#!/bin/bash
#########################################################################
#                                                                       #
#        updater - Automatically update Microsoft Edge on Solus         #
#                                                                       #
#                             Dependencies:                             #
#                                 wget                                  #
#                                gunzip                                 #
#                                  tar                                  #
#                       sort (coreutils >= 8.32)                        #
#                                                                       #
#                                                                       #
#         Disclaimer: This version only works for MS Edge Beta.         #
#          A later release may allow for update of Dev builds           #
#                         and potentially both.                         #
#                                                                       #
#                       Author: Ethan Smith-Coss                        #
#                            Version: 0.1.2                             #
#                    Created: 2021-05-20T16:47+0100                     #
#                 Last Modified: 2021-05-23T21:18+0100                  #
#                                                                       #
#                 ####################################                  #
#                                                                       #
#        updater - Automatically update Microsoft Edge on Solus         #
#                   Copyright ©️ 2021 Ethan Smith-Coss                   #
#                                                                       #
# This program is free software: you can redistribute it and/or modify  #
# it under the terms of the GNU General Public License as published by  #
#   the Free Software Foundation, either version 3 of the License, or   #
#                  (at your option) any later version.                  #
#                                                                       #
#    This program is distributed in the hope that it will be useful,    #
#    but WITHOUT ANY WARRANTY; without even the implied warranty of     #
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the     #
#             GNU General Public License for more details.              #
#                                                                       #
#   You should have received a copy of the GNU General Public License   #
# along with this program.  If not, see <http://www.gnu.org/licenses/>. #
#                                                                       #
#########################################################################
## program name
prog_name="Microsoft Edge Updater"
## version
version="0.1.2"
## usage statement
usage="Usage: $(basename $0) [OPTION]
$prog_name ($version) - An updater program which can install the latest available version of Microsoft Edge to non-Debian-based Linux distros.

DISCLAIMER: Currently this program can only update the Beta release of Microsoft Edge for amd64 architectures.

Options:
  -y, --yes-all    Assume yes to all yes/no decisions.
  -v, --version    Print out the version of the script and exit.
      --help       Print this help message and exit
"

runtime_dir=$(realpath "${BASH_SOURCE[0]}" | xargs -r dirname)
log_file="$runtime_dir/.log.1"
logs_dir="$runtime_dir/logs"
tmp_path="/tmp/microsoft-edge-autoupdater"
garbage="$tmp_path/garbage.tmp"
SECONDS=0

[[ ! -d "$logs_dir" ]] && mkdir "$logs_dir"
[[ ! -d "$tmp_path" ]] && mkdir "$tmp_path"


function clean_up {
	log "DEBUG" "EXIT signal was raised, cleaning up system after session before exiting..." "$log_file"
	printf "Cleaning up system after session..."
	cp "$log_file" "$logs_dir/updater.log" && rm "$log_file"
	[[ -d "$tmp_path/opt" ]] && rm -r "$tmp_path/opt"
	[[ -d "$tmp_path/usr" ]] && rm -r "$tmp_path/usr"

	log "CLEANER" "Finished cleaning up system after session. Nice and clean :D Goodbye." "$runtime_dir/logs/updater.log"
	echo "done. Goodbye."
	
	elapsed_time=$SECONDS
	script_time="$(($elapsed_time / 60))m $(($elapsed_time % 60))s"
	log "END" "Total time for script execution was: $script_time" "$runtime_dir/logs/updater.log"

	echo >> "$runtime_dir/logs/updater.log"
	cat "$logs_dir/updater.log" >> "$logs_dir/updater.history"
}
## iterate over all user inputs
while test $# -gt 0 ; do
	case $1 in
		-y | --yes-all)
			yes_flag=0 ; shift
			;;
		--help)
			echo "$usage"
			exit 0
			;;
		-v | --version)
			echo "$prog_name ($version)"
			exit 0
			;;
		*)
			shift
			;;
	esac
done

source "$runtime_dir/utils/common"
log "PREINIT" "----[New instance of script has been started: $(date -Iseconds)]----" "$log_file"

## setup the yes flag to automatically accept all yes/no inputs
yes_flag="${yes_flag:-1}"
log "DEBUG" "The yes flag has been set to: $yes_flag." "$log_file"

# set trap to trigger clean up function on any exit
trap clean_up EXIT

## check if Microsoft Edge (Beta) is already installed
exit_code=$(command -v microsoft-edge-beta &>/dev/null)
[[ ! $exit_code -eq 0 ]] && { echo "Microsoft Edge (Beta) is not installed. Exiting updater..." ;
log "DEBUG" "Microsoft Edge (Beta) not recognised as an installed program. Exiting...(1)" ; exit 1 ; }
log "DEBUG" "Microsoft Edge (Beta) is installed to system. Proceeding with update..." "$log_file"

## ensure source.list exists
source_list="$runtime_dir/source.list"
log "DEBUG" "Checking for a source.list in current runtime directory..." "$log_file"
printf "Checking for source.list..."
[[ ! -f "$source_list" ]] && { echo -e "\nUpdater encountered an issue: source.list not found. Exiting..." ; 
log "ERROR" "Cannot find source.list in runtime directory ($source_list). Exiting...(2)" "$log_file" ; exit 2 ; }

log "DEBUG" "Found a souce.list in $runtime_dir." "$log_file"
echo "found."

