#!/bin/sh

if [ -e build.ninja ]; then
  echo The build.ninja file already exists.
  echo Remove it with clean-build.sh.
  exit
fi

if [ "$#" -eq 0 ]; then
  echo This script must be run with at least one flag. The recognized flags are:
  echo
  echo "  --                  Do nothing, but silence this message."
  echo
  echo "  --cxx-flags FLAGS   Add FLAGS to the flags sent to the C++ compiler. The flags"
  echo "                      should be quoted, so that they are all read by this script"
  echo "                      as one argument."
  echo
  echo "  --debug             Enable debugging symbols."
  echo
  echo "  --ld-flags FLAGS    Add FLAGS to the flags sent to ld. The flags should be"
  echo "                      quoted, so that they are all read by this script as one"
  echo "                      argument."
  echo
  echo "  --no-optimize       Disable compiler optimizations. This might help with using"
  echo "                      the debugger. A bug could only appear when optimizations"
  echo "                      are enabled, so it might be necessary to run the debugger"
  echo "                      without this flag."
  echo
  echo These options can be combined.
  exit
fi

set -e

CXX_FLAGS="-std=c++17 -ffreestanding -fno-exceptions -fno-rtti -mno-sse -I include -Wall -Wextra"
LD_FLAGS="-L build/libraries"

OPTIMIZE_CXX_FLAGS="-O2"
DEBUG_CXX_FLAGS=""
NO_DEBUG_LD_FLAGS="-s"
EXTRA_CXX_FLAGS=""
EXTRA_LD_FLAGS=""

while [ "$#" -gt 0 ]; do
  case "$1" in
  --cxx-flags)
    shift
    EXTRA_CXX_FLAGS="$EXTRA_CXX_FLAGS $1"
    ;;
  --debug)
    DEBUG_CXX_FLAGS="-ggdb"
    NO_DEBUG_LD_FLAGS=""
    ;;
  --ld-flags)
    shift
    EXTRA_LD_FLAGS="$EXTRA_LD_FLAGS $1"
    ;;
  --no-optimize)
    OPTIMIZE_CXX_FLAGS=""
    ;;
  --)
    ;;
  *)
    echo Unknown argument.
    exit
  esac
  shift
done

CXX_FLAGS="$CXX_FLAGS $OPTIMIZE_CXX_FLAGS $DEBUG_CXX_FLAGS $EXTRA_CXX_FLAGS"
LD_FLAGS="$LD_FLAGS $NO_DEBUG_LD_FLAGS $EXTRA_LD_FLAGS"

rules() {
  echo "rule asm"
  echo "  command = nasm -f elf64 \$in -o \$out"
  echo "rule cxx"
  echo "  depfile = \$out.d"
  echo "  command = c++ -c -MD -MF \$out.d $CXX_FLAGS \$in -o \$out"
  echo "rule core_ld"
  echo "  depfile = \$out.d"
  echo "  command = ld $LD_FLAGS -T src/core/link.ld \$in -o \$out"
  echo "rule service_ld"
  echo "  depfile = \$out.d"
  echo "  command = ld $LD_FLAGS -T src/service/link.ld \$in -o \$out"
  echo "rule disk"
  echo "  command =" \
    "rm -rf build/disk &&" \
    "cp -r disk build/disk &&" \
    "mkdir -p build/disk/EFI/BOOT &&" \
    "mkdir -p build/disk/limine &&" \
    "mkdir -p build/disk/calcite/service &&" \
    "cp dependencies/limine-binary/BOOTX64.EFI build/disk/EFI/BOOT/ &&" \
    "cp dependencies/limine-binary/limine-uefi-cd.bin build/disk/limine/ &&" \
    "cp dependencies/limine-binary/limine-bios-cd.bin build/disk/limine/ &&" \
    "cp dependencies/limine-binary/limine-bios.sys build/disk/limine/ &&" \
    "cp build/core.elf build/disk/calcite/ &&" \
    "cp build/service/*.elf build/disk/calcite/service/ &&" \
    "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-binary/limine bios-install build/disk.iso"
}

build_core() {
  echo "build build/core/core.cxx.o: cxx src/core/core.cxx"
  echo "build build/core/core.asm.o: asm src/core/core.asm"
  echo "build build/core.elf: core_ld build/core/core.cxx.o build/core/core.asm.o"
}

build_service() {
  SERVICE="$1"
  OBJECTS=""
  for SOURCE in $(find "src/service/$SERVICE" -regex '.*\.cxx'); do
    OBJECT="$(echo $SOURCE | sed 's/src/build/').o"
    echo "build $OBJECT: cxx $SOURCE"
    OBJECTS="$OBJECTS $OBJECT"
  done
  for SOURCE in $(find "src/service/$SERVICE" -regex '.*\.asm'); do
    OBJECT="$(echo $SOURCE | sed 's/src/build/').o"
    echo "build $OBJECT: asm $SOURCE"
    OBJECTS="$OBJECTS $OBJECT"
  done
  echo "build build/service/$SERVICE.elf: service_ld$OBJECTS"
}

build_disk() {
  echo "build build/disk.iso: disk | $@"
}

default() {
  echo "default build/disk.iso"
}

rules >> build.ninja

DISK_DEPS="build/core.elf"
build_core >> build.ninja

for DIRECTORY in src/service/*; do
  if [ -d "$DIRECTORY" ]; then
    SERVICE="$(basename $DIRECTORY)"
    DISK_DEPS="$DISK_DEPS build/service/$SERVICE.elf"
    build_service $SERVICE >> build.ninja
  fi
done

build_disk $DISK_DEPS >> build.ninja
default >> build.ninja