import { useState } from 'react'
import { Button, Card, Form, Input, message, Space } from 'antd'
import { PageHeader } from '@ant-design/pro-components'
import { translateChineseToEnglish } from '@/api/zh-en-translator'

const ZhEnTranslator = () => {
  const [form] = Form.useForm()
  const [loading, setLoading] = useState(false)
  const [translationResult, setTranslationResult] = useState('')
  const [currentInput, setCurrentInput] = useState('')
  const maxChars = 5000

  const handleTranslate = async () => {
    try {
      const source_content = form.getFieldValue('source_content') || ''
      if (!source_content.trim()) {
        message.warning('请输入要翻译的中文内容')
        return
      }

      setLoading(true)
      setTranslationResult('')

      const response = await translateChineseToEnglish(source_content)

      if (!response.ok) {
        const errorText = await response.text()
        throw new Error(`翻译请求失败: ${response.status} ${errorText}`)
      }

      if (!response.body) {
        throw new Error('响应体为空')
      }

      const reader = response.body.getReader()
      const decoder = new TextDecoder('utf-8')
      let buffer = ''
      let fullContent = ''

      try {
        while (true) {
          const { done, value } = await reader.read()
          if (done) break

          buffer += decoder.decode(value, { stream: true })
          const lines = buffer.split('\n')
          buffer = lines.pop() || ''

          for (const line of lines) {
            const trimmedLine = line.trim()
            if (!trimmedLine || trimmedLine === 'data: [DONE]') {
              if (trimmedLine === 'data: [DONE]') {
                message.success('翻译完成')
                setLoading(false)
                return
              }
              continue
            }

            if (trimmedLine.startsWith('data: ')) {
              try {
                const data = trimmedLine.slice(6)
                const parsed = JSON.parse(data)

                if (parsed.event === 'message' && parsed.answer) {
                  fullContent += parsed.answer
                  setTranslationResult(fullContent)
                } else if (parsed.event === 'error') {
                  throw new Error(parsed.message || 'Dify API 返回错误')
                }
              } catch (parseError) {
                console.warn('跳过无法解析的行:', trimmedLine)
              }
            }
          }
        }
      } finally {
        reader.releaseLock()
      }

      if (fullContent) {
        message.success('翻译完成')
      } else {
        throw new Error('未收到翻译结果')
      }
    } catch (error) {
      console.error('翻译错误:', error)
      message.error(error instanceof Error ? error.message : '翻译失败，请稍后重试')
    } finally {
      setLoading(false)
    }
  }

  const handleClear = () => {
    form.resetFields()
    setTranslationResult('')
    setCurrentInput('')
    message.info('已清空内容')
  }

  const handleCopy = async () => {
    if (!translationResult) {
      message.warning('没有可复制的内容')
      return
    }

    try {
      await navigator.clipboard.writeText(translationResult)
      message.success('复制成功')
    } catch (error) {
      console.error('复制失败:', error)
      message.error('复制失败，请手动复制')
    }
  }

  return (
    <div style={{ maxWidth: '900px', margin: '0 auto', padding: '20px' }}>
      <PageHeader
        title="中文转英文翻译助手"
        subTitle="专业的中文到英文文本翻译工具，支持流式输出，翻译结果地道自然"
        style={{ marginBottom: '30px' }}
      />

      <Space direction="vertical" style={{ width: '100%' }} size="large">
        <Card title="参数输入区">
          <Form form={form} layout="vertical">
            <Form.Item
              name="source_content"
              label={
                <div style={{ display: 'flex', justifyContent: 'space-between', width: '100%' }}>
                  <span>中文原文</span>
                  <span style={{ color: currentInput.length > maxChars ? '#ff4d4f' : '#999' }}>
                    {currentInput.length} / {maxChars}
                  </span>
                </div>
              }
              rules={[
                { required: true, message: '请输入要翻译的中文内容' },
                { max: maxChars, message: `输入内容不能超过${maxChars}个字符` }
              ]}
            >
              <Input.TextArea
                placeholder="请输入需要翻译的中文内容（最多5000个字符）"
                rows={8}
                value={currentInput}
                onChange={(e) => setCurrentInput(e.target.value)}
                showCount
                maxLength={maxChars}
                style={{ fontSize: '14px' }}
              />
            </Form.Item>
          </Form>
        </Card>

        <Space style={{ width: '100%', justifyContent: 'center' }} size="middle">
          <Button
            type="primary"
            size="large"
            onClick={handleTranslate}
            loading={loading}
            style={{ minWidth: '120px', height: '40px', fontSize: '16px' }}
          >
            翻译
          </Button>
          <Button
            size="large"
            onClick={handleClear}
            disabled={loading}
            style={{ minWidth: '120px', height: '40px', fontSize: '16px' }}
          >
            清空
          </Button>
        </Space>

        <Card
          title="翻译结果"
          extra={
            translationResult && (
              <Button onClick={handleCopy} size="small">
                复制
              </Button>
            )
          }
        >
          <div
            style={{
              minHeight: '150px',
              maxHeight: '400px',
              overflowY: 'auto',
              padding: '15px',
              backgroundColor: '#fafafa',
              border: '1px solid #d9d9d9',
              borderRadius: '4px',
              whiteSpace: 'pre-wrap',
              wordWrap: 'break-word',
              fontSize: '14px',
              lineHeight: '1.6'
            }}
          >
            {loading ? (
              <div style={{ textAlign: 'center', color: '#999', padding: '20px' }}>
                正在翻译中，请稍候...
              </div>
            ) : translationResult || (
              <div style={{ textAlign: 'center', color: '#999' }}>
                翻译结果将在这里显示
              </div>
            )}
          </div>
        </Card>
      </Space>
    </div>
  )
}

export default ZhEnTranslator