import {
	LineChart,
	Line,
	XAxis,
	YAxis,
	CartesianGrid,
	Tooltip,
	ResponsiveContainer,
} from "recharts";

export interface SeriesPoint {
	t: number;
	v: number | null;
}

export interface ChartSeries {
	label: string;
	points: SeriesPoint[];
}

/** Merge multiple time-series into a single recharts-friendly array. */
function mergeSeries(series: ChartSeries[]): Record<string, unknown>[] {
	const map = new Map<number, Record<string, unknown>>();
	for (const s of series) {
		for (const p of s.points) {
			const existing = map.get(p.t) ?? { time: p.t };
			existing[s.label] = p.v;
			map.set(p.t, existing);
		}
	}
	return [...map.values()].sort(
		(a, b) => (a.time as number) - (b.time as number),
	);
}

function formatTime(ms: number): string {
	return new Date(ms).toLocaleTimeString([], {
		hour: "2-digit",
		minute: "2-digit",
	});
}

const CHART_COLORS = [
	"var(--color-chart-1)",
	"var(--color-chart-2)",
	"var(--color-chart-3)",
	"var(--color-chart-4)",
	"var(--color-chart-5)",
];

interface LineSeriesChartProps {
	series: ChartSeries[];
	height?: number;
}

/** Shared recharts line-chart renderer used by PrometheusChart + qBit speed widgets. */
export function LineSeriesChart({
	series,
	height = 300,
}: LineSeriesChartProps) {
	return (
		<ResponsiveContainer width="100%" height={height}>
			<LineChart data={mergeSeries(series)}>
				<CartesianGrid strokeDasharray="3 3" className="stroke-muted" />
				<XAxis
					dataKey="time"
					tickFormatter={formatTime}
					tick={{ fontSize: 11 }}
					className="fill-muted-foreground"
				/>
				<YAxis tick={{ fontSize: 11 }} className="fill-muted-foreground" />
				<Tooltip
					labelFormatter={(label) => formatTime(Number(label))}
					contentStyle={{
						backgroundColor: "hsl(var(--popover))",
						border: "1px solid hsl(var(--border))",
						borderRadius: "0.5rem",
						color: "hsl(var(--popover-foreground))",
					}}
				/>
				{series.map((s, i) => (
					<Line
						key={s.label}
						type="monotone"
						dataKey={s.label}
						stroke={CHART_COLORS[i % CHART_COLORS.length]}
						dot={false}
						strokeWidth={2}
						connectNulls
					/>
				))}
			</LineChart>
		</ResponsiveContainer>
	);
}
