#!/usr/bin/env bash
#This will keep the GitHub Action active by making periodic empty commits.
#export the variables to set values other than defaults before calling the script.
# $ curl -fsSL action-keepalive.bos.li | bash

: <<'EXAMPLE'
 This script keeps a GitHub Action workflow active by making periodic empty commits (default) or using
 the GitHub API (when USE_API is true).
 To enable keep-alive, add a step to your workflow file as shown in the examples below.
 A checkout step is required before invoking this script. This is needed to check the last repo activity or 
 make a commit.
 Use 'env' in the keep-alive step to configure how this script should function.
 GitHub disables repo Actions after 60 days of inactivity. You can set the DAYS_ELAPSED parameter to a value
 < 60 days to trigger API/commit after the last activity. Set this to 0 to trigger every time and you may
 also eliminate the checkout step requirement if USE_API is also true.

 The following options are available by setting 'env' variables. All are optional except GH_TOKEN,
 which must be set to ${{ github.token }} when USE_API is true. 
-------------------------------------------------------------------------------------------------------------
   Option             Default Value       Description
-------------------------------------------------------------------------------------------------------------
   DAYS_ELAPSED       55                  Number of days since last activity to trigger keep-alive via API
                                          or GitHub commit. Use "0" to run keep-alive every time and skip 
                                          the requirement of checkout step if USE_API is also true. 
   USE_API            false               Can be "true" or "false". If true, uses API mode for keep-alive;
                                          otherwise, makes empty commits to keep the repo active.
  
 Options available if USE_API is false, i.e., commit mode for keep-alive:
   COMMIT_USERNAME    SBKeepAliveBot      Username used for empty commits
   COMMIT_EMAIL       SB@keepaliven       Email used for empty commits
   COMMIT_MESSAGE     Keeping alive       Message used for empty commits

 Options available if USE_API is true, i.e., API mode for keep-alive:
   GH_TOKEN           (required to set)   Must always be set to ${{ github.token }}
   WORKFLOWS                              If not set, re-enables the current workflow file via API. 
                                          You can also provide a space-delimited list of workflow filenames,
                                          e.g., "WFfile1.yaml WFfile2.yml WFfile3.yml"
-------------------------------------------------------------------------------------------------------------

 Action permissions required for the workflow run:
 If USE_API is false or unset, i.e., commit mode:
   contents: write
 If USE_API is true:
   actions: write


#############################################################################################################
# Sample workflow file: .github/workflows/example-workflow.yaml

name: Keep Alive example
on:
  schedule:
    - cron: "0 */12 * * *"
  workflow_dispatch:
permissions:
  contents: write  # For non-API, i.e commit mode
  actions: write   # For API use mode (when USE_API is true)

jobs:
  check-expiry:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      
      - name: Keep alive by empty commits
        env:
          DAYS_ELAPSED: 55                   # Def. 50 if omitted
        run: curl -fsSL action-keepalive.bos.li | bash

      #OR
      - name: Keep alive by commits with customization
        env:
          DAYS_ELAPSED: 55                   # Def. 50 if omitted
          COMMIT_USERNAME: SBKeepAliveBot    # Def. 'SBKeepAliveBot' if omitted
          COMMIT_EMAIL: 'SB@keepalive'       # Def. 'SB@keepalive' if omitted
          COMMIT_MESSAGE: 'Keeping alive'    # Def. 'Keeping alive' if omitted
        run: curl -fsSL action-keepalive.bos.li | bash
      
      #OR
      - name: Keep alive by Re-enabling workflow using API
        env:
          DAYS_ELAPSED: 55                   # Def. 50 if omitted
          USE_API: true                      # Def. is false if omitted, i.e, commits will be used
          GH_TOKEN: ${{ github.token }}      # Required if USE_API is true
        run: curl -fsSL action-keepalive.bos.li | bash
      
      #OR
      - name: Keep alive by Re-enabling specified workflow(s) using API
        env:
          DAYS_ELAPSED: 55                   # Def. 50 if omitted
          USE_API: true                      # Def. is false if omitted, i.e, commits will be used
          GH_TOKEN: ${{ github.token }}      # Required if USE_API is true
          WORKFLOWS: WF1.yaml WF2.yml        # By default it will just re-enable the running workflow
        run: curl -fsSL action-keepalive.bos.li | bash
EXAMPLE


: "${DAYS_ELAPSED:=50}"
: "${USE_API:=false}"
: "${COMMIT_USERNAME:=SBKeepAliveBot}"
: "${COMMIT_EMAIL:=SB@keepalive}"
: "${COMMIT_MESSAGE:=Keeping alive}"
: "${WORKFLOWS:=}"

set -o nounset
set -o errexit
set -o pipefail
if [ "${TRACE-0}" -eq 1 ]; then set -o xtrace; fi


if [[ "$DAYS_ELAPSED" == "0" ]]; then
  DAYS_AGO=1
  echo "Not checking last commit, will run Keep alive"
else
  # Get the last commit date for the current branch
  LAST_COMMIT_DATE=$(git log -1 --format="%ct")
  CURRENT_DATE=$(date "+%s")
  TIME_DIFFERENCE=$((CURRENT_DATE - LAST_COMMIT_DATE))
  DAYS_AGO=$((TIME_DIFFERENCE / (60 * 60 * 24)))
  echo "Last commit is '$DAYS_AGO' days ago"
fi

if [ "$DAYS_AGO" -gt "$DAYS_ELAPSED" ]; then
    echo "$DAYS_AGO > $DAYS_ELAPSED -> Keep alive"
    if [ $USE_API = true ]; then
        #Required permission
        #permissions:
        #   actions: write
        #Also set env for the step
        #env:
        #  GH_TOKEN: ${{ github.token }}
        echo "Using API to keep alive"
        case "${GITHUB_WORKFLOW_REF:?}" in
          "${GITHUB_REPOSITORY:?}"/.github/workflows/*.y*ml@*) ;;
          *) false ;;
        esac
        if [ -z "$WORKFLOWS" ]; then
          WORKFLOWS="${GITHUB_WORKFLOW_REF%%@*}"
          WORKFLOWS="${WORKFLOWS#${GITHUB_REPOSITORY}/.github/workflows/}"
        fi
        for workflow in $WORKFLOWS; do
          gh api -X PUT "repos/${GITHUB_REPOSITORY}/actions/workflows/${workflow}/enable"
        done
    else
        #Required permission
        #permissions:
        #   contents: write
        echo "Adding empty commit"
        git config user.name "$COMMIT_USERNAME"
        git config user.email "$COMMIT_EMAIL"
        git commit --allow-empty -m "$COMMIT_MESSAGE"
        git push
    fi
    echo "done"
else
    echo "$DAYS_AGO <= $DAYS_ELAPSED -> nothing to do"
fi