(seconds: number): string {
	if (seconds % 604800 === 0) return `${seconds / 604800} days`;
	if (seconds % 3600 === 0) return `${seconds / 3600} hours`;
	if (seconds % 60 === 0) return `${seconds / 60} minutes`;
	return `${seconds} seconds`;
}

export function chartRangesThrough(maxSeconds: number): ChartRangeOption[] {
	if (!Number.isFinite(maxSeconds) || maxSeconds <= 0) {
		return [DEFAULT_CHART_RANGES[0], ALL_VALUES_CHART_RANGE];
	}
	const ranges = FINITE_CHART_RANGES.filter(
		(range) => range.value < maxSeconds,
	);
	const exact = FINITE_CHART_RANGES.find((range) => range.value === maxSeconds);
	return [
		...(exact
			? [...ranges, exact]
			: [
					...ranges,
					{ value: maxSeconds, label: formatRangeLabel(maxSeconds) },
				]),
		ALL_VALUES_CHART_RANGE,
	];
}

export function rangeSecondsFromWindow(window: unknown): number {
	return (
		FINITE_CHART_RANGES.find((range) => range.key === String(window))?.value ??
		3600
	);
}

/** Numeric chart windows suitable for sources with bounded local retention. */
export function numericChartRangesThrough(maxSeconds: number): number[] {
	return FINITE_CHART_RANGES.flatMap((range) =>
		range.value <= maxSeconds ? [range.value] : [],
	);
}