import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:provider/provider.dart';
import '../models/task_log_model.dart';
import '../models/project_model.dart';
import '../models/branch_model.dart';
import '../services/project_service.dart';
import '../services/task_log_service.dart';
import '../providers/auth_provider.dart';

class LogFormScreen extends StatefulWidget {
  final TaskLogModel? log;
  const LogFormScreen({super.key, this.log});

  @override
  State<LogFormScreen> createState() => _LogFormScreenState();
}

class _LogFormScreenState extends State<LogFormScreen> {
  final _formKey = GlobalKey<FormState>();
  late DateTime _selectedDate;
  ProjectModel? _selectedProject;
  BranchModel? _selectedBranch;
  String? _selectedFlavor;
  String _status = 'in_progress';
  final _moduleController = TextEditingController();
  final _remarksController = TextEditingController();
  
  List<ProjectModel> _projects = [];
  List<BranchModel> _branches = [];
  bool _isLoading = false;
  bool _isInitializing = true;

  @override
  void initState() {
    super.initState();
    _selectedDate = widget.log?.date ?? DateTime.now();
    _status = widget.log?.status ?? 'in_progress';
    _moduleController.text = widget.log?.moduleName ?? '';
    _remarksController.text = widget.log?.remarks ?? '';
    _selectedFlavor = widget.log?.flavor;
    _loadProjects();
  }

  Future<void> _loadProjects() async {
    final stream = context.read<ProjectService>().getProjects();
    final list = await stream.first;
    if (mounted) {
      setState(() {
        _projects = list;
        if (widget.log != null) {
          _selectedProject = _projects.any((p) => p.id == widget.log!.projectId) 
              ? _projects.firstWhere((p) => p.id == widget.log!.projectId) 
              : null;
          if (_selectedProject != null) {
            _loadBranches(_selectedProject!.id);
          }
        }
        _isInitializing = false;
      });
    }
  }

  Future<void> _loadBranches(String projectId) async {
    final list = await context.read<ProjectService>().getBranchesOnce(projectId);
    if (mounted) {
      setState(() {
        _branches = list;
        if (widget.log != null && _selectedBranch == null) {
           _selectedBranch = _branches.any((b) => b.id == widget.log!.branchId)
               ? _branches.firstWhere((b) => b.id == widget.log!.branchId)
               : null;
        } else {
           _selectedBranch = null; 
        }
      });
    }
  }

  void _submit() async {
    if (!_formKey.currentState!.validate() || _selectedProject == null || _selectedBranch == null) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text("Please select Project and Branch"), backgroundColor: Colors.orange)
      );
      return;
    }

    setState(() => _isLoading = true);
    final user = context.read<AuthProvider>().user!;
    
    final newLog = TaskLogModel(
      id: widget.log?.id ?? '',
      userId: user.uid,
      userName: user.name,
      projectId: _selectedProject!.id,
      projectName: _selectedProject!.name,
      branchId: _selectedBranch!.id,
      branchName: _selectedBranch!.name,
      flavor: _selectedFlavor,
      moduleName: _moduleController.text.trim(),
      status: _status,
      remarks: _remarksController.text.trim(),
      date: _selectedDate,
      createdAt: widget.log?.createdAt ?? DateTime.now(),
    );

