github-content-translator.yml

name: GitHub Content Translator
run-name: "Translate: ${{ github.event.issue.title || github.event.pull_request.title || github.event.comment.body || github.event.review.body || 'GitHub content' }}"

concurrency:
  group: translator-${{ github.event.comment.id || github.event.issue.number || github.event.review.id }}
  cancel-in-progress: true

on:
  issues:
    types: [opened]
  issue_comment:
    types: [created, edited]
  pull_request_review:
    types: [submitted, edited]
  pull_request_review_comment:
    types: [created, edited]

jobs:
  translate:
    if: |
      (github.event_name == 'issues')
      || (github.event_name == 'issue_comment' && github.event.sender.type != 'Bot')
      || (
        (github.event_name == 'pull_request_review' || github.event_name == 'pull_request_review_comment')
        && github.event.sender.type != 'Bot'
        && github.event.pull_request.head.repo.fork == false
      )
    runs-on: ubuntu-latest
    timeout-minutes: 5
    permissions:
      issues: write
      pull-requests: write

    steps:
      - name: Translate and update event content
        uses: actions/github-script@v8
        env:
          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
          ANTHROPIC_BASE_URL: ${{ vars.ANTHROPIC_BASE_URL }}
          ANTHROPIC_MODEL: ${{ vars.ANTHROPIC_MODEL }}
        with:
          github-token: ${{ github.token }}
          script: |
            const ORIGINAL_SUMMARY = '<summary>Original Content</summary>'

            const stripCodeFence = (value) =>
              value
                .trim()
                .replace(/^```(?:json)?\s*/i, '')
                .replace(/\s*```$/i, '')
                .trim()

            const parseTranslatorResult = (text, responseMetadata) => {
              const strippedText = stripCodeFence(text)

              try {
                return JSON.parse(strippedText)
              } catch (error) {
                core.startGroup('Translator response metadata')
                core.info(JSON.stringify(responseMetadata, null, 2))
                core.endGroup()

                core.startGroup('Translator raw model response')
                core.info(text)
                core.endGroup()

                if (strippedText !== text) {
                  core.startGroup('Translator response after code-fence stripping')
                  core.info(strippedText)
                  core.endGroup()
                }

                throw new Error(`Translator API returned invalid JSON: ${error.message}`)
              }
            }

            const getTranslatedMarker = (kind) => {
              switch (kind) {
                case 'issue':
                  return 'This issue was translated automatically.'
                case 'issue_comment':
                  return 'This comment was translated automatically.'
                case 'pull_request_review':
                  return 'This review was translated automatically.'
                case 'pull_request_review_comment':
                  return 'This review comment was translated automatically.'
                default:
                  return 'This content was translated automatically.'
              }
            }

            const buildBody = (kind, translatedBody, originalBody) =>
              [
                `> ${getTranslatedMarker(kind)}`,
                '',
                translatedBody.trim(),
                '',
                '---',
                '<details>',
                ORIGINAL_SUMMARY,
                '',
                originalBody.trim(),
                '</details>'
              ].join('\n')

            const getTarget = () => {
              const payload = context.payload

              switch (context.eventName) {
                case 'issues':
                  return {
                    kind: 'issue',
                    issueNumber: payload.issue.number,
                    title: payload.issue.title || '',
                    body: payload.issue.body || ''
                  }
                case 'issue_comment':
                  return {
                    kind: 'issue_comment',
                    issueNumber: payload.issue.number,
                    commentId: payload.comment.id,
                    title: '',
                    body: payload.comment.body || ''
                  }
                case 'pull_request_review':
                  return {
                    kind: 'pull_request_review',
                    pullNumber: payload.pull_request.number,
                    reviewId: payload.review.id,
                    title: '',
                    body: payload.review.body || ''
                  }
                case 'pull_request_review_comment':
                  return {
                    kind: 'pull_request_review_comment',
                    pullNumber: payload.pull_request.number,
                    commentId: payload.comment.id,
                    title: '',
                    body: payload.comment.body || ''
                  }
                default:
                  throw new Error(`Unsupported event: ${context.eventName}`)
              }
            }

            const isWorkflowTranslationEdit = (target) => {
              const previousBody = context.payload.changes?.body?.from
              const translatedMarker = `> ${getTranslatedMarker(target.kind)}`

