#!/bin/sh
set -e  # stop immediately on error

# [0-9]*.cc -> mu.cc -> .build/*.cc -> .build/*.o -> .build/mu_bin
# (layers)   |        |              |             |
#          tangle  cleave          $CXX          $CXX

# can also be called with a layer to only build until
#   $ ./build --until 050
# returns 0 on successful build or nothing to build;
# non-zero exit status only on error during building
UNTIL_LAYER=${2:-zzz}

test $CXX || export CXX=c++
test $CC || export CC=cc
test $CFLAGS || export CFLAGS="-g -O3"
export CFLAGS="$CFLAGS -Wall -Wextra -ftrapv -fno-strict-aliasing"

# return 1 if $1 is older than _any_ of the remaining args
older_than() {
  target=$1
  shift
  if [ ! -e $target ]
  then
#?     echo "$target doesn't exist"
    echo "updating $target" >&2
    return 0  # success
  fi
  for f in $*
  do
    if [ $f -nt $target ]
    then
      echo "updating $target" >&2
      return 0  # success
    fi
  done
  return 1  # failure
}

noisy_cd() {
  cd $1
  echo "-- `pwd`" >&2
}

older_than enumerate/enumerate enumerate/enumerate.cc && {
  $CXX $CFLAGS enumerate/enumerate.cc -o enumerate/enumerate
}

(
  older_than tangle/tangle tangle/*.cc && {
    noisy_cd tangle
      older_than type_list [0-9]*.cc && {
        grep -h "^struct .* {" [0-9]*.cc |sed 's/\(struct *[^ ]*\).*/\1;/' > type_list
        grep -h "^typedef " [0-9]*.cc >> type_list
      }
      older_than function_list [0-9]*.cc && {
        grep -h "^[^ #].*) {" [0-9]*.cc |sed 's/ {.*/;/' > function_list
      }
      older_than file_list [0-9]*.cc && {
        ls [0-9]*.cc |grep -v "\.test\.cc$" |sed 's/.*/#include "&"/' > file_list
      }
      older_than test_file_list [0-9]*.test.cc && {
        ls [0-9]*.test.cc |sed 's/.*/#include "&"/' > test_file_list
      }
      older_than test_list [0-9]*.cc && {
        grep -h "^[[:space:]]*void test_" [0-9]*.cc |sed 's/^\s*void \(.*\)() {$/\1,/' > test_list
      }
      $CXX $CFLAGS boot.cc -o tangle
    noisy_cd ..  # no effect; just to show us returning to the parent directory
  }
  exit 0
)

LAYERS=$(./enumerate/enumerate --until $UNTIL_LAYER |grep -v '.mu$')
older_than mu.cc $LAYERS enumerate/enumerate tangle/tangle && {
  ./tangle/tangle $LAYERS > mu.cc
}
older_than function_list mu.cc && {
  grep -h "^[^[:space:]#].*) {$" mu.cc |grep -v ":.*(" |sed 's/ {.*/;/' > function_list
}
older_than test_list mu.cc && {
  grep -h "^\s*void test_" mu.cc |sed 's/^\s*void \(.*\)() {.*/\1,/' > test_list
}

older_than cleave/cleave cleave/cleave.cc && {
  $CXX -O3 -Wall -Wextra -fno-strict-aliasing cleave/cleave.cc -o cleave/cleave
  rm -rf .build
}

older_than mu_bin mu.cc *_list cleave/cleave termbox/* && {
  mkdir -p .build
  cp function_list test_list .build
  mkdir -p .build/termbox
  cp termbox/termbox.h .build/termbox
  ./cleave/cleave mu.cc .build
  noisy_cd .build
    older_than global_declarations_list global_definitions_list && {
      grep ';' global_definitions_list |sed 's/[=(].*/;/' |sed 's/^[^\/# ]/extern &/' |sed 's/^extern extern /extern /' > global_declarations_list
    }
    for f in mu_*.cc
    do
      older_than `echo $f |sed 's/\.cc$/.o/'` $f && {
        $CXX $CFLAGS -c $f
      }
    done
  noisy_cd ../termbox
    older_than utf8.o utf8.c && {
      $CC $CFLAGS -c utf8.c
    }
    older_than termbox.o termbox.c termbox.h input.inl output.inl bytebuffer.inl && {
      $CC $CFLAGS -c termbox.c
    }
    older_than libtermbox.a *.o && {
      ar rcs libtermbox.a *.o
    }
  noisy_cd ..
  $CXX .build/*.o termbox/libtermbox.a -o .build/mu_bin
  cp .build/mu_bin .
}

## [0-9]*.mu -> core.mu

MU_LAYERS=$(./enumerate/enumerate --until $UNTIL_LAYER |grep '.mu$') || exit 0  # ok if no .mu files
older_than core.mu $MU_LAYERS enumerate/enumerate && {
  cat $MU_LAYERS > core.mu
}

exit 0