'use client';

import { useEffect, useState } from 'react';
import { useSearchParams, useRouter } from 'next/navigation';
import { useSession } from 'next-auth/react';
import toast from 'react-hot-toast';
import { DocumentRenderer } from '@/components/print-builder/DocumentRenderer';
import { buildDataContext } from '@/lib/utils/templateData';
import { DEFAULT_DELIVERY_NOTE } from '@/lib/utils/documentDefaults';
import type { DocumentTemplate } from '@/lib/types/documentTemplate';

interface Transaction {
  id: string;
  companyId: string;
  isDeliveryNote: boolean;
  notes?: string;
  date: string;
  totalCost: number;
  quantity: number;
  deliveryNote?: { id: string; number: number } | null;
  material?: { name: string; unit: string; unitCost: number };
  job?: { jobNumber: string; description: string; site?: string; lpoNumber?: string; quotationNumber?: string };
  performedByUser?: {
    id: string;
    name?: string | null;
    email?: string | null;
    image?: string | null;
    signatureUrl?: string | null;
  } | null;
}

interface Company {
  id: string;
  name: string;
  address?: string;
  phone?: string;
  email?: string;
  letterheadUrl?: string;
  printTemplates?: any[] | null;
}

export default function PrintDeliveryNotePage() {
  const { data: session } = useSession();
  const searchParams = useSearchParams();
  const router = useRouter();
  const transactionId = searchParams.get('id');
  const deliveryNoteId = searchParams.get('deliveryNoteId');
  const templateId = searchParams.get('templateId');

  const [transaction, setTransaction] = useState<Transaction | null>(null);
  const [company, setCompany] = useState<Company | null>(null);
  const [loading, setLoading] = useState(true);
  const [screenPageCount, setScreenPageCount] = useState(1);

  useEffect(() => {
    if (!transactionId && !deliveryNoteId) {
      setLoading(false);
      toast.error('No delivery note or transaction reference provided');
      router.back();
      return;
    }

    if (deliveryNoteId && !transactionId && !session?.user?.activeCompanyId) {
      return;
    }

    let cancelled = false;

    const load = async () => {
      try {
        if (transactionId) {
          const txnRes = await fetch(`/api/transactions/${transactionId}`);

          if (!txnRes.ok) {
            toast.error('Transaction not found');
            router.back();
            return;
          }

          const txnData = await txnRes.json();
          const txn = txnData.data as Transaction;
          if (cancelled) return;
          setTransaction(txn);

          const cid = txn?.companyId;
          if (cid) {
            const companyRes = await fetch(`/api/companies/${cid}`);
            if (companyRes.ok && !cancelled) {
              const companyJson = await companyRes.json();
              setCompany(companyJson.data as Company);
            }
          }
        } else if (deliveryNoteId && session?.user?.activeCompanyId) {
          const dnRes = await fetch(`/api/delivery-notes/${encodeURIComponent(deliveryNoteId)}`);
          const dnJson = await dnRes.json();
          if (!dnRes.ok || !dnJson.data) {
            toast.error(dnJson.error || 'Delivery note not found');
            router.back();
            return;
          }

          const dn = dnJson.data as {
            id: string;
            number: number;
            date: string;
            documentNotes: string | null;
            customItemsJson: unknown;
            job: Record<string, unknown> | null;
          };

          let notesBody = (dn.documentNotes ?? '').trim();
          notesBody = notesBody ? `${notesBody}\n` : '';
          notesBody += `--- DELIVERY NOTE #${dn.number}\n`;
          const contact = typeof dn.job?.contactPerson === 'string' ? dn.job.contactPerson.trim() : '';
          if (contact) {
            notesBody += `--- DELIVERY CONTACT PERSON:${contact}\n`;
          }
          notesBody += '--- DELIVERY NOTE ITEMS (For Printing) ---\n';
          if (Array.isArray(dn.customItemsJson)) {
            for (const row of dn.customItemsJson as Array<Record<string, unknown>>) {
              const name = String(row.name ?? '');
              const desc = typeof row.description === 'string' ? row.description : '';
              const qty = String(row.qty ?? '');
              const unit = String(row.unit ?? '');
              const left = desc.trim() ? `${name} - ${desc.trim()}` : name;
              notesBody += `• ${left} | ${qty} ${unit}\n`;
            }
          }

          const companyId = session.user.activeCompanyId;
          const synthetic: Transaction = {
            id: dn.id,
            companyId,
            isDeliveryNote: true,
            notes: notesBody.trim(),
            date: typeof dn.date === 'string' ? dn.date : new Date(dn.date).toISOString(),
            totalCost: 0,
            quantity: 0,
            deliveryNote: { id: dn.id, number: dn.number },
            job: dn.job as unknown as Transaction['job'],
            material: undefined,
            performedByUser: null,
          };
          if (cancelled) return;
          setTransaction(synthetic);

          const companyRes = await fetch(`/api/companies/${companyId}`);
          if (companyRes.ok && !cancelled) {
            const companyJson = await companyRes.json();
            setCompany(companyJson.data as Company);
          }
        }
      } catch (err) {
        console.error('Failed to load data:', err);
        toast.error('Failed to load delivery note');
      } finally {
        if (!cancelled) {
          setLoading(false);
        }
      }
    };

    void load();
    return () => {
      cancelled = true;
    };
  }, [transactionId, deliveryNoteId, router, session?.user?.activeCompanyId]);

  // Auto-print after data loads
  useEffect(() => {
    if (!loading && transaction && company) {
      // Small delay to let the renderer paint
      const timer = setTimeout(() => window.print(), 400);
      return () => clearTimeout(timer);
    }
  }, [loading, transaction, company]);

