name: PR Triage

on:
  pull_request_target:
    types: [opened, synchronize, reopened, ready_for_review, labeled, unlabeled]

permissions:
  contents: read
  issues: write
  pull-requests: write

concurrency:
  group: pr-triage-${{ github.event.pull_request.number }}
  cancel-in-progress: true

jobs:
  triage:
    name: label-and-summarize
    runs-on: ubuntu-latest
    steps:
      - name: Apply deterministic PR labels and summary
        uses: actions/github-script@v7
        with:
          script: |
            const owner = context.repo.owner
            const repo = context.repo.repo
            const issue_number = context.payload.pull_request.number

            const managedLabels = {
              'area:desktop': '1d76db',
              'area:server': '0e8a16',
              'area:adapters': '5319e7',
              'area:docs': '0075ca',
              'area:release': 'fbca04',
              'area:cli-core': 'b60205',
              'needs-maintainer-approval': 'b60205',
              'allow-cli-core-change': 'c2e0c6',
              'allow-missing-tests': 'c2e0c6',
              'allow-coverage-baseline-change': 'c2e0c6',
            }

            const files = await github.paginate(github.rest.pulls.listFiles, {
              owner,
              repo,
              pull_number: issue_number,
              per_page: 100,
            })
            const filenames = files.map((file) => file.filename)
            const currentLabels = new Set((context.payload.pull_request.labels || []).map((label) => label.name))

            const areas = new Set()
            const cliCoreFiles = []
            const cliPrefixes = [
              'bin/',
              'src/entrypoints/',
              'src/screens/',
              'src/components/',
              'src/commands/',
              'src/tools/',
              'src/utils/',
            ]
            const docsExact = new Set(['README.md', 'README.en.md', 'package.json', 'package-lock.json', '.github/workflows/deploy-docs.yml'])
            const releaseExact = new Set([
              '.github/workflows/pr-quality.yml',
              '.github/workflows/pr-triage.yml',
              '.github/workflows/release-desktop.yml',
              '.github/workflows/build-desktop-dev.yml',
              'scripts/pr/change-policy.ts',
              'scripts/pr/change-policy.test.ts',
              'scripts/pr/check-pr.ts',
              'scripts/pr/run-server-tests.ts',
              'scripts/release.ts',
              'desktop/electron/tsconfig.json',
              'desktop/scripts/build-linux.sh',
              'desktop/scripts/build-macos-arm64.sh',
              'desktop/scripts/build-windows-x64.ps1',
            ])

            for (const filename of filenames) {
              if (filename.startsWith('desktop/')) areas.add('area:desktop')
              if (filename.startsWith('src/server/')) areas.add('area:server')
              if (filename.startsWith('adapters/')) areas.add('area:adapters')
              if (filename.startsWith('docs/') || filename.startsWith('release-notes/') || docsExact.has(filename)) areas.add('area:docs')
              if (releaseExact.has(filename)) areas.add('area:release')
              if (cliPrefixes.some((prefix) => filename.startsWith(prefix))) {
                areas.add('area:cli-core')
                cliCoreFiles.push(filename)
              }
            }

            if (cliCoreFiles.length > 0 && !currentLabels.has('allow-cli-core-change')) {
              areas.add('needs-maintainer-approval')
            }

