import { useMemo, useState } from 'react'
import {
  Alert, Button, Card, Col, Form, Input, InputNumber, Modal, Progress, Row, Select, Space, Statistic, Switch, Tag, Tooltip, Typography, message, Divider,
} from 'antd'
import type { ColumnsType } from 'antd/es/table'
import { ArrowDownOutlined, ArrowUpOutlined, BarChartOutlined, CheckCircleOutlined, CloseCircleOutlined, CloudServerOutlined, PlusOutlined, ReloadOutlined } from '@ant-design/icons'
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
import { useTranslation } from 'react-i18next'

import apiClient, { isEnvelope } from '../../api/client'
import { useAuthStore } from '../../stores/auth'
import DataTable from '../../components/DataTable'
import EmptyState from '../../components/EmptyState'
import PageHeader from '../../components/PageHeader'
import ActionButtons from '../../components/ActionButtons'

const { Text } = Typography

interface ACL {
  id: number
  name: string
  acl_type: string
  value: string
  action: 'allow' | 'deny'
  priority: number
  active: boolean
  comment?: string | null
  created_at: string
  updated_at: string
}

interface ServiceStatus { label: string; unit: string; active: boolean; state: string }

interface ProxySettings {
  id: number
  listen_addresses: string
  listen_port: number
  cache_mem_mb: number
  cache_dir_mb: number
  max_obj_size_mb: number
  connect_timeout: number
  read_timeout: number
  request_timeout: number
}

interface FormValues {
  name: string
  acl_type: string
  value: string
  action: 'allow' | 'deny'
  priority: number
  active: boolean
  comment?: string
}

const ACL_TYPE_KEYS = [
  'src', 'dst', 'dstdomain', 'srcdomain', 'port', 'proto', 'method',
  'time', 'url_regex', 'urlpath_regex', 'dstdom_regex', 'srcdom_regex', 'browser',
] as const

async function listACLs(): Promise<ACL[]> {
  const r = await apiClient.get('/forward-proxy/acls')
  if (!isEnvelope(r.data)) return []
  return (r.data.data as { acls?: ACL[] }).acls ?? []
}

interface SquidStats {
  client_requests: number
  cache_hits: number
  cache_hit_pct: number
  client_errors: number
  bytes_in: number
  bytes_out: number
  server_requests: number
  server_errors: number
}

function fmtBytes(n: number): string {
  if (n >= 1_073_741_824) return (n / 1_073_741_824).toFixed(1) + ' GB'
  if (n >= 1_048_576)     return (n / 1_048_576).toFixed(1) + ' MB'
  if (n >= 1_024)         return (n / 1_024).toFixed(0) + ' KB'
  return n + ' B'
}

export default function ForwardProxyPage() {
  const { t } = useTranslation()
  const qc = useQueryClient()
  const isViewer = useAuthStore((s) => s.user?.role) === 'viewer'
  const { data, isLoading } = useQuery({ queryKey: ['fwd-proxy', 'acls'], queryFn: listACLs })

  const { data: services } = useQuery({
    queryKey: ['system', 'services'],
    queryFn: async () => {
      const r = await apiClient.get('/system/services')
      return isEnvelope(r.data) ? (r.data.data as { services: ServiceStatus[] }).services : []
    },
    refetchInterval: 30_000,
  })
  const squid = services?.find(s => s.unit === 'squid.service' || s.unit === 'squid')

  const { data: statsData, refetch: refetchStats } = useQuery({
    queryKey: ['fwd-proxy', 'stats'],
    queryFn: async () => {
      const r = await apiClient.get('/forward-proxy/stats')
      if (!isEnvelope(r.data)) return null
      const d = r.data.data as { stats?: SquidStats; error?: string }
      if (d.error) return null
      return d.stats ?? null
    },
    refetchInterval: 30_000,
  })

