"use client";
export const dynamic = "force-dynamic";



import { useState } from "react";
import { useQuery } from "@tanstack/react-query";
import { BarChart, Bar, XAxis, YAxis, Tooltip, ResponsiveContainer, PieChart, Pie, Cell, Legend, LineChart, Line, CartesianGrid } from "recharts";
import { RefreshCw, TrendingUp, Users, AlertTriangle, DollarSign } from "lucide-react";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/Card";
import { Button } from "@/components/ui/Button";
import { Badge } from "@/components/ui/Badge";
import { formatCurrency } from "@/lib/utils";
import api from "@/lib/api";

const COLORS = ["#0891B2", "#059669", "#F59E0B", "#EF4444", "#8B5CF6", "#EC4899"];

function KpiCard({ title, value, sub, icon: Icon, color }: { title: string; value: string; sub?: string; icon: any; color: string }) {
  return (
    <Card>
      <CardContent className="pt-5">
        <div className="flex items-start justify-between">
          <div>
            <p className="text-sm text-gray-500">{title}</p>
            <p className="text-2xl font-bold text-gray-900 mt-1">{value}</p>
            {sub && <p className="text-xs text-gray-400 mt-0.5">{sub}</p>}
          </div>
          <div className="w-10 h-10 rounded-xl flex items-center justify-center" style={{ backgroundColor: color + "20" }}>
            <Icon size={20} style={{ color }} />
          </div>
        </div>
      </CardContent>
    </Card>
  );
}

export default function ReportsPage() {
  const today = new Date();
  const firstOfMonth = new Date(today.getFullYear(), today.getMonth(), 1).toISOString().split("T")[0];
  const [from, setFrom] = useState(firstOfMonth);
  const [to, setTo] = useState(today.toISOString().split("T")[0]);

  const { data: collection = [], isLoading: collLoading, refetch: refetchAll } = useQuery({
    queryKey: ["reports-collection", from, to],
    queryFn: async () => {
      const res = await api.get(`/api/v1/reports/collection?from=${from}&to=${to}`);
      return res.data as Array<{ collector: string; totalAmount: number; paymentCount: number }>;
    },
  });

  const { data: aging = [] } = useQuery({
    queryKey: ["reports-aging"],
    queryFn: async () => {
      const res = await api.get("/api/v1/reports/aging");
      return res.data as Array<{ bucket: string; invoiceCount: number; totalAmount: number }>;
    },
  });

  const { data: subscribers = [] } = useQuery({
    queryKey: ["reports-subscribers"],
    queryFn: async () => {
      const res = await api.get("/api/v1/reports/subscribers");
      return res.data as Array<{ status: string; count: number; area?: string; plan?: string }>;
    },
  });

  const { data: revenue = [] } = useQuery({
    queryKey: ["reports-revenue"],
    queryFn: async () => {
      const res = await api.get("/api/v1/reports/revenue");
      return (res.data as Array<{ month: string; revenue: number; totalInvoiced: number }>)
        .filter(r => r.revenue > 0 || r.totalInvoiced > 0)
        .slice(-12);
    },
  });

  // Derived KPIs
  const totalCollected = collection.reduce((s, c) => s + Number(c.totalAmount), 0);
  const totalPayments = collection.reduce((s, c) => s + c.paymentCount, 0);
  const totalOutstanding = aging.reduce((s, a) => s + Number(a.totalAmount), 0);
  const overdueCount = aging.reduce((s, a) => s + a.invoiceCount, 0);

  // Subscriber summary (status-only rows, no area key)
  const subByStatus = subscribers.filter(s => !s.area && !s.plan);
  const activeCount = subByStatus.find(s => s.status === "ACTIVE")?.count ?? 0;
  const pendingCount = subByStatus.find(s => s.status === "PENDING")?.count ?? 0;
  const suspendedCount = subByStatus.find(s => s.status === "SUSPENDED")?.count ?? 0;
  const totalSubs = subByStatus.reduce((s, x) => s + x.count, 0);

