import React, { useState, useEffect } from 'react';
import api from '../services/api';
import { format } from 'date-fns';
import { 
  PlusIcon,
  BellIcon,
  CheckCircleIcon,
  XCircleIcon,
  ExclamationTriangleIcon
} from '@heroicons/react/24/outline';

const Alerts = () => {
  const [alertRules, setAlertRules] = useState([]);
  const [alertLogs, setAlertLogs] = useState([]);
  const [alertStats, setAlertStats] = useState(null);
  const [loading, setLoading] = useState(true);
  const [activeTab, setActiveTab] = useState('rules');
  const [showCreateModal, setShowCreateModal] = useState(false);

  useEffect(() => {
    fetchAlertData();
  }, []);

  const fetchAlertData = async () => {
    try {
      const [rulesRes, logsRes, statsRes] = await Promise.all([
        api.get('/alerts/rules'),
        api.get('/alerts/logs?limit=50'),
        api.get('/alerts/stats?hours=24')
      ]);

      setAlertRules(rulesRes.data.data);
      setAlertLogs(logsRes.data.data);
      setAlertStats(statsRes.data.data);
    } catch (error) {
      console.error('Error fetching alert data:', error);
    } finally {
      setLoading(false);
    }
  };

  const handleDeleteRule = async (ruleId) => {
    if (window.confirm('Are you sure you want to delete this alert rule?')) {
      try {
        await api.delete(`/alerts/rules/${ruleId}`);
        fetchAlertData();
      } catch (error) {
        console.error('Error deleting alert rule:', error);
      }
    }
  };

  const getStatusIcon = (status) => {
    switch (status) {
      case 'sent':
        return <CheckCircleIcon className="h-5 w-5 text-green-500" />;
      case 'failed':
        return <XCircleIcon className="h-5 w-5 text-red-500" />;
      case 'pending':
        return <ExclamationTriangleIcon className="h-5 w-5 text-yellow-500" />;
      default:
        return <BellIcon className="h-5 w-5 text-gray-500" />;
    }
  };

  const getPriorityColor = (priority) => {
    switch (priority) {
      case 'critical':
        return 'bg-red-100 text-red-800';
      case 'high':
        return 'bg-orange-100 text-orange-800';
      case 'medium':
        return 'bg-yellow-100 text-yellow-800';
      case 'low':
        return 'bg-green-100 text-green-800';
      default:
        return 'bg-gray-100 text-gray-800';
    }
  };

  if (loading) {
    return (
      <div className="flex items-center justify-center h-64">
        <div className="animate-spin rounded-full h-32 w-32 border-b-2 border-primary-600"></div>
      </div>
    );
  }

  return (
    <div className="space-y-6">
      <div className="flex items-center justify-between">
        <div>
          <h3 className="text-lg leading-6 font-medium text-gray-900">
            Alert Management
          </h3>
          <p className="mt-1 text-sm text-gray-500">
            Configure and monitor alert rules for drone detections
          </p>
        </div>
        <button
          onClick={() => setShowCreateModal(true)}
          className="btn btn-primary flex items-center space-x-2"
        >
          <PlusIcon className="h-4 w-4" />
          <span>Create Alert Rule</span>
        </button>
      </div>

      {/* Alert Stats */}
      {alertStats && (
        <div className="grid grid-cols-1 md:grid-cols-4 gap-4">
          <div className="bg-white p-4 rounded-lg shadow border">
            <div className="text-2xl font-bold text-gray-900">{alertStats.total_alerts}</div>
            <div className="text-sm text-gray-500">Total Alerts (24h)</div>
          </div>
          <div className="bg-white p-4 rounded-lg shadow border">
            <div className="text-2xl font-bold text-green-600">{alertStats.sent_alerts}</div>
            <div className="text-sm text-gray-500">Sent Successfully</div>
          </div>
          <div className="bg-white p-4 rounded-lg shadow border">
            <div className="text-2xl font-bold text-red-600">{alertStats.failed_alerts}</div>
            <div className="text-sm text-gray-500">Failed</div>
          </div>
          <div className="bg-white p-4 rounded-lg shadow border">
            <div className="text-2xl font-bold text-yellow-600">{alertStats.pending_alerts}</div>
            <div className="text-sm text-gray-500">Pending</div>
          </div>
        </div>
      )}

