import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import '../models/invoice_models.dart';
import '../models/customer_model.dart';
import '../services/invoice_repository.dart';
import '../services/customer_repository.dart';
import 'invoice_detail_page.dart';
import 'management_screen.dart';
import 'company_info_screen.dart';
import '../widgets/slide_to_unlock.dart';
import '../main.dart'; // InvoiceFlowScreen 用
import 'package:package_info_plus/package_info_plus.dart';

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

  @override
  State<InvoiceHistoryScreen> createState() => _InvoiceHistoryScreenState();
}

class _InvoiceHistoryScreenState extends State<InvoiceHistoryScreen> {
  final InvoiceRepository _invoiceRepo = InvoiceRepository();
  final CustomerRepository _customerRepo = CustomerRepository();
  List<Invoice> _invoices = [];
  List<Invoice> _filteredInvoices = [];
  bool _isLoading = true;
  bool _isUnlocked = false; // 保護解除フラグ
  String _searchQuery = "";
  String _sortBy = "date"; // "date", "amount", "customer"
  DateTime? _startDate;
  DateTime? _endDate;
  String _appVersion = "1.0.0";

  @override
  void initState() {
    super.initState();
    _loadData();
    _loadVersion();
  }

  Future<void> _loadVersion() async {
    final packageInfo = await PackageInfo.fromPlatform();
    setState(() {
      _appVersion = packageInfo.version;
    });
  }

  Future<void> _loadData() async {
    setState(() => _isLoading = true);
    final customers = await _customerRepo.getAllCustomers();
    final invoices = await _invoiceRepo.getAllInvoices(customers);
    setState(() {
      _invoices = invoices;
      _applyFilterAndSort();
      _isLoading = false;
    });
  }

  void _applyFilterAndSort() {
    setState(() {
      _filteredInvoices = _invoices.where((inv) {
        final query = _searchQuery.toLowerCase();
        final matchesQuery = inv.customerNameForDisplay.toLowerCase().contains(query) ||
               inv.invoiceNumber.toLowerCase().contains(query) ||
               (inv.notes?.toLowerCase().contains(query) ?? false);
        
        bool matchesDate = true;
        if (_startDate != null && inv.date.isBefore(_startDate!)) matchesDate = false;
        if (_endDate != null && inv.date.isAfter(_endDate!.add(const Duration(days: 1)))) matchesDate = false;
        
        return matchesQuery && matchesDate;
      }).toList();

      if (_sortBy == "date") {
        _filteredInvoices.sort((a, b) => b.date.compareTo(a.date));
      } else if (_sortBy == "amount") {
        _filteredInvoices.sort((a, b) => b.totalAmount.compareTo(a.totalAmount));
      } else if (_sortBy == "customer") {
        _filteredInvoices.sort((a, b) => a.customerNameForDisplay.compareTo(b.customerNameForDisplay));
      }
    });
  }

  void _toggleUnlock() {
    setState(() {
      _isUnlocked = !_isUnlocked;
    });
    if (!_isUnlocked) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text("編集プロテクトを有効にしました")),
      );
    }
  }

