import { useEffect, useState } from 'react'
import {
  Button,
  Card,
  Form,
  Input,
  InputNumber,
  Modal,
  Popconfirm,
  Radio,
  Select,
  Slider,
  Space,
  Switch,
  Tabs,
  Tag,
} from 'antd'
import {
  CloudServerOutlined,
  CommentOutlined,
  DeploymentUnitOutlined,
  ExperimentOutlined,
  PlusOutlined,
  ReloadOutlined,
  DeleteOutlined,
  EditOutlined,
} from '@ant-design/icons'

import {
  createLLMModelConfig,
  deleteLLMModelConfig,
  getLLMModelConfigDetail,
  getLLMModelConfigs,
  getLLMProviderCatalog,
  testLLMModelConfig,
  updateLLMModelConfig,
  updateLLMModelConfigStatus,
} from '@/api/llmModelConfigs'
import ListTable from '@/components/ListTable/ListTable'
import PageHeader from '@/components/PageHeader/PageHeader'
import Toast from '@/components/Toast/Toast'
import './ModelConfigs.css'
import '@/pages/System/AdminPages.css'

const { Search, TextArea } = Input

const MAX_TOKENS_OPTIONS = [
  { label: '4K', value: 4096 },
  { label: '8K', value: 8192 },
  { label: '16K', value: 16384 },
  { label: '32K', value: 32768 },
]

const DEFAULT_MAX_TOKENS = 8192

const MODEL_TYPE_META = {
  chat: {
    label: '对话模型',
    icon: <CommentOutlined />,
    description: '用于知识库对话、问答生成的大语言模型。',
    addText: '新增对话模型',
  },
  embedding: {
    label: '向量模型',
    icon: <DeploymentUnitOutlined />,
    description: '用于文档向量化（ZVec）与语义检索的 Embedding 模型。',
    addText: '新增向量模型',
  },
}

function buildModelCode(provider, llmModelName, modelType) {
  const providerPart = (provider || 'custom').trim().toLowerCase()
  const modelPart = (llmModelName || '').trim().toLowerCase()
  const sanitized = []
  let previousSeparator = false

  for (const char of modelPart) {
    if (/[a-z0-9]/.test(char)) {
      sanitized.push(char)
      previousSeparator = false
    } else if (!previousSeparator) {
      sanitized.push('_')
      previousSeparator = true
    }
  }

  const suffix = sanitized.join('').replace(/^_+|_+$/g, '') || 'model'
  const base = `llm_${providerPart}_${suffix}`
  return modelType === 'embedding' ? `emb_${base}` : base
}

function buildModelName(providerMeta, provider, llmModelName) {
  const label = providerMeta?.label || provider || '自定义模型'
  const modelPart = (llmModelName || '').trim()
  if (!modelPart) {
    return label
  }
  return `${label} ${modelPart}`
}

function formatDateTime(value) {
  if (!value) return '-'
  return new Date(value).toLocaleString('zh-CN')
}

function ModelConfigs() {
  const [form] = Form.useForm()
  const [activeType, setActiveType] = useState('chat')
  const [editingType, setEditingType] = useState('chat')
  const [loading, setLoading] = useState(false)
  const [submitting, setSubmitting] = useState(false)
  const [testing, setTesting] = useState(false)
  const [page, setPage] = useState(1)
  const [pageSize, setPageSize] = useState(10)
  const [total, setTotal] = useState(0)
  const [keyword, setKeyword] = useState('')
  const [providerFilter, setProviderFilter] = useState(undefined)
  const [statusFilter, setStatusFilter] = useState(undefined)
  const [configs, setConfigs] = useState([])
  const [providerCatalog, setProviderCatalog] = useState([])
  const [modalVisible, setModalVisible] = useState(false)
  const [editingConfigId, setEditingConfigId] = useState(null)
  const [autoFillFlags, setAutoFillFlags] = useState({
    endpointUrl: true,
    modelName: true,
    modelCode: true,
  })

