import React, { useState, useEffect } from 'react';
import { Shield, Activity, LogOut, AlertTriangle, CheckCircle2, Clock } from 'lucide-react';
import { toast } from 'react-toastify';
import accountantSecurityService, { AccountantSession, AccountantActivityLog, MFAStatus } from '../../features/security/services/accountantSecurityService';
import Loading from '../../shared/components/Loading';
import EmptyState from '../../shared/components/EmptyState';
import { formatDate } from '../../shared/utils/format';

const SecurityManagementPage: React.FC = () => {
  const [activeTab, setActiveTab] = useState<'sessions' | 'activity' | 'mfa'>('sessions');
  const [loading, setLoading] = useState(true);
  const [sessions, setSessions] = useState<AccountantSession[]>([]);
  const [activityLogs, setActivityLogs] = useState<AccountantActivityLog[]>([]);
  const [mfaStatus, setMfaStatus] = useState<MFAStatus | null>(null);
  const [pagination, setPagination] = useState<any>(null);

  useEffect(() => {
    if (activeTab === 'sessions') fetchSessions();
    else if (activeTab === 'activity') fetchActivityLogs();
    else if (activeTab === 'mfa') fetchMFAStatus();
  }, [activeTab]);

  const fetchSessions = async () => {
    try {
      setLoading(true);
      const response = await accountantSecurityService.getSessions();
      setSessions(response.data.sessions || []);
    } catch (error: any) {
      toast.error(error.response?.data?.detail || 'Failed to load sessions');
    } finally {
      setLoading(false);
    }
  };

  const fetchActivityLogs = async () => {
    try {
      setLoading(true);
      const response = await accountantSecurityService.getActivityLogs({ limit: 50 });
      setActivityLogs(response.data.logs || []);
      setPagination(response.data.pagination);
    } catch (error: any) {
      toast.error(error.response?.data?.detail || 'Failed to load activity logs');
    } finally {
      setLoading(false);
    }
  };

  const fetchMFAStatus = async () => {
    try {
      setLoading(true);
      const response = await accountantSecurityService.getMFAStatus();
      setMfaStatus(response.data);
    } catch (error: any) {
      toast.error(error.response?.data?.detail || 'Failed to load MFA status');
    } finally {
      setLoading(false);
    }
  };

  const handleRevokeSession = async (sessionId: number) => {
    if (!confirm('Are you sure you want to revoke this session?')) return;
    try {
      await accountantSecurityService.revokeSession(sessionId);
      toast.success('Session revoked successfully');
      fetchSessions();
    } catch (error: any) {
      toast.error(error.response?.data?.detail || 'Failed to revoke session');
    }
  };

  const handleRevokeAllSessions = async () => {
    if (!confirm('Are you sure you want to revoke all sessions? You will be logged out.')) return;
    try {
      await accountantSecurityService.revokeAllSessions();
      toast.success('All sessions revoked successfully');
      fetchSessions();
    } catch (error: any) {
      toast.error(error.response?.data?.detail || 'Failed to revoke sessions');
    }
  };

  const getRiskColor = (risk: string) => {
    switch (risk) {
      case 'critical':
        return 'bg-red-100 text-red-800 border-red-200';
      case 'high':
        return 'bg-orange-100 text-orange-800 border-orange-200';
      case 'medium':
        return 'bg-yellow-100 text-yellow-800 border-yellow-200';
      default:
        return 'bg-blue-100 text-blue-800 border-blue-200';
    }
  };

  if (loading && sessions.length === 0 && activityLogs.length === 0 && !mfaStatus) {
    return <Loading fullScreen text="Loading security information..." />;
  }

  return (
    <div className="min-h-screen bg-gradient-to-br from-slate-50 via-white to-slate-50 px-3 sm:px-4 md:px-6 lg:px-8 py-6 sm:py-8 md:py-10">
      {/* Header */}
      <div className="mb-6 sm:mb-8 md:mb-10">
        <div className="flex items-center gap-2 sm:gap-3 mb-2 sm:mb-3">
          <div className="h-1 w-12 sm:w-16 md:w-20 bg-gradient-to-r from-emerald-400 via-green-500 to-emerald-600 rounded-full"></div>
          <h1 className="text-2xl sm:text-3xl md:text-4xl font-bold bg-gradient-to-r from-slate-900 via-slate-800 to-slate-900 bg-clip-text text-transparent">
            Security Management
          </h1>
        </div>
        <p className="text-slate-600 text-sm sm:text-base md:text-lg font-light">
          Manage sessions, view activity logs, and MFA settings
        </p>
      </div>

      {/* Tabs */}
      <div className="flex flex-wrap gap-2 mb-6 border-b border-slate-200">
        <button
          onClick={() => setActiveTab('sessions')}
          className={`px-4 py-2 font-semibold rounded-t-lg transition-colors ${
            activeTab === 'sessions'
              ? 'bg-emerald-500 text-white border-b-2 border-emerald-600'
              : 'text-slate-600 hover:text-emerald-600'
          }`}
        >
          <LogOut className="inline w-4 h-4 mr-2" />
          Active Sessions
        </button>
        <button
          onClick={() => setActiveTab('activity')}
          className={`px-4 py-2 font-semibold rounded-t-lg transition-colors ${
            activeTab === 'activity'
              ? 'bg-emerald-500 text-white border-b-2 border-emerald-600'
              : 'text-slate-600 hover:text-emerald-600'
          }`}
        >
          <Activity className="inline w-4 h-4 mr-2" />
          Activity Logs
        </button>
        <button
          onClick={() => setActiveTab('mfa')}
          className={`px-4 py-2 font-semibold rounded-t-lg transition-colors ${
            activeTab === 'mfa'
              ? 'bg-emerald-500 text-white border-b-2 border-emerald-600'
              : 'text-slate-600 hover:text-emerald-600'
          }`}
        >
          <Shield className="inline w-4 h-4 mr-2" />
          MFA Status
        </button>
      </div>