      {/* Tabs */}
      <div className="border-b border-gray-200">
        <nav className="-mb-px flex space-x-8">
          <button
            onClick={() => setActiveTab('rules')}
            className={`whitespace-nowrap py-2 px-1 border-b-2 font-medium text-sm ${
              activeTab === 'rules'
                ? 'border-primary-500 text-primary-600'
                : 'border-transparent text-gray-500 hover:text-gray-700 hover:border-gray-300'
            }`}
          >
            Alert Rules ({alertRules.length})
          </button>
          <button
            onClick={() => setActiveTab('logs')}
            className={`whitespace-nowrap py-2 px-1 border-b-2 font-medium text-sm ${
              activeTab === 'logs'
                ? 'border-primary-500 text-primary-600'
                : 'border-transparent text-gray-500 hover:text-gray-700 hover:border-gray-300'
            }`}
          >
            Alert Logs ({alertLogs.length})
          </button>
        </nav>
      </div>

      {/* Alert Rules Tab */}
      {activeTab === 'rules' && (
        <div className="bg-white rounded-lg shadow overflow-hidden">
          {alertRules.length === 0 ? (
            <div className="text-center py-12">
              <BellIcon className="mx-auto h-12 w-12 text-gray-400" />
              <h3 className="mt-2 text-sm font-medium text-gray-900">No alert rules</h3>
              <p className="mt-1 text-sm text-gray-500">
                Get started by creating your first alert rule.
              </p>
              <div className="mt-6">
                <button
                  onClick={() => setShowCreateModal(true)}
                  className="btn btn-primary"
                >
                  <PlusIcon className="h-4 w-4 mr-2" />
                  Create Alert Rule
                </button>
              </div>
            </div>
          ) : (
            <div className="table-responsive">
              <table className="table">
                <thead>
                  <tr>
                    <th>Name</th>
                    <th>Priority</th>
                    <th>Channels</th>
                    <th>Conditions</th>
                    <th>Status</th>
                    <th>Created</th>
                    <th>Actions</th>
                  </tr>
                </thead>
                <tbody>
                  {alertRules.map((rule) => (
                    <tr key={rule.id} className="hover:bg-gray-50">
                      <td>
                        <div>
                          <div className="text-sm font-medium text-gray-900">
                            {rule.name}
                          </div>
                          {rule.description && (
                            <div className="text-sm text-gray-500">
                              {rule.description}
                            </div>
                          )}
                        </div>
                      </td>
                      <td>
                        <span className={`px-2 py-1 rounded-full text-xs font-medium ${
                          getPriorityColor(rule.priority)
                        }`}>
                          {rule.priority}
                        </span>
                      </td>
                      <td>
                        <div className="flex space-x-1">
                          {rule.alert_channels.map((channel, index) => (
                            <span
                              key={index}
                              className="px-2 py-1 bg-blue-100 text-blue-800 rounded text-xs"
                            >
                              {channel}
                            </span>
                          ))}
                        </div>
                      </td>
                      <td>
                        <div className="text-sm text-gray-900">
                          {rule.min_detections > 1 && (
                            <div>Min detections: {rule.min_detections}</div>
                          )}
                          {rule.time_window && (
                            <div>Time window: {rule.time_window}s</div>
                          )}
                          {rule.cooldown_period && (
                            <div>Cooldown: {rule.cooldown_period}s</div>
                          )}
                        </div>
                      </td>
                      <td>
                        <span className={`px-2 py-1 rounded-full text-xs font-medium ${
                          rule.is_active 
                            ? 'bg-green-100 text-green-800' 
                            : 'bg-gray-100 text-gray-800'
                        }`}>
                          {rule.is_active ? 'Active' : 'Inactive'}
                        </span>
                      </td>
                      <td>
                        <div className="text-sm text-gray-900">
                          {format(new Date(rule.created_at), 'MMM dd, yyyy')}
                        </div>
                      </td>
                      <td>
                        <div className="flex space-x-2">
                          <button
                            onClick={() => {
                              // TODO: Edit rule
                              console.log('Edit rule:', rule);
                            }}
                            className="text-primary-600 hover:text-primary-900 text-sm"
                          >
                            Edit
                          </button>
                          <button
                            onClick={() => handleDeleteRule(rule.id)}
                            className="text-red-600 hover:text-red-900 text-sm"
                          >
                            Delete
                          </button>
                        </div>
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          )}
        </div>
      )}