  const providerValue = Form.useWatch('provider', form)
  const llmModelNameValue = Form.useWatch('llm_model_name', form)
  const isEmbedding = editingType === 'embedding'

  useEffect(() => {
    loadProviderCatalog()
  }, [])

  useEffect(() => {
    loadConfigs()
  }, [activeType, page, pageSize, keyword, providerFilter, statusFilter])

  useEffect(() => {
    if (!modalVisible || !providerValue) {
      return
    }

    const providerMeta = providerCatalog.find((item) => item.value === providerValue)
    if (!providerMeta) {
      return
    }

    const currentValues = form.getFieldsValue()
    const nextValues = {}

    if (autoFillFlags.endpointUrl) {
      const nextEndpointUrl = providerMeta.default_endpoint_url || ''
      if (nextEndpointUrl !== currentValues.endpoint_url) {
        nextValues.endpoint_url = nextEndpointUrl
      }
    }

    if (llmModelNameValue) {
      if (autoFillFlags.modelName) {
        const nextModelName = buildModelName(providerMeta, providerValue, llmModelNameValue)
        if (nextModelName !== currentValues.model_name) {
          nextValues.model_name = nextModelName
        }
      }

      if (autoFillFlags.modelCode) {
        const nextModelCode = buildModelCode(providerValue, llmModelNameValue, editingType)
        if (nextModelCode !== currentValues.model_code) {
          nextValues.model_code = nextModelCode
        }
      }
    }

    if (Object.keys(nextValues).length > 0) {
      form.setFieldsValue(nextValues)
    }
  }, [modalVisible, providerValue, llmModelNameValue, providerCatalog, autoFillFlags, editingType, form])

  const loadProviderCatalog = async () => {
    try {
      const res = await getLLMProviderCatalog()
      setProviderCatalog(res.data || [])
    } catch (error) {
      console.error('Load LLM provider catalog error:', error)
      Toast.error('加载提供方列表失败')
    }
  }

  const loadConfigs = async () => {
    try {
      setLoading(true)
      const params = {
        page,
        page_size: pageSize,
        model_type: activeType,
      }
      if (keyword) params.keyword = keyword
      if (providerFilter) params.provider = providerFilter
      if (statusFilter !== undefined) params.is_active = statusFilter

      const res = await getLLMModelConfigs(params)
      setConfigs(res.data || [])
      setTotal(res.total || 0)
    } catch (error) {
      console.error('Load llm model configs error:', error)
      Toast.error('加载模型配置失败')
    } finally {
      setLoading(false)
    }
  }

  const getProviderMeta = (provider) => providerCatalog.find((item) => item.value === provider)

  const handleTabChange = (key) => {
    setActiveType(key)
    setPage(1)
    setKeyword('')
    setProviderFilter(undefined)
    setStatusFilter(undefined)
  }

  const openCreateModal = () => {
    const defaultProvider = providerCatalog[0]?.value || 'openai'
    const defaultEndpointUrl = getProviderMeta(defaultProvider)?.default_endpoint_url || ''
    setEditingConfigId(null)
    setEditingType(activeType)
    setAutoFillFlags({
      endpointUrl: true,
      modelName: true,
      modelCode: true,
    })
    form.setFieldsValue({
      model_type: activeType,
      provider: defaultProvider,
      endpoint_url: defaultEndpointUrl,
      llm_timeout: activeType === 'embedding' ? 60 : 120,
      llm_temperature: 0.7,
      llm_top_p: 0.9,
      llm_max_tokens: DEFAULT_MAX_TOKENS,
      embedding_dimension: undefined,
      is_active: true,
      description: '',
      llm_system_prompt: '',
      model_name: '',
      model_code: '',
      llm_model_name: '',
      api_key: '',
    })
    setModalVisible(true)
  }

  const openEditModal = async (record) => {
    try {
      const res = await getLLMModelConfigDetail(record.config_id)
      const detail = res.data
      const detailType = detail.model_type || 'chat'
      const providerMeta = getProviderMeta(detail.provider)

