import * as React from 'react'
import { Plus, Search } from 'lucide-react'

import { AppDataTable, type AppDataTableColumn } from '@/components/app/AppDataTable'
import { AppEmptyState } from '@/components/app/AppEmptyState'
import { AppField } from '@/components/app/AppField'
import { AppPage } from '@/components/app/AppPage'
import { AppPageHeader } from '@/components/app/AppPageHeader'
import { AppSection } from '@/components/app/AppSection'
import { Badge } from '@/components/ui/badge'
import { Button } from '@/components/ui/button'
import { Input } from '@/components/ui/input'
import { formatDateTime } from '@/lib/format'

import { createKnowledgeBase, listKnowledgeBases } from './api'
import type { KnowledgeBase } from './types'

type KnowledgeBaseForm = {
  name: string
  description: string
  scope: string
}

const emptyForm: KnowledgeBaseForm = {
  name: '',
  description: '',
  scope: ''
}

const columns: AppDataTableColumn<KnowledgeBase>[] = [
  {
    key: 'name',
    header: '名称',
    cell: (base) => (
      <div>
        <p className="font-medium text-foreground">{base.name}</p>
        <p className="mt-1 line-clamp-1 text-sm text-muted-foreground">
          {base.description || '暂无描述'}
        </p>
      </div>
    )
  },
  {
    key: 'scope',
    header: '范围',
    cell: (base) => <span className="text-muted-foreground">{base.scope || '-'}</span>
  },
  {
    key: 'enabled',
    header: '启用状态',
    cell: (base) => (
      <Badge variant={base.enabled ? 'success' : 'secondary'}>
        {base.enabled ? '已启用' : '已停用'}
      </Badge>
    )
  },
  {
    key: 'updated_at',
    header: '更新时间',
    cell: (base) => <span className="text-muted-foreground">{formatDateTime(base.updated_at)}</span>
  }
]

export function KnowledgeBaseListPage() {
  const [bases, setBases] = React.useState<KnowledgeBase[]>([])
  const [form, setForm] = React.useState<KnowledgeBaseForm>(emptyForm)
  const [error, setError] = React.useState('')

  async function load() {
    try {
      setBases(await listKnowledgeBases())
      setError('')
    } catch (reason) {
      setError(reason instanceof Error ? reason.message : '加载知识库失败')
    }
  }

  React.useEffect(() => {
    void load()
  }, [])

  async function handleCreate(event: React.FormEvent<HTMLFormElement>) {
    event.preventDefault()
    await createKnowledgeBase(form)
    setForm(emptyForm)
    await load()
  }

  return (
    <AppPage contentClassName="gap-5">
      <AppPageHeader
        title="知识库"
        actions={
          <div className="flex gap-2">
            <Button variant="outline" onClick={() => (window.location.hash = '/knowledge/search')}>
              <Search data-icon="inline-start" />
              知识检索
            </Button>
            <Button onClick={() => (window.location.hash = '/knowledge/items/new')}>
              <Plus data-icon="inline-start" />
              新建知识条目
            </Button>
          </div>
        }
      />

      <AppSection title="新建知识库">
        <form className="grid gap-4 md:grid-cols-[1fr_1fr_1fr_auto] md:items-end" onSubmit={handleCreate}>
          <AppField label="名称" htmlFor="knowledge-base-name" required>
            <Input
              id="knowledge-base-name"
              required
              value={form.name}
              onChange={(event) => setForm((current) => ({ ...current, name: event.target.value }))}
              placeholder="例如：税务采集知识库"
            />
          </AppField>
          <AppField label="范围" htmlFor="knowledge-base-scope">
            <Input
              id="knowledge-base-scope"
              value={form.scope}
              onChange={(event) => setForm((current) => ({ ...current, scope: event.target.value }))}
              placeholder="例如：数据采集"
            />
          </AppField>
          <AppField label="描述" htmlFor="knowledge-base-description">
            <Input
              id="knowledge-base-description"
              value={form.description}
              onChange={(event) => setForm((current) => ({ ...current, description: event.target.value }))}
              placeholder="知识库用途说明"
            />
          </AppField>
          <Button type="submit">创建知识库</Button>
        </form>
      </AppSection>

      {error ? <AppEmptyState title="无法加载知识库" description={error} /> : null}
      {!error ? (
        <AppDataTable
          columns={columns}
          rows={bases}
          getRowKey={(base) => base.id}
          emptyTitle="暂无知识库"
          emptyDescription="创建知识库后，可继续维护文档、知识条目和检索内容。"
          footer={<p className="text-sm text-muted-foreground">共 {bases.length} 个知识库</p>}
        />
      ) : null}
    </AppPage>
  )
}