            const hasTest = (prefix) => filenames.some((file) =>
              file.startsWith(prefix) && (/\.test\.[cm]?[jt]sx?$/.test(file) || file.includes('/__tests__/'))
            )
            const changedProduct = (predicate) => filenames.filter((file) =>
              predicate(file) &&
              /\.[cm]?[jt]sx?$/.test(file) &&
              !/\.test\.[cm]?[jt]sx?$/.test(file) &&
              !file.includes('/__tests__/') &&
              !file.includes('/fixtures/')
            )
            const desktopProduct = changedProduct((file) => file.startsWith('desktop/src/'))
            const serverProduct = changedProduct((file) => file.startsWith('src/server/'))
            const adapterProduct = changedProduct((file) => file.startsWith('adapters/'))
            const agentRuntimeProduct = changedProduct((file) =>
              file.startsWith('src/tools/') ||
              file.startsWith('src/utils/')
            )
            const rootRuntimeProduct = changedProduct((file) =>
              file.startsWith('src/') &&
              !file.startsWith('src/server/') &&
              !file.startsWith('src/tools/') &&
              !file.startsWith('src/utils/')
            )
            const missingTestSignals = []
            if (desktopProduct.length > 0 && !hasTest('desktop/src/')) {
              missingTestSignals.push('Desktop product files changed without a desktop test file in the PR.')
            }
            if (serverProduct.length > 0 && !hasTest('src/server/')) {
              missingTestSignals.push('Server product files changed without a server test file in the PR.')
            }
            if (adapterProduct.length > 0 && !hasTest('adapters/')) {
              missingTestSignals.push('Adapter product files changed without an adapter test file in the PR.')
            }
            if (agentRuntimeProduct.length > 0 && !filenames.some((file) =>
              (file.startsWith('src/tools/') || file.startsWith('src/utils/')) &&
              (/\.test\.[cm]?[jt]sx?$/.test(file) || file.includes('/__tests__/'))
            )) {
              missingTestSignals.push('Agent/runtime product files changed without a tools/utils test file in the PR.')
            }
            if (rootRuntimeProduct.length > 0 && !filenames.some((file) =>
              file.startsWith('src/') &&
              !file.startsWith('src/server/') &&
              !file.startsWith('src/tools/') &&
              !file.startsWith('src/utils/') &&
              (/\.test\.[cm]?[jt]sx?$/.test(file) || file.includes('/__tests__/'))
            )) {
              missingTestSignals.push('Root runtime product files changed without a matching root runtime test file in the PR.')
            }
            if (missingTestSignals.length > 0 && !currentLabels.has('allow-missing-tests')) {
              areas.add('needs-maintainer-approval')
            }
            const coveragePolicyFiles = filenames.filter((file) =>
              file === 'scripts/quality-gate/coverage-baseline.json' ||
              file === 'scripts/quality-gate/coverage-thresholds.json'
            )
            if (coveragePolicyFiles.length > 0 && !currentLabels.has('allow-coverage-baseline-change')) {
              areas.add('needs-maintainer-approval')
            }

            const testSignals = []
            testSignals.push(...missingTestSignals.map((signal) => `BLOCKING unless \`allow-missing-tests\` is applied: ${signal}`))
            if (agentRuntimeProduct.length > 0) {
              testSignals.push('Agent/model runtime path changed: use mock/request-shape tests in PR and maintainer live-model smoke before release.')
            }
            if (testSignals.length === 0) {
              testSignals.push('No obvious missing-test signal from changed paths.')
            }

            const riskNotes = []
            if (filenames.some((file) => file.startsWith('desktop/src-tauri/'))) {
              riskNotes.push('Legacy native resources changed: inspect Electron sidecar/package output and package-smoke results.')
            }
            if (filenames.some((file) => file.startsWith('desktop/src/stores/') || file.startsWith('desktop/src/api/'))) {
              riskNotes.push('Desktop state/API layer changed: verify store persistence, WebSocket behavior, and startup errors.')
            }
            if (filenames.some((file) => file.startsWith('src/server/ws/') || file.startsWith('src/server/services/conversation'))) {
              riskNotes.push('Session runtime changed: review reconnect, startup diagnostics, provider selection, and thinking settings.')
            }
            if (filenames.some((file) => file.includes('provider') || file.includes('WebSearchTool'))) {
              riskNotes.push('Provider/search behavior changed: PR gate uses mock tests; live-provider tests stay maintainer-only.')
            }
            if (filenames.some((file) => file.startsWith('.github/workflows/') || file.startsWith('scripts/pr/'))) {
              riskNotes.push('CI/policy changed: inspect workflow behavior itself, not just application tests.')
            }
            if (riskNotes.length === 0) {
              riskNotes.push('No special risk notes from changed paths.')
            }