      setEditingConfigId(record.config_id)
      setEditingType(detailType)
      setAutoFillFlags({
        endpointUrl: !detail.endpoint_url || detail.endpoint_url === (providerMeta?.default_endpoint_url || ''),
        modelName: !detail.model_name || detail.model_name === buildModelName(providerMeta, detail.provider, detail.llm_model_name),
        modelCode: !detail.model_code || detail.model_code === buildModelCode(detail.provider, detail.llm_model_name, detailType),
      })
      form.setFieldsValue({
        ...detail,
        api_key: detail.api_key || '',
      })
      setModalVisible(true)
    } catch (error) {
      console.error('Load llm model config detail error:', error)
      Toast.error('加载模型配置详情失败')
    }
  }

  const closeModal = () => {
    setModalVisible(false)
    setEditingConfigId(null)
    form.resetFields()
  }

  const handleSubmit = async (values) => {
    try {
      setSubmitting(true)
      const payload = { ...values, model_type: editingType }
      if (editingConfigId) {
        await updateLLMModelConfig(editingConfigId, payload)
        Toast.success('模型配置更新成功')
      } else {
        await createLLMModelConfig(payload)
        Toast.success('模型配置创建成功')
      }
      closeModal()
      loadConfigs()
    } catch (error) {
      Toast.error(error.response?.data?.detail || '保存模型配置失败')
    } finally {
      setSubmitting(false)
    }
  }

  const handleDelete = async (record) => {
    try {
      await deleteLLMModelConfig(record.config_id)
      Toast.success('模型配置删除成功')
      loadConfigs()
    } catch (error) {
      Toast.error(error.response?.data?.detail || '删除模型配置失败')
    }
  }

  const handleStatusChange = async (record, checked) => {
    try {
      await updateLLMModelConfigStatus(record.config_id, checked)
      Toast.success(checked ? '模型已启用' : '模型已停用')
      loadConfigs()
    } catch (error) {
      Toast.error(error.response?.data?.detail || '更新状态失败')
    }
  }

  const showTestResult = (result) => {
    const providerLabel = getProviderMeta(result.provider)?.label || result.provider
    const lines = [
      `提供方：${providerLabel}`,
      `模型：${result.llm_model_name}`,
      `延迟：${result.latency_ms} ms`,
    ]
    if (result.dimension) {
      lines.push(`向量维度：${result.dimension}`)
    }
    if (result.preview) {
      lines.push(`返回预览：${result.preview}`)
    }
    const description = (
      <div style={{ whiteSpace: 'pre-wrap', wordBreak: 'break-word' }}>
        {lines.map((line, index) => (
          <div key={index}>{line}</div>
        ))}
      </div>
    )
    Toast.success('模型测试成功', description, 5)
  }

  const handleFormTest = async () => {
    try {
      const values = await form.validateFields()
      setTesting(true)
      const res = await testLLMModelConfig({ ...values, model_type: editingType })
      showTestResult(res.data)
    } catch (error) {
      // 表单校验未通过：不弹提示，仅高亮表单项
      // 接口失败：已由全局请求拦截器统一弹出错误 Toast，这里不重复提示
    } finally {
      setTesting(false)
    }
  }

  const getColumns = (type) => {
    const baseColumns = [
      {
        title: '模型名称',
        dataIndex: 'model_name',
        key: 'model_name',
        width: 240,
        render: (_, record) => (
          <Space direction="vertical" size={2}>
            <span>{record.model_name}</span>
            <span className="model-config-code">{record.model_code}</span>
          </Space>
        ),
      },
      {
        title: '提供方',
        dataIndex: 'provider',
        key: 'provider',
        width: 140,
        render: (provider) => (
          <Tag color="blue">{getProviderMeta(provider)?.label || provider || '-'}</Tag>
        ),
      },
      {
        title: '模型标识',
        dataIndex: 'llm_model_name',
        key: 'llm_model_name',
        width: 180,
      },
    ]

