on:
  push:
    tags:
      - 'debian_lts-*'

name: Debian LTS

env:
  GPG_KEY_ID: 56C464BAAC421453
  KERNEL_VERSION: 4.19.131
  KDEB_PKGVERSION: 4.19.131-1
  LOCALVERSION: -surface-lts
  MAINLINE_REPO: git://git.launchpad.net/~ubuntu-kernel-test/ubuntu/+source/linux/+git/mainline-crack
  MAINLINE_BRANCH: cod/mainline

jobs:
  build:
    name: Build Kernel
    runs-on: ubuntu-latest
    container: debian:sid
    steps:
    - name: Checkout code
      uses: actions/checkout@v2

    - name: Install build dependencies
      run: |
        sed 's/^deb /deb-src /' /etc/apt/sources.list >> /etc/apt/sources.list
        apt-get -y update
        apt-get -y install build-essential fakeroot rsync git wget python3-debian dpkg-sig lz4 sbsigntool
        apt-get -y build-dep linux

    - name: Prepare kernel source
      run: |
        cd pkg/debian/kernel-lts

        # setup git
        git config --global user.email "surfacebot@users.noreply.github.com"
        git config --global user.name "surfacebot"

        # get ubuntu mainline source
        # see https://kernel.ubuntu.com/~kernel-ppa/mainline
        git clone "$MAINLINE_REPO" --branch "$MAINLINE_BRANCH/v$KERNEL_VERSION" --depth 1 linux

        cd linux

        # apply surface build/packaging patches
        for PATCH in ../*.patch; do
          patch -p1 < ${PATCH}
        done

        git add .
        git commit --allow-empty -m "Apply linux-surface packaging patches"

        # apply surface patches
        for PATCH in ../../../../patches/${KERNEL_VERSION%.*}/*.patch; do
          patch -p1 < ${PATCH}
        done

        git add .
        git commit --allow-empty -m "Apply linux-surface patches"

    - name: Configure
      run: |
        cd pkg/debian/kernel-lts/linux

        # merge configs
        ./scripts/kconfig/merge_config.sh                     \
          debian.master/config/config.common.ubuntu           \
          debian.master/config/amd64/config.common.amd64      \
          debian.master/config/amd64/config.flavour.generic   \
          ../ubuntu.config                                    \
          ../../../../configs/surface-${KERNEL_VERSION%.*}.config

    - name: Setup secureboot certificate
      env:
        SB_KEY: ${{ secrets.SURFACE_SB_KEY }}
      run: |
        cd pkg

        mkdir -p debian/kernel-lts/linux/keys

        # unlock/copy key and certificate
        echo "$SB_KEY" | base64 -d > debian/kernel-lts/linux/keys/MOK.key
        cp keys/surface.crt debian/kernel-lts/linux/keys/MOK.crt

    - name: Build
      run: |
        cd pkg/debian/kernel-lts/linux
        make bindeb-pkg -j2

    - name: Prepare release
      run: |
        mkdir release
        mv pkg/debian/kernel-lts/*.deb release

    - name: Sign packages
      env:
        GPG_KEY: ${{ secrets.SURFACE_GPG_KEY }}
      run: |
        # import GPG key
        echo "$GPG_KEY" | base64 -d | gpg --import --no-tty --batch --yes
        export GPG_TTY=$(tty)

        # sign package
        dpkg-sig -g "--batch --no-tty" --sign builder -k $GPG_KEY_ID release/*.deb

    - name: Upload artifacts
      uses: actions/upload-artifact@v1
      with:
        name: debian-latest
        path: release

  release:
    name: Publish release
    needs: [build]
    runs-on: ubuntu-latest
    steps:
    - name: Download artifacts
      uses: actions/download-artifact@v1
      with:
        name: debian-latest

    - name: Upload assets
      uses: svenstaro/upload-release-action@v1-release
      with:
        repo_token: ${{ secrets.GITHUB_BOT_TOKEN }}
        file: ./*-latest/*
        tag: ${{ github.ref }}
        overwrite: true
        file_glob: true

  repo:
    name: Update package repository
    needs: [release]
    runs-on: ubuntu-latest
    container: debian:sid
    steps:
    - name: Install dependencies
      run: |
        apt-get update
        apt-get install -y reprepro git

    - name: Download artifacts
      uses: actions/download-artifact@v1
      with:
        name: debian-latest

    - name: Update repository
      env:
        SURFACEBOT_TOKEN: ${{ secrets.GITHUB_BOT_TOKEN }}
        BRANCH_STAGING: u/staging
        GIT_REF: ${{ github.ref }}
      run: |
        repo="https://surfacebot:${SURFACEBOT_TOKEN}@github.com/linux-surface/repo.git"

        # clone package repository
        git clone -b "${BRANCH_STAGING}" "${repo}" repo

        # copy packages
        cp debian-latest/* repo/debian/
        cd repo/debian

        # parse git tag from ref
        GIT_TAG=$(echo $GIT_REF | sed 's|^refs/tags/||g')

        # convert packages into references
        for pkg in $(find . -name '*.deb'); do
          echo "linux-surface:$GIT_TAG/$(basename $pkg)" > $pkg.blob
          rm $pkg
        done

        # set git identity
        git config --global user.email "surfacebot@users.noreply.github.com"
        git config --global user.name "surfacebot"

        # commit and push
        update_branch="${BRANCH_STAGING}-$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)"
        git switch -c "${update_branch}"
        git add .
        git commit -m "Update Debian LTS kernel"
        git push --set-upstream origin "${update_branch}"