  const { data: settings, isLoading: settingsLoading } = useQuery({
    queryKey: ['fwd-proxy', 'settings'],
    queryFn: async () => {
      const r = await apiClient.get('/forward-proxy/settings')
      if (!isEnvelope(r.data)) return null
      return r.data.data as ProxySettings
    },
  })

  const [settingsForm] = Form.useForm<ProxySettings>()
  const saveSettings = useMutation({
    mutationFn: async (v: ProxySettings) => {
      await apiClient.put('/forward-proxy/settings', v)
    },
    onSuccess: () => {
      message.success(t('common.save'))
      void qc.invalidateQueries({ queryKey: ['fwd-proxy', 'settings'] })
    },
    onError: () => message.error(t('fwd.settings.saveFailed')),
  })

  const [editing, setEditing] = useState<ACL | null>(null)
  const [creating, setCreating] = useState(false)
  const [form] = Form.useForm<FormValues>()

  const upsert = useMutation({
    mutationFn: async (v: FormValues) => {
      if (editing) return (await apiClient.put(`/forward-proxy/acls/${editing.id}`, v)).data
      return (await apiClient.post('/forward-proxy/acls', v)).data
    },
    onSuccess: () => {
      message.success(t('common.save'))
      setEditing(null); setCreating(false); form.resetFields()
      void qc.invalidateQueries({ queryKey: ['fwd-proxy', 'acls'] })
    },
    onError: (e: Error) => message.error(e.message),
  })
  const del = useMutation({
    mutationFn: async (id: number) => { await apiClient.delete(`/forward-proxy/acls/${id}`) },
    onSuccess: () => { void qc.invalidateQueries({ queryKey: ['fwd-proxy', 'acls'] }) },
    onError: (e: Error) => message.error(e.message),
  })
  const quickToggle = useMutation({
    mutationFn: async ({ id, row, checked }: { id: number; row: ACL; checked: boolean }) => {
      await apiClient.put(`/forward-proxy/acls/${id}`, { ...row, active: checked })
    },
    onSuccess: () => { void qc.invalidateQueries({ queryKey: ['fwd-proxy', 'acls'] }) },
    onError: (e: Error) => message.error(e.message),
  })

  const sortedACLs = useMemo(
    () => [...(data ?? [])].sort((a, b) => a.priority - b.priority),
    [data],
  )
  const swapACLs = useMutation({
    mutationFn: async ({ a, b }: { a: ACL; b: ACL }) => {
      const stripMeta = ({ id: _id, created_at: _ca, updated_at: _ua, ...r }: ACL) => r
      await apiClient.put(`/forward-proxy/acls/${a.id}`, { ...stripMeta(a), priority: b.priority })
      await apiClient.put(`/forward-proxy/acls/${b.id}`, { ...stripMeta(b), priority: a.priority })
    },
    onSuccess: () => { void qc.invalidateQueries({ queryKey: ['fwd-proxy', 'acls'] }) },
    onError: (e: Error) => message.error(e.message),
  })

