import { createFileRoute, Link } from "@tanstack/react-router";
import { useEffect, useMemo, 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 { Badge } from "@/components/ui/badge";
import { supabase } from "@/integrations/supabase/client";
import { useAuth } from "@/lib/auth";
import {
  Briefcase, Receipt, Clock, ArrowRight, CalendarDays, FileText,
  CheckSquare, UserPlus, DollarSign, Wallet, AlertCircle,
} from "lucide-react";
import { formatCurrency, formatDate, statusBadgeClass } from "@/lib/format";
import { format, startOfDay, startOfMonth, endOfMonth, subDays } from "date-fns";

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

interface Financial {
  trustBalance: number;
  paidThisMonth: number;
  overdueTotal: number;
  unsentTotal: number;
}
interface MyTaskCounts {
  dueToday: number;
  overdue: number;
  incomplete: number;
}
interface OpenCases {
  open: number;
  newLast30: number;
  closedLast30: number;
}

function Dashboard() {
  const { user } = useAuth();
  const [financial, setFinancial] = useState<Financial>({ trustBalance: 0, paidThisMonth: 0, overdueTotal: 0, unsentTotal: 0 });
  const [myTasks, setMyTasks] = useState<MyTaskCounts>({ dueToday: 0, overdue: 0, incomplete: 0 });
  const [openCases, setOpenCases] = useState<OpenCases>({ open: 0, newLast30: 0, closedLast30: 0 });
  const [todaysEvents, setTodaysEvents] = useState<any[]>([]);
  const [recentCases, setRecentCases] = useState<any[]>([]);
  const [recentInvoices, setRecentInvoices] = useState<any[]>([]);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    if (!user?.id) return;
    (async () => {
      setLoading(true);
      const today = startOfDay(new Date());
      const todayStr = format(today, "yyyy-MM-dd");
      const monthStart = format(startOfMonth(today), "yyyy-MM-dd");
      const monthEnd = format(endOfMonth(today), "yyyy-MM-dd");
      const thirtyAgo = format(subDays(today, 30), "yyyy-MM-dd");

      const [
        trustRes, paymentsRes, invoicesRes,
        myAssigneeRes,
        openCasesRes, newCasesRes, closedCasesRes,
        tasksTodayRes, hearingsTodayRes,
        recentCasesRes, recentInvRes,
      ] = await Promise.all([
        supabase.from("trust_ledger_entries").select("entry_type, amount"),
        supabase.from("invoice_payments").select("amount, paid_on").gte("paid_on", monthStart).lte("paid_on", monthEnd),
        supabase.from("invoices").select("id, total, amount_paid, status, due_date"),
        supabase.from("task_assignees").select("task_id, task:tasks(id, status, due_date)").eq("user_id", user.id),
        supabase.from("cases").select("id", { count: "exact", head: true }).in("status", ["intake", "active", "on_hold"]),
        supabase.from("cases").select("id", { count: "exact", head: true }).gte("opened_at", thirtyAgo),
        supabase.from("cases").select("id", { count: "exact", head: true }).gte("closed_at", thirtyAgo).not("closed_at", "is", null),
        supabase.from("tasks").select("id, title, due_date, case_id, case:cases(case_number, title)").eq("status", "incomplete").eq("due_date", todayStr),
        supabase.from("cases").select("id, title, case_number, next_hearing_date, next_hearing_notes").eq("next_hearing_date", todayStr),
        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),
      ]);

      // Trust balance
      const trustBalance = (trustRes.data ?? []).reduce((s, e: any) => {
        return s + (e.entry_type === "deposit" ? Number(e.amount) : -Number(e.amount));
      }, 0);

      // Paid this month
      const paidThisMonth = (paymentsRes.data ?? []).reduce((s, p: any) => s + Number(p.amount), 0);

