# Push a release to the lean4-pr-releases repository, whenever someone pushes to a PR branch.

# This needs to run with the `secrets.PR_RELEASES_TOKEN` token available,
# but PR branches will generally come from forks,
# so it is not possible to run this using the `pull_request` or `pull_request_target` workflows.
# Instead we use `workflow_run`, which essentially allows us to escalate privileges
# (but only runs the CI as described in the `master` branch, not in the PR branch).

name: PR release

on:
  workflow_run: # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#workflow_run
    workflows: [CI]
    types: [completed]

jobs:
  on-success:
    runs-on: ubuntu-latest
    if: github.event.workflow_run.conclusion == 'success' && github.event.workflow_run.event == 'pull_request' && github.repository == 'leanprover/lean4'
    steps:
      - name: Retrieve information about the original workflow
        uses: potiuk/get-workflow-origin@v1_1 # https://github.com/marketplace/actions/get-workflow-origin
        # This action is deprecated and archived, but it seems hard to find a better solution for getting the PR number
        # see https://github.com/orgs/community/discussions/25220 for some discussion
        id: workflow-info
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          sourceRunId: ${{ github.event.workflow_run.id }}

      - name: Download artifact from the previous workflow.
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        id: download-artifact
        uses: dawidd6/action-download-artifact@v2 # https://github.com/marketplace/actions/download-workflow-artifact
        with:
          run_id: ${{ github.event.workflow_run.id }}
          path: artifacts
          name: build-.*
          name_is_regexp: true

      - name: Push branch and tag
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        run: |
          git init --bare lean4.git
          git -C lean4.git remote add origin https://github.com/${{ github.repository_owner }}/lean4.git
          git -C lean4.git fetch -n origin master
          git -C lean4.git fetch -n origin "${{ steps.workflow-info.outputs.sourceHeadSha }}"
          git -C lean4.git tag -f pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }} "${{ steps.workflow-info.outputs.sourceHeadSha }}"
          git -C lean4.git remote add pr-releases https://foo:'${{ secrets.PR_RELEASES_TOKEN }}'@github.com/${{ github.repository_owner }}/lean4-pr-releases.git
          git -C lean4.git push -f pr-releases pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}
      - name: Delete existing release if present
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        run: |
          # Try to delete any existing release for the current PR.
          gh release delete --repo ${{ github.repository_owner }}/lean4-pr-releases pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }} -y || true
        env:
          GH_TOKEN: ${{ secrets.PR_RELEASES_TOKEN }}
      - name: Release
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        uses: softprops/action-gh-release@v1
        with:
          name: Release for PR ${{ steps.workflow-info.outputs.pullRequestNumber }}
          # There are coredumps files here as well, but all in deeper subdirectories.
          files: artifacts/*/*
          fail_on_unmatched_files: true
          draft: false
          tag_name: pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}
          repository: ${{ github.repository_owner }}/lean4-pr-releases
        env:
          # The token used here must have `workflow` privileges.
          GITHUB_TOKEN: ${{ secrets.PR_RELEASES_TOKEN }}

      - name: Add label
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        uses: actions/github-script@v7
        with:
          script: |
            await github.rest.issues.addLabels({
              issue_number: ${{ steps.workflow-info.outputs.pullRequestNumber }},
              owner: context.repo.owner,
              repo: context.repo.repo,
              labels: ['toolchain-available']
            })

      # Next, determine the most recent nightly release in this PR's history.
      - name: Find most recent nightly in feature branch
        id: most-recent-nightly-tag
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        run: |
          git -C lean4.git remote add nightly https://github.com/leanprover/lean4-nightly.git
          git -C lean4.git fetch nightly '+refs/tags/nightly-*:refs/tags/nightly-*'
          git -C lean4.git tag --merged "${{ steps.workflow-info.outputs.sourceHeadSha }}" --list "nightly-*" \
            | sort -rV | head -n 1 | sed "s/^nightly-*/MOST_RECENT_NIGHTLY=/" | tee -a $GITHUB_ENV

      - name: 'Setup jq'
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        uses: dcarbone/install-jq-action@v1.0.1

      # Check that the most recently nightly coincides with 'git merge-base HEAD master'
      - name: Check merge-base and nightly-testing-YYYY-MM-DD
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        id: ready
        run: |
          echo "Most recent nightly in your branch: $MOST_RECENT_NIGHTLY"
          NIGHTLY_SHA=$(git -C lean4.git rev-parse "nightly-$MOST_RECENT_NIGHTLY^{commit}")
          echo "SHA of most recent nightly: $NIGHTLY_SHA"
          MERGE_BASE_SHA=$(git -C lean4.git merge-base origin/master "${{ steps.workflow-info.outputs.sourceHeadSha }}")
          echo "SHA of merge-base: $MERGE_BASE_SHA"
          if [ "$NIGHTLY_SHA" = "$MERGE_BASE_SHA" ]; then
            echo "Most recent nightly tag agrees with the merge base."

