name: Regression Tests

on:
  pull_request:
    types: [opened, synchronize, reopened]

env:
  REGRESSION_TESTING: true

permissions:
  contents: read
  pull-requests: write

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

jobs:
  resolve-main:
    name: Resolve main
    runs-on: ubuntu-latest
    outputs:
      main_sha: ${{ steps.resolve.outputs.main_sha }}

    steps:
      - name: Checkout DoltgreSQL
        uses: actions/checkout@v6
        with:
          ref: main

      - name: Resolve main SHA
        id: resolve
        run: echo "main_sha=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"

  pr-regression:
    name: PR regression
    runs-on: ubuntu-latest
    needs: resolve-main

    steps:
      - name: Checkout DoltgreSQL
        uses: actions/checkout@v6
        with:
          ref: ${{ github.event.pull_request.head.sha }}
          fetch-depth: 0

      - name: Setup Git User
        uses: fregante/setup-git-user@v2

      - name: Merge base into PR
        run: |
          git fetch origin ${{ needs.resolve-main.outputs.main_sha }}
          git merge ${{ needs.resolve-main.outputs.main_sha }} --no-commit --no-ff

      - name: Install Go
        uses: actions/setup-go@v5
        with:
          go-version-file: go.mod
          cache: true

      - name: Test PR branch
        continue-on-error: true
        run: |
          ./postgres/parser/build.sh
          cd testing/go/regression
          mkdir -p out
          {
            echo "pr_head=${{ github.event.pull_request.head.sha }}"
            echo "main_head=${{ needs.resolve-main.outputs.main_sha }}"
            echo "merge_base=$(git merge-base HEAD ${{ needs.resolve-main.outputs.main_sha }})"
            git status --short --branch
            git diff --cached --stat
            go version
            go env
            go list -m github.com/dolthub/dolt/go github.com/dolthub/go-mysql-server
          } > out/pr-metadata.txt
          cd tool
          set +e
          go test --timeout=90m ./... --count=1 2>&1 | tee ../out/pr-go-test.log
          test_status=${PIPESTATUS[0]}
          set -e
          if [ -f ../out/results.trackers ]; then
            cp ../out/results.trackers ../out/results2.trackers
          fi
          exit "$test_status"

      - name: Upload PR regression artifacts
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: regression-pr-${{ github.run_id }}-${{ github.run_attempt }}
          path: |
            testing/go/regression/out/results2.trackers
            testing/go/regression/out/pr-go-test.log
            testing/go/regression/out/pr-metadata.txt
          if-no-files-found: warn
          retention-days: 14
          compression-level: 0

  main-regression:
    name: Main regression
    runs-on: ubuntu-latest
    needs: resolve-main

    steps:
      - name: Checkout DoltgreSQL
        uses: actions/checkout@v6
        with:
          ref: ${{ needs.resolve-main.outputs.main_sha }}

      - name: Install Go
        uses: actions/setup-go@v5
        with:
          go-version-file: go.mod
          cache: true

      - name: Test main branch
        continue-on-error: true
        run: |
          ./postgres/parser/build.sh
          cd testing/go/regression
          mkdir -p out
          {
            echo "main_head=${{ needs.resolve-main.outputs.main_sha }}"
            git status --short --branch
            go version
            go env
            go list -m github.com/dolthub/dolt/go github.com/dolthub/go-mysql-server
          } > out/main-metadata.txt
          cd tool
          set +e
          go test --timeout=90m ./... --count=1 2>&1 | tee ../out/main-go-test.log
          test_status=${PIPESTATUS[0]}
          set -e
          if [ -f ../out/results.trackers ]; then
            cp ../out/results.trackers ../out/results1.trackers
          fi
          exit "$test_status"

      - name: Upload main regression artifacts
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: regression-main-${{ github.run_id }}-${{ github.run_attempt }}
          path: |
            testing/go/regression/out/results1.trackers
            testing/go/regression/out/main-go-test.log
            testing/go/regression/out/main-metadata.txt
          if-no-files-found: warn
          retention-days: 14
          compression-level: 0

  regression-tests:
    runs-on: ubuntu-latest
    needs:
      - resolve-main
      - pr-regression
      - main-regression
    if: always() && needs.pr-regression.result != 'cancelled' && needs.main-regression.result != 'cancelled'

    steps:
      - name: Checkout DoltgreSQL
        uses: actions/checkout@v6
        with:
          ref: ${{ needs.resolve-main.outputs.main_sha }}