  const cols: ColumnsType<ACL> = [
    { title: t('fwd.priority'), dataIndex: 'priority', key: 'priority', width: 90 },
    { title: t('fwd.name'), dataIndex: 'name', key: 'name', render: (s: string) => <code>{s}</code> },
    { title: t('fwd.action'), dataIndex: 'action', key: 'action',
      render: (a: string) => <Tag color={a === 'allow' ? 'green' : 'red'}>{a.toUpperCase()}</Tag> },
    { title: t('fwd.aclType'), dataIndex: 'acl_type', key: 'acl_type',
      render: (s: string) => <code>{s}</code> },
    { title: t('fwd.value'), dataIndex: 'value', key: 'value',
      render: (s: string) => <Text code style={{ fontSize: 12 }}>{s}</Text> },
    { title: t('fwd.comment'), dataIndex: 'comment', key: 'comment',
      render: (v?: string | null) => v ?? '—' },
    {
      title: t('common.active'), dataIndex: 'active', key: 'active', width: 80,
      render: (v: boolean, row: ACL) => (
        <Switch
          size="small"
          checked={v}
          disabled={isViewer}
          loading={quickToggle.isPending && quickToggle.variables?.id === row.id}
          onChange={(checked) => quickToggle.mutate({ id: row.id, row, checked })}
        />
      ),
    },
    {
      title: '', key: 'move', width: 64,
      render: (_, row) => {
        const idx = sortedACLs.findIndex(r => r.id === row.id)
        const swapping = swapACLs.isPending
        return (
          <Space size={2}>
            <Tooltip title={t('fw.rule.moveUp')}>
              <Button size="small" icon={<ArrowUpOutlined />}
                disabled={isViewer || idx <= 0 || swapping}
                onClick={() => swapACLs.mutate({ a: row, b: sortedACLs[idx - 1] })} />
            </Tooltip>
            <Tooltip title={t('fw.rule.moveDown')}>
              <Button size="small" icon={<ArrowDownOutlined />}
                disabled={isViewer || idx >= sortedACLs.length - 1 || swapping}
                onClick={() => swapACLs.mutate({ a: row, b: sortedACLs[idx + 1] })} />
            </Tooltip>
          </Space>
        )
      },
    },
    {
      title: t('common.actions'), key: 'actions',
      render: (_, row) => (
        <ActionButtons
          onEdit={() => {
            setEditing(row)
            form.setFieldsValue({
              name: row.name, acl_type: row.acl_type, value: row.value,
              action: row.action, priority: row.priority, active: row.active,
              comment: row.comment ?? undefined,
            })
          }}
          onDelete={() => del.mutate(row.id)}
          deleteConfirm={t('fwd.deleteConfirm', { name: row.name })}
        />
      ),
    },
  ]

  const openCreate = () => {
    setCreating(true); form.resetFields()
    form.setFieldsValue({ priority: 100, active: true, action: 'allow', acl_type: 'dstdomain' })
  }

  return (
    <div>
      <PageHeader
        icon={<CloudServerOutlined />}
        title={t('fwd.title')}
        subtitle={t('fwd.intro')}
        extra={squid && (
          <Tag
            icon={squid.active ? <CheckCircleOutlined /> : <CloseCircleOutlined />}
            color={squid.active ? 'green' : 'red'}
          >
            <Space size={4}>
              <span>squid</span>
              <span style={{ fontWeight: 400, opacity: 0.85 }}>{squid.state}</span>
            </Space>
          </Tag>
        )}
      />

      <Alert
        type="info"
        showIcon
        className="mb-12"
        message={t('fwd.helpTitle')}
        description={t('fwd.helpBody')}
      />

      {statsData && (
        <Card
          size="small"
          className="mb-12"
          title={<><BarChartOutlined /> {t('fwd.statsCard.title')}</>}
          extra={
            <Space size={4}>
              <Typography.Text type="secondary" style={{ fontSize: 11 }}>{t('fwd.statsCard.sinceRestart')}</Typography.Text>
              <Tooltip title={t('common.refresh')}>
                <Button size="small" icon={<ReloadOutlined />} onClick={() => { void refetchStats() }} />
              </Tooltip>
            </Space>
          }
        >
          <Row gutter={[16, 8]}>
            <Col xs={12} sm={6} md={4}>
              <Statistic title={t('fwd.statsCard.clientRequests')} value={statsData.client_requests} />
            </Col>
            <Col xs={12} sm={6} md={4}>
              <Statistic title={t('fwd.statsCard.cacheHits')} value={statsData.cache_hits} />
            </Col>
            <Col xs={12} sm={6} md={4}>
              <Typography.Text type="secondary" style={{ fontSize: 12 }}>{t('fwd.statsCard.cacheHitPct')}</Typography.Text>
              <Progress
                percent={Math.round(statsData.cache_hit_pct)}
                size="small"
                strokeColor={statsData.cache_hit_pct >= 50 ? '#16a34a' : statsData.cache_hit_pct >= 20 ? '#ca8a04' : '#dc2626'}
              />
            </Col>
            <Col xs={12} sm={6} md={4}>
              <Statistic title={t('fwd.statsCard.serverRequests')} value={statsData.server_requests} />
            </Col>
            <Col xs={12} sm={6} md={4}>
              <Statistic title={t('fwd.statsCard.bytesIn')} value={fmtBytes(statsData.bytes_in)} />
            </Col>
            <Col xs={12} sm={6} md={4}>
              <Statistic title={t('fwd.statsCard.bytesOut')} value={fmtBytes(statsData.bytes_out)} />
            </Col>
          </Row>
          {statsData.client_errors > 0 && (
            <Typography.Text type="danger" style={{ fontSize: 12 }}>
              {t('fwd.statsCard.clientErrors')}: {statsData.client_errors}
              {statsData.server_errors > 0 && ` · ${t('fwd.statsCard.serverErrors')}: ${statsData.server_errors}`}
            </Typography.Text>
          )}
        </Card>
      )}