      // Overdue + unsent totals (remaining)
      let overdueTotal = 0;
      let unsentTotal = 0;
      for (const inv of (invoicesRes.data ?? []) as any[]) {
        const remaining = Number(inv.total) - Number(inv.amount_paid);
        if (remaining <= 0) continue;
        if (inv.status === "draft") unsentTotal += remaining;
        if (inv.due_date && inv.due_date < todayStr && inv.status !== "paid") overdueTotal += remaining;
      }

      // My tasks
      const myTaskRows = (myAssigneeRes.data ?? []).map((r: any) => r.task).filter(Boolean);
      let dueToday = 0, overdue = 0, incomplete = 0;
      for (const t of myTaskRows) {
        if (t.status !== "incomplete") continue;
        incomplete++;
        if (t.due_date) {
          if (t.due_date === todayStr) dueToday++;
          else if (t.due_date < todayStr) overdue++;
        }
      }

      // Today's events: combine tasks + hearings
      const evts: any[] = [
        ...((tasksTodayRes.data ?? []) as any[]).map((t) => ({
          id: `task-${t.id}`, kind: "task", title: t.title,
          subtitle: t.case ? `${t.case.case_number} · ${t.case.title}` : null,
          to: t.case_id ? `/cases/${t.case_id}` : "/tasks",
        })),
        ...((hearingsTodayRes.data ?? []) as any[]).map((c) => ({
          id: `hearing-${c.id}`, kind: "hearing", title: `Hearing: ${c.title}`,
          subtitle: c.case_number, to: `/cases/${c.id}`,
        })),
      ];

      setFinancial({ trustBalance, paidThisMonth, overdueTotal, unsentTotal });
      setMyTasks({ dueToday, overdue, incomplete });
      setOpenCases({
        open: openCasesRes.count ?? 0,
        newLast30: newCasesRes.count ?? 0,
        closedLast30: closedCasesRes.count ?? 0,
      });
      setTodaysEvents(evts);
      setRecentCases(recentCasesRes.data ?? []);
      setRecentInvoices(recentInvRes.data ?? []);
      setLoading(false);
    })();
  }, [user?.id]);

  const quickActions = useMemo(() => [
    { label: "Add task", icon: CheckSquare, to: "/tasks" },
    { label: "Add case", icon: Briefcase, to: "/cases/new" },
    { label: "Add contact", icon: UserPlus, to: "/contacts" },
    { label: "Create invoice", icon: Receipt, to: "/invoices" },
    { label: "Add time", icon: Clock, to: "/tasks" },
    { label: "Add expense", icon: DollarSign, to: "/cases" },
  ], []);

  const financialCards = [
    { label: "Trust account balance", value: formatCurrency(financial.trustBalance), tone: "bg-muted/40", icon: Wallet, to: "/clients" },
    { label: "Invoices paid this mo.", value: formatCurrency(financial.paidThisMonth), tone: "bg-emerald-500/10", icon: Receipt, to: "/invoices" },
    { label: "Overdue invoice total", value: formatCurrency(financial.overdueTotal), tone: "bg-destructive/10", icon: AlertCircle, to: "/invoices" },
    { label: "Unsent invoice total", value: formatCurrency(financial.unsentTotal), tone: "bg-muted/40", icon: FileText, to: "/invoices" },
  ];

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

      {/* Quick actions */}
      <Card className="mb-6">
        <CardContent className="p-4">
          <div className="text-xs uppercase tracking-wider text-muted-foreground mb-3">Quick actions</div>
          <div className="flex flex-wrap gap-2">
            {quickActions.map((a) => (
              <Button key={a.label} asChild variant="outline" size="sm">
                <Link to={a.to}><a.icon className="h-3.5 w-3.5 mr-1.5" />{a.label}</Link>
              </Button>
            ))}
          </div>
        </CardContent>
      </Card>

