// lib/screens/pdf_list_screen.dart
// Version: 1.2.0 (DB Integration: List Invoices from SQLite)
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import '../data/database.dart' as db;
import '../main.dart';
import '../models/invoice_models.dart';
import '../models/app_model.dart' as app_model;
import 'invoice_detail_page.dart';

class PdfListScreen extends StatefulWidget {
  const PdfListScreen({Key? key}) : super(key: key);

  @override
  State<PdfListScreen> createState() => _PdfListScreenState();
}

class _PdfListScreenState extends State<PdfListScreen> {
  late Stream<List<db.InvoiceWithCustomer>> _invoiceStream;

  @override
  void initState() {
    super.initState();
    // データベースから「顧客情報付きの請求書一覧」をストリームで取得
    // これにより、保存した瞬間に一覧が自動更新されます
    _invoiceStream = database.watchAllInvoices();
  }

  @override
  Widget build(BuildContext context) {
    final currencyFormat = NumberFormat("#,###");
    final dateFormat = DateFormat('yyyy/MM/dd');

    return Scaffold(
      appBar: AppBar(
        title: const Text("請求書 履歴一覧"),
        backgroundColor: Colors.blueGrey,
        foregroundColor: Colors.white,
      ),
      body: StreamBuilder<List<db.InvoiceWithCustomer>>(
        stream: _invoiceStream,
        builder: (context, snapshot) {
          if (snapshot.connectionState == ConnectionState.waiting) {
            return const Center(child: CircularProgressIndicator());
          }

          if (snapshot.hasError) {
            return Center(child: Text("エラーが発生しました: ${snapshot.error}"));
          }

          final invoices = snapshot.data ?? [];

          if (invoices.isEmpty) {
            return const Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Icon(
                    Icons.description_outlined,
                    size: 64,
                    color: Colors.grey,
                  ),
                  SizedBox(height: 16),
                  Text(
                    "保存された請求書はまだありません。",
                    style: TextStyle(color: Colors.grey),
                  ),
                ],
              ),
            );
          }

          return ListView.separated(
            itemCount: invoices.length,
            separatorBuilder: (context, index) => const Divider(height: 1),
            itemBuilder: (context, index) {
              final item = invoices[index];
              final invoice = item.invoice;
              final customer = item.customer;

              return ListTile(
                leading: CircleAvatar(
                  backgroundColor: Colors.blueGrey.shade100,
                  child: const Icon(
                    Icons.picture_as_pdf,
                    color: Colors.blueGrey,
                  ),
                ),
                title: Text(
                  customer.formalName,
                  style: const TextStyle(fontWeight: FontWeight.bold),
                ),
                subtitle: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      "No: ${invoice.id} | ${dateFormat.format(invoice.date)}",
                    ),
                    if (invoice.notes != null && invoice.notes!.isNotEmpty)
                      Text(
                        invoice.notes!,
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        style: const TextStyle(fontSize: 12),
                      ),
                  ],
                ),
                trailing: Text(
                  "¥${currencyFormat.format(invoice.totalAmount)}",
                  style: const TextStyle(
                    color: Colors.blueGrey,
                    fontWeight: FontWeight.bold,
                    fontSize: 16,
                  ),
                ),
                onTap: () {
                  // タップ時に Invoice モデルを再構築して詳細画面へ
                  _navigateToDetail(item);
                },
              );
            },
          );
        },
      ),
    );
  }

  /// 詳細画面へ遷移する（DBモデルからアプリ内モデルに変換）
  void _navigateToDetail(db.InvoiceWithCustomer data) async {
    // 明細項目をDBから取得
    final items = await (database.select(
      database.invoiceItems,
    )..where((t) => t.invoiceId.equals(data.invoice.id))).get();

    final mappedItems = items
        .map(
          (i) => InvoiceItem(
            description: i.description,
            quantity: i.quantity,
            unitPrice: i.unitPrice,
          ),
        )
        .toList();

    final invoiceModel = Invoice(
      invoiceNumber: data.invoice.id,
      customer: app_model.Customer(
        id: data.customer.id,
        displayName: data.customer.displayName,
        formalName: data.customer.formalName,
        address: data.customer.address ?? "",
        department: data.customer.department ?? "",
      ),
      items: mappedItems,
      date: data.invoice.date,
      notes: data.invoice.notes,
      filePath: data.invoice.filePath,
    );

    if (!mounted) return;
    Navigator.push(
      context,
      MaterialPageRoute(
        builder: (context) => InvoiceDetailPage(invoice: invoiceModel),
      ),
    );
  }
}