#! /bin/bash

. ./bin/utils.sh

HERE=$(
  cd "$(dirname_custom $0)" || exit
  pwd
)
THIS=$(basename $0)

dir=
input=
output=

shortopts='d:i:o:h'
longopts='dir:,input:,output:,help'
usage="\
Usage 1: $THIS [ options ] [ key=value ... ] < file.tt > file
Usage 2: $THIS [ options ] [ key=value ... ] file.tt ...

Options:
    -d, --dir=DIR               Directory of the output file
    -i, --input=FILE            Input file (usage 1 only)
    -o, --output=FILE           Output file (usage 1 only)
    -h, --help                  Output this usage and do nothing else

In usage 1, the template is read from standard input or the file given
with --input and the processing result is output to standard output or
the file given with --output.  When the output goes to stdout, the --dir
option is mandatory.

In usage 2, the templates are read from the files given as argument, and
the processing result for each of them is written to a corresponding file
without the '.tt' suffix.  All given file names must have the '.tt' suffix.
In this usage, --input, --output, standard input and standard output are
ignored.

In both usages, one can also set template variables with with the form
key=value.  They must come before any file name."

# Standard getopt calling sequence
if ! TEMP=$(getopt -o "$shortopts" --long "$longopts" -n $THIS -- "$@"); then
  echo >&2 "$usage"
  exit 1
fi
eval set -- "$TEMP"
unset TEMP

# Check the parsed options
while true; do
  case "$1" in
  '-d' | '--dir')
    dir="$2"
    shift 2
    continue
    ;;
  '-i' | '--input')
    input="$2"
    shift 2
    continue
    ;;
  '-o' | '--output')
    output="$2"
    shift 2
    continue
    ;;
  '-h' | '--help')
    echo >&2 "$usage"
    exit 0
    ;;
  '--')
    shift
    break
    ;;
  *)
    echo >&2 'Internal error!'
    echo >&2 "$usage"
    exit 1
    ;;
  esac
done

tpagecmd="tpage"
while true; do
  case "$1" in
  *=*)
    tpagecmd="$tpagecmd --define '$1'"
    shift
    ;;
  *)
    break
    ;;
  esac
done

# If there are no other arguments, read from stdin, write to stdout.
# Otherwise, read from the input files and write to corresponding output files.
if [ $# -eq 0 ]; then
  if [ -z "$dir" ]; then
    echo >&2 'Directory must be set with -d / --dir in this mode'
    exit 1
  fi
  (
    cd $dir || exit
    (
      cat $HERE/../inc/common.tt
      if [ -n "$input" ]; then cat "$HERE/../$input"; else cat; fi
    ) |
      eval "$tpagecmd --define 'dir=$dir'" |
      (if [ -n "$output" ]; then cat >"$HERE/../$output"; else cat; fi)
  )
else
  errfiles=
  nofiles=
  for f in "$@"; do
    base_with_ext="${f##*/}"
    base=${base_with_ext%.tt}
    # base=$(basename "$f" .tt)

    if [ "$base" = "$f" ]; then
      errfiles="$errfiles '$f'"
    elif [ ! -f "$f" ]; then
      nofiles="$nofiles '$f'"
    fi
  done
  if [ -n "$errfiles" ]; then
    echo >&2 "Files not ending with .tt:$errfiles"
  fi
  if [ -n "$nofiles" ]; then
    echo >&2 "Files no present:$nofiles"
  fi
  if [ -n "$errfiles" ] || [ -n "$nofiles" ]; then
    exit 1
  fi

  for f in "$@"; do
    base_with_ext="${f##*/}"
    base=${base_with_ext%.tt}
    filedir=$(dirname "$f")

    if [ "$f" != "$base" ]; then
      if ! (
        cd $filedir
        (
          cat $HERE/../inc/common.tt
          cat $base.tt
        ) |
          eval "$tpagecmd --define 'dir=${dir:-$filedir}'" \
            >$base
      ); then
        exit $?
      fi
    fi
  done
fi