    try {
      if (widget.log == null) {
        await context.read<TaskLogService>().addTaskLog(newLog);
      } else {
        await context.read<TaskLogService>().updateTaskLog(newLog);
      }
      if (mounted) Navigator.pop(context);
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text("Failed: $e")));
      }
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.log == null ? "Add Work Log" : "Edit Work Log"),
      ),
      body: _isInitializing 
        ? const Center(child: CircularProgressIndicator())
        : SingleChildScrollView(
            padding: const EdgeInsets.all(20),
            child: Form(
              key: _formKey,
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  _buildDateField(),
                  const SizedBox(height: 16),
                  _buildProjectDropdown(),
                  if (_selectedProject != null && _selectedProject!.flavors.isNotEmpty) ...[
                    const SizedBox(height: 16),
                    _buildFlavorDropdown(),
                  ],
                  const SizedBox(height: 16),
                  _buildBranchDropdown(),
                  const SizedBox(height: 16),
                  TextFormField(
                    controller: _moduleController,
                    decoration: const InputDecoration(
                      labelText: "Module/Task Name",
                      hintText: "e.g., Login UI, Bug fixing",
                      border: OutlineInputBorder(),
                    ),
                    validator: (v) => v!.isEmpty ? "Required" : null,
                  ),
                  const SizedBox(height: 24),
                  const Text("Status", style: TextStyle(fontWeight: FontWeight.bold)),
                  const SizedBox(height: 8),
                  _buildStatusChips(),
                  const SizedBox(height: 24),
                  TextFormField(
                    controller: _remarksController,
                    maxLines: 4,
                    decoration: const InputDecoration(
                      labelText: "Remarks",
                      border: OutlineInputBorder(),
                    ),
                    validator: (v) => v!.isEmpty ? "Required" : null,
                  ),
                  const SizedBox(height: 32),
                  _isLoading 
                    ? const Center(child: CircularProgressIndicator())
                    : ElevatedButton(
                        onPressed: _submit, 
                        child: Text(widget.log == null ? "SAVE LOG" : "UPDATE LOG"),
                      ),
                ],
              ),
            ),
          ),
    );
  }

  Widget _buildDateField() {
    return ListTile(
      contentPadding: EdgeInsets.zero,
      title: const Text("Date of Work", style: TextStyle(fontWeight: FontWeight.bold)),
      subtitle: Text(DateFormat('EEEE, dd MMM yyyy').format(_selectedDate)),
      trailing: const Icon(Icons.calendar_month, color: Colors.indigo),
      onTap: () async {
        final date = await showDatePicker(
          context: context, 
          initialDate: _selectedDate, 
          firstDate: DateTime.now().subtract(const Duration(days: 30)), 
          lastDate: DateTime.now(),
        );
        if (date != null) setState(() => _selectedDate = date);
      },
    );
  }

  Widget _buildProjectDropdown() {
    return DropdownButtonFormField<ProjectModel>(
      value: _selectedProject,
      decoration: const InputDecoration(labelText: "Project", border: OutlineInputBorder()),
      items: _projects.map((p) => DropdownMenuItem(value: p, child: Text(p.name))).toList(),
      onChanged: (v) {
        setState(() {
          _selectedProject = v;
          _selectedBranch = null;
          _selectedFlavor = null;
          _branches = [];
        });
        if (v != null) _loadBranches(v.id);
      },
    );
  }

  Widget _buildFlavorDropdown() {
    return DropdownButtonFormField<String>(
      value: _selectedFlavor,
      decoration: const InputDecoration(labelText: "Flavor", border: OutlineInputBorder()),
      items: _selectedProject!.flavors.map((f) => DropdownMenuItem(value: f, child: Text(f))).toList(),
      onChanged: (v) => setState(() => _selectedFlavor = v),
      validator: (v) => v == null ? "Required" : null,
    );
  }

  Widget _buildBranchDropdown() {
    return DropdownButtonFormField<BranchModel>(
      value: _selectedBranch,
      decoration: const InputDecoration(labelText: "Branch", border: OutlineInputBorder()),
      items: _branches.map((b) => DropdownMenuItem(value: b, child: Text(b.name))).toList(),
      onChanged: (v) => setState(() => _selectedBranch = v),
      hint: const Text("Select Branch"),
    );
  }

  Widget _buildStatusChips() {
    return Row(
      mainAxisAlignment: MainAxisAlignment.spaceAround,
      children: [
        _statusChip('in_progress', 'IN PROGRESS', Colors.orange),
        _statusChip('done', 'DONE', Colors.green),
        _statusChip('blocked', 'BLOCKED', Colors.red),
      ],
    );
  }

  Widget _statusChip(String value, String label, Color color) {
    bool selected = _status == value;
    return ChoiceChip(
      label: Text(label, style: TextStyle(color: selected ? Colors.white : color, fontSize: 11)),
      selected: selected,
      selectedColor: color,
      onSelected: (s) {
        if (s) setState(() => _status = value);
      },
    );
  }
}