name: '🐳 Builder Image'

# Reusable workflow: builds (and optionally pushes) the kpnpp-builder image.
# It is called by ci.yaml only when Dockerfile.builder or docs/requirements.txt
# change. It runs on the host runner (NOT inside the builder container) because
# it needs the Docker CLI/daemon.
# Note: `push` is a STRING ("true"/"false"), not a boolean. Gitea's act_runner
# mangles boolean inputs passed from an expression (they arrive as false), so we
# pass an explicit string and compare with == 'true' below.
on:
  workflow_call:
    inputs:
      push:
        description: 'Push the built image to the registry ("true"/"false")'
        type: string
        default: 'true'
  workflow_dispatch:
    inputs:
      push:
        description: 'Push the built image to the registry ("true"/"false")'
        type: string
        default: 'true'

jobs:
  build:
    runs-on: linux/amd64
    steps:
      # This job runs on the host (not in a container) so it can reach the
      # host Docker daemon and reuse the cached registry credentials. The host
      # has no Node, so the JS-based actions/checkout can't run here; do a
      # minimal shallow fetch of this commit with plain git instead.
      - name: Checkout repository
        run: |
          git init -q .
          git remote add origin "${{ github.server_url }}/${{ github.repository }}.git"
          git -c http.extraheader="AUTHORIZATION: basic $(printf '%s' '${{ github.actor }}:${{ github.token }}' | base64 -w0)" \
            fetch --depth 1 origin "${{ github.sha }}"
          git checkout -q FETCH_HEAD

      # No docker login step: the host runner was authenticated to
      # gitea.tourolle.paris with `docker login` during setup, so its cached
      # credentials in ~/.docker/config.json cover the push below.
      - name: Build builder image
        # Context is the repo root because Dockerfile.builder COPYs
        # docs/requirements.txt during the build.
        run: |
          docker build \
            -f Dockerfile.builder \
            -t gitea.tourolle.paris/dtourolle/kpnpp-builder:latest \
            -t gitea.tourolle.paris/dtourolle/kpnpp-builder:${{ github.sha }} \
            .

      - name: Push builder image
        if: ${{ inputs.push == 'true' }}
        run: |
          docker push gitea.tourolle.paris/dtourolle/kpnpp-builder:latest
          docker push gitea.tourolle.paris/dtourolle/kpnpp-builder:${{ github.sha }}