#! /bin/sh


fatal ()
{
  echo >&2 "$0: $@"
  exit 1
}

usage ()
{
  cat <<EOF
Usage: $0 [OPTION]

Options:
  -h, --help              display this message
  -m, --make              run make at the end of the bootstraping

Report bugs to <tiger@lrde.epita.fr>
EOF
}

# Run make at the end of the bootstraping?
run_make_p=false

awk_strverscmp='
  # Use only awk features that work with 7th edition Unix awk (1978).
  # My, what an old awk you have, Mr. Solaris!
  END {
    while (length(v1) || length(v2)) {
      # Set d1 to be the next thing to compare from v1, and likewise for d2.
      # Normally this is a single character, but if v1 and v2 contain digits,
      # compare them as integers and fractions as strverscmp does.
      if (v1 ~ /^[0-9]/ && v2 ~ /^[0-9]/) {
	# Split v1 and v2 into their leading digit string components d1 and d2,
	# and advance v1 and v2 past the leading digit strings.
	for (len1 = 1; substr(v1, len1 + 1) ~ /^[0-9]/; len1++) continue
	for (len2 = 1; substr(v2, len2 + 1) ~ /^[0-9]/; len2++) continue
	d1 = substr(v1, 1, len1); v1 = substr(v1, len1 + 1)
	d2 = substr(v2, 1, len2); v2 = substr(v2, len2 + 1)
	if (d1 ~ /^0/) {
	  if (d2 ~ /^0/) {
	    # Compare two fractions.
	    while (d1 ~ /^0/ && d2 ~ /^0/) {
	      d1 = substr(d1, 2); len1--
	      d2 = substr(d2, 2); len2--
	    }
	    if (len1 != len2 && ! (len1 && len2 && substr(d1, 1, 1) == substr(d2, 1, 1))) {
	      # The two components differ in length, and the common prefix
	      # contains only leading zeros.  Consider the longer to be less.
	      d1 = -len1
	      d2 = -len2
	    } else {
	      # Otherwise, compare as strings.
	      d1 = "x" d1
	      d2 = "x" d2
	    }
	  } else {
	    # A fraction is less than an integer.
	    exit 1
	  }
	} else {
	  if (d2 ~ /^0/) {
	    # An integer is greater than a fraction.
	    exit 2
	  } else {
	    # Compare two integers.
	    d1 += 0
	    d2 += 0
	  }
	}
      } else {
	# The normal case, without worrying about digits.
	if (v1 == "") d1 = v1; else { d1 = substr(v1, 1, 1); v1 = substr(v1,2) }
	if (v2 == "") d2 = v2; else { d2 = substr(v2, 1, 1); v2 = substr(v2,2) }
      }
      if (d1 < d2) exit 1
      if (d1 > d2) exit 2
    }
  }
'

version_compare ()
{
  (
    # Locally ignore failures, otherwise we'll exit whenever $1 and $2
    # are not equal!
    set +e

    awk "$awk_strverscmp" v1="$1" v2="$2" /dev/null
    case $? in
      1)  echo '<';;
      0)  echo '=';;
      2)  echo '>';;
    esac
  )
}

# require TOOL REQUIREMENT
# ------------------------
# Test that TOOL exists, and its version is at least REQUIREMENT.
# Check whether the environment contains a variable named like TOOL,
# but upper-cased, and use it instead of TOOL if so.
require ()
{
  envvar_name=$(echo $1 | tr '[:lower:]' '[:upper:]')
  tool=$(printenv $envvar_name || echo $1)
  local version=$($tool --version | \
    sed -n 's/[^0-9.]*\([0-9][0-9.]*\).*/\1/p;q')
  test x"$version" != x ||
    fatal "$tool is required"
  case $(version_compare "$2" "$version") in
    '>') fatal "$1 $2 or better is required: this is $tool $version";;
  esac
}


# Failures do matter.
set -e

for arg in "$@"; do
  case "$arg" in
    -h|--help) usage; exit 0 ;;
    -m|--make) run_make_p=true ;;
    *) fatal "error: unrecognized option: $1" ;;
  esac
done

# The ast/ is generated, including its Makefile.
if test -f dev/ast-nodes-mk-gen.py && test -f src/ast/ast.yml; then
  python_check_mod_yaml='
import sys, importlib
try:
  importlib.import_module("yaml")
except ImportError:
  sys.exit(1)
'
  if ! python3 -c ''; then
    fatal "Python is required"
  elif ! python3 -c "$python_check_mod_yaml"; then
    fatal "Python module \`yaml' is required (http://pyyaml.org/)"
  fi

  rm -f src/ast/ast-nodes.mk
  python3 dev/ast-nodes-mk-gen.py src/ast <src/ast/ast.yml >src/ast/ast-nodes.mk \
    || {
      rv=$?
      cat >&2 <<EOF

-----------------------------------------------------------------------
If the last error is "./bootstrap: Python module \`yaml' is required"
Then you need to install Python bindings for libyaml (http://pyyaml.org/).

Try 'sudo pip install pyyaml'.
EOF
      (exit $rv); exit $rv
    }
fi

# Swig makefiles.
if test -d tcsh; then
  here=$(pwd)
  cd tcsh
  for i in python
  do
    rm -f $i/swig.mk
    top_srcdir=.. ./generate-swig-mk $i $i/swig.mk
  done
  cd $here
fi

# Requirements over bootstrap tools.
require autoconf 2.64
require automake 1.11.1
libtoolize=libtoolize
for l in "$LIBTOOLIZE" glibtoolize libtoolize;
do
  if ($l --version) >/dev/null 2>&1; then
    libtoolize=$l
    break
  fi
done
export LIBTOOLIZE=$libtoolize
require $libtoolize 2.2.6

# Tell what's going on.
set -x

# Finally, install the GNU Build System.
autoreconf -f -v -i

# FIXME: autoheader does not obey --force.
find . -name 'config.h.in' | xargs touch


# If the pseudo-standard name "_build" is used and if asked so, then
# try and continue the re-build.
if $run_make_p && test -f _build/config.status; then
  cd _build
  ./config.status --recheck
  ./config.status
  make
fi