import "server-only";

import { redis } from "@/lib/redis";

// === CrowdSec daily counters ===============================================
//
// Small Redis counters so ops can see whether the reputation pipeline is
// actually doing anything: lookups executed, blocks created, signals pushed,
// and push failures — all bucketed per UTC calendar day
// (crowdsec:stat:{metric}:{YYYY-MM-DD}). Both the CTI client and the signal
// pusher feed them; the admin panel renders the last N days. Cheap INCRs on
// non-hot paths only, so they never tax the request path.

export type CrowdsecStatMetric =
	| "lookups"
	| "blocks"
	| "reports"
	| "report_fail";

const STAT_PREFIX = "crowdsec:stat:";
const STAT_KEY_TTL_SECONDS = 16 * 24 * 3_600;

function statDate(): string {
	return new Date().toISOString().slice(0, 10);
}

function statKey(metric: CrowdsecStatMetric, date: string): string {
	return `${STAT_PREFIX}${metric}:${date}`;
}

/** Count one occurrence of a pipeline event for today. Best effort. */
export async function bumpCrowdsecStat(
	metric: CrowdsecStatMetric,
): Promise<void> {
	if (!redis) return;
	const key = statKey(metric, statDate());
	try {
		await redis.incr(key);
		await redis.expire(key, STAT_KEY_TTL_SECONDS);
	} catch {
		// tracking is best-effort — a miss only loses a day's histogram
	}
}

export interface CrowdsecDailyStat {
	/** UTC calendar day (YYYY-MM-DD). */
	date: string;
	lookups: number;
	blocks: number;
	reports: number;
	reportFailures: number;
}

/**
 * Read the per-day counters for the last `days` days (oldest first, ending
 * with today). Reads the four metric keys per day via one round-trip of
 * parallel GETs; never throws.
 */
export async function getCrowdsecStats(
	days = 14,
): Promise<CrowdsecDailyStat[]> {
	const today = statDate();
	const rows: CrowdsecDailyStat[] = [];
	if (!redis) {
		// No shared store — still return a blank timeline for the UI.
		for (let i = days - 1; i >= 0; i -= 1) {
			const date = new Date(Date.now() - i * 86_400_000)
				.toISOString()
				.slice(0, 10);
			rows.push({ date, lookups: 0, blocks: 0, reports: 0, reportFailures: 0 });
		}
		return rows;
	}
	for (let i = days - 1; i >= 0; i -= 1) {
		const date = new Date(Date.now() - i * 86_400_000)
			.toISOString()
			.slice(0, 10);
		try {
			const [lookups, blocks, reports, reportFailures] = await Promise.all([
				redis.get(statKey("lookups", date)),
				redis.get(statKey("blocks", date)),
				redis.get(statKey("reports", date)),
				redis.get(statKey("report_fail", date)),
			]);
			const num = (raw: string | null): number => {
				const n = Number(raw ?? 0);
				return Number.isFinite(n) ? n : 0;
			};
			rows.push({
				date,
				lookups: num(lookups),
				blocks: num(blocks),
				reports: num(reports),
				reportFailures: num(reportFailures),
			});
		} catch {
			rows.push({ date, lookups: 0, blocks: 0, reports: 0, reportFailures: 0 });
		}
	}
	// Guard against an odd clock roll-back leaving a hole; keep chronological.
	if (rows.length && rows[rows.length - 1]?.date !== today) {
		rows.push({
			date: today,
			lookups: 0,
			blocks: 0,
			reports: 0,
			reportFailures: 0,
		});
	}
	return rows;
}