name: 'Maven Cache'
description: 'The .m2/repository caching mechanism'

inputs:
  root-cache-key:
    description: 'The unique root key for the cache. For example `m2-cache-project-name`.'
    required: true

runs:
  using: 'composite'
  steps:
    - name: Generate cache keys
      id: generate-cache-keys
      shell: bash
      run: |
        CURRENT_BRANCH="${{ github.head_ref || github.ref_name }}"
        CURRENT_MONTH=$(/bin/date -u "+%Y-%m")
        CURRENT_DAY=$(/bin/date -u "+%d")
        echo "m2-monthly-cache-key=${{ inputs.root-cache-key }}-${CURRENT_MONTH}" >> $GITHUB_OUTPUT
        echo "m2-monthly-branch-cache-key=${{ inputs.root-cache-key }}-${CURRENT_MONTH}-${CURRENT_BRANCH}" >> $GITHUB_OUTPUT
        echo "m2-cache-key=${{ inputs.root-cache-key }}-${CURRENT_MONTH}-${CURRENT_BRANCH}-${CURRENT_DAY}" >> $GITHUB_OUTPUT

    - name: Cache Maven repository
      id: cache-maven-repository
      uses: actions/cache@v4
      with:
        path: ~/.m2/repository
        # The cache is per branch but in case we don't find a branch for a given branch, we will get a cache from another branch.
        key: ${{ steps.generate-cache-keys.outputs.m2-cache-key }}
        restore-keys: |
          ${{ steps.generate-cache-keys.outputs.m2-monthly-branch-cache-key }}
          ${{ steps.generate-cache-keys.outputs.m2-monthly-cache-key }}