name: Build DAWN

on:
  push:
  pull_request:
    types: [opened, synchronize, reopened]

jobs:
  build:
    name: Build DAWN
    runs-on: ubuntu-latest

    steps:
      # Step 1: Checkout the repository
      - uses: actions/checkout@v4
        with:
          path: dawn

      # Step 2: Install dependencies and cache them
      - name: Install dependencies
        run: |
          sudo apt update
          sudo apt install -y \
            git subversion build-essential python3 gawk unzip \
            libncurses5-dev zlib1g-dev libssl-dev wget time \
            libncurses-dev zstd curl jq

      # Step 3: Cache OpenWrt SDK
      - name: Cache OpenWrt SDK
        uses: actions/cache@v4
        with:
          path: /tmp/openwrt-sdk
          key: openwrt-sdk-${{ runner.os }}-${{ hashFiles('**/openwrt-sdk-ath79-generic_*.tar.zst') }}
          restore-keys: |
            openwrt-sdk-${{ runner.os }}-

      # Step 4: Determine the latest OpenWrt SDK version
      - name: Determine latest OpenWrt SDK version
        id: sdk_version
        run: |
          # Use curl to scrape the OpenWrt download server and extract the latest SDK tar file URL
          SDK_URL=$(curl -s https://downloads.openwrt.org/snapshots/targets/ath79/generic/ | \
                    grep -oP 'href="openwrt-sdk-[^"]+\.tar\.zst"' | \
                    sort -V | tail -n 1 | \
                    sed 's/href="//' | sed 's/"//')

          echo "Latest OpenWrt SDK URL: https://downloads.openwrt.org/snapshots/targets/ath79/generic/$SDK_URL"

          # Save the SDK URL into an environment variable so it can be used in the next steps
          echo "sdk_url=https://downloads.openwrt.org/snapshots/targets/ath79/generic/$SDK_URL" >> $GITHUB_ENV

      # Step 5: Download OpenWrt SDK if not cached
      - name: Download OpenWrt SDK
        run: |
          if [ ! -d "/tmp/openwrt-sdk" ]; then
            echo "OpenWrt SDK not cached, downloading..."
            curl -L -o openwrt-sdk.tar.zst ${{ env.sdk_url }}
            mkdir -p /tmp/openwrt-sdk
            tar -I zstd -xvf openwrt-sdk.tar.zst -C /tmp/openwrt-sdk --strip-components=1
          fi

      # Step 6: Create config for DAWN
      - name: Create config
        run: |
          cd /tmp/openwrt-sdk
          make defconfig
          echo "CONFIG_SRC_TREE_OVERRIDE=y" >> .config

      # Step 7: Update and install feeds
      - name: Update package feeds
        run: |
          cd /tmp/openwrt-sdk
          ./scripts/feeds update -a
          ./scripts/feeds install -a

      # Step 8: Link DAWN source
      - name: Link DAWN source
        run: |
          ln -s $GITHUB_WORKSPACE/dawn/.git /tmp/openwrt-sdk/feeds/packages/net/dawn/git-src

      # Step 9: Compile DAWN package
      - name: Compile DAWN
        run: |
          cd /tmp/openwrt-sdk
          make package/dawn/{clean,compile} V=s

      # Step 10: Archive build output
      - uses: actions/upload-artifact@v4
        with:
          name: output
          path: /tmp/openwrt-sdk/bin/packages/mips_24kc/packages