      <Card
        size="small"
        className="mb-12"
        title={t('fwd.settings.title')}
        loading={settingsLoading}
      >
        <Form
          form={settingsForm}
          layout="vertical"
          initialValues={settings ?? {
            listen_addresses: '', listen_port: 3128,
            cache_mem_mb: 64, cache_dir_mb: 100, max_obj_size_mb: 4,
            connect_timeout: 60, read_timeout: 300, request_timeout: 300,
          }}
          key={settings?.id ?? 'loading'}
          onFinish={(v) => saveSettings.mutate(v)}
        >
          <Row gutter={16}>
            <Col xs={24} md={16}>
              <Form.Item
                label={t('fwd.settings.listenAddresses')}
                name="listen_addresses"
                extra={t('fwd.settings.listenAddressesExtra')}
              >
                <Input placeholder="10.0.5.1, 10.0.20.1" disabled={isViewer} />
              </Form.Item>
            </Col>
            <Col xs={24} md={8}>
              <Form.Item
                label={t('fwd.settings.listenPort')}
                name="listen_port"
                extra={t('fwd.settings.listenPortExtra')}
              >
                <InputNumber min={1} max={65535} style={{ width: '100%' }} disabled={isViewer} />
              </Form.Item>
            </Col>
          </Row>

          <Divider plain>{t('fwd.settings.cacheSection')}</Divider>
          <Row gutter={16}>
            <Col xs={24} sm={8}>
              <Form.Item label={t('fwd.settings.cacheMemMB')} name="cache_mem_mb" extra={t('fwd.settings.cacheMemMBExtra')}>
                <InputNumber min={16} max={8192} style={{ width: '100%' }} addonAfter="MB" disabled={isViewer} />
              </Form.Item>
            </Col>
            <Col xs={24} sm={8}>
              <Form.Item label={t('fwd.settings.cacheDirMB')} name="cache_dir_mb" extra={t('fwd.settings.cacheDirMBExtra')}>
                <InputNumber min={100} max={102400} style={{ width: '100%' }} addonAfter="MB" disabled={isViewer} />
              </Form.Item>
            </Col>
            <Col xs={24} sm={8}>
              <Form.Item label={t('fwd.settings.maxObjSizeMB')} name="max_obj_size_mb" extra={t('fwd.settings.maxObjSizeMBExtra')}>
                <InputNumber min={1} max={1024} style={{ width: '100%' }} addonAfter="MB" disabled={isViewer} />
              </Form.Item>
            </Col>
          </Row>

