"use client";

import { useState } from "react";
import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import { useParams, useRouter } from "next/navigation";
import { ArrowLeft, Wifi, FileText, Ticket, CreditCard, RefreshCw } from "lucide-react";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/Card";
import { Badge } from "@/components/ui/Badge";
import { Button } from "@/components/ui/Button";
import { Modal } from "@/components/ui/Modal";
import { Input } from "@/components/ui/Input";
import { Table, TableHead, TableBody, TableRow, Th, Td, EmptyState } from "@/components/ui/Table";
import { formatDate, formatCurrency } from "@/lib/utils";
import api from "@/lib/api";
import { toast } from "sonner";
import type { Client, Subscription, Invoice, Ticket as TicketType, Payment, LegacyPaginatedResponse } from "@/types";

type Tab = "profile" | "subscriptions" | "invoices" | "payments" | "tickets";

const statusColor: Record<string, "success" | "warning" | "danger" | "muted"> = {
  ACTIVE: "success", active: "success",
  SUSPENDED: "warning", suspended: "warning",
  CANCELLED: "danger", cancelled: "danger",
  DISCONNECTED: "danger",
  PENDING: "muted", pending: "muted",
};

const invColor: Record<string, "success" | "warning" | "danger" | "muted"> = {
  PAID: "success", paid: "success",
  PARTIAL: "warning", partial: "warning",
  OVERDUE: "danger", overdue: "danger",
  SENT: "muted", DRAFT: "muted", VOID: "muted",
};

const channelColors: Record<string, string> = {
  CASH: "bg-green-100 text-green-700",
  GCASH: "bg-blue-100 text-blue-700",
  MAYA: "bg-purple-100 text-purple-700",
  BANK_TRANSFER: "bg-yellow-100 text-yellow-700",
  CHECK: "bg-gray-100 text-gray-700",
};

export default function ClientDetailPage() {
  const { id } = useParams<{ id: string }>();
  const router = useRouter();
  const qc = useQueryClient();
  const [activeTab, setActiveTab] = useState<Tab>("profile");
  const [payInvoice, setPayInvoice] = useState<Invoice | null>(null);
  const [payForm, setPayForm] = useState({ amount: "", channel: "CASH", referenceNumber: "", notes: "" });

  const { data: client, isLoading, refetch: refetchClient } = useQuery<Client>({
    queryKey: ["client", id],
    queryFn: async () => { const r = await api.get<Client>(`/api/v1/clients/${id}`); return r.data; },
  });

  const { data: subscriptions, isError: subsError } = useQuery<Subscription[]>({
    queryKey: ["client-subscriptions", id],
    queryFn: async () => { const r = await api.get<Subscription[]>(`/api/v1/clients/${id}/subscriptions`); return r.data; },
    enabled: activeTab === "subscriptions",
  });

  const { data: invoicesData, refetch: refetchInvoices } = useQuery<LegacyPaginatedResponse<Invoice>>({
    queryKey: ["client-invoices", id],
    queryFn: async () => { const r = await api.get<LegacyPaginatedResponse<Invoice>>(`/api/v1/invoices?clientId=${id}&page=1&limit=30`); return r.data; },
    enabled: activeTab === "invoices",
  });

  const { data: paymentsData } = useQuery<LegacyPaginatedResponse<Payment>>({
    queryKey: ["client-payments", id],
    queryFn: async () => {
      const r = await api.get<LegacyPaginatedResponse<Payment>>(`/api/v1/payments?clientId=${id}&page=1&limit=30`);
      return r.data;
    },
    enabled: activeTab === "payments",
  });

  const { data: ticketsData } = useQuery<LegacyPaginatedResponse<TicketType>>({
    queryKey: ["client-tickets", id],
    queryFn: async () => { const r = await api.get<LegacyPaginatedResponse<TicketType>>(`/api/v1/tickets?clientId=${id}&page=1&limit=20`); return r.data; },
    enabled: activeTab === "tickets",
  });

