#!/bin/bash

name="epub"
version="1.0"
read -r -d '' help_message <<-EOF
	Dumps HTML from an epub e-book archive
	Usage: epub TARGET [FILENAMES] [OPTIONS]
	Options:
	 -d, --dump            print to STDOUT
	 -h, --help            print this message
	 -l, --list            list HTML entries of archive
	 -L, --list-all        list all entries of archive
	 -q, --quiet           suppress error messages and prompts
	 -v, --verbose         show additional messages
	 -V, --version         print version number and exit
	 -w WIDTH,             set width of pager
	     --width WIDTH
EOF

source /usr/local/lib/mylib.bash

target_archive=""
positional=()
quiet=0
verbose=0
dump=0
list=0
list_all=0
width="$(/usr/bin/tput cols)"
while [[ $# -gt 0 ]]; do
  case "$1" in

  -d|--dump)
    debug_msg "Setting dump option to 1 (was ${dump})"
    dump=1
    shift
    ;;

  -h|--help)
    help_msg
    shift
    ;;

  -l|--list)
    debug_msg "Setting list option to 1 (was ${list})"
    list=1
    shift
    ;;

  -L|--list-all)
    debug_msg "Setting list all option to 1 (was ${list_all})"
    list_all=1
    shift
    ;;

  -q|--quiet)
    debug_msg "Setting quiet option to 1 (was ${quiet})"
    quiet=1
    shift
    ;;

  -v|--verbose)
    debug_msg "Setting verbose option to 1 (was ${verbose})"
    verbose=1
    shift
    ;;

  -V|--version)
    version_msg
    ;;

  -w|--width)
    if ! is_positive_integer "$2"; then
      error_msg "Cannot set column width to '${2}' (not an integer >= 1)"
    fi
    debug_msg "Setting column width to ${2} (was ${width})"
    width="$2"
    shift; shift
    ;;

  *)
    if [ -z "$target_archive" ]; then
      debug_msg "Setting target filename to '${1}'"
      target_archive="$1"
    else
      debug_msg "Argument '${1}' added to positional array"
      positional+=("$1")
    fi
    shift
    ;;
  esac
done

# error if no filenames given
if [[ -z "$target_archive" ]]; then
  debug_msg "No input filename was given"
  usage_msg
elif [[ ! -f "$target_archive" ]]; then
  error_msg "No such file '${target_archive}'"
fi

# listing subroutine
list_target_archive() {
  if ! /usr/bin/zipinfo -1 "$target_archive" 2>/dev/null; then
    debug_msg "Error in listing subroutine"
    code=1
  fi
}

# extract subroutine
extract_from_target_archive() {
  if ! /usr/bin/unzip -caaqq "$target_archive" "$target_fn"; then
    code=1
  fi
}

# render subroutine
render_html() {
  if ! /usr/bin/w3m -T text/html -cols "$width" -dump; then
    code=1
  fi
}

# dump subroutine
dump_target_archive() {
  if [[ "${#positional[@]}" -eq 0 ]]; then
    debug_msg "Opening all HTML files within '${target_archive}'..."
    for fn in "${list_fn[@]}"; do
      target_fn="$fn"
      debug_msg "Opening '${target_fn}'..."
      extract_from_target_archive | render_html
    done
  else
    for fn in "${positional[@]}"; do
      target_fn="$fn"
      debug_msg "Opening '${target_fn}'..."
      extract_from_target_archive | render_html
    done
  fi
}

# main routine
code=0
if [[ "$list_all" -eq 1 ]]; then
  list_target_archive | sort
elif [[ "$list" -eq 1 ]]; then
  list_target_archive | grep -E '\.xml|\.html|\.xhtml' | sort
else
  IFS=$'\n' list_fn=( $(list_target_archive | grep -E '\.xml|\.html|\.xhtml' | sort) )

  if [[ "$code" -eq 1 || "${#list_fn[@]}" -eq 0 ]]; then
    error_msg "'${target_archive}' is not a valid archive"
  else
    for target_fn in "${positional[@]}"; do
      debug_msg "Opening '${target_fn}'..."
      if ! contains "$target_fn" "${list_fn[@]}"; then
        error_msg "'${target_fn}' not in archive '${target_archive}'"
      fi
    done
  fi

  if [[ "$dump" -eq 1 ]]; then
    dump_target_archive
  else
    dump_target_archive | ${PAGER:=/usr/bin/less}
  fi
fi

# return stored code
exit "$code"