"use client";

import { use } from "react";
import Link from "next/link";
import { AppShell } from "@/components/app-shell";
import { Card, CardContent } from "@/components/ui/card";
import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
import { Button } from "@/components/ui/button";
import { Skeleton } from "@/components/ui/skeleton";
import { CaseHeader } from "@/components/cases/case-header";
import { CaseEditDialog } from "@/components/cases/case-edit-dialog";
import { DocumentsPanel } from "@/components/cases/documents-panel";
import { DraftsPanel } from "@/components/cases/drafts-panel";
import { DecisionBlocksPanel } from "@/components/cases/decision-blocks-panel";
import { LegalArgumentsPanel } from "@/components/cases/legal-arguments-panel";
import { AgentActivityFeed } from "@/components/cases/agent-activity-feed";
import { AgentActivityPreview } from "@/components/cases/agent-activity-preview";
import { UploadSheet } from "@/components/documents/upload-sheet";
import { useCase, useStartWorkflow } from "@/lib/api/cases";
import { toast } from "sonner";
import {
  Play, Loader2, LayoutGrid, Scale, FileText, MessageSquare, Users,
  type LucideIcon,
} from "lucide-react";

/*
 * Next 16 breaking change: route params are now a Promise.
 * The `use()` hook unwraps them inside a client component.
 */
export default function CaseDetailPage({
  params,
}: {
  params: Promise<{ caseNumber: string }>;
}) {
  const { caseNumber } = use(params);
  const { data, isPending, error, refetch } = useCase(caseNumber);
  const startWorkflow = useStartWorkflow(caseNumber);
  const canStartWorkflow = data?.status === "new" || data?.status === "documents_ready";

  // Only take over the whole page when there is NO data to show. A transient
  // 5xx on the 5s background refetch must not blow away an already-loaded page.
  if (error && !data) {
    return (
      <AppShell>
        <section className="space-y-6">
          <Card className="bg-danger-bg border-danger/40">
            <CardContent className="px-6 py-6 text-center space-y-3">
              <p className="text-danger font-semibold">שגיאה בטעינת התיק</p>
              <p className="text-sm text-ink-muted">{error.message}</p>
              <div className="flex items-center justify-center gap-2">
                <Button variant="outline" onClick={() => refetch()}>
                  נסה שוב
                </Button>
                <Button asChild variant="ghost">
                  <Link href="/">חזרה לרשימת התיקים</Link>
                </Button>
              </div>
            </CardContent>
          </Card>
        </section>
      </AppShell>
    );
  }

  const tabDefs: [string, string, LucideIcon][] = [
    ["overview", "סקירה", LayoutGrid],
    ["arguments", "טיעונים", Scale],
    ["decision", "ההחלטה", FileText],
    ["drafts", "טיוטות והערות", MessageSquare],
    ["agents", "סוכנים", Users],
  ];

  // V2 "segmented" tab strip (X17): each tab a pill, active = raised white card.
  const tabsList = (
    <TabsList
      variant="line"
      className="!h-auto gap-1.5 p-0 flex-wrap justify-start"
    >
      {tabDefs.map(([value, label, Icon]) => (
        <TabsTrigger
          key={value}
          value={value}
          className="flex-none gap-1.5 rounded-lg border border-transparent px-3.5 py-1.5 text-[0.9rem] font-medium text-ink-soft after:hidden hover:bg-parchment/60 data-active:bg-surface data-active:text-navy data-active:font-semibold data-active:border-rule data-active:shadow-sm [&_svg]:text-ink-light data-active:[&_svg]:text-gold-deep"
        >
          <Icon className="w-4 h-4" />
          {label}
        </TabsTrigger>
      ))}
    </TabsList>
  );

  const bandActions = (
    <>
      {data && <CaseEditDialog data={data} />}
      <UploadSheet caseNumber={caseNumber} />
      <Button asChild className="bg-gold text-white hover:bg-gold-deep border-transparent">
        <Link href={`/cases/${caseNumber}/compose`}>פתח עורך החלטה</Link>
      </Button>
      {canStartWorkflow && (
        <Button
          className="bg-gold-deep hover:bg-gold-deep/90 text-parchment"
          disabled={startWorkflow.isPending}
          onClick={() =>
            startWorkflow.mutate(undefined, {
              onSuccess: (res) =>
                toast.success(`תהליך הופעל — ${res.issue_identifier}`),
              onError: (err) => toast.error(`שגיאה: ${err.message}`),
            })
          }
        >
          {startWorkflow.isPending ? (
            <Loader2 className="w-4 h-4 animate-spin me-1.5" />
          ) : (
            <Play className="w-4 h-4 me-1.5" />
          )}
          התחל תהליך
        </Button>
      )}
    </>
  );

  return (
    <AppShell>
      <Tabs defaultValue="overview" dir="rtl">
        {/* parchment band — header (title/chips/parties/actions) + tab strip */}
        {isPending ? (
          <div className="-mx-10 -mt-10 mb-2 bg-parchment border-b border-rule px-10 pt-6 pb-4 space-y-3">
            <Skeleton className="h-4 w-40" />
            <Skeleton className="h-8 w-64" />
            <Skeleton className="h-6 w-96" />
          </div>
        ) : (
          <CaseHeader caseNumber={caseNumber} data={data} actions={bandActions} tabs={tabsList} />
        )}

        {/* full-width tab content — status now lives in the always-visible band
            StatusRail (banner A, X17), so every tab keeps the status context. */}
        <div className="min-w-0 mt-6">
          <TabsContent value="overview" className="mt-0">
            {/* documents + agents two-column (mockup 18j) */}
            <div className="grid gap-6 lg:grid-cols-2 items-start">
              <DocumentsPanel data={data} />
              <AgentActivityPreview caseNumber={caseNumber} />
            </div>
          </TabsContent>

          <TabsContent value="arguments" className="mt-0">
            <Card className="bg-surface border-rule shadow-sm">
              <CardContent className="px-6 py-5">
                <LegalArgumentsPanel caseNumber={caseNumber} />
              </CardContent>
            </Card>
          </TabsContent>

          <TabsContent value="decision" className="mt-0">
            <Card className="bg-surface border-rule shadow-sm">
              <CardContent className="px-6 py-5">
                <DecisionBlocksPanel caseNumber={caseNumber} />
              </CardContent>
            </Card>
          </TabsContent>

          <TabsContent value="drafts" className="mt-0">
            <Card className="bg-surface border-rule shadow-sm">
              <CardContent className="px-6 py-5">
                <DraftsPanel caseNumber={caseNumber} status={data?.status} />
              </CardContent>
            </Card>
          </TabsContent>

          <TabsContent value="agents" className="mt-0">
            <Card className="bg-surface border-rule shadow-sm">
              <CardContent className="px-6 py-5">
                <AgentActivityFeed caseNumber={caseNumber} />
              </CardContent>
            </Card>
          </TabsContent>
        </div>
      </Tabs>
    </AppShell>
  );
}