      {/* Alert Logs Tab */}
      {activeTab === 'logs' && (
        <div className="bg-white rounded-lg shadow overflow-hidden">
          {alertLogs.length === 0 ? (
            <div className="text-center py-12">
              <BellIcon className="mx-auto h-12 w-12 text-gray-400" />
              <h3 className="mt-2 text-sm font-medium text-gray-900">No alert logs</h3>
              <p className="mt-1 text-sm text-gray-500">
                Alert logs will appear here when alerts are triggered.
              </p>
            </div>
          ) : (
            <div className="table-responsive">
              <table className="table">
                <thead>
                  <tr>
                    <th>Status</th>
                    <th>Type</th>
                    <th>Recipient</th>
                    <th>Rule</th>
                    <th>Message</th>
                    <th>Sent At</th>
                  </tr>
                </thead>
                <tbody>
                  {alertLogs.map((log) => (
                    <tr key={log.id} className="hover:bg-gray-50">
                      <td>
                        <div className="flex items-center space-x-2">
                          {getStatusIcon(log.status)}
                          <span className="text-sm text-gray-900 capitalize">
                            {log.status}
                          </span>
                        </div>
                      </td>
                      <td>
                        <span className="px-2 py-1 bg-blue-100 text-blue-800 rounded text-xs">
                          {log.alert_type}
                        </span>
                      </td>
                      <td>
                        <div className="text-sm text-gray-900">
                          {log.recipient}
                        </div>
                      </td>
                      <td>
                        <div className="text-sm text-gray-900">
                          {log.rule?.name || 'Unknown Rule'}
                        </div>
                      </td>
                      <td>
                        <div className="text-sm text-gray-900 max-w-xs truncate">
                          {log.message}
                        </div>
                      </td>
                      <td>
                        <div className="text-sm text-gray-900">
                          {log.sent_at 
                            ? format(new Date(log.sent_at), 'MMM dd, HH:mm')
                            : 'Not sent'
                          }
                        </div>
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          )}
        </div>
      )}

      {/* Create Alert Rule Modal */}
      {showCreateModal && (
        <CreateAlertRuleModal
          onClose={() => setShowCreateModal(false)}
          onSave={() => {
            setShowCreateModal(false);
            fetchAlertData();
          }}
        />
      )}
    </div>
  );
};

const CreateAlertRuleModal = ({ onClose, onSave }) => {
  const [formData, setFormData] = useState({
    name: '',
    description: '',
    priority: 'medium',
    alert_channels: ['sms'],
    min_detections: 1,
    time_window: 300,
    cooldown_period: 600,
    device_ids: null,
    drone_types: null,
    min_rssi: '',
    max_rssi: '',
    frequency_ranges: []
  });
  const [saving, setSaving] = useState(false);

  const handleSubmit = async (e) => {
    e.preventDefault();
    setSaving(true);

    try {
      const payload = { ...formData };
      
      // Clean up empty values
      if (!payload.min_rssi) delete payload.min_rssi;
      if (!payload.max_rssi) delete payload.max_rssi;
      if (!payload.device_ids || payload.device_ids.length === 0) payload.device_ids = null;
      if (!payload.drone_types || payload.drone_types.length === 0) payload.drone_types = null;
      if (!payload.frequency_ranges || payload.frequency_ranges.length === 0) payload.frequency_ranges = null;

      await api.post('/alerts/rules', payload);
      onSave();
    } catch (error) {
      console.error('Error creating alert rule:', error);
    } finally {
      setSaving(false);
    }
  };

  const handleChange = (e) => {
    const { name, value, type } = e.target;
    setFormData(prev => ({
      ...prev,
      [name]: type === 'number' ? parseInt(value) || 0 : value
    }));
  };

  const handleChannelChange = (channel, checked) => {
    setFormData(prev => ({
      ...prev,
      alert_channels: checked
        ? [...prev.alert_channels, channel]
        : prev.alert_channels.filter(c => c !== channel)
    }));
  };

  return (
    <div className="fixed inset-0 z-50 overflow-y-auto">
      <div className="flex items-end justify-center min-h-screen pt-4 px-4 pb-20 text-center sm:block sm:p-0">
        <div className="fixed inset-0 bg-gray-500 bg-opacity-75 transition-opacity" onClick={onClose} />
        
        <div className="inline-block align-bottom bg-white rounded-lg text-left overflow-hidden shadow-xl transform transition-all sm:my-8 sm:align-middle sm:max-w-2xl sm:w-full">
          <form onSubmit={handleSubmit}>
            <div className="bg-white px-4 pt-5 pb-4 sm:p-6 sm:pb-4">
              <div className="mb-4">
                <h3 className="text-lg leading-6 font-medium text-gray-900">
                  Create Alert Rule
                </h3>
              </div>