            for (const [name, color] of Object.entries(managedLabels)) {
              try {
                await github.rest.issues.createLabel({
                  owner,
                  repo,
                  name,
                  color,
                })
              } catch (error) {
                if (error.status !== 422) throw error
              }
            }

            const desiredLabels = [...areas]
            if (desiredLabels.length > 0) {
              await github.rest.issues.addLabels({
                owner,
                repo,
                issue_number,
                labels: desiredLabels,
              })
            }

            for (const label of Object.keys(managedLabels)) {
              if (label === 'allow-cli-core-change' || label === 'allow-missing-tests' || label === 'allow-coverage-baseline-change') continue
              if (!areas.has(label) && currentLabels.has(label)) {
                try {
                  await github.rest.issues.removeLabel({
                    owner,
                    repo,
                    issue_number,
                    name: label,
                  })
                } catch (error) {
                  if (error.status !== 404) throw error
                }
              }
            }

            const marker = '<!-- pr-quality-triage -->'
            const areaText = [...areas].filter((label) => label.startsWith('area:')).sort().join(', ') || 'none'
            const approvalText = cliCoreFiles.length > 0 && !currentLabels.has('allow-cli-core-change')
              ? 'Blocked by policy until a maintainer applies `allow-cli-core-change` and approves the PR.'
              : 'No CLI-core policy block detected.'
            const missingTestText = missingTestSignals.length > 0 && !currentLabels.has('allow-missing-tests')
              ? 'Blocked by policy until a maintainer applies `allow-missing-tests` or matching tests are added.'
              : 'No missing-test policy block detected.'
            const coveragePolicyText = coveragePolicyFiles.length > 0 && !currentLabels.has('allow-coverage-baseline-change')
              ? 'Blocked by policy until a maintainer applies `allow-coverage-baseline-change` after reviewing the baseline or threshold change.'
              : 'No coverage-baseline policy block detected.'
            const cliFilesText = cliCoreFiles.length
              ? cliCoreFiles.slice(0, 20).map((file) => `- \`${file}\``).join('\n')
              : '- none'
            const coveragePolicyFilesText = coveragePolicyFiles.length
              ? coveragePolicyFiles.slice(0, 20).map((file) => `- \`${file}\``).join('\n')
              : '- none'

            const body = [
              marker,
              '## PR quality triage',
              '',
              `**Changed areas:** ${areaText}`,
              '',
              `**CLI core policy:** ${approvalText}`,
              '',
              `**Missing-test policy:** ${missingTestText}`,
              '',
              `**Coverage baseline policy:** ${coveragePolicyText}`,
              '',
              '**CLI core files:**',
              cliFilesText,
              '',
              '**Coverage policy files:**',
              coveragePolicyFilesText,
              '',
              '**Required check plan:**',
              '- See `PR Quality / scope-plan`; it is the single source of truth for selected jobs.',
              '',
              '**Test coverage signals:**',
              testSignals.map((signal) => `- ${signal}`).join('\n'),
              '',
              '**Risk notes:**',
              riskNotes.map((note) => `- ${note}`).join('\n'),
              '',
              'Hard merge gates come from the deterministic GitHub Actions contract lanes above.',
            ].join('\n')

            const comments = await github.paginate(github.rest.issues.listComments, {
              owner,
              repo,
              issue_number,
              per_page: 100,
            })
            const existing = comments.find((comment) => comment.body && comment.body.includes(marker))

            if (existing) {
              await github.rest.issues.updateComment({
                owner,
                repo,
                comment_id: existing.id,
                body,
              })
            } else {
              await github.rest.issues.createComment({
                owner,
                repo,
                issue_number,
                body,
              })
            }