# Copyright 2023 The Flutter Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

name: Cherry-pick Labeled PR to Release Branch

on:
  # Safe because we only checkout the trusted 'master' branch from the flutteractionsbot/flutter repository
  # and run cherry-picks on merged commits from the upstream master branch. It does not execute arbitrary user-controlled code.
  pull_request_target: # zizmor: ignore[dangerous-triggers]
    branches: [master]
    types: [labeled]
  issues:
    types: [labeled]

permissions:
  contents: read

jobs:
  cherrypick_not_merged_remove_label:
    name: cherrypick_not_merged_remove_label
    runs-on: ubuntu-latest
    if: |
      github.event_name == 'pull_request_target' &&
      (github.event.label.name == format('cp{0} beta', ':') || github.event.label.name == format('cp{0} stable', ':')) &&
      (github.event.pull_request.merged == false)
    steps:
      - name: Leave Comment and Remove Label
        run: |
          gh pr edit ${{ github.event.pull_request.number }} --remove-label "cp: beta"
          gh pr edit ${{ github.event.pull_request.number }} --remove-label "cp: stable"
          gh pr comment ${{ github.event.pull_request.number }} -R flutter/flutter -b "Only merged pull requests can be cherrypicked."
        env:
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}

  remove_label_from_issues:
    name: remove_label_from_issues
    runs-on: ubuntu-latest
    if: |
      github.event_name == 'issues' &&
      (github.event.label.name == format('cp{0} beta', ':') || github.event.label.name == format('cp{0} stable', ':'))
    steps:
      - name: Remove Label and Leave Comment
        run: |
          gh issue edit $ISSUE_NUMBER -R flutter/flutter --remove-label "$LABEL_NAME"
          gh issue comment $ISSUE_NUMBER -R flutter/flutter -b "Cherry-pick labels should only be applied to merged pull requests."
        env:
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
          LABEL_NAME: ${{ github.event.label.name }}
          ISSUE_NUMBER: ${{ github.event.issue.number }}

  cherrypick_to_release:
    name: cherrypick_to_release
    runs-on: ubuntu-latest
    if: |
      github.event_name == 'pull_request_target' &&
      (github.event.label.name == format('cp{0} beta', ':') || github.event.label.name == format('cp{0} stable', ':')) &&
      (github.event.pull_request.merged == true)
    steps:
      - name: Get Release Channel
        id: get-channel
        env:
          LABEL_NAME: ${{ github.event.label.name }}
        run: echo "channel=$(echo $LABEL_NAME | cut -d ':' -f 2 | xargs)" >> "$GITHUB_OUTPUT"

      - name: Export Release Candidate Branch
        id: get-branch
        env:
          CHANNEL: ${{ steps.get-channel.outputs.channel }}
        run: |
          branch=$(curl -f -s "https://raw.githubusercontent.com/flutter/flutter/$CHANNEL/bin/internal/release-candidate-branch.version" | tr -d '\n')
          if [ -z "$branch" ]; then
            echo "Error: Failed to fetch release candidate branch for channel $CHANNEL" >&2
            exit 1
          fi
          echo "branch=$branch" >> "$GITHUB_OUTPUT"

      - name: Checkout Flutter Repo
        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0
        with:
          repository: flutteractionsbot/flutter
          path: flutter
          ref: master
          token: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
          # Checkout all history commits on master branch, so that the cp commit is a known object
          fetch-depth: 0
          persist-credentials: false

      - name: Configure Git
        run: |
          gh auth setup-git
          git config --global user.name "flutteractionsbot"
          git config --global user.email "<flutter-actions-bot@google.com>"
        env:
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}

      # use same name when checking out branch, since the marketplace action does a hard reset.
      - name: Attempt CP
        id: attempt-cp
        working-directory: ./flutter
        run: |
          git remote add upstream https://github.com/flutter/flutter.git
          git fetch upstream "$RELEASE_BRANCH"
          git fetch upstream master
          git checkout -b "cp-${CHANNEL}-${MERGE_COMMIT_SHA}" --track "upstream/$RELEASE_BRANCH"
          git cherry-pick "$MERGE_COMMIT_SHA"
        env:
          CHANNEL: ${{ steps.get-channel.outputs.channel }}
          RELEASE_BRANCH: ${{ steps.get-branch.outputs.branch }}
          MERGE_COMMIT_SHA: ${{ github.event.pull_request.merge_commit_sha }}
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}

      - name: Create PR on CP success
        if: ${{ steps.attempt-cp.conclusion == 'success' }}
        working-directory: ./flutter
        id: create-pr
        run: |
          git push origin "cp-${CHANNEL}-${MERGE_COMMIT_SHA}"
          pr_url=$(gh pr create --title "[CP-${CHANNEL}]${PR_TITLE}" --body-file ".github/PR_TEMPLATE/PULL_REQUEST_CP_TEMPLATE.md" --base "${RELEASE_BRANCH}" --label "cp: review" --repo flutter/flutter --head "flutteractionsbot:cp-${CHANNEL}-${MERGE_COMMIT_SHA}")
          echo "pr_url=$pr_url" >> "$GITHUB_OUTPUT"
        env:
          CHANNEL: ${{ steps.get-channel.outputs.channel }}
          RELEASE_BRANCH: ${{ steps.get-branch.outputs.branch }}
          MERGE_COMMIT_SHA: ${{ github.event.pull_request.merge_commit_sha }}
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
          PR_TITLE: ${{ github.event.pull_request.title }}

      - name: Leave Comment on CP success
        if: ${{ steps.create-pr.conclusion == 'success' }}
        run: |
          echo "$PR_URL"
          NEW_PR_NUMBER="${PR_URL##*/}"
          SUCCESS_MSG=" @$ACTOR please fill out the PR description above, afterwards the release team will review this request."
          gh pr comment "$NEW_PR_NUMBER" -R flutter/flutter -b "${SUCCESS_MSG}"
        env:
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
          ACTOR: ${{ github.actor }}
          PR_URL: ${{ steps.create-pr.outputs.pr_url }}

      - name: Leave Comment on CP failure
        if: ${{ failure() && steps.attempt-cp.conclusion == 'failure' }}
        run: |
          FAILURE_MSG="Failed to create CP due to merge conflicts.<br>"
          FAILURE_MSG+="You will need to create the PR manually. See [the cherrypick wiki](https://github.com/flutter/flutter/blob/main/docs/releases/Flutter-Cherrypick-Process.md) for more info."
          gh pr comment ${{ github.event.pull_request.number }} -R flutter/flutter -b "${FAILURE_MSG}"
        env:
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}