import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import '../api_service.dart';
import '../theme.dart';

class LeaveScreen extends StatefulWidget {
  final ApiService api;
  final VoidCallback onAuthError;
  const LeaveScreen({super.key, required this.api, required this.onAuthError});

  @override
  State<LeaveScreen> createState() => _LeaveScreenState();
}

class _LeaveScreenState extends State<LeaveScreen> {
  List<LeaveBalance> _balances = [];
  List<LeaveRequest> _requests = [];
  bool _loading = true;

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

  Future<void> _load() async {
    try {
      final b = await widget.api.leaveBalances();
      final r = await widget.api.myLeave();
      if (mounted) setState(() { _balances = b; _requests = r; _loading = false; });
    } on ApiException catch (e) {
      if (e.status == 401) return widget.onAuthError();
      if (mounted) setState(() => _loading = false);
    }
  }

  Future<void> _apply() async {
    final types = await widget.api.leaveTypes().catchError((_) => <LeaveType>[]);
    if (!mounted || types.isEmpty) {
      if (mounted) ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('No leave types set up')));
      return;
    }
    final ok = await showModalBottomSheet<bool>(
      context: context,
      isScrollControlled: true,
      builder: (_) => _ApplySheet(api: widget.api, types: types),
    );
    if (ok == true) _load();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton.extended(
        onPressed: _apply, backgroundColor: AppColors.emerald,
        icon: const Icon(Icons.add), label: const Text('Apply'),
      ),
      backgroundColor: Colors.transparent,
      body: _loading
          ? const Center(child: CircularProgressIndicator(color: AppColors.emerald))
          : RefreshIndicator(
              onRefresh: _load,
              color: AppColors.emerald,
              child: ListView(
                padding: const EdgeInsets.fromLTRB(16, 12, 16, 90),
                children: [
                  const Text('Balances', style: TextStyle(fontWeight: FontWeight.w600, color: AppColors.navy)),
                  const SizedBox(height: 8),
                  if (_balances.isEmpty)
                    const Text('No leave types.', style: TextStyle(color: AppColors.muted))
                  else
                    ..._balances.map((b) => Card(
                          margin: const EdgeInsets.only(bottom: 8),
                          child: ListTile(
                            title: Text(b.leaveTypeName, style: const TextStyle(fontWeight: FontWeight.w600)),
                            subtitle: Text('${b.used} used of ${b.allocated}'),
                            trailing: Text('${b.available}',
                                style: const TextStyle(fontSize: 20, fontWeight: FontWeight.bold, color: AppColors.emerald)),
                          ),
                        )),
                  const SizedBox(height: 16),
                  const Text('My requests', style: TextStyle(fontWeight: FontWeight.w600, color: AppColors.navy)),
                  const SizedBox(height: 8),
                  if (_requests.isEmpty)
                    const Text('No requests yet.', style: TextStyle(color: AppColors.muted))
                  else
                    ..._requests.map((r) => Card(
                          margin: const EdgeInsets.only(bottom: 8),
                          child: ListTile(
                            title: Text('${r.leaveTypeName ?? 'Leave'} · ${r.days ?? ''} day(s)'),
                            subtitle: Text('${r.fromDate} → ${r.toDate}${r.reason != null ? '\n${r.reason}' : ''}'),
                            isThreeLine: r.reason != null,
                            trailing: _statusChip(r.status),
                          ),
                        )),
                ],
              ),
            ),
    );
  }
}

Widget _statusChip(String s) {
  final c = s == 'APPROVED' ? AppColors.emerald : s == 'REJECTED' ? AppColors.danger : AppColors.gold;
  return Container(
    padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
    decoration: BoxDecoration(color: c.withValues(alpha: 0.12), borderRadius: BorderRadius.circular(20)),
    child: Text(s, style: TextStyle(fontSize: 11, fontWeight: FontWeight.w600, color: c)),
  );
}

class _ApplySheet extends StatefulWidget {
  final ApiService api;
  final List<LeaveType> types;
  const _ApplySheet({required this.api, required this.types});

  @override
  State<_ApplySheet> createState() => _ApplySheetState();
}

class _ApplySheetState extends State<_ApplySheet> {
  String? _type;
  DateTime? _from, _to;
  final _reason = TextEditingController();
  bool _busy = false;

  Future<void> _pick(bool from) async {
    final d = await showDatePicker(
      context: context,
      initialDate: DateTime.now(),
      firstDate: DateTime.now().subtract(const Duration(days: 30)),
      lastDate: DateTime.now().add(const Duration(days: 365)),
    );
    if (d != null) setState(() => from ? _from = d : _to = d);
  }

  Future<void> _submit() async {
    if (_type == null || _from == null || _to == null) return;
    setState(() => _busy = true);
    final fmt = DateFormat('yyyy-MM-dd');
    try {
      await widget.api.applyLeave(_type!, fmt.format(_from!), fmt.format(_to!), _reason.text);
      if (mounted) Navigator.pop(context, true);
    } on ApiException catch (e) {
      if (mounted) ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(e.message)));
      setState(() => _busy = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final fmt = DateFormat('dd MMM yyyy');
    return Padding(
      padding: EdgeInsets.only(bottom: MediaQuery.of(context).viewInsets.bottom),
      child: Padding(
        padding: const EdgeInsets.all(20),
        child: Column(mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.stretch, children: [
          const Text('Apply for leave', style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold, color: AppColors.navy)),
          const SizedBox(height: 16),
          DropdownButtonFormField<String>(
            initialValue: _type,
            decoration: const InputDecoration(labelText: 'Leave type'),
            items: widget.types.map((t) => DropdownMenuItem(value: t.gid, child: Text(t.name))).toList(),
            onChanged: (v) => setState(() => _type = v),
          ),
          const SizedBox(height: 12),
          Row(children: [
            Expanded(child: OutlinedButton(onPressed: () => _pick(true), child: Text(_from == null ? 'From' : fmt.format(_from!)))),
            const SizedBox(width: 10),
            Expanded(child: OutlinedButton(onPressed: () => _pick(false), child: Text(_to == null ? 'To' : fmt.format(_to!)))),
          ]),
          const SizedBox(height: 12),
          TextField(controller: _reason, decoration: const InputDecoration(labelText: 'Reason'), maxLines: 2),
          const SizedBox(height: 16),
          FilledButton(
            onPressed: _busy ? null : _submit,
            child: _busy
                ? const SizedBox(height: 20, width: 20, child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white))
                : const Text('Submit request'),
          ),
        ]),
      ),
    );
  }
}