#!/bin/sh

COMMON_CC_EXTRA_FLAGS="-O3 -Wall -Wextra"
COMMON_CC_FLAGS="-std=c23 -ffreestanding -I include ${COMMON_CC_EXTRA_FLAGS}"
KERNEL_CC_FLAGS="-mno-sse -I dependencies/limine ${COMMON_CC_FLAGS}"
#in the future user code will be allowed to use sse
USER_CC_FLAGS="-mno-sse ${COMMON_CC_FLAGS}"

if [ -e build.ninja ]; then
  echo build.ninja already exists.
  exit
fi

set -e

echo "rule nasm" >> build.ninja
echo "  command = nasm -f elf64 \$in -o \$out" >> build.ninja

echo "rule kernel_cc" >> build.ninja
echo "  depfile = \$out.d" >> build.ninja
echo "  command = cc -c -MD -MF \$out.d ${KERNEL_CC_FLAGS} \$in -o \$out" >> build.ninja

echo "rule user_cc" >> build.ninja
echo "  depfile = \$out.d" >> build.ninja
echo "  command = cc -c -MD -MF \$out.d ${USER_CC_FLAGS} \$in -o \$out" >> build.ninja

echo "rule kernel_ld" >> build.ninja
echo "  command = ld -T src/kernel/link.ld \$in -o \$out" >> build.ninja

echo "rule user_lib_ld" >> build.ninja
echo "  command = ld -r \$in -o \$out" >> build.ninja

#eventually maybe a libc will be linked in
echo "rule user_app_ld" >> build.ninja
echo "  command = ld \$in -o \$out" >> build.ninja

#builds everything in a directory
#  $1 - source directory
#  $2 - cc rule
#  $3 - ld rule
#  $4 - linked object name
#  $5 - extra objects to link in
build_all() {

  sources="$1/*.asm $1/*.c"
  objects="$5"

  for src in $sources; do
    if echo $src | grep -q -v '*'; then
      build=$(echo $src | sed -e 's/^src/build/').o
      if echo $src | grep -q '.c$'; then
        echo "build $build: $2 $src" >> build.ninja
      else
        echo "build $build: nasm $src" >> build.ninja
      fi
      objects="$objects $build"
    fi
  done

  build_dir=$(echo $1 | sed -e 's/^src/build/')
  echo "build $build_dir/$4: $3 $objects" >> build.ninja

}

build_all src/kernel kernel_cc kernel_ld kernel.elf

for dir in src/user-libs/*; do
  lib_name=$(echo $dir | sed -e 's/^src\/user-libs\///')
  build_all $dir user_cc user_lib_ld lib$lib_name.o
done

apps=""

for dir in src/user-apps/*; do

  if [ -e $dir/libraries.txt ]; then
    lib_paths=$(cat $dir/libraries.txt | sed -e 's/^.*$/build\/user-libs\/\0\/lib\0.o/')
  else
    lib_paths=""
  fi

  app_name=$(echo $dir | sed -e 's/^src\/user-apps\///')
  build_all $dir user_cc user_app_ld $app_name.elf $lib_paths
  build_dir=$(echo $dir | sed -e 's/^src/build/')
  apps="$apps $build_dir/$app_name.elf"

done

echo "rule initfs" >> build.ninja
echo "  command =" \
  "rm -rf build/initfs &&" \
  "mkdir -p build/initfs/apps &&" \
  "cp build/user-apps/hello/hello.elf build/initfs/apps/ &&" \
  "cd build/initfs &&" \
  "tar cf ../initfs.tar *" >> build.ninja

echo "build build/initfs.tar: initfs $apps" >> build.ninja

echo "rule disk" >> build.ninja
echo "  command =" \
  "rm -rf build/disk &&" \
  "cp -r disk build/disk &&" \
  "cp dependencies/limine/limine-uefi-cd.bin build/disk/limine/ &&" \
  "cp dependencies/limine/limine-bios-cd.bin build/disk/limine/ &&" \
  "cp dependencies/limine/limine-bios.sys build/disk/limine/ &&"\
  "mkdir -p build/disk/EFI/BOOT &&" \
  "cp dependencies/limine/BOOTX64.EFI build/disk/EFI/BOOT/ &&" \
  "mkdir build/disk/calcite &&" \
  "cp build/kernel/kernel.elf build/disk/calcite/ &&" \
  "cp build/initfs.tar build/disk/calcite/ &&" \
  "xorriso -as mkisofs -R -r -J -b limine/limine-bios-cd.bin -no-emul-boot -boot-load-size 4 -boot-info-table -hfsplus -apm-block-size 2048 --efi-boot limine/limine-uefi-cd.bin -efi-boot-part --efi-boot-image --protective-msdos-label build/disk -o build/disk.iso &&" \
  "dependencies/limine/limine bios-install build/disk.iso" >> build.ninja

echo "build build/disk.iso: disk | build/kernel/kernel.elf build/initfs.tar" >> build.ninja

echo "default build/disk.iso" >> build.ninja