  // Subscriber by area (rows with area key)
  const subByArea = subscribers.filter(s => !!s.area);

  const agingRisk: Record<string, string> = { "0-30": "text-yellow-600", "31-60": "text-orange-600", "61-90": "text-red-500", "90+": "text-red-700" };

  return (
    <div className="space-y-6">
      <div className="flex items-center justify-between flex-wrap gap-3">
        <div>
          <h1 className="text-2xl font-bold text-gray-900">Reports</h1>
          <p className="text-sm text-gray-500">Financial and operational analytics</p>
        </div>
        <div className="flex items-center gap-2">
          <div className="flex items-center gap-2 text-sm">
            <label className="text-gray-500">From</label>
            <input type="date" value={from} onChange={e => setFrom(e.target.value)}
              className="border rounded-lg px-3 py-1.5 text-sm focus:outline-none focus:ring-2 focus:ring-blue-500" />
            <label className="text-gray-500">To</label>
            <input type="date" value={to} onChange={e => setTo(e.target.value)}
              className="border rounded-lg px-3 py-1.5 text-sm focus:outline-none focus:ring-2 focus:ring-blue-500" />
          </div>
          <Button onClick={() => refetchAll()} variant="outline" size="sm"><RefreshCw size={14} className="mr-1" />Refresh</Button>
        </div>
      </div>

      {/* KPI Summary */}
      <div className="grid grid-cols-2 lg:grid-cols-4 gap-4">
        <KpiCard title="Total Collected" value={formatCurrency(totalCollected)} sub={`${totalPayments} payments`} icon={DollarSign} color="#059669" />
        <KpiCard title="Active Subscribers" value={String(activeCount)} sub={`${pendingCount} pending · ${suspendedCount} suspended`} icon={Users} color="#0891B2" />
        <KpiCard title="Outstanding Balance" value={formatCurrency(totalOutstanding)} sub={`${overdueCount} overdue invoices`} icon={AlertTriangle} color="#EF4444" />
        <KpiCard title="Total Subscribers" value={String(totalSubs)} sub={`across all statuses`} icon={TrendingUp} color="#8B5CF6" />
      </div>

      {/* Collection Report */}
      <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
        <Card>
          <CardHeader><CardTitle>Collection by Collector</CardTitle></CardHeader>
          <CardContent>
            {collLoading ? <div className="h-40 animate-pulse bg-gray-100 rounded" /> :
              collection.length === 0 ? <p className="text-sm text-gray-400 py-6 text-center">No collection data for this period</p> : (
                <>
                  <div className="space-y-2 mb-4">
                    {collection.map((c, i) => (
                      <div key={i} className="flex items-center justify-between py-2 border-b last:border-0">
                        <div>
                          <p className="text-sm font-medium text-gray-800">{c.collector}</p>
                          <p className="text-xs text-gray-400">{c.paymentCount} payments</p>
                        </div>
                        <div className="text-right">
                          <p className="text-sm font-bold text-green-700">{formatCurrency(c.totalAmount)}</p>
                          <p className="text-xs text-gray-400">{totalCollected > 0 ? ((c.totalAmount / totalCollected) * 100).toFixed(1) : 0}%</p>
                        </div>
                      </div>
                    ))}
                    <div className="flex justify-between pt-1 font-semibold text-sm">
                      <span>Total</span>
                      <span className="text-green-700">{formatCurrency(totalCollected)}</span>
                    </div>
                  </div>
                  <ResponsiveContainer width="100%" height={160}>
                    <BarChart data={collection} margin={{ top: 0, right: 0, left: 0, bottom: 0 }}>
                      <XAxis dataKey="collector" tick={{ fontSize: 11 }} />
                      <YAxis tick={{ fontSize: 11 }} tickFormatter={v => `₱${(v/1000).toFixed(0)}k`} />
                      <Tooltip formatter={(v: any) => formatCurrency(Number(v))} />
                      <Bar dataKey="totalAmount" fill="#0891B2" radius={[4,4,0,0]} />
                    </BarChart>
                  </ResponsiveContainer>
                </>
              )
            }
          </CardContent>
        </Card>