    if (type === 'embedding') {
      baseColumns.push({
        title: '向量维度',
        dataIndex: 'embedding_dimension',
        key: 'embedding_dimension',
        width: 110,
        render: (value) => (value ? <Tag color="purple">{value}</Tag> : <Tag>自动</Tag>),
      })
    }

    baseColumns.push(
      {
        title: 'Base URL',
        dataIndex: 'endpoint_url',
        key: 'endpoint_url',
        ellipsis: true,
        render: (value) => value || '-',
      },
      {
        title: '状态',
        dataIndex: 'is_active',
        key: 'is_active',
        width: 100,
        render: (value, record) => (
          <Switch
            checked={value}
            checkedChildren="启用"
            unCheckedChildren="停用"
            onChange={(checked) => handleStatusChange(record, checked)}
          />
        ),
      },
      {
        title: '更新时间',
        dataIndex: 'updated_at',
        key: 'updated_at',
        width: 180,
        render: (value) => formatDateTime(value),
      },
      {
        title: '操作',
        key: 'action',
        fixed: 'right',
        width: 170,
        render: (_, record) => (
          <Space size="small" className="model-config-actions">
            <Button
              type="link"
              size="small"
              icon={<EditOutlined />}
              onClick={() => openEditModal(record)}
            >
              编辑
            </Button>
            <Popconfirm
              title="确认删除该模型配置？"
              description="删除后将无法恢复。"
              okText="删除"
              cancelText="取消"
              onConfirm={() => handleDelete(record)}
            >
              <Button
                type="link"
                size="small"
                danger
                icon={<DeleteOutlined />}
              >
                删除
              </Button>
            </Popconfirm>
          </Space>
        ),
      },
    )

    return baseColumns
  }

  const renderListPanel = (type) => (
    <>
      <div className="admin-toolbar">
        <div className="admin-toolbar-left">
          <Search
            allowClear
            placeholder="搜索模型名称、编码或模型标识"
            value={keyword}
            style={{ width: 320 }}
            onChange={(event) => {
              setPage(1)
              setKeyword(event.target.value)
            }}
            onSearch={(value) => {
              setPage(1)
              setKeyword(value)
            }}
          />
          <Select
            allowClear
            placeholder="筛选提供方"
            style={{ width: 180 }}
            value={providerFilter}
            options={providerCatalog.map((item) => ({
              label: item.label,
              value: item.value,
            }))}
            onChange={(value) => {
              setPage(1)
              setProviderFilter(value)
            }}
          />
          <Select
            allowClear
            placeholder="筛选状态"
            style={{ width: 140 }}
            value={statusFilter}
            options={[
              { label: '启用', value: true },
              { label: '停用', value: false },
            ]}
            onChange={(value) => {
              setPage(1)
              setStatusFilter(value)
            }}
          />
        </div>

        <div className="admin-toolbar-right">
          <Button
            type="primary"
            icon={<PlusOutlined />}
            onClick={openCreateModal}
          >
            {MODEL_TYPE_META[type].addText}
          </Button>
          <Button icon={<ReloadOutlined />} onClick={loadConfigs}>
            刷新
          </Button>
        </div>
      </div>

      <ListTable
        rowKey="config_id"
        className="model-config-table"
        loading={loading}
        columns={getColumns(type)}
        dataSource={configs}
        scroll={{ x: 1280 }}
        pagination={{
          current: page,
          pageSize,
          total,
          showSizeChanger: true,
          showQuickJumper: true,
          onChange: (nextPage, nextPageSize) => {
            setPage(nextPage)
            setPageSize(nextPageSize)
          },
          showTotal: (value) => `共 ${value} 条`,
        }}
      />
    </>
  )

  const tabItems = Object.entries(MODEL_TYPE_META).map(([type, meta]) => ({
    key: type,
    label: (
      <span>
        {meta.icon}
        {meta.label}
      </span>
    ),
    children: (
      <div className="model-config-tab-panel">
        <p className="model-config-tab-desc">{meta.description}</p>
        {activeType === type ? renderListPanel(type) : null}
      </div>
    ),
  }))

  return (
    <div className="admin-page">
      <PageHeader
        title="模型配置"
        description="分类管理对话模型与向量模型的提供方、接口地址、参数模板与连通性测试。"
        icon={<CloudServerOutlined />}
      />