          <Divider plain>{t('fwd.settings.timeoutSection')}</Divider>
          <Row gutter={16}>
            <Col xs={24} sm={8}>
              <Form.Item label={t('fwd.settings.connectTimeout')} name="connect_timeout" extra={t('fwd.settings.connectTimeoutExtra')}>
                <InputNumber min={5} max={3600} style={{ width: '100%' }} addonAfter="s" disabled={isViewer} />
              </Form.Item>
            </Col>
            <Col xs={24} sm={8}>
              <Form.Item label={t('fwd.settings.readTimeout')} name="read_timeout" extra={t('fwd.settings.readTimeoutExtra')}>
                <InputNumber min={30} max={3600} style={{ width: '100%' }} addonAfter="s" disabled={isViewer} />
              </Form.Item>
            </Col>
            <Col xs={24} sm={8}>
              <Form.Item label={t('fwd.settings.requestTimeout')} name="request_timeout" extra={t('fwd.settings.requestTimeoutExtra')}>
                <InputNumber min={30} max={3600} style={{ width: '100%' }} addonAfter="s" disabled={isViewer} />
              </Form.Item>
            </Col>
          </Row>

          <Tooltip title={isViewer ? t('auth.viewerBadge') : undefined}>
            <Button
              type="primary"
              htmlType="submit"
              loading={saveSettings.isPending}
              disabled={isViewer}
            >
              {t('common.save')}
            </Button>
          </Tooltip>
        </Form>
      </Card>

      <Divider />

      <DataTable
        rowKey="id"
        loading={isLoading}
        dataSource={data ?? []}
        columns={cols}
        extraActions={
          <Tooltip title={isViewer ? t('auth.viewerBadge') : undefined}>
            <Button type="primary" icon={<PlusOutlined />} disabled={isViewer} onClick={openCreate}>
              {t('fwd.add')}
            </Button>
          </Tooltip>
        }
        emptyContent={
          <EmptyState
            icon={<CloudServerOutlined />}
            title={t('fwd.emptyTitle')}
            description={t('fwd.emptyDesc')}
            action={
              <Tooltip title={isViewer ? t('auth.viewerBadge') : undefined}>
                <Button type="primary" icon={<PlusOutlined />} disabled={isViewer} onClick={openCreate}>
                  {t('fwd.add')}
                </Button>
              </Tooltip>
            }
          />
        }
      />

      <Modal
        title={editing ? t('fwd.edit') : t('fwd.add')}
        open={editing !== null || creating}
        onCancel={() => { setEditing(null); setCreating(false); form.resetFields() }}
        onOk={() => { void form.submit() }}
        confirmLoading={upsert.isPending}
        width={620}
        destroyOnClose
      >
        <Form form={form} layout="vertical" onFinish={(v) => upsert.mutate(v)}>
          <Form.Item label={t('fwd.name')} name="name" rules={[{ required: true }]}
                     extra={t('fwd.nameExtra')}>
            <Input placeholder="allow_internal_lan" />
          </Form.Item>
          <Form.Item label={t('fwd.action')} name="action" rules={[{ required: true }]}>
            <Select options={[
              { value: 'allow', label: t('fwd.actions.allow') },
              { value: 'deny',  label: t('fwd.actions.deny') },
            ]} />
          </Form.Item>
          <Form.Item label={t('fwd.aclType')} name="acl_type" rules={[{ required: true }]}
                     extra={t('fwd.aclTypeExtra')}>
            <Select
              options={ACL_TYPE_KEYS.map(k => ({ value: k, label: t(`fwd.aclTypes.${k}`) }))}
              showSearch
              optionFilterProp="value"
            />
          </Form.Item>
          <Form.Item label={t('fwd.value')} name="value" rules={[{ required: true }]}
                     extra={t('fwd.valueExtra')}>
            <Input.TextArea rows={2} placeholder={t('fwd.valuePlaceholder')} />
          </Form.Item>
          <Form.Item label={t('fwd.priority')} name="priority" rules={[{ required: true }]}
                     extra={t('fwd.priorityExtra')}>
            <InputNumber min={0} max={1000} style={{ width: '100%' }} />
          </Form.Item>
          <Form.Item label={t('fwd.comment')} name="comment">
            <Input.TextArea rows={2} />
          </Form.Item>
          <Form.Item label={t('common.active')} name="active" valuePropName="checked">
            <Switch />
          </Form.Item>
        </Form>
      </Modal>
    </div>
  )
}