#!/bin/bash
#
# Generates Makefile containing dependencies for each package
#
#   Copyright (C) 2016 R-T Specialty, LLC.
#
#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
##

# windows machines may not have the tools to resolve a path, so let's do so
# ourselves (TODO: there's better (and more performant) ways of doing this than
# repeated string replacements); TODO: ./
resolv-path()
{
  # no need to do anything if the string does not contain a parent dir reference
  # (we use this convoluted string replacement check for woe32/64 to prevent
  # additional spawns (e.g. sed) that would slow us down and because =~ is not
  # properly supported in msys
  [[ "$1" != "${1/..\//}"a ]] || {
    echo "$1"
    return
  }

  local path=
  while read name; do
    if [ "$name" == .. ]; then
      [ -n "$path" ] || {
        echo "warning: will not resolve $1" >&2
        return 5
      }

      path="${path%/*}"
      continue
    fi

    path="$path/$name"
  done <<< "${1//\//$'\n'}"

  # echo path without leading /
  echo -n "${path:1}"
}


# rule for building
[ -z "$GEN_MAKE" ] && {
  echo "%.xmlo:: %.tmp"
  echo -e "\t@rm -f \$@ \$<"
  [ -n "$xmlo_cmd" ] \
    && echo -e "\t$xmlo_cmd" \
    || echo -e "\ttouch \$@"

  echo "%.xmlo:: %.xml | prexmlo"
  [ -n "$xmlo_cmd" ] \
    && echo -e "\t$xmlo_cmd" \
    || echo -e "\ttouch \$@"

  export GEN_MAKE="$( pwd )/$0"
  exec "$GEN_MAKE" "$@"
}

until [ $# -eq 0 ]; do (
  path="${1%%/}"
  echo "[gen-make] scanning $path" >&2

  cd "$path" || exit $?

  deps=$( find -maxdepth 1 -iname '*.dep' -o -iname '*.typelist' )

  for dpath in $deps; do
    # equivalent to basename command; use this since spawning processes on
    # windoze is slow as shit (originally we did find -exec bashename)
    d="${dpath##*/}"
    sansext="${d%.*}"

    echo "[gen-make] found $path/$d" >&2

    # this might be derived from another file
    # TODO: handle all cases, not just typelists!
    if [ -f "$sansext.typelist" ]; then
      echo "$path/$sansext.xml: $path/$sansext.typelist"
    fi

    # begin this file's dependencies
    echo -n "$path/$sansext.xmlo: $path/$sansext.xml "

    # only further process dependency files
    if [[ ! $dpath =~ .dep$ ]]; then
      echo
      continue;
    fi

    # output deps
    while read dep; do
      # if the first character is a slash, then it's relative to the project
      # root---the resolution has already been done for us!
      if [ "${dep:0:1}" == '/' ]; then
        echo -n " ${dep:1}.xmlo"
        continue
      fi

      echo -n ' '
      resolv-path "$path/$dep.xmlo"
    done < "$d"

    echo
  done

  # recurse on every subdirectory
  for p in */; do
    [ "$p" == ./ -o "$p" == ../ ] && continue
    [ ! -d "$p" ] || ( cd "$OLDPWD" && "$GEN_MAKE" "$path/$p" ) || {
      echo "fatal: failed to recurse on $( pwd )/$path/$p" >&2
      exit 1
    }
  done
); shift; done