#!/bin/bash

cont() {
    read c
    if [ "$c" != "yes" ] && [ "$c" != "Yes" ] && [ "$c" != "y" ] && [ "$c" != "Y" ]
    then
      exit 3
    fi
}

if [ ! -e `which cmake` ]
then
  echo "CMake required."
  exit 1
fi

if [ -x "$(which ninja 2>/dev/null)" ]; then
  echo "Using Ninja ($(which ninja))"
  cmake_type="Ninja"
  exec_bin="ninja"
elif [ -x "$(which ninja-build 2>/dev/null)" ]; then
  echo "Using Ninja ($(which ninja-build))"
  cmake_type="Ninja"
  exec_bin="ninja-build"
elif [ -x "$(which make 2>/dev/null)" ]; then
  echo "Using Make ($(which make))"
  cmake_type="Unix Makefiles"
  exec_bin="make"
  printf "Using Ninja improves build experience, continue with Make? [y/N] "
  cont
else
  echo "No compatible build system (Ninja, Make) found."
  exit 4
fi

if [ -f ./build  ]
then
  echo "./build file exists. ./configure can't continue"
  exit 2
fi

if [ -d build ]
then
  if [ ! -f "build/.cmake_type" ]
  then
    printf "./build exists but was not created by ./configure script, continue? [y/N] "
    cont
  fi
  last_type=`cat build/.cmake_type`
  if [ "$cmake_type" != "$last_type" ]
  then
    echo "Using different build system, cleaning build system files"
    cd build
    rm -r CMakeCache.txt CMakeFiles
    cd ..
  fi
fi

mkdir -p build
cd build

echo "$cmake_type" > .cmake_type
cmake -G "$cmake_type" ..

if [ "$cmake_type" == "Ninja" ]
then
cat << EOF > Makefile
default:
	@sh -c "$exec_bin"
%:
	@sh -c "$exec_bin \"\$@\""
EOF
fi

cd ..

cat << EOF > Makefile
default:
	@sh -c "cd build; $exec_bin"
%:
	@sh -c "cd build; $exec_bin \"\$@\""
EOF