import Link from "next/link";
import { requireOperator } from "@/lib/auth";
import { prisma } from "@/lib/prisma";

/**
 * Operator dashboard. Because phones often have the browser open between scans,
 * we want this page to answer one question fast: "what am I currently working
 * on?" Active claims are the headline list; below that we show a generic
 * "scan a card to start" hint so a fresh operator knows what to do.
 */
const OP_INCLUDE = {
  machine: { select: { name: true } },
  part: {
    select: {
      code: true,
      name: true,
      qty: true,
      assembly: {
        select: {
          code: true,
          qty: true,
          project: { select: { code: true, name: true } },
        },
      },
    },
  },
} as const;

export default async function OperatorHomePage() {
  const user = await requireOperator();

  const [claims, resumable] = await Promise.all([
    prisma.operation.findMany({
      where: { claimedByUserId: user.id, status: "in_progress" },
      orderBy: { claimedAt: "desc" },
      include: OP_INCLUDE,
    }),
    // B1: partial ops are unclaimed after a release and only re-surface when
    // someone physically re-scans the card. List them here so any operator
    // can pick up where the last shift left off.
    prisma.operation.findMany({
      where: { status: "partial", claimedByUserId: null },
      orderBy: { updatedAt: "desc" },
      take: 50,
      include: OP_INCLUDE,
    }),
  ]);

  return (
    <div className="mx-auto max-w-3xl px-4 py-6 space-y-6">
      <div>
        <h1 className="text-2xl font-semibold">Hi, {user.name}</h1>
        <p className="text-slate-500 mt-1 text-sm">
          Scan a QR card with your phone camera to start a step, or continue an active one below.
        </p>
      </div>

      {claims.length === 0 && resumable.length === 0 ? (
        <div className="rounded-xl bg-white border border-slate-200 p-6 text-slate-600 text-sm text-center">
          You have no active steps. Scan a traveler QR to begin.
        </div>
      ) : null}

      {claims.length > 0 ? (
        <div className="space-y-3">
          <h2 className="text-sm font-semibold text-slate-900 uppercase tracking-wide">
            Active ({claims.length})
          </h2>
          {claims.map((c) => (
            <Link
              key={c.id}
              href={`/op/scan/${c.qrToken}`}
              className="block rounded-xl bg-white border border-slate-200 p-4 hover:border-slate-900 hover:shadow-sm transition"
            >
              <div className="text-xs text-slate-500">
                {c.part.assembly.project.code} · {c.part.assembly.code}
              </div>
              <div className="font-medium mt-0.5">{c.part.name}</div>
              <div className="text-sm text-slate-700 mt-1">
                Step {c.sequence}: {c.name}
              </div>
              <div className="text-xs text-slate-500 mt-1 flex flex-wrap gap-x-3">
                <span className="font-mono">{c.part.code}</span>
                {c.machine ? <span>{c.machine.name}</span> : null}
                {c.claimedAt ? <span>since {new Date(c.claimedAt).toLocaleTimeString()}</span> : null}
              </div>
            </Link>
          ))}
        </div>
      ) : null}

      {resumable.length > 0 ? (
        <div className="space-y-3">
          <h2 className="text-sm font-semibold text-slate-900 uppercase tracking-wide">
            Resumable ({resumable.length})
          </h2>
          <p className="text-xs text-slate-500 -mt-1">
            Previously started and released with units still to run. Tap to pick up where the last shift left off.
          </p>
          {resumable.map((c) => {
            const total = c.part.qty * c.part.assembly.qty;
            const remaining = Math.max(total - c.unitsCompleted, 0);
            return (
              <Link
                key={c.id}
                href={`/op/scan/${c.qrToken}`}
                className="block rounded-xl bg-white border border-amber-300 p-4 hover:border-amber-500 hover:shadow-sm transition"
              >
                <div className="text-xs text-slate-500">
                  {c.part.assembly.project.code} · {c.part.assembly.code}
                </div>
                <div className="font-medium mt-0.5">{c.part.name}</div>
                <div className="text-sm text-slate-700 mt-1">
                  Step {c.sequence}: {c.name}
                </div>
                <div className="text-xs text-slate-600 mt-1 flex flex-wrap gap-x-3">
                  <span className="font-mono">{c.part.code}</span>
                  {c.machine ? <span>{c.machine.name}</span> : null}
                  <span className="text-amber-700 font-medium">
                    {c.unitsCompleted} of {total} done · {remaining} remaining
                  </span>
                </div>
              </Link>
            );
          })}
        </div>
      ) : null}
    </div>
  );
}