#! /usr/bin/env bash
#set -e
shopt -s extglob
[ -n "$BUILD_THEME_DEBUG" ] && set -x

trim() {
  local string="$*"
  string="${string#"${string%%[![:space:]]*}"}"
  string="${string%"${string##*[![:space:]]}"}"
  echo -n "$string"
}

find-included() {
  local needle source dir found
  needle="$1"
  source="$2"
  dir="$(dirname "$source")"
  found=""

  if [[ "${needle:0:1}" == "/" ]]; then
    echo "$needle"
    return 0
  fi

  while [ -z "$found" ] && [[ ! "$dir" =~ ^(\/|\.|\.\.)$ ]]; do
    if [ -f "${dir}/${needle}" ]; then
      found="${dir}/${needle}"
    elif [ -f "${dir}/${needle}.tmuxsh" ]; then
      found="${dir}/${needle}.tmuxsh"
    elif [ -f "${dir}/${needle}.tmuxtheme" ]; then
      found="${dir}/${needle}.tmuxtheme"
    else
      dir="$(dirname "$dir")"
    fi
  done

  if [ -z "$found" ]; then
    echo "ERROR: Could not find \"$needle\" to include in \"$source\"" 1>&2
    return 1
  else
    # echo "INFO: Found \"$needle\" to include in \"$source\"" 1>&2
    echo "$found"
    return 0
  fi
}

build-theme() {
  local source target output file line included err
  source="$1"
  target="$2"
  output=""
  err="0"

  while IFS= read -r line; do
    if [[ "$line" =~ ^#=\ *include\ \"(.+)\".*$ ]]; then
      if file="$(find-included "${BASH_REMATCH[1]}" "$source")"; then
        if included="$(build-theme "${file}")"; then
          output="${output}${included}
"
        else
          err="1"
        fi
      else
        err="1"
      fi
    else
      output="${output}${line}
"
    fi
  done < "$source"

  if [ "$err" != "0" ]; then
    return "$err"
  elif [ -z "$target" ]; then
    echo "$(trim "$output")"
  else
    mkdir -p "$(dirname "$target")"
    echo "$(trim "$output")" > "$target"
  fi
}

help() {
  echo "usage: build-theme <source-file> [<target-file>]"
  echo ""
  echo "Arguments:"
  echo "  <source-file>  - The theme file to build."
  echo "  <target-file>  - Write output to specified file. If not given, print"
  echo "                   output to STDOUT."
}

main() {
  local source="$1"
  local target="$2"

  if [ -z "$source" ]; then
    help
    exit 1
  elif [[ " $* " =~ ^.*\ (-h|--help)\ .*$ ]]; then
    help
  else
    build-theme "$source" "$target"
    return "$?"
  fi
}

main "$@"
exit "$?"