              return (
                context.payload.action === 'edited' &&
                typeof previousBody === 'string' &&
                !previousBody.includes(translatedMarker) &&
                target.body.startsWith(translatedMarker) &&
                target.body.includes(ORIGINAL_SUMMARY)
              )
            }

            const updateTarget = async (target, translatedTitle, translatedBody, originalBody) => {
              const body = buildBody(target.kind, translatedBody, originalBody)
              const { owner, repo } = context.repo

              switch (target.kind) {
                case 'issue':
                  await github.rest.issues.update({
                    owner,
                    repo,
                    issue_number: target.issueNumber,
                    title: translatedTitle || target.title,
                    body
                  })
                  return
                case 'issue_comment':
                  await github.rest.issues.updateComment({
                    owner,
                    repo,
                    comment_id: target.commentId,
                    body
                  })
                  return
                case 'pull_request_review':
                  await github.request('PUT /repos/{owner}/{repo}/pulls/{pull_number}/reviews/{review_id}', {
                    owner,
                    repo,
                    pull_number: target.pullNumber,
                    review_id: target.reviewId,
                    body
                  })
                  return
                case 'pull_request_review_comment':
                  await github.rest.pulls.updateReviewComment({
                    owner,
                    repo,
                    comment_id: target.commentId,
                    body
                  })
                  return
              }
            }

            const callTranslator = async (target) => {
              const apiKey = process.env.ANTHROPIC_API_KEY
              if (!apiKey) {
                throw new Error('Missing ANTHROPIC_API_KEY')
              }

              const baseUrl = (process.env.ANTHROPIC_BASE_URL || 'https://api.anthropic.com').replace(/\/$/, '')
              const model = process.env.ANTHROPIC_MODEL
              if (!model) {
                throw new Error('Missing ANTHROPIC_MODEL')
              }

              const response = await fetch(`${baseUrl}/v1/messages`, {
                method: 'POST',
                headers: {
                  'content-type': 'application/json',
                  'x-api-key': apiKey,
                  'anthropic-version': '2023-06-01'
                },
                body: JSON.stringify({
                  model,
                  max_tokens: 4096,
                  temperature: 0,
                  system: `You translate GitHub issue, issue comment, pull request review, and pull request review comment content into English.

            Return only compact JSON with this exact shape:
            {
              "should_update": boolean,
              "translated_title": string | null,
              "translated_body": string | null,
              "original_body": string | null
            }

            Rules:
            - If the content is already fully English, return should_update=false.
            - If the content already follows the automatic translation format and its Original Content matches the current source, return should_update=false.
            - If the content is translated but the original and translated content do not match, return should_update=true and fix it.
            - Translate non-English or partially non-English content to natural English.
            - For issues, translate the title when it is non-English. For all other event kinds, translated_title must be null.
            - Preserve Markdown structure, code blocks, task lists, links, and mentions.
            - If the content quotes an earlier automatic translation, keep only the English quoted content and remove translation markers and Original Content sections from the quote.
            - If the content quotes non-translated content, keep that quote unchanged.
            - If the content is an email reply, remove quoted email history from both translated_body and original_body.
            - original_body must be the source text that corresponds to translated_body, after any required email quote cleanup.`,
                  messages: [
                    {
                      role: 'user',
                      content: JSON.stringify({
                        event: context.eventName,
                        target
                      })
                    }
                  ]
                })
              })

              if (!response.ok) {
                throw new Error(`Translator API failed with ${response.status}: ${await response.text()}`)
              }

              const data = await response.json()
              const text = data.content?.find((part) => part.type === 'text')?.text
              if (!text) {
                throw new Error('Translator API returned no text content')
              }

              return parseTranslatorResult(text, {
                id: data.id,
                model: data.model,
                stop_reason: data.stop_reason,
                stop_sequence: data.stop_sequence,
                usage: data.usage
              })
            }

            const target = getTarget()
            if (isWorkflowTranslationEdit(target)) {
              core.info('Skipping the edit event emitted by this workflow translation.')
              return
            }

            const result = await callTranslator(target)
            if (!result.should_update) {
              core.info('Translator reported that no translation update is needed.')
              return
            }

            if (typeof result.translated_body !== 'string' || typeof result.original_body !== 'string') {
              throw new Error('Translator requested an update without translated_body and original_body')
            }

            await updateTarget(target, result.translated_title, result.translated_body, result.original_body)
            core.info(`Updated ${target.kind} with English translation.`)