import React, { useState, useEffect } from 'react';
import {
  Table,
  Button,
  Stack,
  Title,
  Modal,
  TextInput,
  MultiSelect,
  Group,
  ActionIcon,
  Badge,
  Card,
  Text,
  Loader,
  Alert,
  Textarea,
  Select,
  NumberInput,
} from '@mantine/core';
import {
  IconPlus,
  IconEdit,
  IconTrash,
  IconEye,
  IconCopy,
  IconAlertCircle,
} from '@tabler/icons-react';
import { useForm } from '@mantine/form';
import { notifications } from '@mantine/notifications';
import { apiService, Application, CreateApplicationRequest } from '../services/apiService';
import dayjs from 'dayjs';

const Applications: React.FC = () => {
  const [applications, setApplications] = useState<Application[]>([]);
  const [loading, setLoading] = useState(false);
  const [modalOpen, setModalOpen] = useState(false);
  const [editingApp, setEditingApp] = useState<Application | null>(null);
  const [detailModalOpen, setDetailModalOpen] = useState(false);
  const [selectedApp, setSelectedApp] = useState<Application | null>(null);

  const form = useForm<CreateApplicationRequest>({
    initialValues: {
      app_id: '',
      app_link: '',
      type: [],
      callback_url: '',
      token_prefix: '',
      token_renewal_duration: '24h',
      max_token_duration: '168h',
      owner: {
        type: 'individual',
        name: 'Admin User',
        owner: 'admin@example.com',
      },
    },
    validate: {
      app_id: (value) => value.length < 1 ? 'App ID is required' : null,
      app_link: (value) => value.length < 1 ? 'App Link is required' : null,
      callback_url: (value) => value.length < 1 ? 'Callback URL is required' : null,
    },
  });

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

  const loadApplications = async () => {
    try {
      setLoading(true);
      const response = await apiService.getApplications(100, 0);
      setApplications(response.data);
    } catch (error) {
      console.error('Failed to load applications:', error);
      notifications.show({
        title: 'Error',
        message: 'Failed to load applications',
        color: 'red',
      });
    } finally {
      setLoading(false);
    }
  };

  const parseDuration = (duration: string): number => {
    // Convert duration string like "24h" to seconds
    const match = duration.match(/^(\d+)([hmd]?)$/);
    if (!match) return 86400; // Default to 24h in seconds
    
    const value = parseInt(match[1]);
    const unit = match[2] || 'h';
    
    switch (unit) {
      case 'm': return value * 60; // minutes to seconds
      case 'h': return value * 3600; // hours to seconds  
      case 'd': return value * 86400; // days to seconds
      default: return value * 3600; // default to hours
    }
  };

  const handleSubmit = async (values: CreateApplicationRequest) => {
    try {
      // Convert duration strings to seconds for API
      const apiValues = {
        ...values,
        token_renewal_duration: parseDuration(values.token_renewal_duration),
        max_token_duration: parseDuration(values.max_token_duration),
      };

      if (editingApp) {
        await apiService.updateApplication(editingApp.app_id, apiValues);
        notifications.show({
          title: 'Success',
          message: 'Application updated successfully',
          color: 'green',
        });
      } else {
        await apiService.createApplication(apiValues);
        notifications.show({
          title: 'Success',
          message: 'Application created successfully',
          color: 'green',
        });
      }
      setModalOpen(false);
      setEditingApp(null);
      form.reset();
      loadApplications();
    } catch (error) {
      console.error('Failed to save application:', error);
      notifications.show({
        title: 'Error',
        message: 'Failed to save application',
        color: 'red',
      });
    }
  };

  const handleEdit = (app: Application) => {
    setEditingApp(app);
    form.setValues({
      app_id: app.app_id,
      app_link: app.app_link,
      type: app.type,
      callback_url: app.callback_url,
      token_prefix: app.token_prefix || '',
      token_renewal_duration: `${app.token_renewal_duration / 3600}h`,
      max_token_duration: `${app.max_token_duration / 3600}h`,
      owner: app.owner,
    });
    setModalOpen(true);
  };

