name: Build and publish Docker image

on:
  push:
    branches:
      - master

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Derive registry host and image name
        id: registry
        run: |
          host="$(printf '%s' "${{ gitea.server_url }}" | sed -E 's#^[a-zA-Z][a-zA-Z0-9+.-]*://##; s#/.*$##')"
          image="$(printf '%s' "${{ gitea.repository }}" | tr '[:upper:]' '[:lower:]')"
          echo "host=${host}" >> "$GITHUB_OUTPUT"
          echo "image=${image}" >> "$GITHUB_OUTPUT"

      - name: Log in to Gitea Container Registry
        uses: docker/login-action@v3
        with:
          registry: ${{ steps.registry.outputs.host }}
          username: ${{ gitea.repository_owner }}
          password: ${{ secrets.REGISTRY_TOKEN }}

      - name: Build and push image
        run: |
          docker build -t "${{ steps.registry.outputs.host }}/${{ steps.registry.outputs.image }}:latest" .
          docker push "${{ steps.registry.outputs.host }}/${{ steps.registry.outputs.image }}:latest"