#! /bin/bash

# output file
confile='fxlibc.cfg'

# Build options
toolchain=sh-elf
prefix=
cflags=

# wanted Makefile
makefile='Makefile.default'

# configuration
declare -A config
config[__SUPPORT_VHEX_KERNEL]=false
config[__DEBUG]=false
config[__ENABLE_VALGRIND]=false
config[__SUPPORT_CASIO_ABI_FX9860]=false
config[__SUPPORT_CASIO_ABI_FXCG50]=false

#
# Help screen
#
help()
{
cat << EOF
Configuration script for the fx calculator libc.
Usage: $0 [OPTION]...

You should build out-of-tree by creating a build directory and configuring from
there.

Debug the fxlibc
  --debug        enable valgrind flags (-g3)
  --unit-test    check C-functoon validity with Criterion

Build options:
  --toolchain=TRIPLET    Build with a different toolchain
                         [sh-elf-gcc] (or [gcc] when the '--unit_test' flag is set)
  --cflags=FLAGS         Additional compiler flags at end of command

ABI support:
  --vhex-support                 Enable the Vhex kernel support
  --casio-support=fx9860|fxcg50
    enable the support of the Casio' ABI (used by malloc, free, ...)
      
    fx9860 covers all fx-9860G II-like monochromes models that support add-ins
    or can be flashed with an OS that does. This includes SH3 and SH4 machines.

    fxcg50 covers just the fx-CG 50; there is some unofficial compatibility with
    fx-CG 10/20. All of these are SH4-only.

The 'ABI support' is used to allow some part of the code, in particular the 'unistd'
part, I/O management and additionnal feature (process, fs, ...).

Format:
    --dyn-lib   generate dynamic librairies (Vhex kernel dependant)

Little note for the generation of dynamic libraries.
The superH toolchain currently used (GCC) does not support the '--shared' flags
when the archive is build. So we need to create manually an archive that can be
used like a shared librairy.

To do this we need to do several steps:
1) build the sources with the PIE mode as if it were a executable without entry point.
2) manually extract symbols defined as 'global' from the generated ELF.
3) we create "stubs": functions that will have the same name than the wanted
     shared librairies and will call internal VHEX loader primitives with the
     librairies name, function address and size, etc....Then the loader will
     load the shared function and override the "user function (stub)" to force
     it to jump into the "real" function (trampoline)
4) all generated stubs will be compiled and linked throught a static lib that
     SHOULD be used in the user program which use the "dynamic librairy"

EOF
  exit 0
}


#
# Check mandatory build location
# @note:
# * You should build out-of-tree by creating a build directory and configuring
#   from there.
#
if [ -f 'make/Makefile.default' ]; then
  echo "error: you should configure from a build directory, like this:" >&2
  echo "  mkdir build && cd build && ../configure [options..]" >&2
  exit 1
fi


#
# Parsing arguments
#
for arg; do case "$arg" in
  --help | -h) 
    help;;

  --debug)
    config[__DEBUG]=true;;
  --unit-test)
    makefile='Malefile.unitest';;

  
  --toolchain=*)
    toolchain=${arg#*=};;
  --prefix=*)
    prefix=${arg#*=};;
  --cflags=*)
    cflags=${arg#*=};;

  --vhex-support)
    config[__SUPPORT_VHEX_KERNEL]=true;;
  --casio-abi=*)
    case ${arg#*=} in
      "fx9860g")
        config[__SUPPORT_CASIO_ABI_FX9860]=true;;
      "fcg50")
        config[__SUPPORT_CASIO_ABI_FXCG50]=true;;
      *)
        echo -e "\033[1;33merror\033[0m unreconized target '$arg'"
        exit 1
    esac;;

  --dyn-lib)
    makefile='Makefile.dynlib';;
  *)
    echo -e "\033[1;33merror\033[0m unreconized argument '$arg'"
    exit 1
esac; done


#
# Check error
#
if [ ${config[__SUPPORT_CASIO_ABI_FX9860]} = true ] && [ ${config[__SUPPORT_CASIO_ABI_FXCG50]} = true ]; then
  echo -e "\033[1;33merror\033[0m too many target"
  exit 1
fi


#
# Dump appropriate Makefile
# @note:
# * We have 3 makefile: normal, dynlib, unit_test
#
dst='Makefile'
src="../make/$makefile"
if ! test $src; then
  echo -e "\033[1;33merror\033[0m target makefile ($src) does not exist !"
  exit 1
fi
[ -L $src ] && [ "$(readlink $src)" == $dst ] && rm $dst
ln -s $src $dst


#
# Generate the configuration file
#
function generate_config()
{
  echo "CONFIG.TOOLCHAIN = $toolchain"
  [ "$prefix" ] && echo "PREFIX = $prefix"
  [ "$cflags" ] && echo "CONFIG.CFLAGS = $cflags"

  [ ${config[__DEBUG]} = true ] && echo -n '-g3'
  [ ${config[__SUPPORT_VHEX_KERNEL]} = true ] && echo -n ' -D __SUPPORT_VHEX_KERNEL'
  [ ${config[__SUPPORT_CASIO_ABI_FX9860]} = true ] && echo -n ' -D ___SUPPORT_CASIO_ABI_FX9860'
  [ ${config[__SUPPORT_CASIO_ABI_FXCG50]} = true ] && echo -n ' -D ___SUPPORT_CASIO_ABI_FXCG50'
  echo ''
}
generate_config > $confile


echo "Configuration saved in $confile, ready to make!"
exit 0