## ensure host is reachable
host=$(grep "\[host\]" "$source_list" | cut -d' ' -f 2)
log "DEBUG" "Checking if host is available according to defined value of [host]: $host..." "$log_file"
echo "Checking to see if the host is known and reachable..."
if ! wget --spider "$host" >/dev/null 2>&1 ; then
	echo "Cannot reach end-point for distribution information. Check your Internet connection and try again. Exiting..."
	log "DEBUG" "Upstream end-point is cannot be contacted. Potential Internet connection issue or end-point address ($dist_upstream). Exiting...(3)" "$log_file"
	exit 3
fi
log "DEBUG" "Host is known and reachable. Continuing update to fetch data..." "$log_file"
echo "Host known and reachable: (host) $host"

## identify the end-point URL for distribution information
dist_upstream=$(grep "\[dists.*\]" "$source_list" | cut -d' ' -f 2-4 --output-delimiter '/')
archi=$(grep -o "\[dists.*\]" "$source_list" | sed -E 's/\[dists=(.*)\]/\1/')
log "DEBUG" "Fetching Packages file from $dist_upstream for $archi architectures..." "$log_file"
## fetch the file - :@Ethan: there's no reason to inform the user of this operation unless it fails
exit_code=$(wget -a "$log_file" -O "$tmp_path/Packages.gz" "$dist_upstream/binary-$archi/Packages.gz")
[[ ! $exit_code -eq 0 ]] && { echo "There was an issue retrieving the package information for the update. Please check $logs_dir/updater.log, for more information. Exiting..." ;
	log "DEBUG" "Encountered an issue with wget. Exiting...(4)" "$log_file" ; exit 4 ; }
log "DEBUG" "Successfully downloaded release package information." "$log_file"

log "DEBUG" "Fetching Contents-$archi.gz from ${dist_upstream::-4}" "$log_file"
exit_code=$(wget -a "$log_file" -O "$tmp_path/Contents-$archi.gz" "${dist_upstream::-4}/Contents-$archi.gz")
[[ ! $exit_code -eq 0 ]] && { echo "There was an issue retrieving the package contents for the update. Please check $log_file/updater.log, so more information. Exiting..." ;
	log "ERROR" "Encountered an issue with wget. Exiting...(4)" "$log_file" ; exit 4 ; }
log "DEBUG" "Successfully downloaded release contents information." "$log_file"

### :@TODO: continue with TODO list. Finish off above code section to ensure wget is successful and logging appropriately.
log "DEBUG" "Uncompressing downloaded gz file using gunzip, $tmp_path/Packages.gz..." "$log_file"
## force gunzip to overwrite decompressed file if it already exists
gunzip -f "$tmp_path/Packages.gz" "$tmp_path/Contents-$archi.gz" >/dev/null 2>&1
log "DEBUG" "Successfully uncompressed content." "$log_file"

## get the most recent package entry from Packages list for Beta version of browser
log "DEBUG" "Identifying the most recent package information from Packages catelogue..." "$log_file"
## find the earliest entry for Edge Beta release
start_point=$(grep -n 'Package:.*-beta' "$tmp_path/Packages" | tr '\n' ' ' | cut -d: -f1)
## make a list of all lines which are blank - used to identify end of package information entry
end_points=( $(grep -n '^\s*$' "$tmp_path/Packages" | sed 's/://g') )
## loop over all potential end points
for (( i=0 ; i<"${#end_points[@]}"; i++)) ; do
	## if the end point is greater than start point, set $end_point to the index of i
	### :@NOTE: this will more often then not be the first value in the array. However,
	### if a dev release comes out before the next beta version, the package entry may be
	### much later in the file. We break once the correct end point is found.
	[[ "${end_points[$i]}" -gt $start_point ]] && end_point="${end_points[$i]}" && break
done
## adjust the start and end point values
((start_point--)) ; ((end_point++))
## this ensures end_point is set. :@Ethan: I could just test if the variable exists but I like the clarity of this for now
end_point="${end_point:--1}"
## if for some reason $end_point is set to -1, we have an issue with the Packages file and should exit
[[ $end_point -eq -1 ]] && { log "ERROR" "EOF reached and indexing out of bounds value has been set. Exiting...(5)" "$log_file" ; exit 255 ; }
## extrapolate the package information and save to Release
package_entry=$(awk -v start=$start_point -v end=$end_point 'NR>1*start&&NR<1*end' "$tmp_path/Packages" > "$tmp_path/Release")
log "DEBUG" "Extrapolated most recent package information entry from $tmp_path/Release. Package information selected is as below:" "$log_file"
## pretty print each line when appending to make it easier to read in log file
sed 's/^/  (Release Info)   /' "$tmp_path/Release" | sed -E 's/(^\s*\(Release Info\)\s*$)/\1(END)/' >> "$log_file"

### :@Ethan: at this point we can start ensuring that a newer release is available, inform the user of the new size,
### check dependences, and just ensure the user wants to go ahead with the update.

