import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import './leave_model.dart';
import './leave_api.dart';

class LeaveDetail extends StatefulWidget {
  final Leave leave;
  const LeaveDetail({required this.leave, super.key});

  @override
  State<LeaveDetail> createState() => _LeaveDetailState();
}

class _LeaveDetailState extends State<LeaveDetail> {
  final LeaveApiService _apiService = LeaveApiService();
  bool _isWithdrawing = false;

  // 實作撤回邏輯
  Future<void> _handleWithdraw() async {
    final confirm = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('確認撤回'),
        content: const Text('您確定要撤回此張請假單嗎？'),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('取消')),
          TextButton(onPressed: () => Navigator.pop(ctx, true), child: const Text('確定', style: TextStyle(color: Colors.red))),
        ],
      ),
    );

    if (confirm == true) {
      setState(() => _isWithdrawing = true);
      final success = await _apiService.withdrawLeave(widget.leave.billNo);
      setState(() => _isWithdrawing = false);

      if (success && mounted) {
        ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('已成功撤回')));
        Navigator.pop(context, true); // 回傳 true 讓前一頁 (Manager) 重新整理列表
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final leave = widget.leave;
    return Scaffold(
      appBar: AppBar(title: const Text('請假單詳情')),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(20.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            _buildHeaderStatus(),
            const SizedBox(height: 24),
            _buildInfoCard(context),
            const SizedBox(height: 24),

            // 修正 3: 新增簽核進度區塊
            const Text('簽核進度', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold, color: Colors.blueGrey)),
            const SizedBox(height: 8),
            _buildFlowTimeline(),
            const SizedBox(height: 24),

            // 修正 5: 實作撤回按鈕邏輯
            if (leave.flowStatus == '0' || leave.flowStatus == '1')
              SizedBox(
                width: double.infinity,
                child: OutlinedButton.icon(
                  onPressed: _isWithdrawing ? null : _handleWithdraw,
                  icon: _isWithdrawing ? const CircularProgressIndicator(strokeWidth: 2) : const Icon(Icons.history_outlined),
                  label: Text(_isWithdrawing ? '處理中...' : '撤回申請'),
                  style: OutlinedButton.styleFrom(
                    foregroundColor: Colors.red,
                    side: const BorderSide(color: Colors.red),
                    padding: const EdgeInsets.symmetric(vertical: 12),
                  ),
                ),
              ),
          ],
        ),
      ),
    );
  }

  Widget _buildHeaderStatus() {
    return Row(
      mainAxisAlignment: MainAxisAlignment.spaceBetween,
      children: [
        Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text('單號: ${widget.leave.billNo}', style: const TextStyle(fontSize: 14, color: Colors.grey)),
            const SizedBox(height: 4),
            // 修正 4: 顯示 leaveTypeName
            Text(widget.leave.leaveTypeName, style: const TextStyle(fontSize: 28, fontWeight: FontWeight.bold)),
          ],
        ),
        Chip(
          backgroundColor: widget.leave.statusColor.withOpacity(0.1),
          side: BorderSide(color: widget.leave.statusColor),
          label: Text(widget.leave.statusText, style: TextStyle(color: widget.leave.statusColor, fontWeight: FontWeight.bold)),
        ),
      ],
    );
  }

  Widget _buildInfoCard(BuildContext context) {
    // 處理代理人顯示文字 (防呆處理)
    String displayAgent = widget.leave.agentName.isNotEmpty
        ? '${widget.leave.agentName} (${widget.leave.agentId})'
        : widget.leave.agentId;

    return Card(
      elevation: 0,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(15), side: BorderSide(color: Colors.grey.shade200)),
      child: Padding(
        padding: const EdgeInsets.all(20),
        child: Column(
          children: [
            _buildDetailRow(Icons.calendar_month, '請假期間', widget.leave.formattedRange),
            const Divider(height: 30),
            _buildDetailRow(Icons.timer_outlined, '請假時數', '${widget.leave.days} 天 ${widget.leave.hours} 小時'),
            const Divider(height: 30),
            // 修正 6: 顯示帶有姓名的代理人資訊
            _buildDetailRow(Icons.person_outline, '代理人', displayAgent),
            const Divider(height: 30),
            _buildDetailRow(Icons.edit_note, '事由', widget.leave.leaveNote ?? '未填寫'),
          ],
        ),
      ),
    );
  }

  Widget _buildDetailRow(IconData icon, String label, String value) {
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Icon(icon, size: 20, color: Colors.blueAccent),
        const SizedBox(width: 12),
        Text(label, style: const TextStyle(color: Colors.grey, fontSize: 14)),
        const Spacer(),
        Expanded(
          flex: 2,
          child: Text(value, textAlign: TextAlign.end, style: const TextStyle(fontWeight: FontWeight.w600, fontSize: 15)),
        ),
      ],
    );
  }

  // 實作簽核時間軸 (搭配 FutureBuilder)
  Widget _buildFlowTimeline() {
    return FutureBuilder<List<FlowLog>>(
      future: _apiService.fetchFlowLogs(widget.leave.billNo),
      builder: (context, snapshot) {
        if (snapshot.connectionState == ConnectionState.waiting) return const Center(child: CircularProgressIndicator());
        if (!snapshot.hasData || snapshot.data!.isEmpty) return const Text('尚無簽核歷程', style: TextStyle(color: Colors.grey));

        final logs = snapshot.data!;
        return Container(
          padding: const EdgeInsets.all(16),
          decoration: BoxDecoration(color: Colors.grey.shade50, borderRadius: BorderRadius.circular(10), border: Border.all(color: Colors.grey.shade200)),
          child: Column(
            children: logs.map((log) {
              return ListTile(
                contentPadding: EdgeInsets.zero,
                leading: Icon(
                  log.status == '1' ? Icons.check_circle : (log.status == 'X' ? Icons.cancel : Icons.pending),
                  color: log.status == '1' ? Colors.green : (log.status == 'X' ? Colors.red : Colors.orange),
                ),
                title: Text('${log.stepName} - ${log.approverName}'),
                subtitle: Text(log.time != null ? DateFormat('MM/dd HH:mm').format(log.time!) : ''),
              );
            }).toList(),
          ),
        );
      },
    );
  }
}