import type { SnapshotPayload } from '$lib/types/stats';
import { sortSignals } from './signals';

/** Compose the ~6-line plain-language daily digest. Pure / testable. */
export function composeDigest(payload: SnapshotPayload): string {
	const { activity, kpis } = payload;
	const top = sortSignals(payload.signals)[0];
	const lines = [
		`**Bibdle stats — ${payload.asOfDate}**`,
		`Players: ${activity.dau} today · ${activity.wau} this week · ${activity.mau} this month`,
		`New ${activity.newPlayers} · returning ${activity.returningShare ?? '—'}% · net ${activity.netGrowth >= 0 ? '+' : ''}${activity.netGrowth}`,
		`D1 return ${kpis.d1Return ?? '—'}% · 7-day ${kpis.return7 ?? '—'}%`,
		top ? `Top signal: ${top.title} — ${top.detail}` : 'No signals.',
		`https://bibdle.com/admin/stats?date=${payload.asOfDate}`
	];
	return lines.join('\n');
}

/**
 * POST the digest to the admin Discord webhook. No-op (with a log) when the
 * webhook is unset; never throws so a digest failure can't fail the build.
 */
export async function sendDigest(
	payload: SnapshotPayload,
	webhookUrl: string | undefined = Bun.env.DISCORD_ADMIN_WEBHOOK
): Promise<boolean> {
	const message = composeDigest(payload);
	if (!webhookUrl) {
		console.log('[stats] DISCORD_ADMIN_WEBHOOK not set; digest skipped:\n' + message);
		return false;
	}
	try {
		const res = await fetch(webhookUrl, {
			method: 'POST',
			headers: { 'Content-Type': 'application/json' },
			body: JSON.stringify({ content: message })
		});
		if (!res.ok) console.error('[stats] digest webhook responded', res.status);
		return res.ok;
	} catch (err) {
		console.error('[stats] digest failed', err);
		return false;
	}
}