            REMOTE_BRANCHES=$(git ls-remote -h https://github.com/leanprover-community/mathlib4.git nightly-testing-$MOST_RECENT_NIGHTLY)

            if [[ -n "$REMOTE_BRANCHES" ]]; then
              echo "... and Mathlib has a 'nightly-testing-$MOST_RECENT_NIGHTLY' branch."
              MESSAGE=""
            else
              echo "... but Mathlib does not yet have a 'nightly-testing-$MOST_RECENT_NIGHTLY' branch."
              MESSAGE="- ❗ Mathlib CI can not be attempted yet, as the 'nightly-testing-$MOST_RECENT_NIGHTLY' branch does not exist there yet. We will retry when you push more commits. It may be necessary to rebase onto 'nightly' tomorrow."
            fi

          else
            echo "The most recently nightly tag on this branch has SHA: $NIGHTLY_SHA"
            echo "but 'git merge-base origin/master HEAD' reported: $MERGE_BASE_SHA"
            git -C lean4.git log -10 origin/master

            MESSAGE="- ❗ Mathlib CI will not be attempted unless you rebase your PR onto the 'nightly' branch."
          fi

          if [[ -n "$MESSAGE" ]]; then

            echo "Checking existing messages"

            # Use GitHub API to check if a comment already exists
            existing_comment=$(curl -L -s -H "Authorization: token ${{ secrets.MATHLIB4_BOT }}" \
                                    -H "Accept: application/vnd.github.v3+json" \
                                    "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments" \
                                    | jq '.[] | select(.body | startswith("- ❗ Mathlib") or startswith("- ✅ Mathlib") or startswith("- ❌ Mathlib") or startswith("- 💥 Mathlib") or startswith("- 🟡 Mathlib"))')
            existing_comment_id=$(echo "$existing_comment" | jq -r .id)
            existing_comment_body=$(echo "$existing_comment" | jq -r .body)

            if [[ "$existing_comment_body" != *"$MESSAGE"* ]]; then
              MESSAGE="$MESSAGE ($(date "+%Y-%m-%d %H:%M:%S"))"

              echo "Posting message to the comments: $MESSAGE"

              # Append new result to the existing comment or post a new comment
              # It's essential we use the MATHLIB4_BOT token here, so that Mathlib CI can subsequently edit the comment.
              if [ -z "$existing_comment_id" ]; then
                # Post new comment with a bullet point
                echo "Posting as new comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
                curl -L -s \
                  -X POST \
                  -H "Authorization: token ${{ secrets.MATHLIB4_BOT }}" \
                  -H "Accept: application/vnd.github.v3+json" \
                  -d "$(jq --null-input --arg val "$MESSAGE" '{"body": $val}')" \
                  "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
              else
                # Append new result to the existing comment
                echo "Appending to existing comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
                curl -L -s \
                  -X PATCH \
                  -H "Authorization: token ${{ secrets.MATHLIB4_BOT }}" \
                  -H "Accept: application/vnd.github.v3+json" \
                  -d "$(jq --null-input --arg existing "$existing_comment_body" --arg message "$MESSAGE" '{"body":($existing + "\n" + $message)}')" \
                  "https://api.github.com/repos/leanprover/lean4/issues/comments/$existing_comment_id"
              fi
            else
              echo "The message already exists in the comment body."
            fi
            echo "mathlib_ready=false" >> $GITHUB_OUTPUT
          else
            echo "mathlib_ready=true" >> $GITHUB_OUTPUT
          fi

      # We next automatically create a Mathlib branch using this toolchain.
      # Mathlib CI will be responsible for reporting back success or failure
      # to the PR comments asynchronously.
      - name: Cleanup workspace
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        run: |
          sudo rm -rf *

      # Checkout the mathlib4 repository with all branches
      - name: Checkout mathlib4 repository
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        uses: actions/checkout@v3
        with:
          repository: leanprover-community/mathlib4
          token: ${{ secrets.MATHLIB4_BOT }}
          ref: nightly-testing
          fetch-depth: 0 # This ensures we check out all tags and branches.

      - name: Check if branch exists
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        id: check_branch
        run: |
          git config user.name "leanprover-community-mathlib4-bot"
          git config user.email "leanprover-community-mathlib4-bot@users.noreply.github.com"

          if git branch -r | grep -q "nightly-testing-${MOST_RECENT_NIGHTLY}"; then
            BASE=nightly-testing-${MOST_RECENT_NIGHTLY}
          else
            echo "This shouldn't be possible: couldn't find a 'nightly-testing-${MOST_RECENT_NIGHTLY}' branch at Mathlib. Falling back to 'nightly-testing'."
            BASE=nightly-testing
          fi

          echo "Using base branch: $BASE"

          git checkout $BASE

          EXISTS=$(git ls-remote --heads origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} | wc -l)
          echo "Branch exists: $EXISTS"
          if [ "$EXISTS" = "0" ]; then
            echo "Branch does not exist, creating it."
            git checkout -b lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}
            echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}" > lean-toolchain
            git add lean-toolchain
            git commit -m "Update lean-toolchain for testing https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
          else
            echo "Branch already exists, pushing an empty commit."
            git checkout lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}
            # The Mathlib `nightly-testing` or `nightly-testing-YYYY-MM-DD` branch may have moved since this branch was created, so merge their changes.
            git merge $BASE --strategy-option ours --no-commit --allow-unrelated-histories
            git commit --allow-empty -m "Trigger CI for https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
          fi

      - name: Push changes
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        run: |
          git push origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}