#!/bin/sh
# Purpose {{{
## Create a temp file (to monitor) if an upgrade is available for Alacritty
## project on Github.
## It's based on .deb package installation to check the current version.
## It can also compare the current available version in APT repositories
##   if "repo" is given as first argument.
## How-to use {{{
### 1. Needs releasetags script, in the same directory
### cf. https://git.ipr.univ-rennes1.fr/cellinfo/scripts/src/master/github/releasetags
# wget https://git.ipr.univ-rennes1.fr/cellinfo/scripts/raw/master/github/releasetags
### 2. Create a cron job, eg :
#00 20 * * * root /opt/repos/ipr.scripts/github/check.alacritty.update
### 2-1 Create a cron job to compare the version available in a Debian repository :
#00 20 * * * root /opt/repos/ipr.scripts/github/check.alacritty.update repo
### 3. Monitor the temp file : /tmp/.github.alacritty.upgrade
# Or enable MAILTO in cronjob and edit the script to print a message.
# Or send a mail.
# …
## }}}
# }}}

# Expect maximum 1 argument {{{
if [ $# -gt 1 ]
then
	cat << HELP

check.alacritty.update    --
Compare current version of an installed Alacritty and the last available.

EXAMPLE :
    - Compare the current version installed from .deb file
        check.alacritty.update

    - Compare the current version from apt's repository
        check.alacritty.update repo

HELP

	exit 1
fi
# }}}

# Vars {{{
DEBUG=1

script_wd=$(dirname "${0}")

alacritty_repo_url="https://github.com/barnumbirr/alacritty-debian"

if [ $# -eq 1 ] && [ "${1}" = "repo" ]  ## If repository's version should be compared
then
	alacritty_current_version=$(apt-cache policy alacritty | awk '/Candidate:/ {print $2}' | sed 's/.:\(.*\)-.*/\1/')
else
	alacritty_current_version=$(dpkg -l alacritty | awk '/^ii.*alacritty/ {print $3}' | sed 's/.:\(.*\)-.*/\1/')
fi

alacritty_new_version=$("${script_wd}"/releasetags "${alacritty_repo_url}" | head -n1 | sed 's/v//g')

alacritty_new_version_file="/tmp/.github.alacritty.upgrade"
alacritty_new_pkg_url="${alacritty_repo_url}/releases/download/v${alacritty_new_version}/alacritty_${alacritty_new_version}_amd64_unstable.deb"
alacritty_tmp_pkg_path="/tmp/.alacritty_${alacritty_new_version}_amd64_unstable.deb"
alacritty_new_pkg_path="/tmp/alacritty_${alacritty_new_version}_amd64_unstable.deb"
# }}}

# Check if the current version is the last one {{{
if [ "${alacritty_current_version}" != "${alacritty_new_version}" ]; then
	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Test version — Current version (${alacritty_current_version}) and new one (${alacritty_new_version}) seems to be different."

	## If it doesn't already exists, download this new package
	if [ ! -f "${alacritty_new_pkg_path}" ]; then
		[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Download .deb file from Alacritty repository on Github to: ${alacritty_new_pkg_path} ."
		wget --quiet "${alacritty_new_pkg_url}" --output-document="${alacritty_new_pkg_path}"
	fi

else
	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Test version — The current version is up-to-date."
	## Ensure to remove any temp file and useless .deb file
	rm --force -- "${alacritty_new_version_file}" "${alacritty_new_pkg_path}" "${alacritty_tmp_pkg_path}"
	## Exit
	exit 0
fi
# }}}

# Verify downloaded package {{{

## If the downloaded package has a size greater than zero {{{
if [ -s "${alacritty_new_pkg_path}" ]; then
	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Empty file ? — \
Downloaded package looks good."
	### Create a temp file to monitor
	touch -- "${alacritty_new_version_file}"
	printf '\e[1;35m%-6s\e[m\n' "An upgrade is available for Alacritty terminal (current : ${alacritty_current_version}) : ${alacritty_new_version}." >> "${alacritty_new_version_file}"

	### Exit
	exit 0
else
	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Empty file ? — \
Empty file, don't need to go further."
	### Ensure to remove the file to monitor
	rm --force -- "${alacritty_new_version_file}"

	### Keep a record of the downloaded package because as a new release might come soon
	mv --force -- "${alacritty_new_pkg_path}" "${alacritty_tmp_pkg_path}"

	### Exit
	exit 0
fi
## }}}

# }}}

exit 255