#!/bin/sh
QEMU_EXECUTABLES="qemu-system-x86_64"
GDB_EXECUTABLES="gdb x86_64-elf-gdb"

event() {
    printf "$1... "
}

# $1: OS NAME
# $2: CROSS COMPILE FLAG
# $3: FDISK_BIN
generate_cross_compile_script() {
cat > cross-compile.cmake <<EOF
set(CMAKE_SYSTEM_NAME $1)

set(TOOLCHAIN_PATH_AND_PREFIX "$2")

set(CMAKE_C_COMPILER \${TOOLCHAIN_PATH_AND_PREFIX}gcc)
set(CMAKE_CXX_COMPILER \${TOOLCHAIN_PATH_AND_PREFIX}c++)
set(CMAKE_AR \${TOOLCHAIN_PATH_AND_PREFIX}ar)
set(CMAKE_LINKER \${TOOLCHAIN_PATH_AND_PREFIX}ld)
set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)

SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
# for libraries and headers in the target directories
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
SET(FDISK_BIN $3)
EOF
}

event "finding qemu"
for item in $QEMU_EXECUTABLES; do
    if $item --version > /dev/null 2>&1; then
        QEMU="$item"
        break
    fi
done
if [ "$QEMU" = "" ]; then
    echo "failed"
    exit 1
fi
echo "$QEMU"

check_gdb_arch() {
    local item="$1"
    if $item --init-eval-command 'set arch' \
             --init-eval-command 'q' 2>&1 \
             | grep 'x86-64' >/dev/null 2>&1; then
        return 0
    else
        return 1
    fi
}

if [ "$GDB" = "" ]; then
    event "finding gdb"
    for item in $GDB_EXECUTABLES; do
        if check_gdb_arch "$item"; then
            GDB="$item"
            break
        fi
    done
    if [ "$GDB" = "" ]; then
        echo "failed"
        exit 1
    fi
else
    event 'checking given gdb'
    if ! check_gdb_arch "$GDB"; then
        echo "failed"
        exit 1
    fi
fi
echo "$GDB"

event "checking os type"
OS=`uname`
case "$OS" in
    "Linux")
        echo "Linux"
        ;;
    "Darwin")
        echo "macOS"
        ;;
    *)
        echo "unknown"
        exit 1
        ;;
esac

event "setting hardware acceleration type"
case "$OS" in
    "Linux")
        echo "kvm"
        QEMU_ACCEL='-enable-kvm'
        ;;
    "Darwin")
        echo "tcg"
        QEMU_ACCEL='-accel tcg'
        ;;
esac

event "checking util-linux fdisk"
if [ "$FDISK_BIN" = "" -a "$CROSS_COMPILE" = "" ]; then
    if ! which fdisk > /dev/null 2>&1; then
        echo "no"
        exit 1
    fi
    FDISK_BIN=`which fdisk`
fi

if ! $FDISK_BIN -v 2>&1 | grep util-linux > /dev/null 2>&1 ; then
    echo "no, fdisk is not from util-linux"
    exit 1
else
    echo "$FDISK_BIN"
fi

event "checking cross compiling"
if [ "$CROSS_COMPILE" != "" ]; then
    echo "yes"
    CROSS_COMPILE_FLAG='--toolchain cross-compile.cmake'
    generate_cross_compile_script "$OS" "$CROSS_COMPILE" "$FDISK_BIN"
else
    echo "no"
    CROSS_COMPILE_FLAG=
fi

event "checking mkfs tool"
if ! which mkfs.fat > /dev/null 2>&1; then
    echo "no"
    exit 1
else
    echo `which mkfs.fat`
fi

event "checking mtools"
if ! which mcopy > /dev/null 2>&1; then
    echo "no"
    exit 1
else
    echo `which mcopy`
fi

cp Makefile.src Makefile
sed -i '' -e "s/##PLACEHOLDER_1##/$QEMU/" Makefile > /dev/null 2>&1
sed -i '' -e "s/##PLACEHOLDER_2##/$GDB/" Makefile > /dev/null 2>&1
sed -i '' -e "s/##PLACEHOLDER_3##/$QEMU_ACCEL/" Makefile > /dev/null 2>&1
sed -i '' -e "s/##PLACEHOLDER_4##/$CROSS_COMPILE_FLAG/" Makefile > /dev/null 2>&1
exit 0