name: Open a PR to main

on:
  push:
    branches:
      - dev
  workflow_dispatch:

permissions:
  pull-requests: write
  contents: read

jobs:
  pull-request:
    name: Open pull request
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Open pull request
        env:
          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
          GITEA_URL: ${{ gitea.server_url }}
          GITEA_REPOSITORY: ${{ gitea.repository }}
          SOURCE_BRANCH: ${{ gitea.ref_name }}
          TARGET_BRANCH: main
        shell: bash
        run: |
          set -euo pipefail

          api_url="${GITEA_URL%/}/api/v1"
          auth_header="Authorization: token ${GITEA_TOKEN}"

          open_pulls="$(
            curl --fail-with-body --silent --show-error \
              --get \
              --header "$auth_header" \
              --data-urlencode "state=open" \
              --data-urlencode "base_branch=${TARGET_BRANCH}" \
              --data-urlencode "limit=50" \
              "${api_url}/repos/${GITEA_REPOSITORY}/pulls"
          )"
          if jq -e --arg branch "$SOURCE_BRANCH" \
            'any(.[]; .head.ref == $branch)' <<<"$open_pulls" >/dev/null; then
            echo "Pull request already exists."
            exit 0
          fi

          commits="$(git rev-list --count "origin/${TARGET_BRANCH}..HEAD")"
          if [[ "$commits" -eq 0 ]]; then
            echo "No commits between ${TARGET_BRANCH} and ${SOURCE_BRANCH}. Skipping pull request creation."
            exit 0
          fi

          payload="$(
            jq -n \
              --arg base "$TARGET_BRANCH" \
              --arg head "$SOURCE_BRANCH" \
              --arg title 'chore: Merge branch `dev` to `main`' \
              --arg body 'When dev (pre-release) is ready, merge this pull request to create a new stable release.' \
              '{base: $base, head: $head, title: $title, body: $body}'
          )"

          curl --fail-with-body --silent --show-error \
            --request POST \
            --header "$auth_header" \
            --header "Content-Type: application/json" \
            --data "$payload" \
            "${api_url}/repos/${GITEA_REPOSITORY}/pulls" >/dev/null
          echo "Pull request created."