# Nadir Kernel CI. Runs on every pull request and every push to main.
#
# Builds nadir.img with make, verifies the image, then boots it headless in
# QEMU and asserts the kernel's welcome message reaches the screen.

name: CI

on:
  push:
    branches: [main]
  pull_request:

permissions:
  contents: read

jobs:
  build-and-boot:
    name: Build and boot in QEMU
    runs-on: ubuntu-latest
    steps:
      - name: Check out repository
        uses: actions/checkout@v4

      - name: Install toolchain
        # gcc, make and binutils ship with the runner; nasm and qemu do not.
        run: sudo apt-get update && sudo apt-get install -y nasm qemu-system-x86

      - name: Build image
        run: make

      - name: Verify image
        # Every check prints what it saw: a silent bare `test` once hid a
        # failure here, so each assertion reports and names its own failure.
        run: |
          set -euo pipefail
          ls -l nadir.img
          size=$(stat -c %s nadir.img)
          echo "image size: $size bytes"
          test "$size" -ge 1024 || { echo "FAIL: image smaller than sector+kernel minimum"; exit 1; }
          test $(( (size - 512) % 512 )) -eq 0 || { echo "FAIL: kernel part is not sector-aligned"; exit 1; }
          sig=$(dd if=nadir.img bs=1 skip=510 count=2 2>/dev/null | od -A n -t x1 | tr -d ' \n')
          echo "boot signature: $sig"
          test "$sig" = "55aa" || { echo "FAIL: missing 0xAA55 boot signature"; exit 1; }
          grep -q "Nadir" nadir.img || { echo "FAIL: kernel payload missing from image"; exit 1; }
          echo "OK: nadir.img valid, boot signature and payload present"

      - name: Boot and check welcome message in QEMU
        run: python3 .github/scripts/check_boot.py nadir.img