name: Report backend memory

on:
  workflow_run:
    types: [completed]
    workflows:
      - Get backend memory usage # get-backend-memory.yml

jobs:
  compare-memory:
    runs-on: ubuntu-latest
    if: ${{ github.event.workflow_run.conclusion == 'success' }}
    permissions:
      pull-requests: write

    steps:
      - name: Download artifact
        uses: actions/github-script@v8.0.0
        with:
          script: |
            const fs = require('fs');
            let allArtifacts = await github.rest.actions.listWorkflowRunArtifacts({
              owner: context.repo.owner,
              repo: context.repo.repo,
              run_id: context.payload.workflow_run.id,
            });
            let matchArtifacts = allArtifacts.data.artifacts.filter((artifact) => {
              return artifact.name.startsWith("memory-artifact-") || artifact.name == "memory-artifact"
            });
            await Promise.all(matchArtifacts.map(async (artifact) => {
              let download = await github.rest.actions.downloadArtifact({
                owner: context.repo.owner,
                repo: context.repo.repo,
                artifact_id: artifact.id,
                archive_format: 'zip',
              });
              await fs.promises.writeFile(`${process.env.GITHUB_WORKSPACE}/${artifact.name}.zip`, Buffer.from(download.data));
            }));
      - name: Extract all artifacts
        run: |
          find . -mindepth 1 -maxdepth 1 -type f -name '*.zip' -exec unzip {} -d artifacts ';'
          ls -la artifacts/
      - name: Load PR Number
        id: load-pr-num
        run: echo "pr-number=$(cat artifacts/pr_number)" >> "$GITHUB_OUTPUT"

      - name: Output base
        run: cat ./artifacts/memory-base.json
      - name: Output head
        run: cat ./artifacts/memory-head.json
      - name: Compare memory usage
        id: compare
        run: |
          BASE_MEMORY=$(cat ./artifacts/memory-base.json)
          HEAD_MEMORY=$(cat ./artifacts/memory-head.json)

          calc() {
            BASE=$(echo "$BASE_MEMORY" | jq -r '.memory.'"$1"' // 0')
            HEAD=$(echo "$HEAD_MEMORY" | jq -r '.memory.'"$1"' // 0')

            DIFF=$((HEAD - BASE))
            if [ "$BASE" -gt 0 ]; then
              DIFF_PERCENT=$(echo "scale=2; ($DIFF * 100) / $BASE" | bc)
            else
              DIFF_PERCENT=0
            fi

            # Convert KB to MB for readability
            BASE_MB=$(echo "scale=2; $BASE / 1024" | bc)
            HEAD_MB=$(echo "scale=2; $HEAD / 1024" | bc)
            DIFF_MB=$(echo "scale=2; $DIFF / 1024" | bc)

            echo "$1-base=$BASE_MB" >> "$GITHUB_OUTPUT"
            echo "$1-head=$HEAD_MB" >> "$GITHUB_OUTPUT"
            echo "$1-diff=$DIFF_MB" >> "$GITHUB_OUTPUT"
            echo "$1-diff_percent=$DIFF_PERCENT" >> "$GITHUB_OUTPUT"
          }

          calc VmRSS
          calc VmHWM
          calc VmSize
      - id: build-comment
        name: Build memory comment
        run: |
          HEADER="## Backend memory usage comparison"
          FOOTER="[See workflow logs for details](https://github.com/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID})"

          echo "$HEADER" > ./output.md
          echo >> ./output.md

          echo "| Metric | base | head | Diff |" >> ./output.md
          echo "|--------|------|------|------|" >> ./output.md
          echo "| RSS | ${{ steps.compare.outputs.VmRSS-base }} MB | ${{ steps.compare.outputs.VmRSS-head }} MB | ${{ steps.compare.outputs.VmRSS-diff }} MB (${{ steps.compare.outputs.VmRSS-diff_percent }}%) |" >> ./output.md
          echo "| HWM | ${{ steps.compare.outputs.VmHWM-base }} MB | ${{ steps.compare.outputs.VmHWM-head }} MB | ${{ steps.compare.outputs.VmHWM-diff }} MB (${{ steps.compare.outputs.VmHWM-diff_percent }}%) |" >> ./output.md
          echo "| VMS | ${{ steps.compare.outputs.VmSize-base }} MB | ${{ steps.compare.outputs.VmSize-head }} MB | ${{ steps.compare.outputs.VmSize-diff }} MB (${{ steps.compare.outputs.VmSize-diff_percent }}%) |" >> ./output.md
          echo >> ./output.md

          # Determine if this is a significant change (more than 5% increase)
          if [ "$(echo "${{ steps.compare.outputs.VmRSS-diff_percent }} > 5" | bc)" -eq 1 ]; then
            echo "⚠️ **Warning**: Memory usage has increased by more than 5%. Please verify this is not an unintended change." >> ./output.md
            echo >> ./output.md
          fi

          echo "$FOOTER" >> ./output.md
      - uses: thollander/actions-comment-pull-request@v3
        with:
          pr-number: ${{ steps.load-pr-num.outputs.pr-number }}
          comment-tag: show_memory_diff
          file-path: ./output.md
      - name: Tell error to PR
        uses: thollander/actions-comment-pull-request@v3
        if: failure() && steps.load-pr-num.outputs.pr-number
        with:
          pr-number: ${{ steps.load-pr-num.outputs.pr-number }}
          comment-tag: show_memory_diff_error
          message: |
            An error occurred while comparing backend memory usage. See [workflow logs](https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}) for details.