#!/bin/bash

# Start Vim on a copy of the tutor file.

# Usage: vimtutor [-g] [xx]
# Where optional argument -g starts vimtutor in gvim (GUI) instead of vim.
# and xx is a language code like "es" or "nl".
# When an argument is given, it tries loading that tutor.
# When this fails or no argument was given, it tries using 'v:lang'
# When that also fails, it uses the English version.

# Vim could be called "vim" or "vi".  Also check for "vimN", for people who
# have Vim installed with its version number.
# We anticipate up to a future Vim 8.1 version :-).
seq="vim vim81 vim80 vim8 vim74 vim73 vim72 vim71 vim70 vim7 vim6 vi"

usage()
{
    echo "==USAGE========================================================================================="
    echo "${0##*/} [-(-l)anguage ISO639] [-(-c)hapter) NUMBER] [-(-g)ui] | [-(-h)elp] | [--list]"
    printf "\twhere:\n"
    printf "\t\tISO639 (default=en) is a 2 or 3 character language code\n"
    printf "\t\tNUMBER (default=01) is one or two digits representing the chapter number\n"
    printf "\texamples:\n"
    printf "\t\tvimtutor -l es -c 2 -g\n"
    printf "\t\tvimtutor --language de --chapter 02\n"
    printf "\t\tvimtutor fr\n"
    echo "More information at 'man vimtutor'"
    echo "================================================================================================"
}

listOptions()
{
  declare -A language
  language[bar]=Bavarian
  language[bg]=Bulgarian
  language[ca]=Catalan
  language[cs]=Czech
  language[da]=Danish
  language[de]=German
  language[el]=Greek
  language[en]=English\(default\)
  language[eo]=Esperanto
  language[es]=Spanish
  language[fr]=French
  language[hr]=Croatian
  language[hu]=Hungarian
  language[it]=Italian
  language[ja]=Japanese
  language[ko]=Korean
  language[lv]=Latvian
  language[nb]=Bokmål
  language[nl]=Dutch
  language[no]=Norwegian
  language[pl]=Polish
  language[pt]=Portuguese
  language[ru]=Russian
  language[sk]=Slovak
  language[sr]=Serbian
  language[sv]=Swedish
  language[tr]=Turkish
  language[uk]=English
  language[vi]=Vietnamese
  language[zh]=Chinese

  echo "==OPTIONS======================================================================================="
  echo "Chapter: 1"
  for code in bar bg ca cs da de el en eo es fr hr hu it ja ko lv nb nl no pl pt ru sk sr sv tr uk vi zh
  do
    printf "\tLang: %s => %s\n" ${code} ${language[${code}]}
  done
  echo "Chapter: 2"
  for code in en
  do
    printf "\tLang: %s => %s\n" ${code} ${language[${code}]}
  done
  echo "================================================================================================"
}

validateLang()
{
  if [[ $xx =~ ^[^a-z]*$ ]]; then echo "Error: iso639 code must contain only [a-z]" && exit 1; fi
  if [ ${#xx} == 2 ] || [ ${#xx} == 3 ]; then :; else echo "Error: iso639 code must be 2 or 3 characters only" && exit 1; fi
  export xx
}

validateChapter()
{
  if [[ $cc =~ ^[0-9]*$ ]]; then :; else echo "Error: chapter argument must contain digits only" && exit 1; fi
  if [ $cc == "0" ]; then echo "Error: chapter must be non-zero" && exit 1; fi
  if [ $cc == "00" ]; then echo "Error: chapter must be non-zero" && exit 1; fi
  export CHAPTER="$cc"
}

shopt -s extglob
while [ "$1" != "" ]; do
  case $1 in
    -g | --gui )                    seq="gvim gvim91 gvim90 gvim81 gvim80 gvim8 gvim74 gvim73 gvim72 gvim71 gvim70 gvim7 gvim6 $seq"
                                    ;;
    -l | --language )               shift
                                    xx=$1
                                    validateLang
                                    ;;
    -l[a-z][a-z]?([a-z]) )          xx=${1#*l}
                                    validateLang
                                    ;;
    --language[a-z][a-z]?([a-z]) )  xx=${1#*e}
                                    validateLang
                                    ;;
    [a-z][a-z]?([a-z]) )            xx=$1
                                    validateLang
                                    ;;
    -c | --chapter )                shift
                                    cc=$1
                                    validateChapter
                                    ;;
    -c[0-9]?([0-9]) )               cc=${1#*c}
                                    validateChapter
                                    ;;
    --chapter[0-9]?([0-9]) )        cc=${1#*r}
                                    validateChapter
                                    ;;
    -h | --help )                   usage
                                    exit
                                    ;;
    --list )                        listOptions
                                    exit
                                    ;;
    "" )                            ;;
    * )                             usage
                                    exit 1
    esac
    shift
done


# We need a temp file for the copy.  First try using a standard command.
tmp="${TMPDIR-/tmp}"
TUTORCOPY=`mktemp $tmp/tutorXXXXXX || tempfile -p tutor || echo none`

# If the standard commands failed then create a directory to put the copy in.
# That is a secure way to make a temp file.
if test "$TUTORCOPY" = none; then
	tmpdir=$tmp/vimtutor$$
	OLD_UMASK=`umask`
	umask 077
	getout=no
	mkdir $tmpdir || getout=yes
	umask $OLD_UMASK
	if test $getout = yes; then
		echo "Could not create directory for tutor copy, exiting."
		exit 1
	fi
	TUTORCOPY=$tmpdir/tutorcopy
	touch $TUTORCOPY
	TODELETE=$tmpdir
else
	TODELETE=$TUTORCOPY
fi

export TUTORCOPY

# remove the copy of the tutor on exit
trap "rm -rf $TODELETE" 0 1 2 3 9 11 13 15

for i in $seq; do
    testvim=$(which $i 2>/dev/null)
    if test -f "$testvim"; then
        VIM=$i
        break
    fi
done

# When no Vim version was found fall back to "vim", you'll get an error message
# below.
if test -z "$VIM"; then
    VIM=vim
fi

# Use Vim to copy the tutor, it knows the value of $VIMRUNTIME
# The script tutor.vim tells Vim which file to copy

$VIM -f -u NONE -c 'so $VIMRUNTIME/tutor/tutor.vim'

# Start vim without any .vimrc, set 'nocompatible' and 'showcmd'
$VIM -f -u NONE -c "set nocp showcmd" "$TUTORCOPY"