workflow:
  rules: # disable tag pipelines and duplicate MR pipelines
    - if: $CI_COMMIT_BRANCH

variables:
  MAIN_BRANCH_PATH: "."
  EPHEMERAL_BRANCHES_PATH: preview # subpath to ephemeral branches content for preview

pages:
  stage: build
  cache:
    key: gitlab-pages
    paths: [public]
  before_script:
    - sudo apk add git ikiwiki po4a perl-yaml-tiny tree
    # CURRENT_CONTENT_PATH is defined in rules, different between main branch and ephemeral branches
    - mkdir -p public/$CURRENT_CONTENT_PATH && ls public/$CURRENT_CONTENT_PATH/..
    - | # create ephermetal branched path if not existent
      if [ ! -d "public/$EPHEMERAL_BRANCHES_PATH" ]; then
        mkdir -p public/$EPHEMERAL_BRANCHES_PATH
      fi
    - | # avoid deleting main branch content when cache has been erased
      if [ "$CI_COMMIT_BRANCH" != "$CI_DEFAULT_BRANCH" ] && [ ! -f public/$MAIN_BRANCH_PATH/index.html ]; then
        echo -e "💥\e[91;1m Unable to retrieve $CI_DEFAULT_BRANCH generated files from cache ; please regenerate $CI_DEFAULT_BRANCH files first\e[0m"
        exit 1
      fi
    - rm -rf public/$CURRENT_CONTENT_PATH || true # remove last version of current branch
  script:
    - | # sed needs to be in its own section
      sed -i "s|destdir.*|destdir: ./public/$CURRENT_CONTENT_PATH|" ikiwiki.setup
    - ikiwiki --setup ikiwiki.setup
    - | # create symbolic link to index.en.html if public/index.html does not exist
      if [ ! -L "public/$CURRENT_CONTENT_PATH/index.html"  ]; then
        ln -s index.en.html public/$CURRENT_CONTENT_PATH/index.html
      fi
    - cd public/$EPHEMERAL_BRANCHES_PATH
    - tree -d -H '.' -L 1 --noreport --charset utf-8 -T "Versions" -o index.html # generate a root HTML listing all previews for easier access
  environment:
    name: pages/$CI_COMMIT_BRANCH
    action: start
    url: $CI_PAGES_URL/$CURRENT_CONTENT_PATH
    on_stop: pages-clean-preview
  rules:
    # 'main branch' is exposed at GitLab Pages root
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
      variables:
        CURRENT_CONTENT_PATH: $MAIN_BRANCH_PATH
    # other (short-lived) branches generation are exposed in 'EPHEMERAL_BRANCHES_PATH/branch-name-sanitized' sub path
    - variables:
        CURRENT_CONTENT_PATH: $EPHEMERAL_BRANCHES_PATH/$CI_COMMIT_REF_SLUG
  artifacts:
    paths: [public]
    expire_in: 1h
  tags:
    - knit

pages-clean-preview:
  stage: build
  cache:
    key: gitlab-pages
    paths: [public]
  variables:
    GIT_STRATEGY: none # git files not available after branch deletion
    FOLDER_TO_DELETE: $EPHEMERAL_BRANCHES_PATH/$CI_COMMIT_REF_SLUG # an indirection to allow arbitrary deletion when launching this job
  script:
    - rm -rf public/$FOLDER_TO_DELETE
  environment:
    name: pages/$CI_COMMIT_BRANCH
    action: stop
  rules:
    - if: $CI_COMMIT_BRANCH != $CI_DEFAULT_BRANCH
      when: manual
      allow_failure: true
  tags:
    - knit