  const recordPayment = useMutation({
    mutationFn: async () => {
      await api.post("/api/v1/payments", {
        clientId: id, invoiceId: payInvoice?.id,
        amount: Number(payForm.amount), channel: payForm.channel,
        referenceNumber: payForm.referenceNumber || undefined,
        notes: payForm.notes || undefined,
        paymentDate: new Date().toISOString(),
      });
    },
    onSuccess: () => {
      toast.success("Payment recorded!");
      setPayInvoice(null);
      setPayForm({ amount: "", channel: "CASH", referenceNumber: "", notes: "" });
      qc.invalidateQueries({ queryKey: ["client-invoices", id] });
      qc.invalidateQueries({ queryKey: ["client-payments", id] });
      refetchInvoices();
    },
    onError: (e: any) => toast.error(e.response?.data?.message ?? "Payment failed"),
  });

  const tabs = [
    { key: "profile" as Tab, label: "Profile" },
    { key: "subscriptions" as Tab, label: "Subscriptions" },
    { key: "invoices" as Tab, label: "Invoices" },
    { key: "payments" as Tab, label: "Payments" },
    { key: "tickets" as Tab, label: "Tickets" },
  ];

  if (isLoading) return (
    <div className="space-y-4">
      <div className="h-8 w-48 animate-pulse bg-gray-200 rounded" />
      <Card><CardContent className="py-10"><div className="h-32 animate-pulse bg-gray-100 rounded-lg" /></CardContent></Card>
    </div>
  );

  if (!client) return (
    <div className="text-center py-20 text-gray-400">
      <p>Client not found</p>
      <Button variant="secondary" className="mt-4" onClick={() => router.push("/clients")}>Back to Clients</Button>
    </div>
  );

  const sub = client.subscriptions?.[0];
  const clientStatus = sub?.status ?? (client.isActive ? "ACTIVE" : "INACTIVE");

  return (
    <div className="space-y-4">
      {/* Header */}
      <div className="flex items-center gap-3">
        <Button variant="ghost" size="sm" onClick={() => router.push("/clients")}>
          <ArrowLeft className="h-4 w-4 mr-1" /> Back
        </Button>
        <div className="flex-1">
          <h1 className="text-2xl font-bold text-gray-900">{client.firstName} {client.lastName}</h1>
          <p className="text-sm text-gray-500">{client.accountNumber} · {client.area?.name ?? "No area"}</p>
        </div>
        <Badge variant={statusColor[clientStatus] ?? "muted"}>{clientStatus}</Badge>
        <Button size="sm" variant="outline" onClick={() => refetchClient()}><RefreshCw className="h-4 w-4" /></Button>
      </div>

      {/* Tabs */}
      <div className="flex border-b border-gray-200 overflow-x-auto">
        {tabs.map(tab => (
          <button key={tab.key} onClick={() => setActiveTab(tab.key)}
            className={`px-4 py-2.5 text-sm font-medium border-b-2 whitespace-nowrap transition-colors ${
              activeTab === tab.key ? "border-blue-600 text-blue-600" : "border-transparent text-gray-500 hover:text-gray-700"
            }`}>{tab.label}</button>
        ))}
      </div>

      {/* Profile */}
      {activeTab === "profile" && (
        <Card>
          <CardHeader><CardTitle>Client Profile</CardTitle></CardHeader>
          <CardContent>
            <dl className="grid grid-cols-1 sm:grid-cols-2 gap-4">
              {[
                { label: "Account Number", value: client.accountNumber },
                { label: "Full Name", value: `${client.firstName} ${client.lastName}` },
                { label: "Email", value: client.email || "—" },
                { label: "Phone", value: client.phone },
                { label: "Address", value: client.address || "—" },
                { label: "Area", value: client.area?.name || "—" },
                { label: "Status", value: client.isActive ? "Active" : "Inactive" },
                { label: "Joined", value: formatDate(client.createdAt) },
              ].map(({ label, value }) => (
                <div key={label}>
                  <dt className="text-xs font-medium text-gray-400 uppercase tracking-wide">{label}</dt>
                  <dd className="mt-0.5 text-sm text-gray-900">{value}</dd>
                </div>
              ))}
            </dl>
          </CardContent>
        </Card>
      )}

