#!/bin/sh

##
## Post-Update Hook to update Jekyll Website
## Copyright (C) 2016 Assaf Gordon <assafgordon@gmail.com>
## License: GPLv2-or-later

## Example of a 'post-update' hook script
## to trigger a jekyll site rebuild after a push to a git repository.
## This script should be placed in the git repository's ./hooks/ directory
## as 'post-update' (and be made executable).
##
## After every 'push' to the repository, the script will rebuild
## the jekyll static web-pages (by default, in ${HOME}/jekyll/www/[PROJECT]).
## Point your webserver's root directory to this directory and it will
## serve the website.
##
## The BASEDIR directory must be writable by the user running the git push
## (e.g. gitolite3 user if using gitolite). It must be readable by the
## web-server user (e.g. www-data on Debian/ubuntu).
##

## see:
##  http://demonastery.org/2012/11/jekyll-gitolite-hook/
##  http://blog.zerosum.org/2010/11/01/pure-git-deploy-workflow.html

die()
{
    BASE=$(basename "$0")
    echo "$BASE: error: $@" >&2
    exit 1
}

# Get project name
PROJECT=$(basename "$PWD")
PROJECT=${PROJECT%.git}

BASEDIR=${HOME}/jekyll/

WORKDIR=${BASEDIR}/cache/${PROJECT}
SITEDIR=${BASEDIR}/www/${PROJECT}

##
## Directory when the checked out repository is
##
mkdir -p "$WORKDIR" "$SITEDIR" \
    || die "failed to create Jekyll directories"

##
## Update to the latest version
##
git --work-tree=${WORKDIR}/ reset --hard \
    || die "failed to checkout latest revision on '$WORKDIR'"

# Abort if no Jekyll config found
test -e "${WORKDIR}/_config.yml" \
    || die "no Jekyll _config.yml file found. aborting"

##
## Rebuild
##
echo "=== Running Jekyll ==="
jekyll build --source "$WORKDIR" \
             --destination "$SITEDIR" \
    || die "Jekyll failed to build website '$WORKDIR'"