name: 'Nix Flake Outputs Size Report'
author: Jalil David Salamé Messina
description: |
  Use `nix path-info` to query the size of flake outputs and produce a markdown
  report.

  You can post this report as a comment to the PR associated with the current
  branch and/or export the report as a markdown artifact.

  Requires `nix`, `jq`, `curl`, `sed`, `gunzip`, `tar` and `coreutils` to be in
  the runner's path.

  Usage:

  ```yaml
  - name: Generate size report
    uses: https://git.salame.cl/jalil/nix-flake-outputs-size@main
    with: # Default values
      comment-on-pr: 'true'
      generate-artifact: 'false'
      artifact-name: 'size-report.md'
      base-branch: ${{ github.base_ref }} # set to e.g. main if not triggered by a pull_request
      job-name: '' # set to the name of this job if you want to enable comparisons
  ```
inputs:
  comment-on-pr:
    description: Comment the report on the PR associated with the current branch.
    default: 'true'
  generate-artifact:
    description: Export the generated markdown document as an artifact.
    default: 'false'
  artifact-name:
    description: The name of the generated artifact.
    default: report.json
  base-branch:
    description: |
      The name of the base branch, defaults to github.base_ref which is only
      available in pull_request triggered workflows, for other workflows
      specify it manually.

      It will try to download the generated artifact from this branch so make
      sure `generate-artifacte: true` when the workflow is running on that
      branch.
    default: ${{ github.base_ref }}
  job-name:
    description: |
      The name of the job running this action. If not set, no comparisons can
      be made.
    default: ''
  private-repo-workaround:
    description: |
      Forgejo doesn't support downloading artifacts through the API [see
      codeberg.org/forgejo/forgejo#6315](https://codeberg.org/forgejo/forgejo/issues/6315).

      As a workaround, checkout the base branch and regenerate the report.

      This is very innefficient T-T and slow.
    default: 'false'
outputs:
runs:
  using: 'composite'
  steps:
    - name: Create report
      run: |
        "$GITHUB_ACTION_PATH/create-report.sh" > report.json
    - name: Upload Artifact
      uses: https://code.forgejo.org/forgejo/upload-artifact@v4
      if: inputs.generate-artifact == 'true'
      with:
        path: report.json
        name: ${{ inputs.artifact-name }}
    - name: Comment Report
      if: inputs.comment-on-pr == 'true'
      env:
        ARTIFACT_NAME: ${{ inputs.artifact-name }}
        HEAD_BRANCH: ${{ inputs.base-branch }}
        JOB_NAME: ${{ inputs.job-name }}
        PRIVATE_REPO: ${{ inputs.private-repo-workaround }}
      run: |
        . "${GITHUB_ACTION_PATH}/utils.sh"

        # USAGE: base_report_url
        base_report_url() {
          curl -X 'GET' \
            "$GITHUB_API_URL/repos/$GITHUB_REPOSITORY/actions/tasks" \
            -H "Authorization: token $GITHUB_TOKEN" \
            -H 'accept: application/json' |
              jq --raw-output \
                --arg name "$JOB_NAME" \
                --arg head_branch "$HEAD_BRANCH" \
                '[.workflow_runs[] | select(.name == $name and .head_branch == $head_branch)] | first | .url'
        }
        # USAGE: has_report <REPORT_URL>
        has_report() {
          http_code=$(curl -X 'GET' -o /dev/null --silent -Iw '%{http_code}' \
            "$1" -H "Authorization: token $GITHUB_TOKEN")
          log "Got code $http_code for $1"
          test "$http_code" = '200'
        }

        if [ "$PRIVATE_REPO" = 'true' ]; then 
          log "In a private repo, downloading $HEAD_BRANCH to build the old report"

          old=$(mktemp -d)
          curl -X 'GET' \
            "$GITHUB_API_URL/repos/$GITHUB_REPOSITORY/archive/$HEAD_BRANCH.tar.gz" \
            -H "Authorization: token $GITHUB_TOKEN" |
              tar -zvx --strip-components=1 -C "$old"

          (cd "$old" && "$GITHUB_ACTION_PATH/create-report.sh") > old-report.json

          log "Reporting on sizes and comparing to sizes in $HEAD_BRANCH"
          "$GITHUB_ACTION_PATH/comment_on_pr.sh" report.json old-report.json
          exit 0
        # If we have a previous report compare against it
        elif [ "$JOB_NAME" ] && [ "$HEAD_BRANCH" ]; then
          url=$(base_report_url)
          log "Found previous run at: $url"
          report_url="$url/artifacts/$ARTIFACT_NAME"
          if has_report "$report_url"; then
            log 'Found previous report, downloading...'
            curl -X 'GET' \
              "$report_url" \
              -H "Authorization: token $GITHUB_TOKEN" |
              gunzip > old-report.json
            log "Reporting on sizes and comparing to sizes in $HEAD_BRANCH"
            "$GITHUB_ACTION_PATH/comment_on_pr.sh" report.json old-report.json
            exit 0
          else
            log "Failed to find previous report, expected at: $report_url"
          fi
        fi

        log 'Reporting on sizes'
        "$GITHUB_ACTION_PATH/comment_on_pr.sh" report.json