import { createFileRoute, Link } from "@tanstack/react-router";
import { useEffect, useState } from "react";
import { ProtectedLayout } from "@/components/protected-layout";
import { PageContainer, PageHeader } from "@/components/app-shell";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Button } from "@/components/ui/button";
import { supabase } from "@/integrations/supabase/client";
import { useAuth } from "@/lib/auth";
import { Briefcase, Users, Receipt, Clock, ArrowRight } from "lucide-react";
import { formatCurrency, formatDate, statusBadgeClass } from "@/lib/format";
import { Badge } from "@/components/ui/badge";

export const Route = createFileRoute("/")({
  component: () => (
    <ProtectedLayout>
      <Dashboard />
    </ProtectedLayout>
  ),
});

interface Stats {
  activeCases: number;
  clients: number;
  unpaidInvoices: number;
  unbilledHours: number;
}

function Dashboard() {
  const { user } = useAuth();
  const [stats, setStats] = useState<Stats>({ activeCases: 0, clients: 0, unpaidInvoices: 0, unbilledHours: 0 });
  const [recentCases, setRecentCases] = useState<any[]>([]);
  const [recentInvoices, setRecentInvoices] = useState<any[]>([]);

  useEffect(() => {
    (async () => {
      const [casesRes, clientsRes, invoicesRes, timeRes, recentCasesRes, recentInvRes] = await Promise.all([
        supabase.from("cases").select("id", { count: "exact", head: true }).in("status", ["intake", "active", "on_hold"]),
        supabase.from("clients").select("id", { count: "exact", head: true }),
        supabase.from("invoices").select("total, amount_paid").in("status", ["sent", "overdue"]),
        supabase.from("time_entries").select("hours").is("invoice_id", null).eq("billable", true),
        supabase.from("cases").select("id, case_number, title, status, updated_at, client:clients(name)").order("updated_at", { ascending: false }).limit(5),
        supabase.from("invoices").select("id, invoice_number, total, status, issue_date, client:clients(name)").order("created_at", { ascending: false }).limit(5),
      ]);

      const unpaid = (invoicesRes.data ?? []).reduce(
        (sum, i) => sum + (Number(i.total) - Number(i.amount_paid)),
        0,
      );
      const hours = (timeRes.data ?? []).reduce((s, t) => s + Number(t.hours), 0);

      setStats({
        activeCases: casesRes.count ?? 0,
        clients: clientsRes.count ?? 0,
        unpaidInvoices: unpaid,
        unbilledHours: hours,
      });
      setRecentCases(recentCasesRes.data ?? []);
      setRecentInvoices(recentInvRes.data ?? []);
    })();
  }, [user?.id]);

  const cards = [
    { label: "Active cases", value: stats.activeCases, icon: Briefcase, to: "/cases" },
    { label: "Clients", value: stats.clients, icon: Users, to: "/clients" },
    { label: "Unbilled hours", value: stats.unbilledHours.toFixed(1), icon: Clock, to: "/cases" },
    { label: "Outstanding A/R", value: formatCurrency(stats.unpaidInvoices), icon: Receipt, to: "/invoices" },
  ];

  return (
    <PageContainer>
      <PageHeader title="Dashboard" description="Practice snapshot and recent activity." />

      <div className="grid grid-cols-2 lg:grid-cols-4 gap-4 mb-8">
        {cards.map((c) => (
          <Link key={c.label} to={c.to} className="group">
            <Card className="border-border/60 hover:border-primary/40 transition-colors">
              <CardContent className="p-5">
                <div className="flex items-start justify-between mb-3">
                  <div className="text-xs uppercase tracking-wider text-muted-foreground">{c.label}</div>
                  <c.icon className="h-4 w-4 text-muted-foreground group-hover:text-primary" />
                </div>
                <div className="font-serif text-3xl text-foreground">{c.value}</div>
              </CardContent>
            </Card>
          </Link>
        ))}
      </div>

      <div className="grid lg:grid-cols-2 gap-6">
        <Card className="border-border/60">
          <CardHeader className="flex flex-row items-center justify-between">
            <CardTitle className="font-serif text-lg">Recent cases</CardTitle>
            <Button asChild variant="ghost" size="sm">
              <Link to="/cases">View all <ArrowRight className="h-3 w-3 ml-1" /></Link>
            </Button>
          </CardHeader>
          <CardContent className="space-y-1">
            {recentCases.length === 0 && <p className="text-sm text-muted-foreground">No cases yet.</p>}
            {recentCases.map((c) => (
              <Link
                key={c.id}
                to="/cases/$caseId"
                params={{ caseId: c.id }}
                className="flex items-center justify-between py-2.5 px-2 rounded-md hover:bg-muted/60 -mx-2"
              >
                <div className="min-w-0">
                  <div className="text-sm font-medium truncate">{c.title}</div>
                  <div className="text-xs text-muted-foreground">
                    {c.case_number} · {c.client?.name}
                  </div>
                </div>
                <Badge variant="outline" className={statusBadgeClass(c.status)}>{c.status.replace("_", " ")}</Badge>
              </Link>
            ))}
          </CardContent>
        </Card>

        <Card className="border-border/60">
          <CardHeader className="flex flex-row items-center justify-between">
            <CardTitle className="font-serif text-lg">Recent invoices</CardTitle>
            <Button asChild variant="ghost" size="sm">
              <Link to="/invoices">View all <ArrowRight className="h-3 w-3 ml-1" /></Link>
            </Button>
          </CardHeader>
          <CardContent className="space-y-1">
            {recentInvoices.length === 0 && <p className="text-sm text-muted-foreground">No invoices yet.</p>}
            {recentInvoices.map((i) => (
              <Link
                key={i.id}
                to="/invoices/$invoiceId"
                params={{ invoiceId: i.id }}
                className="flex items-center justify-between py-2.5 px-2 rounded-md hover:bg-muted/60 -mx-2"
              >
                <div className="min-w-0">
                  <div className="text-sm font-medium">{i.invoice_number}</div>
                  <div className="text-xs text-muted-foreground">
                    {i.client?.name} · {formatDate(i.issue_date)}
                  </div>
                </div>
                <div className="flex items-center gap-2">
                  <span className="text-sm font-medium">{formatCurrency(i.total)}</span>
                  <Badge variant="outline" className={statusBadgeClass(i.status)}>{i.status}</Badge>
                </div>
              </Link>
            ))}
          </CardContent>
        </Card>
      </div>
    </PageContainer>
  );
}