import { NextResponse } from "next/server";
import { prisma } from "@/lib/prisma";
import { sendPushover } from "@/lib/push-notify";

// Call daily with:
// POST /api/cron/milk-expiry
// Authorization: Bearer <CRON_SECRET>

async function getCronSecret(): Promise<string> {
  const row = await prisma.systemConfig.findUnique({ where: { key: "cron_secret" } });
  return row?.value || process.env.CRON_SECRET || "";
}

export async function POST(req: Request) {
  const secret = await getCronSecret();
  if (secret) {
    const authHeader = req.headers.get("authorization") ?? "";
    if (authHeader !== `Bearer ${secret}`) {
      return NextResponse.json({ error: "Non autorisé" }, { status: 401 });
    }
  }

  const windowEnd = new Date(Date.now() + 24 * 3600 * 1000);

  const expiringLots = await prisma.milkStock.findMany({
    where: {
      used: false,
      expiresAt: { lte: windowEnd },
    },
    include: {
      baby: {
        include: {
          family: {
            include: {
              users: {
                where: { pushoverUserKey: { not: null } },
                select: { pushoverUserKey: true },
              },
            },
          },
        },
      },
    },
    orderBy: { expiresAt: "asc" },
  });

  if (expiringLots.length === 0) {
    return NextResponse.json({ ok: true, sent: 0 });
  }

  // Group by family
  const byFamily = new Map<string, { users: { pushoverUserKey: string | null }[]; lines: string[]; babyName: string }>();

  for (const lot of expiringLots) {
    const familyId = lot.baby.family.id;
    if (!byFamily.has(familyId)) {
      byFamily.set(familyId, { users: lot.baby.family.users, lines: [], babyName: lot.baby.name });
    }
    const entry = byFamily.get(familyId)!;
    const expiresIn = lot.expiresAt.getTime() - Date.now();
    const hoursLeft = Math.max(0, Math.floor(expiresIn / 3600000));
    const loc = lot.location === "fridge" ? "frigo" : lot.location === "freezer" ? "congélateur" : "ambiant";
    const alreadyExpired = expiresIn <= 0;
    entry.lines.push(
      alreadyExpired
        ? `⚠️ ${lot.volume} mL (${loc}) — expiré`
        : `🥛 ${lot.volume} mL (${loc}) — expire dans ${hoursLeft}h`
    );
  }

  let sent = 0;
  for (const { users, lines, babyName } of byFamily.values()) {
    const message = [`🥛 Stock lait — ${babyName}`, "", ...lines].join("\n");
    for (const user of users) {
      if (user.pushoverUserKey) {
        await sendPushover(user.pushoverUserKey, message, `🥛 Alerte stock lait`);
        sent++;
      }
    }
  }

  return NextResponse.json({ ok: true, sent, lots: expiringLots.length });
}