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 } from "@/components/ui/card";
import { Input } from "@/components/ui/input";
import { Button } from "@/components/ui/button";
import { Tabs, TabsList, TabsTrigger } from "@/components/ui/tabs";
import { supabase } from "@/integrations/supabase/client";
import { formatCurrency, formatDate } from "@/lib/format";
import { Search, Wallet, Download, ArrowDownToLine, ArrowUpFromLine } from "lucide-react";

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

interface Entry {
  id: string;
  client_id: string;
  case_id: string | null;
  entry_date: string;
  entry_type: "deposit" | "withdrawal";
  amount: number;
  note: string | null;
}

interface ClientLite {
  id: string;
  name: string | null;
  archived_at: string | null;
}

interface CaseLite {
  id: string;
  case_number: string | null;
  title: string | null;
}

function TrustLedgerPage() {
  const [entries, setEntries] = useState<Entry[]>([]);
  const [clients, setClients] = useState<Map<string, ClientLite>>(new Map());
  const [cases, setCases] = useState<Map<string, CaseLite>>(new Map());
  const [loading, setLoading] = useState(true);
  const [search, setSearch] = useState("");
  const [view, setView] = useState<"all" | "active" | "archived">("active");

  useEffect(() => {
    (async () => {
      setLoading(true);
      const [entriesRes, clientsRes, casesRes] = await Promise.all([
        supabase
          .from("trust_ledger_entries")
          .select("id, client_id, case_id, entry_date, entry_type, amount, note")
          .order("entry_date", { ascending: false })
          .limit(5000),
        supabase.from("clients").select("id, name, archived_at"),
        supabase.from("cases").select("id, case_number, title"),
      ]);
      setEntries((entriesRes.data ?? []) as Entry[]);
      const cm = new Map<string, ClientLite>();
      ((clientsRes.data ?? []) as ClientLite[]).forEach((c) => cm.set(c.id, c));
      setClients(cm);
      const csm = new Map<string, CaseLite>();
      ((casesRes.data ?? []) as CaseLite[]).forEach((c) => csm.set(c.id, c));
      setCases(csm);
      setLoading(false);
    })();
  }, []);

  // Per-client balances
  const balancesByClient = useMemo(() => {
    const m = new Map<string, { client: ClientLite | null; balance: number; count: number; lastDate: string | null }>();
    for (const e of entries) {
      const k = e.client_id;
      if (!m.has(k)) m.set(k, { client: clients.get(k) ?? null, balance: 0, count: 0, lastDate: null });
      const g = m.get(k)!;
      g.balance += e.entry_type === "deposit" ? Number(e.amount) : -Number(e.amount);
      g.count += 1;
      if (!g.lastDate || e.entry_date > g.lastDate) g.lastDate = e.entry_date;
    }
    return m;
  }, [entries, clients]);

  const filteredClients = useMemo(() => {
    const q = search.trim().toLowerCase();
    let arr = Array.from(balancesByClient.entries()).map(([id, v]) => ({ id, ...v }));
    if (view === "active") arr = arr.filter((r) => !r.client?.archived_at);
    else if (view === "archived") arr = arr.filter((r) => !!r.client?.archived_at);
    if (q) {
      arr = arr.filter((r) => (r.client?.name ?? "").toLowerCase().includes(q));
    }
    return arr.sort((a, b) => (a.client?.name ?? "").localeCompare(b.client?.name ?? ""));
  }, [balancesByClient, search, view]);

  const totalBalance = useMemo(
    () => filteredClients.reduce((s, r) => s + r.balance, 0),
    [filteredClients],
  );

  const visibleClientIds = useMemo(() => new Set(filteredClients.map((c) => c.id)), [filteredClients]);
  const recentEntries = useMemo(
    () => entries.filter((e) => visibleClientIds.has(e.client_id)).slice(0, 100),
    [entries, visibleClientIds],
  );

  const exportCsv = () => {
    const rows = entries
      .filter((e) => visibleClientIds.has(e.client_id))
      .map((e) => {
        const c = clients.get(e.client_id);
        const cs = e.case_id ? cases.get(e.case_id) : null;
        return {
          date: e.entry_date,
          client: c?.name ?? "",
          archived: c?.archived_at ? "yes" : "",
          case_number: cs?.case_number ?? "",
          case_title: cs?.title ?? "",
          type: e.entry_type,
          amount: Number(e.amount).toFixed(2),
          note: (e.note ?? "").replace(/"/g, '""'),
        };
      });
    const headers = ["date", "client", "archived", "case_number", "case_title", "type", "amount", "note"];
    const csv = [
      headers.join(","),
      ...rows.map((r) => headers.map((h) => `"${(r as any)[h]}"`).join(",")),
    ].join("\n");
    const blob = new Blob([csv], { type: "text/csv;charset=utf-8;" });
    const a = document.createElement("a");
    a.href = URL.createObjectURL(blob);
    a.download = `trust-ledger-${new Date().toISOString().slice(0, 10)}.csv`;
    a.click();
  };

  return (
    <PageContainer>
      <PageHeader
        title="Trust accounting"
        description="All client trust balances and ledger activity."
        actions={
          <Button variant="outline" size="sm" onClick={exportCsv}>
            <Download className="h-3.5 w-3.5 mr-1.5" /> Export CSV
          </Button>
        }
      />

