name: Build

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - main

concurrency:
  group: ${{ github.workflow }}-$${{ github.head_ref || github.run_id }}
  cancel-in-progress: true

jobs:
  build:
    runs-on: ubuntu-latest
    permissions: write-all

    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 2

      - name: Get changed files
        id: changed-files
        uses: tj-actions/changed-files@v34
        with:
          files: |
            *.nix
            go.*
            **/*.go
            integration_test/
            config-example.yaml

      - uses: DeterminateSystems/nix-installer-action@main
        if: steps.changed-files.outputs.any_changed == 'true'
      - uses: DeterminateSystems/magic-nix-cache-action@main
        if: steps.changed-files.outputs.any_changed == 'true'

      - name: Run build
        id: build
        if: steps.changed-files.outputs.any_changed == 'true'
        run: |
          nix build |& tee build-result
          BUILD_STATUS="${PIPESTATUS[0]}"

          OLD_HASH=$(cat build-result | grep specified: | awk -F ':' '{print $2}' | sed 's/ //g')
          NEW_HASH=$(cat build-result | grep got: | awk -F ':' '{print $2}' | sed 's/ //g')

          echo "OLD_HASH=$OLD_HASH" >> $GITHUB_OUTPUT
          echo "NEW_HASH=$NEW_HASH" >> $GITHUB_OUTPUT

          exit $BUILD_STATUS

      - name: Nix gosum diverging
        uses: actions/github-script@v6
        if: failure() && steps.build.outcome == 'failure'
        with:
          github-token: ${{secrets.GITHUB_TOKEN}}
          script: |
            github.rest.pulls.createReviewComment({
              pull_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: 'Nix build failed with wrong gosum, please update "vendorSha256" (${{ steps.build.outputs.OLD_HASH }}) for the "headscale" package in flake.nix with the new SHA: ${{ steps.build.outputs.NEW_HASH }}'
            })

      - uses: actions/upload-artifact@v3
        if: steps.changed-files.outputs.any_changed == 'true'
        with:
          name: headscale-linux
          path: result/bin/headscale