#! /bin/dash

# this script is 20% faster with dash than with bash

#############################################################################
# download function

download_noto () {

# download noto third-party region flags
if [ -d noto-emoji-flags ]
then	if [ -d noto-emoji-flags/.git ]
	then	(cd noto-emoji-flags; git pull)
	else	echo WARNING: directory noto-emoji-flags already exists but no git config - Exit
		exit 9
	fi
else
	notogit=https://github.com/googlefonts/noto-emoji
	git clone --depth 1 -n --filter=blob:none $notogit noto-emoji-flags
	(cd noto-emoji-flags
	 git sparse-checkout set --no-cone third_party/region-flags/png
	 git checkout
	)
fi
(cd noto-emoji-flags; rm -f *.png; ln third_party/region-flags/png/*.png ./)

}

download_other () {

# download Puellanivis’ flag emojis
if [ -d puellanivis-flags ]
then	if [ -d puellanivis-flags/.git ]
	then	(cd puellanivis-flags; git pull)
	else	echo WARNING: directory puellanivis-flags already exists but no git config - Exit
		exit 9
	fi
else
	puelgit=https://github.com/puellanivis/emoji.git
	git clone --depth 1 $puelgit puellanivis-flags
fi
(cd puellanivis-flags; rm -f *.png; ln flags/*.png flags/*/*.png ./)

}

download () {
	download_noto

	# drop download of old Google region flags
	#git clone --depth 1 https://github.com/google/region-flags.git google-region-flags &&
	#ln google-region-flags/png/*.png google-region-flags/

	download_other
}

#############################################################################
# extract emoji files:
# pre-deploy them with proper filename, according to codepoint pattern

extract () {
	mkdir -p common

	for f in `ls *-flags/*.png`
	do	e=${f##*/}
		e=${e%.png}
		if [ -n "$BASH_VERSION" ]
		then
			e=${e//-}
			e=${e//\'}
		#else filter them out by missing case below
		fi
		case $e in
		??)	# 1F1E6 1F1E8 ; RGI_Emoji_Flag_Sequence
			tagseq=false;;
		*)	# 1F3F4 E0067 E0062 E0065 E006E E0067 E007F; RGI_Emoji_Tag_Sequence; flag: England
			tagseq=true;;
		esac
		if $tagseq
		then	n=1f3f4
		else	n=
		fi
		# speed-up possible by using a common sed script...
		for l in $( echo "$e" | tr 'A-Z' 'a-z' | sed -e 's,.,& ,g' )
		do	d=$( printf %d "'$l'" )
			if $tagseq
			then	case "$l" in
				[a-z]|[0-9])
					d=$(( $d + 917504 ))
					n=$n-$( printf %x $d )
					;;
				#[a-z])	d=$(( $d - 97 + 917601 ))	# 'a' -> U+E0061 ...
				#	n=$n-$( printf %x $d )
				#	;;
				#[0-9])	d=$(( $d - 48 + 917552 ))	# '0' -> U+E0030 ...
				#	n=$n-$( printf %x $d )
				#	;;
				esac
			else	d=$(( $d - 97 + 127462 ))	# U+1F1E6
				n=$n-$( printf %x $d )
			fi
		done
		if $tagseq
		then	n=$n-e007f.png
		else	n=${n#-}.png
		fi

		echo "$f -> common/$n"
		if [ -L "$f" ]
		then	# linking a symbolic link while renaming the target 
			# would yield a dangling link, so copy it
			cp "$f" "common/$n"
		else	ln "$f" "common/$n"
		fi
	done
}

#############################################################################
# perform download and extraction/deployment

case "$1" in
""|-h|--help)
	echo "Usage: `basename $0` [-d | -e | -de]" >&2
	echo >&2
	echo "This script retrieves flag emojis from various sources." >&2
	echo >&2
	echo "Options:" >&2
	echo "	-d	Download flags emojis repositories" >&2
	echo "	-n	Download only Noto flags" >&2
	echo "	-e	Extract emoji files with proper filenames into common/" >&2
	echo "	-de	-d and -e" >&2
	echo "	-ne	-n and -e" >&2
	echo >&2
	if [ `uname` = "Linux" ] && type wslpath 2> /dev/null 1>&2
	then	echo "Note: for direct deployment from WSL, first go into the common config directory:" >&2
		echo '  cd `wslpath "$APPDATA/mintty/emojis"` || cd `wslpath "$APPDATA/wsltty/emojis"`' >&2
	else	echo "Note: for direct deployment, first go into subdirectory 'emojis' of one of the" >&2
		echo "mintty config directories:" >&2
		echo '  ~/.mintty' >&2
		echo '  ~/.config/mintty' >&2
		echo '  $APPDATA/mintty' >&2
		echo '  /usr/share/mintty' >&2
	fi
	exit;;
-n|--download-noto)
	download_noto
	;;
-ne|--noto)
	download_noto
	extract
	;;
-d|--download)
	download
	;;
-e|--extract)
	extract
	;;
-de|--all)
	download
	extract
	;;
esac

#############################################################################
# end