  // Screen preview: estimate number of A4 pages and expose it to CSS.
  useEffect(() => {
    if (loading || !transaction || !company) return;
    const root = document.querySelector('.document-renderer-root') as HTMLElement | null;
    if (!root) return;
    const widthPx = root.getBoundingClientRect().width || 1;
    const pxPerMm = widthPx / 210;
    const pagePx = 297 * pxPerMm;
    const pages = Math.max(1, Math.ceil(root.scrollHeight / pagePx));
    setScreenPageCount(pages);
  }, [loading, transaction, company, templateId]);

  if (loading) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-white">
        <p style={{ color: '#666', fontFamily: 'Arial' }}>Loading document...</p>
      </div>
    );
  }

  if (!transaction || !company) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-white">
        <p style={{ color: '#c00', fontFamily: 'Arial' }}>Failed to load data</p>
      </div>
    );
  }

  // Resolve template
  let template: DocumentTemplate = DEFAULT_DELIVERY_NOTE;
  if (company.printTemplates && Array.isArray(company.printTemplates)) {
    if (templateId) {
      const found = company.printTemplates.find((t: any) => t.id === templateId);
      if (found) template = found;
    } else {
      const defaultDN = company.printTemplates.find(
        (t: any) => t.itemType === 'delivery-note' && t.isDefault
      );
      if (defaultDN) template = defaultDN;
      else {
        const firstDN = company.printTemplates.find((t: any) => t.itemType === 'delivery-note');
        if (firstDN) template = firstDN;
      }
    }
  }

  const creatorOrFallbackUser = transaction.performedByUser ?? {
    name: session?.user?.name,
    image: session?.user?.image,
    signatureUrl: session?.user?.signatureUrl,
  };

  const data = buildDataContext('delivery-note', transaction as any, company as any, creatorOrFallbackUser);

  return (
    <>
      {/* Print-specific CSS */}
      <style>{`
        /* Reset everything for print */
        *, *::before, *::after {
          box-sizing: border-box;
        }

        html, body {
          margin: 0;
          padding: 0;
          background: white;
          -webkit-print-color-adjust: exact;
          print-color-adjust: exact;
        }

        @page {
          size: A4;
          margin: 0;
        }

        @media print {
          /* Hide screen-only controls */
          .screen-only {
            display: none !important;
          }

          /* Let tables break across pages with repeated headers */
          thead {
            display: table-header-group;
          }

          /* Prevent rows from splitting across pages */
          tr {
            page-break-inside: avoid;
            break-inside: avoid;
          }

          /* Prevent signatures from splitting */
          .document-renderer > div:last-child {
            page-break-inside: avoid;
            break-inside: avoid;
          }
        }

        @media screen {
          body {
            background: #e5e7eb;
          }
          .print-page-wrapper {
            max-width: 210mm;
            margin: 20px auto;
            box-shadow: 0 4px 20px rgba(0,0,0,0.15);
            position: relative;
            --preview-total-pages: 1;
          }

          /* Screen-only visual page separators */
          .screen-page-separator {
            position: absolute;
            left: 0;
            right: 0;
            border-top: 1px dashed rgba(71, 85, 105, 0.45);
            pointer-events: none;
          }

          .screen-page-label {
            position: absolute;
            right: 8px;
            transform: translateY(-50%);
            font-size: 10px;
            color: #64748b;
            background: rgba(255,255,255,0.8);
            padding: 2px 6px;
            border-radius: 999px;
            pointer-events: none;
          }

          /* In screen preview, show total pages from JS-estimated count */
          .print-page-total::before {
            content: var(--preview-total-pages);
          }
        }
      `}</style>

      {/* Screen-only controls */}
      <div className="screen-only" style={{
        position: 'fixed', top: 0, left: 0, right: 0,
        padding: '12px 20px',
        background: '#1e293b',
        display: 'flex', alignItems: 'center', gap: '12px',
        zIndex: 100,
        boxShadow: '0 2px 10px rgba(0,0,0,0.3)',
      }}>
        <button
          onClick={() => window.print()}
          style={{
            padding: '8px 20px', background: '#059669', color: '#fff',
            border: 'none', borderRadius: '6px', cursor: 'pointer',
            fontWeight: 600, fontSize: '14px',
          }}
        >
          Print
        </button>
        <button
          onClick={() => window.close()}
          style={{
            padding: '8px 20px', background: '#475569', color: '#fff',
            border: 'none', borderRadius: '6px', cursor: 'pointer',
            fontWeight: 600, fontSize: '14px',
          }}
        >
          Close
        </button>
        <span style={{ color: '#94a3b8', fontSize: '13px', marginLeft: '8px' }}>
          {template.name} &mdash; DN #{(data as any).dn?.number ?? ''}
        </span>
      </div>

      {/* Spacer for the fixed header on screen */}
      <div className="screen-only" style={{ height: '60px' }} />

      {/* The actual document */}
      <div
        className="print-page-wrapper"
        style={{ ['--preview-total-pages' as any]: `"${screenPageCount}"` }}
      >
        <div className="screen-only">
          {Array.from({ length: Math.max(0, screenPageCount - 1) }).map((_, i) => (
            <div
              key={`sep-${i}`}
              className="screen-page-separator"
              style={{ top: `${(i + 1) * 297}mm` }}
            />
          ))}
          {Array.from({ length: screenPageCount }).map((_, i) => (
            <div
              key={`lbl-${i}`}
              className="screen-page-label"
              style={{ top: `${(i + 1) * 297 - 6}mm` }}
            >
              Page {i + 1} / {screenPageCount}
            </div>
          ))}
        </div>
        <DocumentRenderer template={template} data={data} mode="print" />
      </div>
    </>
  );
}