      <Card className="admin-card model-config-card">
        <Tabs
          items={tabItems}
          activeKey={activeType}
          onChange={handleTabChange}
          tabPosition="left"
          className="model-config-tabs"
        />
      </Card>

      <Modal
        title={`${editingConfigId ? '编辑' : '新增'}${MODEL_TYPE_META[editingType].label}`}
        open={modalVisible}
        width={860}
        className="model-config-modal"
        style={{ maxWidth: 'calc(100vw - 32px)' }}
        destroyOnClose
        onCancel={closeModal}
        onOk={() => form.submit()}
        confirmLoading={submitting}
        okText={editingConfigId ? '保存修改' : '创建'}
        cancelText="取消"
        styles={{
          body: {
            maxHeight: 'calc(80vh - 180px)',
            overflowY: 'auto',
            paddingRight: 8,
          },
        }}
        footer={(_, { OkBtn, CancelBtn }) => (
          <>
            <CancelBtn />
            <Button
              icon={<ExperimentOutlined />}
              loading={testing}
              onClick={handleFormTest}
            >
              测试模型
            </Button>
            <OkBtn />
          </>
        )}
      >
        <div className="model-config-modal-hint">
          <strong>自动生成规则：</strong> 选择提供方后会自动带出默认 `base_url`；填写模型标识后会自动生成“模型名称”和“模型编码”。
          如果你手动改过这些字段，后续就不会再被自动覆盖。
          {isEmbedding && (
            <>
              <br />
              <strong>向量维度：</strong> 留空时按模型实际返回维度自动建立向量库；如填写，需与模型输出维度一致。更换不同维度的模型会重建该项目的向量库。
            </>
          )}
        </div>

        <Form
          form={form}
          layout="vertical"
          onFinish={handleSubmit}
          initialValues={{
            llm_timeout: 120,
            llm_temperature: 0.7,
            llm_top_p: 0.9,
            llm_max_tokens: DEFAULT_MAX_TOKENS,
            is_active: true,
          }}
        >
          <Form.Item name="model_type" hidden>
            <Input />
          </Form.Item>

          <Space direction="vertical" style={{ width: '100%' }} size={4}>
            <Form.Item
              label="提供方"
              name="provider"
              rules={[{ required: true, message: '请选择模型提供方' }]}
            >
              <Select
                showSearch
                placeholder="请选择模型提供方"
                optionFilterProp="label"
                options={providerCatalog.map((item) => ({
                  label: item.label,
                  value: item.value,
                }))}
              />
            </Form.Item>

            <Form.Item
              label="Base URL"
              name="endpoint_url"
              rules={[{ required: true, message: '请输入 base_url' }]}
            >
              <Input
                placeholder="选择提供方后自动带出，也可以手动覆盖"
                onChange={() => {
                  setAutoFillFlags((current) => ({ ...current, endpointUrl: false }))
                }}
              />
            </Form.Item>
          </Space>

          <Space style={{ width: '100%' }} size={16} align="start">
            <Form.Item
              label="模型标识"
              name="llm_model_name"
              style={{ flex: 1 }}
              rules={[{ required: true, message: '请输入模型标识或部署名' }]}
            >
              <Input
                placeholder={
                  isEmbedding
                    ? '如 text-embedding-3-small / text-embedding-v4 / bge-large-zh'
                    : '如 gpt-4.1-mini / qwen3.6-plus / claude-3-5-sonnet-latest'
                }
              />
            </Form.Item>

