'use client';

import { useCallback, useEffect, useRef, useState } from 'react';
import useAuthStore from '../../../store/authStore';

export type AdminInvoice = {
  id: string | number;
  invoice_number?: string | null;
  user_id?: string | number | null;
  buyer_name?: string | null;
  buyer_email?: string | null;
  buyer_street?: string | null;
  buyer_postal_code?: string | null;
  buyer_city?: string | null;
  buyer_country?: string | null;
  currency?: string | null;
  total_net?: number | null;
  total_tax?: number | null;
  total_gross?: number | null;
  vat_rate?: number | null;
  status?: string;
  issued_at?: string | null;
  due_at?: string | null;
  pdf_storage_key?: string | null;
  context?: any | null;
  created_at?: string | null;
  updated_at?: string | null;
};

export type AdminInvoiceRevenueSummary = {
  totalPaidAllTime: number;
  currency?: string | null;
  paidInvoiceCount?: number;
};

export function useAdminInvoices(params?: { status?: string; limit?: number; offset?: number }) {
  const accessToken = useAuthStore(s => s.accessToken);
  const [invoices, setInvoices] = useState<AdminInvoice[]>([]);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string>('');
  const inFlight = useRef<AbortController | null>(null);

  const fetchInvoices = useCallback(async () => {
    setError('');
    // Abort previous
    inFlight.current?.abort();
    const controller = new AbortController();
    inFlight.current = controller;

    try {
      const base = process.env.NEXT_PUBLIC_API_BASE_URL || '';
      const qp = new URLSearchParams();
      if (params?.status) qp.set('status', params.status);
      qp.set('limit', String(params?.limit ?? 200));
      qp.set('offset', String(params?.offset ?? 0));
      const url = `${base}/api/admin/invoices${qp.toString() ? `?${qp.toString()}` : ''}`;

      setLoading(true);
      const res = await fetch(url, {
        method: 'GET',
        credentials: 'include',
        headers: {
          'Accept': 'application/json',
          ...(accessToken ? { Authorization: `Bearer ${accessToken}` } : {}),
        },
        signal: controller.signal,
      });

      const body = await res.json().catch(() => ({}));
      if (!res.ok || body?.success === false) {
        setInvoices([]);
        setError(body?.message || `Failed to load invoices (${res.status})`);
        return;
      }
      const list: AdminInvoice[] = Array.isArray(body?.data) ? body.data : [];
      // sort fallback (issued_at DESC then created_at DESC)
      list.sort((a, b) => {
        const ad = new Date(a.issued_at ?? a.created_at ?? 0).getTime();
        const bd = new Date(b.issued_at ?? b.created_at ?? 0).getTime();
        return bd - ad;
      });
      setInvoices(list);
    } catch (e: any) {
      if (e?.name === 'AbortError') return;
      setError(e?.message || 'Network error');
      setInvoices([]);
    } finally {
      setLoading(false);
      if (inFlight.current === controller) inFlight.current = null;
    }
  }, [accessToken, params?.status, params?.limit, params?.offset]);

  useEffect(() => {
    if (accessToken) fetchInvoices();
    return () => inFlight.current?.abort();
  }, [accessToken, fetchInvoices]);

  return { invoices, loading, error, reload: fetchInvoices };
}

export function useAdminInvoiceRevenueSummary() {
  const accessToken = useAuthStore(s => s.accessToken);
  const [summary, setSummary] = useState<AdminInvoiceRevenueSummary | null>(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string>('');
  const inFlight = useRef<AbortController | null>(null);

  const fetchSummary = useCallback(async () => {
    setError('');
    inFlight.current?.abort();
    const controller = new AbortController();
    inFlight.current = controller;

    try {
      const base = process.env.NEXT_PUBLIC_API_BASE_URL || '';
      const url = `${base}/api/admin/invoices/revenue-summary`;

      setLoading(true);
      const res = await fetch(url, {
        method: 'GET',
        credentials: 'include',
        headers: {
          Accept: 'application/json',
          ...(accessToken ? { Authorization: `Bearer ${accessToken}` } : {}),
        },
        signal: controller.signal,
      });

      const body = await res.json().catch(() => ({}));
      if (!res.ok || body?.success === false) {
        setSummary(null);
        setError(body?.message || `Failed to load revenue summary (${res.status})`);
        return;
      }

      setSummary(body?.data || { totalPaidAllTime: 0, currency: 'EUR', paidInvoiceCount: 0 });
    } catch (e: any) {
      if (e?.name === 'AbortError') return;
      setError(e?.message || 'Network error');
      setSummary(null);
    } finally {
      setLoading(false);
      if (inFlight.current === controller) inFlight.current = null;
    }
  }, [accessToken]);

  useEffect(() => {
    if (accessToken) fetchSummary();
    return () => inFlight.current?.abort();
  }, [accessToken, fetchSummary]);

  return { summary, loading, error, reload: fetchSummary };
}