  const handleDelete = async (appId: string) => {
    if (window.confirm('Are you sure you want to delete this application?')) {
      try {
        await apiService.deleteApplication(appId);
        notifications.show({
          title: 'Success',
          message: 'Application deleted successfully',
          color: 'green',
        });
        loadApplications();
      } catch (error) {
        console.error('Failed to delete application:', error);
        notifications.show({
          title: 'Error',
          message: 'Failed to delete application',
          color: 'red',
        });
      }
    }
  };

  const handleViewDetails = (app: Application) => {
    setSelectedApp(app);
    setDetailModalOpen(true);
  };

  const copyToClipboard = (text: string) => {
    navigator.clipboard.writeText(text);
    notifications.show({
      title: 'Copied',
      message: 'Copied to clipboard',
      color: 'blue',
    });
  };

  const appTypeOptions = [
    { value: 'static', label: 'Static' },
    { value: 'user', label: 'User' },
  ];

  const rows = applications.map((app) => (
    <Table.Tr key={app.app_id}>
      <Table.Td>
        <Text fw={500}>{app.app_id}</Text>
      </Table.Td>
      <Table.Td>
        <Group gap="xs">
          {app.type.map((type) => (
            <Badge key={type} variant="light" size="sm">
              {type}
            </Badge>
          ))}
        </Group>
      </Table.Td>
      <Table.Td>
        <Text size="sm" c="dimmed">
          {app.owner.name} ({app.owner.owner})
        </Text>
      </Table.Td>
      <Table.Td>
        <Text size="sm">
          {dayjs(app.created_at).format('MMM DD, YYYY')}
        </Text>
      </Table.Td>
      <Table.Td>
        <Group gap="xs">
          <ActionIcon
            variant="subtle"
            color="blue"
            onClick={() => handleViewDetails(app)}
            title="View Details"
          >
            <IconEye size={16} />
          </ActionIcon>
          <ActionIcon
            variant="subtle"
            color="gray"
            onClick={() => handleEdit(app)}
            title="Edit"
          >
            <IconEdit size={16} />
          </ActionIcon>
          <ActionIcon
            variant="subtle"
            color="red"
            onClick={() => handleDelete(app.app_id)}
            title="Delete"
          >
            <IconTrash size={16} />
          </ActionIcon>
        </Group>
      </Table.Td>
    </Table.Tr>
  ));

  return (
    <Stack gap="lg">
      <Group justify="space-between">
        <div>
          <Title order={2} mb="xs">
            Applications
          </Title>
        </div>
        <Button
          leftSection={<IconPlus size={16} />}
          onClick={() => {
            setEditingApp(null);
            form.reset();
            setModalOpen(true);
          }}
        >
          New Application
        </Button>
      </Group>

      {loading ? (
        <Stack align="center" justify="center" h={200}>
          <Loader size="lg" />
          <Text>Loading applications...</Text>
        </Stack>
      ) : applications.length === 0 ? (
        <Card shadow="sm" radius="md" withBorder p="xl">
          <Stack align="center" gap="md">
            <IconAlertCircle size={48} color="gray" />
            <div style={{ textAlign: 'center' }}>
              <Text fw={500} mb="xs">
                No applications found
              </Text>
              <Text size="sm" c="dimmed">
                Create your first application to get started with the key management system
              </Text>
            </div>
            <Button
              leftSection={<IconPlus size={16} />}
              onClick={() => {
                setEditingApp(null);
                form.reset();
                setModalOpen(true);
              }}
            >
              Create Application
            </Button>
          </Stack>
        </Card>
      ) : (
        <Card shadow="sm" radius="md" withBorder>
          <Table>
            <Table.Thead>
              <Table.Tr>
                <Table.Th>Application ID</Table.Th>
                <Table.Th>Type</Table.Th>
                <Table.Th>Owner</Table.Th>
                <Table.Th>Created</Table.Th>
                <Table.Th>Actions</Table.Th>
              </Table.Tr>
            </Table.Thead>
            <Table.Tbody>{rows}</Table.Tbody>
          </Table>
        </Card>
      )}