            <Form.Item
              label="请求超时（秒）"
              name="llm_timeout"
              style={{ width: 180 }}
              rules={[{ required: true, message: '请输入超时时间' }]}
            >
              <InputNumber min={5} max={600} style={{ width: '100%' }} />
            </Form.Item>
          </Space>

          <Space style={{ width: '100%' }} size={16} align="start">
            <Form.Item
              label="模型名称"
              name="model_name"
              style={{ flex: 1 }}
              rules={[{ required: true, message: '请输入模型名称' }]}
            >
              <Input
                placeholder="会根据提供方和模型标识自动生成"
                onChange={() => {
                  setAutoFillFlags((current) => ({ ...current, modelName: false }))
                }}
              />
            </Form.Item>

            <Form.Item
              label="模型编码"
              name="model_code"
              style={{ flex: 1 }}
              rules={[{ required: true, message: '请输入模型编码' }]}
            >
              <Input
                placeholder="会自动生成，支持手动调整"
                onChange={() => {
                  setAutoFillFlags((current) => ({ ...current, modelCode: false }))
                }}
              />
            </Form.Item>
          </Space>

          <Form.Item label="API Key" name="api_key">
            <Input.Password
              placeholder="支持留空后稍后补齐；测试非 Ollama 模型时建议填写"
              autoComplete="new-password"
            />
          </Form.Item>

          {isEmbedding ? (
            <Form.Item
              label="向量维度"
              name="embedding_dimension"
              extra="留空则按模型实际返回维度自动建立；填写需与模型输出一致。"
            >
              <InputNumber
                min={1}
                max={8192}
                step={1}
                style={{ width: '100%' }}
                placeholder="如 1536 / 1024 / 768，可留空自动识别"
              />
            </Form.Item>
          ) : (
            <>
              <Space style={{ width: '100%' }} size={24} align="start">
                <Form.Item
                  label="Temperature"
                  name="llm_temperature"
                  style={{ flex: 1 }}
                  tooltip="数值越高回答越发散，越低越稳定保守"
                  rules={[{ required: true, message: '请设置 temperature' }]}
                >
                  <Slider
                    min={0}
                    max={2}
                    step={0.05}
                    marks={{ 0: '0', 0.7: '0.7', 1: '1', 2: '2' }}
                    tooltip={{ open: undefined }}
                  />
                </Form.Item>

                <Form.Item
                  label="Top P"
                  name="llm_top_p"
                  style={{ flex: 1 }}
                  tooltip="核采样阈值，控制候选词的累计概率范围"
                  rules={[{ required: true, message: '请设置 top_p' }]}
                >
                  <Slider
                    min={0}
                    max={1}
                    step={0.05}
                    marks={{ 0: '0', 0.5: '0.5', 0.9: '0.9', 1: '1' }}
                    tooltip={{ open: undefined }}
                  />
                </Form.Item>
              </Space>

              <Form.Item
                label="Max Tokens"
                name="llm_max_tokens"
                tooltip="单次回复的最大输出长度"
                rules={[{ required: true, message: '请选择 max_tokens' }]}
              >
                <Radio.Group
                  className="max-tokens-group"
                  optionType="button"
                  buttonStyle="solid"
                  options={MAX_TOKENS_OPTIONS}
                />
              </Form.Item>

              <Form.Item label="系统提示词" name="llm_system_prompt">
                <TextArea
                  rows={4}
                  placeholder="可选。对话与测试时会作为 system prompt 一并发送。"
                />
              </Form.Item>
            </>
          )}

          <Form.Item label="描述" name="description">
            <TextArea rows={2} placeholder="可填写用途、场景、适用业务等说明" />
          </Form.Item>

          <Form.Item label="启用状态" name="is_active" valuePropName="checked">
            <Switch checkedChildren="启用" unCheckedChildren="停用" />
          </Form.Item>
        </Form>
      </Modal>
    </div>
  )
}

export default ModelConfigs