      {/* Subscriptions */}
      {activeTab === "subscriptions" && (
        <Card>
          <CardHeader><CardTitle>Subscriptions</CardTitle></CardHeader>
          <CardContent className="p-0">
            <Table>
              <TableHead><TableRow><Th>Plan</Th><Th>Type</Th><Th>Status</Th><Th>Start Date</Th><Th>Monthly Rate</Th></TableRow></TableHead>
              <TableBody>
                {!subscriptions || subscriptions.length === 0 ? <EmptyState message="No subscriptions" /> :
                  subscriptions.map(sub => (
                    <TableRow key={sub.id}>
                      <Td className="font-medium">{sub.plan?.name ?? "—"}</Td>
                      <Td><Badge variant="muted">{sub.type ?? sub.plan?.type ?? "—"}</Badge></Td>
                      <Td><Badge variant={statusColor[sub.status] ?? "muted"}>{sub.status}</Badge></Td>
                      <Td>{formatDate(sub.startDate)}</Td>
                      <Td>{formatCurrency(Number(sub.monthlyPrice ?? sub.plan?.monthlyPrice ?? 0))}</Td>
                    </TableRow>
                  ))
                }
              </TableBody>
            </Table>
          </CardContent>
        </Card>
      )}

      {/* Invoices */}
      {activeTab === "invoices" && (
        <Card>
          <CardHeader><CardTitle>Invoices</CardTitle></CardHeader>
          <CardContent className="p-0">
            <Table>
              <TableHead><TableRow><Th>Invoice #</Th><Th>Total</Th><Th>Balance</Th><Th>Due Date</Th><Th>Status</Th><Th></Th></TableRow></TableHead>
              <TableBody>
                {!invoicesData?.data || invoicesData.data.length === 0 ? <EmptyState message="No invoices" /> :
                  invoicesData.data.map((inv: any) => (
                    <TableRow key={inv.id}>
                      <Td className="font-mono text-xs">{inv.invoiceNumber ?? inv.id.slice(0, 8)}</Td>
                      <Td>{formatCurrency(Number(inv.total ?? inv.amount ?? 0))}</Td>
                      <Td className={Number(inv.balance) > 0 ? "text-red-600 font-medium" : "text-gray-500"}>
                        {formatCurrency(Number(inv.balance ?? 0))}
                      </Td>
                      <Td>{inv.dueDate ? formatDate(inv.dueDate) : "—"}</Td>
                      <Td><Badge variant={invColor[inv.status] ?? "muted"}>{inv.status}</Badge></Td>
                      <Td>
                        {["SENT", "PARTIAL", "OVERDUE"].includes(inv.status) && (
                          <Button size="sm" onClick={() => {
                            setPayInvoice(inv);
                            setPayForm(f => ({ ...f, amount: String(Number(inv.balance ?? inv.total ?? 0)) }));
                          }}>Pay</Button>
                        )}
                      </Td>
                    </TableRow>
                  ))
                }
              </TableBody>
            </Table>
          </CardContent>
        </Card>
      )}

      {/* Payments */}
      {activeTab === "payments" && (
        <Card>
          <CardHeader><CardTitle>Payment History</CardTitle></CardHeader>
          <CardContent className="p-0">
            <Table>
              <TableHead><TableRow><Th>Date</Th><Th>Amount</Th><Th>Channel</Th><Th>Reference</Th><Th>Notes</Th></TableRow></TableHead>
              <TableBody>
                {!paymentsData?.data || paymentsData.data.length === 0 ? <EmptyState message="No payments yet" /> :
                  paymentsData.data.map((p: any) => (
                    <TableRow key={p.id}>
                      <Td className="text-sm">{p.paymentDate ? formatDate(p.paymentDate) : formatDate(p.createdAt)}</Td>
                      <Td className="font-medium text-green-700">{formatCurrency(Number(p.amount))}</Td>
                      <Td><span className={`px-2 py-0.5 rounded-full text-xs font-medium ${channelColors[p.channel] ?? "bg-gray-100 text-gray-600"}`}>{p.channel}</span></Td>
                      <Td className="text-xs text-gray-500">{p.referenceNumber ?? p.orNumber ?? "—"}</Td>
                      <Td className="text-xs text-gray-500">{p.notes ?? "—"}</Td>
                    </TableRow>
                  ))
                }
              </TableBody>
            </Table>
          </CardContent>
        </Card>
      )}

