import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:intl/intl.dart';
import 'package:open_filex/open_filex.dart';
import '../../models/project_model.dart';
import '../../models/user_model.dart';
import '../../services/report_service.dart';
import '../../services/task_log_service.dart';
import '../../services/project_service.dart';
import '../../services/auth_service.dart';

class ReportsTab extends StatefulWidget {
  const ReportsTab({super.key});

  @override
  State<ReportsTab> createState() => _ReportsTabState();
}

class _ReportsTabState extends State<ReportsTab> {
  DateTime _startDate = DateTime.now().subtract(const Duration(days: 30));
  DateTime _endDate = DateTime.now().add(const Duration(hours: 23, minutes: 59));
  String? _selectedProjectId;
  String? _selectedUserId;

  bool _isGenerating = false;
  List<ProjectModel> _projects = [];
  List<UserModel> _users = [];

  @override
  void initState() {
    super.initState();
    _loadFilters();
  }

  void _loadFilters() async {
    final projects = await context.read<ProjectService>().getProjects().first;
    final users = await context.read<AuthService>().getUsers().first;
    if (mounted) {
      setState(() {
        _projects = projects;
        _users = users;
      });
    }
  }

  Future<void> _generateReport(String type) async {
    if (_isGenerating) return;
    setState(() => _isGenerating = true);

    try {
      final logs = await context.read<TaskLogService>().getTaskLogs(
        from: _startDate,
        to: _endDate,
        projectId: _selectedProjectId,
        userId: _selectedUserId,
      ).first;

      if (logs.isEmpty) {
        if (mounted) ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text("No data found for selected filters.")));
        setState(() => _isGenerating = false);
        return;
      }

      final reportService = context.read<ReportService>();
      dynamic file;

      if (type == 'pdf') {
        file = await reportService.generatePDF(logs, _startDate, _endDate);
      } else {
        file = await reportService.generateExcel(logs);
      }

      if (file != null && mounted) {
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text("Report generated! Opening..."), backgroundColor: Colors.green));
        await OpenFilex.open(file.path);
      }
    } catch (e) {
      if (mounted) ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text("Report generation failed: $e")));
    } finally {
      if (mounted) setState(() => _isGenerating = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final DateFormat formatter = DateFormat('EEE, dd MMM yyyy');

    return Scaffold(
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(24),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            const Card(
              color: Colors.indigo,
              shape: RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(16))),
              child: Padding(
                padding: EdgeInsets.all(24),
                child: Column(
                  children: [
                    Icon(Icons.bar_chart, color: Colors.white, size: 48),
                    SizedBox(height: 16),
                    Text(
                      "Generate Analytics Report", 
                      style: TextStyle(color: Colors.white, fontWeight: FontWeight.bold, fontSize: 18),
                    ),
                    SizedBox(height: 8),
                    Text(
                      "Select filters below to download your team work log report.",
                      textAlign: TextAlign.center,
                      style: TextStyle(color: Colors.white70, fontSize: 14),
                    ),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 32),
            _buildFilterRow("Date Range", "${formatter.format(_startDate)} - ${formatter.format(_endDate)}", Icons.date_range, _pickDateRange),
            _buildDropdownFilter<String?>(
              "Project", 
              _selectedProjectId, 
              _projects.map((p) => DropdownMenuItem(value: p.id, child: Text(p.name))).toList(),
              (v) => setState(() => _selectedProjectId = v),
              Icons.folder_outlined,
            ),
            _buildDropdownFilter<String?>(
              "Team Member", 
              _selectedUserId, 
              _users.map((u) => DropdownMenuItem(value: u.uid, child: Text(u.name))).toList(),
              (v) => setState(() => _selectedUserId = v),
              Icons.person_outline,
            ),
            const SizedBox(height: 48),
            _isGenerating 
              ? const Center(child: CircularProgressIndicator())
              : Column(
                  children: [
                    ElevatedButton.icon(
                      onPressed: () => _generateReport('pdf'), 
                      icon: const Icon(Icons.picture_as_pdf),
                      label: const Text("DOWNLOAD PDF"),
                      style: ElevatedButton.styleFrom(
                         backgroundColor: Colors.red.shade700, 
                         foregroundColor: Colors.white,
                         minimumSize: const Size(double.infinity, 55),
                      ),
                    ),
                    const SizedBox(height: 16),
                    OutlinedButton.icon(
                      onPressed: () => _generateReport('excel'), 
                      icon: const Icon(Icons.table_chart),
                      label: const Text("DOWNLOAD EXCEL"),
                      style: OutlinedButton.styleFrom(
                         minimumSize: const Size(double.infinity, 55),
                         side: const BorderSide(color: Colors.green, width: 2),
                         foregroundColor: Colors.green.shade800,
                      ),
                    ),
                  ],
                ),
          ],
        ),
      ),
    );
  }

  Widget _buildFilterRow(String label, String value, IconData icon, VoidCallback onTap) {
    return ListTile(
      contentPadding: EdgeInsets.zero,
      leading: CircleAvatar(backgroundColor: Colors.indigo.shade50, child: Icon(icon, color: Colors.indigo, size: 20)),
      title: Text(label, style: const TextStyle(fontWeight: FontWeight.bold, fontSize: 14)),
      subtitle: Text(value),
      trailing: const Icon(Icons.chevron_right),
      onTap: onTap,
    );
  }

  Widget _buildDropdownFilter<T>(String label, T value, List<DropdownMenuItem<T>> items, ValueChanged<T> onChanged, IconData icon) {
    return ListTile(
      contentPadding: EdgeInsets.zero,
      leading: CircleAvatar(backgroundColor: Colors.indigo.shade50, child: Icon(icon, color: Colors.indigo, size: 20)),
      title: Text(label, style: const TextStyle(fontWeight: FontWeight.bold, fontSize: 14)),
      subtitle: DropdownButton<T>(
        value: value,
        isExpanded: true,
        underline: const SizedBox(),
        hint: const Text("All"),
        items: [
           DropdownMenuItem<T>(value: null, child: const Text("All")),
           ...items,
        ],
        onChanged: (v) {
          if (v != null || true) onChanged(v as T);
        },
      ),
    );
  }

  void _pickDateRange() async {
    final range = await showDateRangePicker(
      context: context, 
      firstDate: DateTime(2024), 
      lastDate: DateTime.now(),
      initialDateRange: DateTimeRange(start: _startDate, end: _endDate),
    );
    if (range != null) {
      setState(() {
        _startDate = range.start;
        _endDate = DateTime(range.end.year, range.end.month, range.end.day, 23, 59, 59);
      });
    }
  }
}