      - name: Install Go
        uses: actions/setup-go@v5
        with:
          go-version-file: go.mod
          cache: true

      - name: Download PR regression artifacts
        uses: actions/download-artifact@v4
        continue-on-error: true
        with:
          name: regression-pr-${{ github.run_id }}-${{ github.run_attempt }}
          path: testing/go/regression/out

      - name: Download main regression artifacts
        uses: actions/download-artifact@v4
        continue-on-error: true
        with:
          name: regression-main-${{ github.run_id }}-${{ github.run_attempt }}
          path: testing/go/regression/out

      - name: Check result trackers
        id: check_trackers
        run: |
          cd testing/go/regression/out
          if [[ -f "results1.trackers" && -f "results2.trackers" ]]; then
            echo "trackers_exist=true" >> $GITHUB_OUTPUT
            echo "trackers exist"
          else
            echo "trackers_exist=false" >> $GITHUB_OUTPUT
            echo "One of the branches could not successfully complete their tests."
            echo "Please review uploaded regression artifacts for errors, which must be fixed."
            exit 1
          fi

      - name: Build Regression Test Results Comment
        id: build_results
        if: steps.check_trackers.outputs.trackers_exist == 'true'
        run: |
          ./postgres/parser/build.sh
          cd testing/go/regression/tool
          # Pass via file, not $GITHUB_OUTPUT: large output through env trips ARG_MAX in github-script.
          go run . results1.trackers results2.trackers > "$RUNNER_TEMP/regression-comment.md"
          cp "$RUNNER_TEMP/regression-comment.md" ../out/regression-comment.md
          cat "$RUNNER_TEMP/regression-comment.md"
          if [ -s "$RUNNER_TEMP/regression-comment.md" ]; then
            echo "has_output=true" >> "$GITHUB_OUTPUT"
          else
            echo "has_output=false" >> "$GITHUB_OUTPUT"
          fi

      - name: Upload comparison artifacts
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: regression-comparison-${{ github.run_id }}-${{ github.run_attempt }}
          path: testing/go/regression/out/regression-comment.md
          if-no-files-found: warn
          retention-days: 14
          compression-level: 0

      - name: Is PR From Fork
        id: from_fork
        run: |
          if [ "${{ github.event.pull_request.head.repo.full_name }}" != "${{ github.repository }}" ]; then
            echo "This is running from a fork, skipping commenting"
            echo "fork=true" >> $GITHUB_OUTPUT
          else
            echo "This is not running from a fork"
            echo "fork=false" >> $GITHUB_OUTPUT
          fi

      - name: Post Comment
        if: steps.from_fork.outputs.fork == 'false' && steps.build_results.outputs.has_output == 'true'
        uses: actions/github-script@v7
        env:
          COMMENT_PATH: ${{ runner.temp }}/regression-comment.md
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const fs = require('fs')
            const commentMarker = '<!-- go-run-output -->'
            // GitHub caps comment bodies at 65536 chars.
            const MAX_BODY = 65000
            let output = fs.readFileSync(process.env.COMMENT_PATH, 'utf8')
            let body = `${commentMarker}\n${output}`
            if (body.length > MAX_BODY) {
              const notice = '\n\n_Output truncated; see workflow logs for the full report._'
              body = body.slice(0, MAX_BODY - notice.length) + notice
            }

            // List comments on the PR
            const { data: comments } = await github.rest.issues.listComments({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
            })

            // Check if a comment already exists
            const comment = comments.find(comment => comment.body.includes(commentMarker))

            if (comment) {
              // Update the existing comment
              await github.rest.issues.updateComment({
                comment_id: comment.id,
                owner: context.repo.owner,
                repo: context.repo.repo,
                body: body
              })
            } else {
              // Create a new comment
              await github.rest.issues.createComment({
                issue_number: context.issue.number,
                owner: context.repo.owner,
                repo: context.repo.repo,
                body: body
              })
            }