#!/bin/sh

fname=$(basename "$0")
usage()
{
  echo "$fname <file>
Compile the target shell script into a single output
Resolves '%include' lines with shell capacity"
}

# no arg
unset infile
if [ $# -lt 1 ]
then
  if ! [ -t 0 ]
  then infile=/dev/stdin
  else usage && exit 1
  fi
fi

[ -z "$TMPDIR" ] && TMPDIR=/tmp
tmpdir="$TMPDIR/shcompile_$(tr -dc '[:alnum:]' < /dev/urandom | head -c10)"
mkdir -p "$tmpdir"
tmpfile="$tmpdir/ret"
filelist="$tmpdir/list"
headfile="$tmpdir/head"
tailfile="$tmpdir/tail"

stop()
{
  rm -rf "$tmpdir"
  exit $1
}

[ -z "$infile" ] && infile=$1
dirname=$()
[ "$infile" = '-' ] && infile=/dev/stdin

# create copy
cat "$infile" > "$tmpfile" 2>&1 || { echo "Error: cannot read '$infile'" >&2 && stop 2; }

# env when file
[ "$infile" != "/dev/stdin" ] && {
  echo "$(readlink -f "$infile")" > "$filelist"
  cd "$(dirname "$infile")"
}

firstline=$(head -n1 "$tmpfile" | grep '^#!/')

[ -z "$firstline" ] && firstline='#!/bin/sh'

get_include_line()
{
  grep -m1 -n '^%include ' "$1" | cut -d':' -f1
}

n=$(get_include_line "$tmpfile")
while [ -n "$n" ]
do
  pre=$(head -n $((n-1)) "$tmpfile" > "$headfile")
  post=$(tail -n +$((n+1)) "$tmpfile" > "$tailfile")
  incarg=$(sed "$n""q;d" "$tmpfile" | cut -d ' ' -f2-)
  inc=$(echo "for I in $incarg ; do echo \$I ; done" | sh)

  cp "$headfile" "$tmpfile"
  echo "$inc" | while read -r file
  do
    cat "$file" >/dev/null 2>&1 || { echo "Error when trying to include '$incarg': '$file' could not be read" >&2 && stop 10; }
    if ! grep -q "^$(readlink -f "$file")\$" "$filelist"
    then # not already included
      cat "$file" >> "$tmpfile"
      echo "$(readlink -f "$file")" >> "$filelist"
    fi
    cd "$pwd"
  done
  cat "$tailfile" >> "$tmpfile"
  # get next include line
  n=$(get_include_line "$tmpfile")
done

which shfmt >/dev/null 2>&1 && shfmt -w -mn "$tmpfile"
echo "$firstline"
cat "$tmpfile"

stop 0