      {/* Tickets */}
      {activeTab === "tickets" && (
        <Card>
          <CardHeader><CardTitle>Tickets</CardTitle></CardHeader>
          <CardContent className="p-0">
            <Table>
              <TableHead><TableRow><Th>Subject</Th><Th>Type</Th><Th>Priority</Th><Th>Status</Th><Th>Created</Th></TableRow></TableHead>
              <TableBody>
                {!ticketsData?.data || ticketsData.data.length === 0 ? <EmptyState message="No tickets" /> :
                  ticketsData.data.map(t => (
                    <TableRow key={t.id}>
                      <Td className="font-medium">{t.subject}</Td>
                      <Td><Badge variant="muted">{t.type}</Badge></Td>
                      <Td><Badge variant={t.priority === "HIGH" ? "warning" : "muted"}>{t.priority}</Badge></Td>
                      <Td><Badge variant={t.status === "RESOLVED" ? "success" : t.status === "OPEN" ? "warning" : "muted"}>{t.status}</Badge></Td>
                      <Td className="text-xs text-gray-400">{formatDate(t.createdAt)}</Td>
                    </TableRow>
                  ))
                }
              </TableBody>
            </Table>
          </CardContent>
        </Card>
      )}

      {/* Pay Invoice Modal */}
      <Modal isOpen={!!payInvoice} onClose={() => setPayInvoice(null)} title={`Record Payment — ${payInvoice?.invoiceNumber ?? ""}`}>
        {payInvoice && (
          <div className="space-y-4">
            <div className="bg-gray-50 rounded-lg p-3 text-sm space-y-1">
              <div className="flex justify-between"><span className="text-gray-500">Invoice Total</span><span className="font-medium">{formatCurrency(Number((payInvoice as any).total ?? payInvoice.amount))}</span></div>
              <div className="flex justify-between"><span className="text-gray-500">Amount Paid</span><span>{formatCurrency(Number((payInvoice as any).amountPaid ?? 0))}</span></div>
              <div className="flex justify-between font-medium text-red-600"><span>Balance Due</span><span>{formatCurrency(Number((payInvoice as any).balance ?? payInvoice.amount))}</span></div>
            </div>
            <Input label="Amount" type="number" value={payForm.amount} onChange={e => setPayForm(f => ({ ...f, amount: e.target.value }))} />
            <div className="flex flex-col gap-1.5">
              <label className="text-sm font-medium text-gray-700">Payment Method</label>
              <select className="border rounded-lg px-3 py-2 text-sm" value={payForm.channel} onChange={e => setPayForm(f => ({ ...f, channel: e.target.value }))}>
                {["CASH","GCASH","MAYA","BANK_TRANSFER","CHECK"].map(c => <option key={c} value={c}>{c}</option>)}
              </select>
            </div>
            <Input label="Reference # (optional)" value={payForm.referenceNumber} onChange={e => setPayForm(f => ({ ...f, referenceNumber: e.target.value }))} />
            <Input label="Notes (optional)" value={payForm.notes} onChange={e => setPayForm(f => ({ ...f, notes: e.target.value }))} />
            <div className="flex justify-end gap-2 pt-1">
              <Button variant="outline" onClick={() => setPayInvoice(null)}>Cancel</Button>
              <Button onClick={() => recordPayment.mutate()} isLoading={recordPayment.isPending} disabled={!payForm.amount}>Record Payment</Button>
            </div>
          </div>
        )}
      </Modal>
    </div>
  );
}