      <div className="grid grid-cols-1 md:grid-cols-3 gap-4 mb-6">
        <Card>
          <CardContent className="p-4">
            <div className="text-xs uppercase tracking-wider text-muted-foreground">Total balance ({view})</div>
            <div className={`font-serif text-2xl mt-1 tabular-nums ${totalBalance < 0 ? "text-destructive" : ""}`}>
              {formatCurrency(totalBalance)}
            </div>
          </CardContent>
        </Card>
        <Card>
          <CardContent className="p-4">
            <div className="text-xs uppercase tracking-wider text-muted-foreground">Clients with activity</div>
            <div className="font-serif text-2xl mt-1 tabular-nums">{filteredClients.length}</div>
          </CardContent>
        </Card>
        <Card>
          <CardContent className="p-4">
            <div className="text-xs uppercase tracking-wider text-muted-foreground">Total entries</div>
            <div className="font-serif text-2xl mt-1 tabular-nums">{entries.length}</div>
          </CardContent>
        </Card>
      </div>

      <div className="flex flex-col md:flex-row gap-3 mb-4">
        <div className="relative flex-1">
          <Search className="absolute left-2.5 top-2.5 h-4 w-4 text-muted-foreground" />
          <Input
            value={search}
            onChange={(e) => setSearch(e.target.value)}
            placeholder="Search clients…"
            className="pl-8"
          />
        </div>
        <Tabs value={view} onValueChange={(v) => setView(v as any)}>
          <TabsList>
            <TabsTrigger value="active">Active</TabsTrigger>
            <TabsTrigger value="archived">Archived</TabsTrigger>
            <TabsTrigger value="all">All</TabsTrigger>
          </TabsList>
        </Tabs>
      </div>

      <Card className="mb-6">
        <CardContent className="p-0">
          {loading ? (
            <p className="p-4 text-sm text-muted-foreground">Loading…</p>
          ) : filteredClients.length === 0 ? (
            <p className="p-4 text-sm text-muted-foreground italic">No trust activity matches.</p>
          ) : (
            <div className="divide-y">
              <div className="grid grid-cols-12 px-4 py-2 text-[11px] uppercase tracking-wider text-muted-foreground bg-muted/30">
                <div className="col-span-6">Client</div>
                <div className="col-span-2 text-right">Entries</div>
                <div className="col-span-2">Last activity</div>
                <div className="col-span-2 text-right">Balance</div>
              </div>
              {filteredClients.map((r) => (
                <Link
                  key={r.id}
                  to="/clients/$clientId"
                  params={{ clientId: r.id }}
                  className="grid grid-cols-12 items-center px-4 py-2.5 text-sm hover:bg-muted/30"
                >
                  <div className="col-span-6 flex items-center gap-2 min-w-0">
                    <Wallet className="h-3.5 w-3.5 text-muted-foreground shrink-0" />
                    <span className="truncate font-medium">{r.client?.name ?? "Unknown client"}</span>
                    {r.client?.archived_at && (
                      <span className="text-[10px] uppercase tracking-wider text-muted-foreground">archived</span>
                    )}
                  </div>
                  <div className="col-span-2 text-right tabular-nums text-muted-foreground">{r.count}</div>
                  <div className="col-span-2 text-muted-foreground">{r.lastDate ? formatDate(r.lastDate) : "—"}</div>
                  <div className={`col-span-2 text-right tabular-nums font-medium ${r.balance < 0 ? "text-destructive" : ""}`}>
                    {formatCurrency(r.balance)}
                  </div>
                </Link>
              ))}
            </div>
          )}
        </CardContent>
      </Card>

      <PageHeader title="Recent activity" description="Last 100 ledger entries (matching filters)." />
      <Card>
        <CardContent className="p-0">
          {recentEntries.length === 0 ? (
            <p className="p-4 text-sm text-muted-foreground italic">No entries.</p>
          ) : (
            <div className="divide-y">
              {recentEntries.map((e) => {
                const c = clients.get(e.client_id);
                const cs = e.case_id ? cases.get(e.case_id) : null;
                const isDeposit = e.entry_type === "deposit";
                return (
                  <div key={e.id} className="flex items-center justify-between gap-3 px-4 py-2.5 text-sm">
                    <div className="flex items-center gap-2 min-w-0">
                      <div
                        className={`h-6 w-6 rounded-full flex items-center justify-center shrink-0 ${
                          isDeposit ? "bg-emerald-500/15 text-emerald-700" : "bg-orange-500/15 text-orange-700"
                        }`}
                      >
                        {isDeposit ? <ArrowDownToLine className="h-3 w-3" /> : <ArrowUpFromLine className="h-3 w-3" />}
                      </div>
                      <div className="min-w-0">
                        <div className="truncate">
                          <Link
                            to="/clients/$clientId"
                            params={{ clientId: e.client_id }}
                            className="font-medium hover:text-primary"
                          >
                            {c?.name ?? "Unknown client"}
                          </Link>
                          {cs && (
                            <span className="text-muted-foreground"> · {cs.case_number ?? cs.title}</span>
                          )}
                          {e.note && <span className="text-muted-foreground"> · {e.note}</span>}
                        </div>
                        <div className="text-[11px] text-muted-foreground">{formatDate(e.entry_date)}</div>
                      </div>
                    </div>
                    <div
                      className={`tabular-nums font-medium shrink-0 ${
                        isDeposit ? "text-emerald-700" : "text-orange-700"
                      }`}
                    >
                      {isDeposit ? "+" : "−"}
                      {formatCurrency(e.amount)}
                    </div>
                  </div>
                );
              })}
            </div>
          )}
        </CardContent>
      </Card>
    </PageContainer>
  );
}