#!/bin/bash
args="$@"  # backup for ninja regen

OCAMLC=ocamlc
OCAMLDEP=ocamldep
OCAMLC_ARGS=
OCAMLDEP_ARGS=-bytecode
OBJEXT=cmo
OCAMLLD=ocamlc
OCAMLLD_ARGS=

while [[ $# -gt 0 ]]; do
  case $1 in
    *=*)
      eval "$1"
      shift 1
      ;;

    --help|-help|-h|--h)
      echo "Usage: ./configure [options] key=value ..."
      echo ""
      echo "Options:"
      echo "  --help"
      echo ""
      echo "Varaibles:"
      echo "  OBJEXT        = $OBJEXT"
      echo "  OCAMLC        = $OCAMLC"
      echo "  OCAMLDEP      = $OCAMLDEP"
      echo "  OCAMLC_ARGS   = $OCAMLC_ARGS"
      echo "  OCAMLDEP_ARGS = $OCAMLDEP_ARGS"
      echo "  OCAMLLD       = $OCAMLLD"
      echo "  OCAMLLD_ARGS  = $OCAMLLD_ARGS"
      exit 0
      ;;

    *)
      echo "Unexpected argument: $1"
      exit 1
      ;;
  esac
done

mkdir -p build

echo '# generated by ../configure
OCAMLDEP=$1
shift
echo ninja_dyndep_version = 1
$OCAMLDEP -one-line $@ | while read d; do
  outs="$(echo "$d" | cut -d":" -f1)"
  ins="$(echo "$d" | cut -d":" -f2)"
  echo -ne "build build/$outs : dyndep |"
  for f in $ins; do
    echo -ne " build/$f"
  done
  echo
done
' > build/deps.sh

echo "# generated by ../configure" > build/invokeld.sh
echo "OCAMLDEP=\"$OCAMLDEP\"" >> build/invokeld.sh
echo "OCAMLDEP_ARGS=\"$OCAMLDEP_ARGS\"" >> build/invokeld.sh
echo "OCAMLLD=\"$OCAMLLD\"" >> build/invokeld.sh
echo "OCAMLLD_ARGS=\"$OCAMLLD_ARGS\"" >> build/invokeld.sh
echo "OBJEXT=\"$OBJEXT\"" >> build/invokeld.sh
echo '
set -e
got=""
get() {
  set -e
  got+=" $1"
  deps="$($OCAMLDEP $OCAMLDEP_ARGS -one-line -bytecode $1.ml | cut -d":" -f2)"
  fixdeps=""
  for dep in $deps; do
    dep="$(basename $dep .cmi)"
    if ! [ $dep = $1 ]; then
      fixdeps+=" $dep"
    fi
  done
  for dep in $fixdeps; do
    echo "$dep $1"
  done
  for dep in $fixdeps; do
    if ! [[ " $got " =~ " $dep " ]]; then
      get "$dep"
    fi
  done
}

files=""
for dep in $(get "$(basename $1 .ml)" | tsort); do
  files+=" build/$dep.$OBJEXT"
done
shift
$OCAMLLD $files $OCAMLLD_ARGS $@
' >> build/invokeld.sh


if ! [ -f project ]; then
  touch project
  echo "# ocaml project description" >> project
  echo "# (this is a bash script)" >> project
  echo "#" >> project
  echo "# functions:" >> project
  echo "#   application [name]" >> project
  echo "#     create module from \$name.ml, which will be linked with it's dependencies to an executable" >> project
  echo "#" >> project
  echo "#   module [name]" >> project
  echo "#     create module from \$name.ml and \$name.mli" >> project
  echo "#" >> project
  echo "#   include [path]" >> project
  echo "#     include other config path." >> project
  echo "#     prefer this over regular 'source', because this also adds" >> project
  echo "#     a dependency to the ninja build file" >> project
  echo ""
  echo "# put in project configuration here" >> project
fi

project_files=""
module() {
  true
}
application() {
  true
}
include() {
  project_files+=" $1"
  source "$1"
}
include "project"

rm -f build.ninja
touch build.ninja

echo "rule regen" >> build.ninja
echo "  command = ./configure $args" >> build.ninja
echo "  generator = 1" >> build.ninja
echo "build build.ninja | build/deps.sh build/invokeld.sh : regen | configure $project_files" >> build.ninja
echo "" >> build.ninja
echo "rule ocamlc" >> build.ninja
echo "  command = $OCAMLC $OCAMLC_ARGS -nocwd -I build -c \$in -o \$out" >> build.ninja
echo "" >> build.ninja
echo "rule ocamlld" >> build.ninja
echo "  command = bash build/invokeld.sh \$in -o \$out" >> build.ninja
echo "" >> build.ninja
echo "rule ocamldep" >> build.ninja
echo "  command = sh build/deps.sh $OCAMLDEP $OCAMLDEP_ARGS \$in > \$out" >> build.ninja

module() {
  echo "" >> build.ninja
  echo "build build/$1.dd : ocamldep $1.ml $1.mli || build/deps.sh" >> build.ninja
  echo "build build/$1.cmi : ocamlc $1.mli || build/$1.dd" >> build.ninja
  echo "  dyndep = build/$1.dd" >> build.ninja
  echo "build build/$1.$OBJEXT : ocamlc $1.ml | build/$1.cmi || build/$1.dd " >> build.ninja
  echo "  dyndep = build/$1.dd" >> build.ninja
}

application() {
  echo "" >> build.ninja
  echo "build build/$1.dd : ocamldep $1.ml || build/deps.sh" >> build.ninja
  echo "build build/$1.$OBJEXT | build/$1.cmi : ocamlc $1.ml || build/$1.dd" >> build.ninja
  echo "  dyndep = build/$1.dd" >> build.ninja
  echo "build build/$1 : ocamlld $1.ml | build/$1.$OBJEXT || build/invokeld.sh" >> build.ninja
}

include() {
  project_files+=" $1"
  source "$1"
}

for f in $project_files; do
  source "$f"
done


echo Configuration Done!
echo Run \"ninja\" to start build