#!/bin/sh

COMMON_CC_EXTRA_FLAGS="-Wall -Wextra"
COMMON_LD_EXTRA_FLAGS=""

COMMON_CC_FLAGS="-std=c23 -ffreestanding -I include ${COMMON_CC_EXTRA_FLAGS}"
COMMON_LD_FLAGS="${COMMON_LD_EXTRA_FLAGS}"

if [ "$1" = debug ]; then
  COMMON_CC_FLAGS="-O0 -ggdb -D CALCITE_DEBUG ${COMMON_CC_FLAGS}"
elif [ "$1" = release ]; then
  COMMON_CC_FLAGS="-O3 -D CALCITE_RELEASE ${COMMON_CC_FLAGS}"
  COMMON_LD_FLAGS="-s ${COMMON_LD_FLAGS}"
else
  echo pass either "debug" or "release" as an argument.
  exit
fi

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 -I dependencies/flanterm/src ${COMMON_CC_FLAGS}"

FLANTERM_CC_FLAGS="-D FLANTERM_FB_DISABLE_BUMP_ALLOC ${USER_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 flanterm_cc" >> build.ninja
echo "  depfile = \$out.d" >> build.ninja
echo "  command = cc -c -MD -MF \$out.d ${FLANTERM_CC_FLAGS} \$in -o \$out" >> build.ninja

echo "rule kernel_ld" >> build.ninja
echo "  command = ld ${COMMON_LD_FLAGS} -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 ${COMMON_LD_FLAGS} -T src/user-apps/link.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

objects=""
for file in flanterm.c flanterm_backends/fb.c; do
  src="dependencies/flanterm/src/$file"
  build="build/user-libs/flanterm/$file.o"
  echo "build $build: flanterm_cc $src" >> build.ninja
  objects="$objects $build"
done
echo "build build/user-libs/flanterm/libflanterm.o: user_lib_ld $objects" >> build.ninja

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

cp_apps=""
app_deps=""

for dir in src/user-apps/*; do
  if [ -d $dir ]; then

    if [ -e $dir/libraries.txt ]; then
      lib_paths=$(cat $dir/libraries.txt | sed -e 's/^.*$/build\/user-libs\/\0\/lib\0.o/' | tr '\n' ' ')
    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_elf=$(echo $dir | sed -e 's/^src/build/')/$app_name.elf
    disk_dir=build/disk/calcite/apps/$app_name
    disk_elf=$disk_dir/$app_name.elf

    cp_apps=$(echo "$cp_apps" \
      "mkdir -p $disk_dir &&" \
      "cp $build_elf $disk_elf &&")
    app_deps="$app_deps $build_elf"

  fi
done

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 -p build/disk/calcite &&" \
  "cp build/kernel/kernel.elf build/disk/calcite/ &&" \
  $cp_apps \
  "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 -quiet build/disk -o build/disk.iso &&" \
  "dependencies/limine/limine bios-install --quiet build/disk.iso" >> build.ninja

echo "build build/disk.iso: disk | build/kernel/kernel.elf $app_deps" >> build.ninja

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