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

    return Scaffold(
      appBar: AppBar(
        title: GestureDetector(
          onLongPress: () {
            Navigator.push(
              context,
              MaterialPageRoute(builder: (context) => const CompanyInfoScreen()),
            ).then((_) => _loadData());
          },
          child: Text("伝票マスター v$_appVersion"),
        ),
        backgroundColor: _isUnlocked ? Colors.blueGrey : Colors.blueGrey.shade800,
        actions: [
          if (_isUnlocked)
            IconButton(
              icon: const Icon(Icons.lock_open, color: Colors.orangeAccent),
              onPressed: _toggleUnlock,
              tooltip: "再度プロテクトする",
            ),
          IconButton(
            icon: const Icon(Icons.sort),
            onPressed: () {
              showMenu<String>(
                context: context,
                position: const RelativeRect.fromLTRB(100, 80, 0, 0),
                items: [
                  const PopupMenuItem(value: "date", child: Text("日付順")),
                  const PopupMenuItem(value: "amount", child: Text("金額順")),
                  const PopupMenuItem(value: "customer", child: Text("顧客名順")),
                ],
              ).then((val) {
                if (val != null) {
                  setState(() => _sortBy = val);
                  _applyFilterAndSort();
                }
              });
            },
            tooltip: "ソート切り替え",
          ),
          IconButton(
            icon: Icon(Icons.date_range, color: (_startDate != null || _endDate != null) ? Colors.orange : Colors.white),
            onPressed: () async {
              final picked = await showDateRangePicker(
                context: context,
                initialDateRange: (_startDate != null && _endDate != null) 
                    ? DateTimeRange(start: _startDate!, end: _endDate!) 
                    : null,
                firstDate: DateTime(2020),
                lastDate: DateTime.now().add(const Duration(days: 365)),
              );
              if (picked != null) {
                setState(() {
                  _startDate = picked.start;
                  _endDate = picked.end;
                });
                _applyFilterAndSort();
              } else if (_startDate != null) {
                // リセット
                setState(() {
                  _startDate = null;
                  _endDate = null;
                });
                _applyFilterAndSort();
              }
            },
            tooltip: "日付範囲で絞り込み",
          ),
          IconButton(
            icon: const Icon(Icons.refresh),
            onPressed: _loadData,
          ),
        ],
        bottom: PreferredSize(
          preferredSize: const Size.fromHeight(60),
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
            child: TextField(
              decoration: InputDecoration(
                hintText: "検索 (顧客名、伝票番号...)",
                prefixIcon: const Icon(Icons.search),
                filled: true,
                fillColor: Colors.white,
                border: OutlineInputBorder(borderRadius: BorderRadius.circular(12), borderSide: BorderSide.none),
                isDense: true,
              ),
              onChanged: (val) {
                _searchQuery = val;
                _applyFilterAndSort();
              },
            ),
          ),
        ),
      ),
      drawer: Drawer(
        child: ListView(
          padding: EdgeInsets.zero,
          children: [
            const DrawerHeader(
              decoration: BoxDecoration(color: Colors.blueGrey),
              child: Text("販売アシスト1号", style: TextStyle(color: Colors.white, fontSize: 24)),
            ),
            ListTile(
              leading: const Icon(Icons.history),
              title: const Text("伝票マスター一覧"),
              onTap: () => Navigator.pop(context),
            ),
            ListTile(
              leading: const Icon(Icons.add_task),
              title: const Text("新規伝票作成"),
              onTap: () {
                Navigator.pop(context);
                Navigator.push(
                  context,
                  MaterialPageRoute(builder: (context) => InvoiceFlowScreen(onComplete: _loadData)),
                );
              },
            ),
            const Divider(),
            ListTile(
              leading: const Icon(Icons.admin_panel_settings),
              title: const Text("マスター管理・同期"),
              onTap: () {
                Navigator.pop(context);
                Navigator.push(
                  context,
                  MaterialPageRoute(builder: (context) => const ManagementScreen()),
                );
              },
            ),
          ],
        ),
      ),
      body: Column(
        children: [
          SlideToUnlock(
            isLocked: !_isUnlocked,
            onUnlocked: _toggleUnlock,
            text: "スライドして編集モード解除",
          ),
          Expanded(
            child: _isLoading
                ? const Center(child: CircularProgressIndicator())
                : _filteredInvoices.isEmpty
                    ? Center(
                        child: Column(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: [
                            const Icon(Icons.folder_open, size: 64, color: Colors.grey),
                            const SizedBox(height: 16),
                            Text(_searchQuery.isEmpty ? "保存された伝票がありません" : "該当する伝票が見つかりません"),
                          ],
                        ),
                      )
                    : ListView.builder(
                        itemCount: _filteredInvoices.length,
                        itemBuilder: (context, index) {
                          final invoice = _filteredInvoices[index];
                          return ListTile(
                            leading: CircleAvatar(
                              backgroundColor: _isUnlocked ? Colors.indigo.shade100 : Colors.grey.shade200,
                              child: Icon(Icons.description_outlined, color: _isUnlocked ? Colors.indigo : Colors.grey),
                            ),
                            title: Text(invoice.customerNameForDisplay),
                            subtitle: Text("${dateFormatter.format(invoice.date)} - ${invoice.invoiceNumber}"),
                            trailing: Column(
                              mainAxisAlignment: MainAxisAlignment.center,
                              crossAxisAlignment: CrossAxisAlignment.end,
                              children: [
                                Text("￥${amountFormatter.format(invoice.totalAmount)}", 
                                     style: const TextStyle(fontWeight: FontWeight.bold)),
                                if (invoice.isSynced)
                                  const Icon(Icons.sync, size: 16, color: Colors.green)
                                else
                                  const Icon(Icons.sync_disabled, size: 16, color: Colors.orange),
                              ],
                            ),
                            onTap: () async {
                              await Navigator.push(
                                context,
                                MaterialPageRoute(
                                  builder: (context) => InvoiceDetailPage(
                                    invoice: invoice,
                                    isUnlocked: _isUnlocked, // 状態を渡す
                                  ),
                                ),
                              );
                              _loadData();
                            },
                            onLongPress: () async {
                              if (!_isUnlocked) {
                                ScaffoldMessenger.of(context).showSnackBar(
                                  const SnackBar(content: Text("削除するにはアンロックが必要です")),
                                );
                                return;
                              }
                              final confirm = await showDialog<bool>(
                                context: context,
                                builder: (context) => AlertDialog(
                                  title: const Text("伝票の削除"),
                                  content: Text("「${invoice.customerNameForDisplay}」の伝票(${invoice.invoiceNumber})を削除しますか？\nこの操作は取り消せません。"),
                                  actions: [
                                    TextButton(onPressed: () => Navigator.pop(context, false), child: const Text("キャンセル")),
                                    TextButton(
                                      onPressed: () => Navigator.pop(context, true),
                                      child: const Text("削除", style: TextStyle(color: Colors.red)),
                                    ),
                                  ],
                                ),
                              );
                              if (confirm == true) {
                                await _invoiceRepo.deleteInvoice(invoice.id);
                                _loadData();
                              }
                            },
                          );
                        },
                      ),
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: () async {
          await Navigator.push(
            context,
            MaterialPageRoute(
              builder: (context) => InvoiceFlowScreen(onComplete: _loadData),
            ),
          );
        },
        label: const Text("新規伝票作成"),
        icon: const Icon(Icons.add),
        backgroundColor: Colors.indigo,
      ),
    );
  }
}