deploy.sh

#!/usr/bin/env bash
set -o errexit #abort if any command fails

deploy_directory=dist
deploy_branch=gh-pages

#if no user identity is already set in the current git environment, use this:
default_username=deploy.sh
default_email=XX1011+deploy.sh@gmail.com

#repository to deploy to. must be readable and writable.
#using https url instead of ssh to avoid issues with host authenticity checks
repo=https://$GITHUB_TOKEN@github.com/X1011/verge-mobile-bingo.git

if [[ $1 = "-v" || $1 = "--verbose" ]]; then
	verbose=true
fi

#echo expanded commands as they are executed (for debugging)
function enable_expanded_output {
	if [ $verbose ]; then
		set -o xtrace
		set +o verbose
	fi
}

#this is used to avoid outputting the repo URL, which may contain a secret token
function disable_expanded_output {
	if [ $verbose ]; then
		set +o xtrace
		set -o verbose
	fi
}

enable_expanded_output

commit_title=`git log -n 1 --format="%s" HEAD`
commit_hash=`git log -n 1 --format="%H" HEAD`

function set_user_id {
	if [[ -z `git config user.name` ]]; then
		git config user.name "$default_username"
	fi
	if [[ -z `git config user.email` ]]; then
		git config user.email "$default_email"
	fi
}

previous_branch=`git rev-parse --abbrev-ref HEAD`

if ! git diff --exit-code --quiet --cached; then
	echo Aborting due to uncommitted changes in the index
	exit 1
fi

disable_expanded_output
git fetch --force $repo $deploy_branch:$deploy_branch
enable_expanded_output

#make deploy_branch the current branch
git symbolic-ref HEAD refs/heads/$deploy_branch

#put the previously committed contents of deploy_branch branch into the index 
git --work-tree "$deploy_directory" reset --mixed --quiet

git --work-tree "$deploy_directory" add --all

set +o errexit
diff=$(git --work-tree "$deploy_directory" diff --exit-code --quiet HEAD)$?
set -o errexit
case $diff in
	0) echo No changes to files in $deploy_directory. Skipping commit.;;
	1)
		set_user_id
		git --work-tree "$deploy_directory" commit -m \
			"publish: $commit_title"$'\n\n'"generated from commit $commit_hash"
		
		disable_expanded_output
		#--quiet is important here to avoid outputting the repo URL, which may contain a secret token
		git push --quiet $repo $deploy_branch
		enable_expanded_output
		;;
	*)
		echo git diff exited with code $diff. Aborting.
		exit $diff
		;;
esac

if [[ $previous_branch = "HEAD" ]]; then
	#we weren't on any branch before, so just set HEAD back to the commit it was on
	git update-ref --no-deref HEAD $commit_hash $deploy_branch
else
	git symbolic-ref HEAD refs/heads/$previous_branch
fi

git reset --mixed