              <div className="space-y-4">
                <div>
                  <label className="block text-sm font-medium text-gray-700 mb-1">
                    Rule Name *
                  </label>
                  <input
                    type="text"
                    name="name"
                    required
                    className="w-full border border-gray-300 rounded-md px-3 py-2 focus:ring-primary-500 focus:border-primary-500"
                    value={formData.name}
                    onChange={handleChange}
                  />
                </div>

                <div>
                  <label className="block text-sm font-medium text-gray-700 mb-1">
                    Description
                  </label>
                  <textarea
                    name="description"
                    rows="2"
                    className="w-full border border-gray-300 rounded-md px-3 py-2 focus:ring-primary-500 focus:border-primary-500"
                    value={formData.description}
                    onChange={handleChange}
                  />
                </div>

                <div className="grid grid-cols-2 gap-4">
                  <div>
                    <label className="block text-sm font-medium text-gray-700 mb-1">
                      Priority
                    </label>
                    <select
                      name="priority"
                      className="w-full border border-gray-300 rounded-md px-3 py-2 focus:ring-primary-500 focus:border-primary-500"
                      value={formData.priority}
                      onChange={handleChange}
                    >
                      <option value="low">Low</option>
                      <option value="medium">Medium</option>
                      <option value="high">High</option>
                      <option value="critical">Critical</option>
                    </select>
                  </div>

                  <div>
                    <label className="block text-sm font-medium text-gray-700 mb-1">
                      Min Detections
                    </label>
                    <input
                      type="number"
                      name="min_detections"
                      min="1"
                      className="w-full border border-gray-300 rounded-md px-3 py-2 focus:ring-primary-500 focus:border-primary-500"
                      value={formData.min_detections}
                      onChange={handleChange}
                    />
                  </div>
                </div>

                <div className="grid grid-cols-2 gap-4">
                  <div>
                    <label className="block text-sm font-medium text-gray-700 mb-1">
                      Time Window (seconds)
                    </label>
                    <input
                      type="number"
                      name="time_window"
                      min="60"
                      className="w-full border border-gray-300 rounded-md px-3 py-2 focus:ring-primary-500 focus:border-primary-500"
                      value={formData.time_window}
                      onChange={handleChange}
                    />
                  </div>

                  <div>
                    <label className="block text-sm font-medium text-gray-700 mb-1">
                      Cooldown Period (seconds)
                    </label>
                    <input
                      type="number"
                      name="cooldown_period"
                      min="0"
                      className="w-full border border-gray-300 rounded-md px-3 py-2 focus:ring-primary-500 focus:border-primary-500"
                      value={formData.cooldown_period}
                      onChange={handleChange}
                    />
                  </div>
                </div>

                <div>
                  <label className="block text-sm font-medium text-gray-700 mb-2">
                    Alert Channels
                  </label>
                  <div className="space-y-2">
                    {['sms', 'email', 'webhook'].map(channel => (
                      <label key={channel} className="flex items-center">
                        <input
                          type="checkbox"
                          checked={formData.alert_channels.includes(channel)}
                          onChange={(e) => handleChannelChange(channel, e.target.checked)}
                          className="h-4 w-4 text-primary-600 focus:ring-primary-500 border-gray-300 rounded"
                        />
                        <span className="ml-2 text-sm text-gray-700 capitalize">
                          {channel}
                        </span>
                      </label>
                    ))}
                  </div>
                </div>
              </div>
            </div>

            <div className="bg-gray-50 px-4 py-3 sm:px-6 sm:flex sm:flex-row-reverse">
              <button
                type="submit"
                disabled={saving}
                className="w-full inline-flex justify-center rounded-md border border-transparent shadow-sm px-4 py-2 bg-primary-600 text-base font-medium text-white hover:bg-primary-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-primary-500 sm:ml-3 sm:w-auto sm:text-sm disabled:opacity-50"
              >
                {saving ? 'Creating...' : 'Create Rule'}
              </button>
              <button
                type="button"
                onClick={onClose}
                className="mt-3 w-full inline-flex justify-center rounded-md border border-gray-300 shadow-sm px-4 py-2 bg-white text-base font-medium text-gray-700 hover:bg-gray-50 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-primary-500 sm:mt-0 sm:ml-3 sm:w-auto sm:text-sm"
              >
                Cancel
              </button>
            </div>
          </form>
        </div>
      </div>
    </div>
  );
};

export default Alerts;