      {/* Create/Edit Modal */}
      <Modal
        opened={modalOpen}
        onClose={() => {
          setModalOpen(false);
          setEditingApp(null);
          form.reset();
        }}
        title={editingApp ? 'Edit Application' : 'Create New Application'}
        size="lg"
      >
        <form onSubmit={form.onSubmit(handleSubmit)}>
          <Stack gap="md">
            <TextInput
              label="Application ID"
              placeholder="my-app-id"
              required
              {...form.getInputProps('app_id')}
              disabled={!!editingApp}
            />

            <TextInput
              label="Application Link"
              placeholder="https://myapp.example.com"
              required
              {...form.getInputProps('app_link')}
            />

            <MultiSelect
              label="Application Type"
              placeholder="Select application types"
              data={appTypeOptions}
              required
              {...form.getInputProps('type')}
            />

            <TextInput
              label="Callback URL"
              placeholder="https://myapp.example.com/callback"
              required
              {...form.getInputProps('callback_url')}
            />

            <TextInput
              label="Token Prefix (Optional)"
              placeholder="myapp_"
              {...form.getInputProps('token_prefix')}
            />

            <Group grow>
              <TextInput
                label="Token Renewal Duration"
                placeholder="24h"
                {...form.getInputProps('token_renewal_duration')}
              />
              <TextInput
                label="Max Token Duration"
                placeholder="168h"
                {...form.getInputProps('max_token_duration')}
              />
            </Group>

            <Group justify="flex-end" mt="md">
              <Button
                variant="subtle"
                onClick={() => {
                  setModalOpen(false);
                  setEditingApp(null);
                  form.reset();
                }}
              >
                Cancel
              </Button>
              <Button type="submit">
                {editingApp ? 'Update Application' : 'Create Application'}
              </Button>
            </Group>
          </Stack>
        </form>
      </Modal>

      {/* Detail Modal */}
      <Modal
        opened={detailModalOpen}
        onClose={() => setDetailModalOpen(false)}
        title="Application Details"
        size="md"
      >
        {selectedApp && (
          <Stack gap="md">
            <Group justify="space-between">
              <Text fw={500}>Application ID:</Text>
              <Group gap="xs">
                <Text>{selectedApp.app_id}</Text>
                <ActionIcon
                  size="sm"
                  variant="subtle"
                  onClick={() => copyToClipboard(selectedApp.app_id)}
                >
                  <IconCopy size={12} />
                </ActionIcon>
              </Group>
            </Group>

            <Group justify="space-between">
              <Text fw={500}>HMAC Key:</Text>
              <Group gap="xs">
                <Text size="sm" style={{ fontFamily: 'monospace' }}>
                  {selectedApp.hmac_key.substring(0, 16)}...
                </Text>
                <ActionIcon
                  size="sm"
                  variant="subtle"
                  onClick={() => copyToClipboard(selectedApp.hmac_key)}
                >
                  <IconCopy size={12} />
                </ActionIcon>
              </Group>
            </Group>

            <Group justify="space-between">
              <Text fw={500}>Application Link:</Text>
              <Text size="sm">{selectedApp.app_link}</Text>
            </Group>

            <Group justify="space-between">
              <Text fw={500}>Callback URL:</Text>
              <Text size="sm">{selectedApp.callback_url}</Text>
            </Group>

            <Group justify="space-between">
              <Text fw={500}>Token Renewal:</Text>
              <Text size="sm">{selectedApp.token_renewal_duration / 3600}h</Text>
            </Group>

            <Group justify="space-between">
              <Text fw={500}>Max Duration:</Text>
              <Text size="sm">{selectedApp.max_token_duration / 3600}h</Text>
            </Group>

            <Group justify="space-between">
              <Text fw={500}>Created:</Text>
              <Text size="sm">{dayjs(selectedApp.created_at).format('MMM DD, YYYY HH:mm')}</Text>
            </Group>
          </Stack>
        )}
      </Modal>
    </Stack>
  );
};

export default Applications;