import { auth } from "@/auth";
import { db } from "@/lib/db";
import { hasPermission } from "@/lib/permissions";
import { CREWING_ENABLED } from "@/lib/feature-flags";
import { redirect, notFound } from "next/navigation";
import Link from "next/link";
import { ArrowLeft, Check } from "lucide-react";
import { Badge } from "@/components/ui/badge";
import { ApplicationActionCard } from "../application-action-card";
import { STAGE_ORDER, STAGE_LABEL, STAGE_VARIANT, stageIndex } from "../application-ui";
import { experienceLabel } from "../../candidates/candidate-ui";
import { cn } from "@/lib/utils";
import type { Metadata } from "next";

export const metadata: Metadata = { title: "Application" };

export default async function ApplicationDetailPage({ params }: { params: Promise<{ id: string }> }) {
  if (!CREWING_ENABLED) notFound();

  const session = await auth();
  if (!session?.user) redirect("/login");
  const role = session.user.role;
  if (!hasPermission(role, "view_requisitions") && !hasPermission(role, "manage_candidates")) redirect("/dashboard");

  const { id } = await params;
  const app = await db.application.findUnique({
    where: { id },
    include: {
      requisition: { include: { rank: { select: { name: true } }, vessel: { select: { name: true } }, site: { select: { name: true } } } },
      crewMember: { include: { appliedRank: { select: { name: true } }, currentRank: { select: { name: true } } } },
      gates: true,
      salaryStructures: { orderBy: { createdAt: "desc" } },
    },
  });
  if (!app) notFound();

  const gate = (t: string) => app.gates.find((g) => g.gate === t);
  const salaryPending = gate("SALARY")?.result === "PENDING";
  const waiverPending = gate("WAIVER")?.result === "PENDING";
  const selectionPending = gate("SELECTION")?.result === "PENDING";
  const proposed = app.salaryStructures.find((s) => !s.approvedById) ?? app.salaryStructures[0] ?? null;

  const loc = app.requisition.vessel?.name ?? app.requisition.site?.name ?? "—";
  const curIdx = stageIndex(app.stage);

  return (
    <div className="max-w-4xl">
      <Link href={`/crewing/requisitions/${app.requisition.id}/pipeline`} className="inline-flex items-center gap-1.5 text-sm text-neutral-500 hover:text-neutral-800 mb-4">
        <ArrowLeft className="h-4 w-4" /> Pipeline · {app.requisition.code}
      </Link>

      <div className="mb-6 flex items-center gap-3">
        <h1 className="text-2xl font-semibold text-neutral-900">{app.crewMember.name}</h1>
        <Badge variant={STAGE_VARIANT[app.stage]}>{STAGE_LABEL[app.stage]}</Badge>
        {app.crewMember.type === "EX_HAND" && (
          <span className="rounded-full bg-purple-100 text-purple-700 px-2.5 py-0.5 text-xs font-medium">Returning crew</span>
        )}
      </div>
      <p className="text-sm text-neutral-500 -mt-4 mb-6">
        {app.requisition.rank.name} · {loc} · <span className="font-mono">{app.requisition.code}</span>
      </p>

      {/* 7-step stepper */}
      <div className="mb-6 flex flex-wrap gap-2">
        {STAGE_ORDER.map((s, i) => {
          const done = curIdx > i || app.stage === "ONBOARDED";
          const current = curIdx === i;
          return (
            <div key={s} className={cn(
              "flex items-center gap-1.5 rounded-full px-3 py-1 text-xs font-medium",
              done ? "bg-success-100 text-success-700" : current ? "bg-primary-100 text-primary-700" : "bg-neutral-100 text-neutral-400"
            )}>
              {done && <Check className="h-3 w-3" />}
              {STAGE_LABEL[s]}
            </div>
          );
        })}
      </div>

      <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
        {/* Adaptive action card */}
        <ApplicationActionCard
          id={app.id}
          stage={app.stage}
          isExHand={app.crewMember.type === "EX_HAND"}
          interviewResult={app.interviewResult}
          interviewWaived={app.interviewWaived}
          rejectedReason={app.rejectedReason}
          salaryPending={salaryPending}
          waiverPending={waiverPending}
          selectionPending={selectionPending}
          employeeNo={app.crewMember.employeeId}
          salary={proposed ? {
            rateBasis: proposed.rateBasis,
            basic: Number(proposed.basic),
            victualingPerDay: Number(proposed.victualingPerDay),
            currency: proposed.currency,
            approved: Boolean(proposed.approvedById),
          } : null}
          perms={{
            manage: hasPermission(role, "manage_candidates"),
            recordReference: hasPermission(role, "record_reference_check"),
            recordInterview: hasPermission(role, "record_interview_result"),
            requestWaiver: hasPermission(role, "request_interview_waiver"),
            approveSalary: hasPermission(role, "approve_salary_structure"),
            approveWaiver: hasPermission(role, "approve_interview_waiver"),
            select: hasPermission(role, "select_candidate"),
            onboard: hasPermission(role, "onboard_crew"),
          }}
        />

        {/* Profile */}
        <div className="rounded-lg border border-neutral-200 bg-white overflow-hidden h-fit">
          <div className="px-4 py-3 border-b border-neutral-200 bg-neutral-50">
            <h2 className="text-sm font-semibold text-neutral-900">Profile</h2>
          </div>
          <dl className="divide-y divide-neutral-100">
            {([
              ["Rank applied", app.crewMember.appliedRank?.name ?? app.requisition.rank.name],
              ["Last rank held", app.crewMember.currentRank?.name ?? "—"],
              ["Experience", experienceLabel(app.crewMember.experienceMonths)],
              ["Source", app.crewMember.source],
            ] as [string, string][]).map(([k, v]) => (
              <div key={k} className="flex justify-between gap-4 px-4 py-2.5">
                <dt className="text-sm text-neutral-500">{k}</dt>
                <dd className="text-sm text-neutral-900 text-right">{v}</dd>
              </div>
            ))}
          </dl>
          {app.crewMember.type === "EX_HAND" && (
            <div className="px-4 py-3 border-t border-neutral-100 text-xs text-purple-700 bg-purple-50">
              Returning crew — prior docs/bank/tour on file; interview may be waived with Manager approval.
            </div>
          )}
          <div className="px-4 py-3 border-t border-neutral-100">
            <Link href={`/crewing/candidates/${app.crewMember.id}`} className="text-sm text-primary-600 hover:underline">
              View full candidate profile →
            </Link>
          </div>
        </div>
      </div>
    </div>
  );
}