      {/* Content */}
      {activeTab === 'sessions' && (
        <div className="bg-white rounded-xl shadow-lg p-6">
          <div className="flex justify-between items-center mb-4">
            <h2 className="text-xl font-bold">Active Sessions</h2>
            <button
              onClick={handleRevokeAllSessions}
              className="px-4 py-2 bg-red-500 text-white rounded-lg hover:bg-red-600"
            >
              Revoke All Sessions
            </button>
          </div>
          {sessions.length === 0 ? (
            <EmptyState title="No Active Sessions" description="Active sessions will appear here" />
          ) : (
            <div className="space-y-4">
              {sessions.map((session) => (
                <div key={session.id} className="border border-slate-200 rounded-lg p-4">
                  <div className="flex justify-between items-start">
                    <div className="flex-1">
                      <div className="flex items-center gap-3 mb-2">
                        <h3 className="font-bold">Session #{session.id}</h3>
                        {session.step_up_authenticated && (
                          <span className="px-2 py-1 bg-green-100 text-green-800 rounded-full text-xs">
                            Step-up Authenticated
                          </span>
                        )}
                      </div>
                      <div className="space-y-1 text-sm text-slate-600">
                        <p>IP Address: {session.ip_address || 'N/A'}</p>
                        <p>Location: {session.city && session.country ? `${session.city}, ${session.country}` : 'N/A'}</p>
                        <p>Last Activity: {formatDate(session.last_activity)}</p>
                        <p>Expires: {formatDate(session.expires_at)}</p>
                      </div>
                    </div>
                    <button
                      onClick={() => handleRevokeSession(session.id)}
                      className="px-4 py-2 bg-red-500 text-white rounded-lg hover:bg-red-600"
                    >
                      Revoke
                    </button>
                  </div>
                </div>
              ))}
            </div>
          )}
        </div>
      )}

      {activeTab === 'activity' && (
        <div className="bg-white rounded-xl shadow-lg p-6">
          <h2 className="text-xl font-bold mb-4">Activity Logs</h2>
          {activityLogs.length === 0 ? (
            <EmptyState title="No Activity Logs" description="Activity logs will appear here" />
          ) : (
            <div className="space-y-4">
              {activityLogs.map((log) => (
                <div key={log.id} className="border border-slate-200 rounded-lg p-4">
                  <div className="flex justify-between items-start">
                    <div className="flex-1">
                      <div className="flex items-center gap-3 mb-2">
                        <h3 className="font-bold">{log.activity_type.replace(/_/g, ' ')}</h3>
                        <span className={`px-2 py-1 rounded-full text-xs font-semibold border ${getRiskColor(log.risk_level)}`}>
                          {log.risk_level}
                        </span>
                        {log.is_unusual && (
                          <span className="px-2 py-1 bg-orange-100 text-orange-800 rounded-full text-xs">
                            Unusual
                          </span>
                        )}
                      </div>
                      <p className="text-slate-600 mb-2">{log.activity_description}</p>
                      <div className="flex flex-wrap gap-4 text-sm text-slate-500">
                        <span>IP: {log.ip_address || 'N/A'}</span>
                        {log.country && <span>Location: {log.country}</span>}
                        <span>•</span>
                        <span>{formatDate(log.created_at)}</span>
                      </div>
                    </div>
                  </div>
                </div>
              ))}
            </div>
          )}
        </div>
      )}

      {activeTab === 'mfa' && mfaStatus && (
        <div className="bg-white rounded-xl shadow-lg p-6">
          <h2 className="text-xl font-bold mb-4">MFA Status</h2>
          <div className="space-y-4">
            <div className="p-4 bg-slate-50 rounded-lg">
              <div className="flex items-center justify-between mb-2">
                <span className="font-semibold">MFA Required</span>
                <span className={mfaStatus.requires_mfa ? 'text-green-600' : 'text-gray-600'}>
                  {mfaStatus.requires_mfa ? 'Yes' : 'No'}
                </span>
              </div>
              <div className="flex items-center justify-between mb-2">
                <span className="font-semibold">MFA Enabled</span>
                <span className={mfaStatus.mfa_enabled ? 'text-green-600' : 'text-red-600'}>
                  {mfaStatus.mfa_enabled ? 'Yes' : 'No'}
                </span>
              </div>
              <div className="flex items-center justify-between mb-2">
                <span className="font-semibold">MFA Enforced</span>
                <span className={mfaStatus.is_enforced ? 'text-green-600' : 'text-red-600'}>
                  {mfaStatus.is_enforced ? 'Yes' : 'No'}
                </span>
              </div>
              <div className="flex items-center justify-between">
                <span className="font-semibold">Backup Codes</span>
                <span>{mfaStatus.backup_codes_count} remaining</span>
              </div>
            </div>
            {mfaStatus.enforcement_reason && (
              <div className="p-4 bg-yellow-50 border border-yellow-200 rounded-lg">
                <p className="text-yellow-800">
                  <strong>Note:</strong> {mfaStatus.enforcement_reason}
                </p>
              </div>
            )}
          </div>
        </div>
      )}
    </div>
  );
};

export default SecurityManagementPage;