      {/* Financial + My tasks */}
      <div className="grid lg:grid-cols-[2fr_1fr] gap-6 mb-6">
        <Card>
          <CardHeader>
            <CardTitle className="text-base">Financial overview</CardTitle>
          </CardHeader>
          <CardContent>
            <div className="grid grid-cols-2 lg:grid-cols-4 gap-3">
              {financialCards.map((c) => (
                <Link key={c.label} to={c.to}>
                  <div className={`rounded-lg p-4 ${c.tone} hover:opacity-80 transition-opacity`}>
                    <div className="text-xs text-muted-foreground mb-1">{c.label}</div>
                    <div className="font-serif text-2xl">{loading ? "—" : c.value}</div>
                  </div>
                </Link>
              ))}
            </div>
          </CardContent>
        </Card>

        <Card>
          <CardHeader>
            <CardTitle className="text-base">My tasks</CardTitle>
          </CardHeader>
          <CardContent>
            <div className="grid grid-cols-3 gap-3">
              <Link to="/tasks" className="rounded-lg p-4 bg-amber-500/10 hover:opacity-80 transition-opacity">
                <div className="text-xs text-muted-foreground">Due today</div>
                <div className="font-serif text-2xl">{myTasks.dueToday}</div>
              </Link>
              <Link to="/tasks" className="rounded-lg p-4 bg-destructive/10 hover:opacity-80 transition-opacity">
                <div className="text-xs text-muted-foreground">Overdue</div>
                <div className="font-serif text-2xl">{myTasks.overdue}</div>
              </Link>
              <Link to="/tasks" className="rounded-lg p-4 bg-muted/40 hover:opacity-80 transition-opacity">
                <div className="text-xs text-muted-foreground">Incomplete</div>
                <div className="font-serif text-2xl">{myTasks.incomplete}</div>
              </Link>
            </div>
          </CardContent>
        </Card>
      </div>

      {/* Open cases + Today's events */}
      <div className="grid lg:grid-cols-[2fr_1fr] gap-6 mb-6">
        <Card>
          <CardHeader className="flex flex-row items-center justify-between">
            <CardTitle className="text-base">Open 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>
            <div className="font-serif text-5xl mb-4">{openCases.open}</div>
            <div className="space-y-2 text-sm border-t pt-3">
              <div className="flex items-center justify-between">
                <span className="text-muted-foreground">New cases in last 30 days</span>
                <span className="font-medium">{openCases.newLast30}</span>
              </div>
              <div className="flex items-center justify-between">
                <span className="text-muted-foreground">Cases closed in last 30 days</span>
                <span className="font-medium">{openCases.closedLast30}</span>
              </div>
            </div>
          </CardContent>
        </Card>

        <Card>
          <CardHeader className="flex flex-row items-center justify-between">
            <CardTitle className="text-base">Today's events</CardTitle>
            <Button asChild variant="ghost" size="sm">
              <Link to="/calendar">View all <ArrowRight className="h-3 w-3 ml-1" /></Link>
            </Button>
          </CardHeader>
          <CardContent>
            {todaysEvents.length === 0 ? (
              <p className="text-sm text-muted-foreground">Nothing scheduled today.</p>
            ) : (
              <div className="space-y-1">
                {todaysEvents.map((e) => (
                  <Link key={e.id} to={e.to} className="flex items-start gap-2 py-2 px-2 -mx-2 rounded-md hover:bg-muted/60">
                    <CalendarDays className="h-4 w-4 mt-0.5 text-muted-foreground shrink-0" />
                    <div className="min-w-0">
                      <div className="text-sm font-medium truncate">{e.title}</div>
                      {e.subtitle && <div className="text-xs text-muted-foreground truncate">{e.subtitle}</div>}
                    </div>
                  </Link>
                ))}
              </div>
            )}
          </CardContent>
        </Card>
      </div>

      {/* Recent cases & invoices */}
      <div className="grid lg:grid-cols-2 gap-6">
        <Card>
          <CardHeader className="flex flex-row items-center justify-between">
            <CardTitle className="text-base">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>
          <CardHeader className="flex flex-row items-center justify-between">
            <CardTitle className="text-base">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>
  );
}