        {/* Aging Report */}
        <Card>
          <CardHeader><CardTitle>Accounts Receivable Aging</CardTitle></CardHeader>
          <CardContent>
            <div className="space-y-3">
              {aging.map((a) => (
                <div key={a.bucket} className="flex items-center justify-between p-3 rounded-lg bg-gray-50">
                  <div>
                    <p className={`text-sm font-semibold ${agingRisk[a.bucket] ?? "text-gray-700"}`}>{a.bucket} days overdue</p>
                    <p className="text-xs text-gray-400">{a.invoiceCount} invoice{a.invoiceCount !== 1 ? "s" : ""}</p>
                  </div>
                  <div className="text-right">
                    <p className={`text-base font-bold ${a.totalAmount > 0 ? agingRisk[a.bucket] ?? "text-gray-800" : "text-gray-400"}`}>
                      {formatCurrency(a.totalAmount)}
                    </p>
                  </div>
                </div>
              ))}
              <div className="flex justify-between px-3 py-2 bg-red-50 rounded-lg font-semibold text-sm">
                <span className="text-red-700">Total Outstanding</span>
                <span className="text-red-700">{formatCurrency(totalOutstanding)}</span>
              </div>
            </div>
          </CardContent>
        </Card>
      </div>

      {/* Revenue Trend */}
      {revenue.length > 0 && (
        <Card>
          <CardHeader><CardTitle>Revenue Trend (Monthly)</CardTitle></CardHeader>
          <CardContent>
            <ResponsiveContainer width="100%" height={220}>
              <LineChart data={revenue} margin={{ top: 5, right: 20, left: 0, bottom: 5 }}>
                <CartesianGrid strokeDasharray="3 3" stroke="#F1F5F9" />
                <XAxis dataKey="month" tick={{ fontSize: 11 }} />
                <YAxis tick={{ fontSize: 11 }} tickFormatter={v => `₱${(v/1000).toFixed(0)}k`} />
                <Tooltip formatter={(v: any) => formatCurrency(Number(v))} />
                <Legend />
                <Line type="monotone" dataKey="revenue" stroke="#059669" strokeWidth={2} dot={false} name="Collected" />
                <Line type="monotone" dataKey="totalInvoiced" stroke="#0891B2" strokeWidth={2} dot={false} name="Invoiced" strokeDasharray="4 2" />
              </LineChart>
            </ResponsiveContainer>
          </CardContent>
        </Card>
      )}

      {/* Subscribers by Status + Area */}
      <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
        <Card>
          <CardHeader><CardTitle>Subscribers by Status</CardTitle></CardHeader>
          <CardContent>
            {subByStatus.length === 0 ? <p className="text-sm text-gray-400 py-4 text-center">No subscriber data</p> : (
              <div className="flex gap-6 items-center">
                <ResponsiveContainer width="50%" height={160}>
                  <PieChart>
                    <Pie data={subByStatus} dataKey="count" nameKey="status" cx="50%" cy="50%" outerRadius={60} label={false}>
                      {subByStatus.map((_, i) => <Cell key={i} fill={COLORS[i % COLORS.length]} />)}
                    </Pie>
                    <Tooltip />
                  </PieChart>
                </ResponsiveContainer>
                <div className="space-y-2">
                  {subByStatus.map((s, i) => (
                    <div key={s.status} className="flex items-center gap-2">
                      <div className="w-3 h-3 rounded-full" style={{ backgroundColor: COLORS[i % COLORS.length] }} />
                      <span className="text-sm text-gray-700">{s.status}</span>
                      <span className="text-sm font-bold text-gray-900 ml-auto">{s.count}</span>
                    </div>
                  ))}
                  <div className="border-t pt-1 flex justify-between text-sm font-semibold">
                    <span>Total</span><span>{totalSubs}</span>
                  </div>
                </div>
              </div>
            )}
          </CardContent>
        </Card>

        {subByArea.length > 0 && (
          <Card>
            <CardHeader><CardTitle>Active Subscribers by Area</CardTitle></CardHeader>
            <CardContent>
              <div className="space-y-2">
                {subByArea.map((a) => (
                  <div key={a.area} className="flex items-center justify-between py-2 border-b last:border-0">
                    <span className="text-sm font-medium text-gray-800">{a.area}</span>
                    <div className="flex items-center gap-2">
                      <div className="w-20 bg-gray-100 rounded-full h-2 overflow-hidden">
                        <div className="h-2 rounded-full bg-blue-500" style={{ width: `${Math.min(100, (a.count / (activeCount || 1)) * 100)}%` }} />
                      </div>
                      <span className="text-sm font-bold text-gray-700 w-6 text-right">{a.count}</span>
                    </div>
                  </div>
                ))}
              </div>
            </CardContent>
          </Card>
        )}
      </div>
    </div>
  );
}