## get the current version number and the version in Release
current_version=$(microsoft-edge-beta --version | cut -d' ' -f3)
release_version=$(grep 'Version' "$tmp_path/Release" | sed -E 's/Version:\s*(.*)-.*/\1/')
log "DEBUG" "Checking if there is an update available (release: $release_version) or if most recent version is already installed to the system..." "$log_file"
## compare the versions - using sort -V.
if [[ "$release_version" == "$current_version" ]]; then
	upgradeable=1
else
	[[ "$current_version" != "$(echo -e "$current_version\n$release_version" | sort -V | head -n2)" ]] && upgradeable=0
fi
## this should never be substituted to 1 - but it's a cover if the release version happens to be behind the current version
##"${upgradeable:=1}"
upgradeable=${upgradeable:-1}
## check if we can upgrade, can exit 1 for passive exit - exit not notifying a failure for another reason
if [[ $upgradeable -eq 1 ]] ; then 
	elapsed_time=$SECONDS
	script_time="$(($elapsed_time / 60))m $(($elapsed_time % 60))s"
	echo "Most recent version of Microsoft Edge (Beta) [v$current_version] is already installed on this system, no need to update. Finished in $script_time"
	log "DEBUG" "Most recent version of Microsoft Edge (Beta) is already installed to the system (v$current_version). Completed in $script_time. Exiting...(1)" "$log_file"
	
	exit 1
fi
log "DEBUG" "There is a more recent release of Microsoft Edge (Beta) available for download (v$release_version). Continuing with update."
echo "Identified a new release of Microsoft Edge (Beta) [Current: v$current_version. New: v$release_version]. Starting the download and installation process..."

## check if msedge process is already running
is_running=$(ps -aux | grep -oc 'msedge')
if [[ $is_running -gt 1 ]] ; then
	log "DEBUG" "Identified running processes for msedge. Determining how script should handle process..." "$log_file"
	if [[ ! $yes_flag -eq 0 ]] ; then
		echo -n "Microsoft Edge (Beta) is already open. To continue update, the browser must be closed. Are you sure you wish to proceed? [(Y)es/No]: " && read -n 1 choice ; echo
		[[ $(echo $choice | awk '{print tolower($0)}') == "n" ]] && { log "DEBUG" "User opted against allowing the script to close Microsoft Edge (Beta) by default. Exiting...(1)" "$log_file" ; exit 1 ; }
	fi
	log "DEBUG" "Confirmation has been given to proceed with killing Microsoft Edge (Beta) processes. Killing msedge..." "$log_file"
	exit_code=$(killall msedge)
	[[ ! $exit_code -eq 0 ]] && { log "ERROR" "Process is refusing to exit. Sending SIGKILL signal." "$log_file" ;
		pkill -9 msedge ; }
fi
log "DEBUG" "Microsoft Edge (Beta) has been closed, either by yes flag enabled or by user decision. Process may not have been running thus never killed." "$log_file"


# Download the newest version of Microsoft Edge (Beta)
## get the end-point for .deb file location and filename
pool=$(grep '\[pool\]' "$source_list" | cut -d' ' -f2)
filename=$(grep 'Filename:.*' "$tmp_path/Release" | cut -d' ' -f2)
url="$pool$filename" ## set URL to be concatenation of pool + filename
## check if the file end-point is actually reachable before trying to download
log "DEBUG" "Checking the following release version file end-point is accessible ($url)..." "$log_file"

### :@Ethan: This is trying to download the file for a response so effectively we will be doing the same work twice
### so is inefficient for testing if the end-point is reachable. ping and telnet are not suitable for this operation.
### An assumption will have to be made for now.

### :@Ethan: The above message has been addressed and wget commands for checking end-points has been changed from
### `wget -qO- [URL] >/dev/null 2>&1` to: `wget --spider [URL] >/dev/null 2>&1`. Check manpage for more about the
### spider argument.

if ! wget --spider "$url" >/dev/null 2>&1 ; then
	echo "Cannot reach end-point for latest release. Check your Internet connection and try again."
	log "DEBUG" "Pool end-point is cannot be contacted. Potential Internet connection issue or end-point address ($url). Exiting...(5)" "$log_file"
	exit 5
fi
log "DEBUG" "Pool is known and reachable. Beginning download..." "$log_file"
echo "Host known and reachable: (download) $url"

## set filename to not be pool address but the name of file
filename=$(echo "$url" | rev | cut -d'/' -f1 | rev)
filesize=$(grep '^Size:.*' "$tmp_path/Release" | cut -d' ' -f2)
log "DEBUG" "Checking if user wishes to proceed with the update installation..." "$log_file"
## inform the user of the new download size before downloading
if [[ $yes_flag -eq 1 ]] ; then
	echo -n "The following package will be installed, $filename [$filesize]. Are you sure you wish to continue? [(Y)es/No]: " && read -n 1 choice
	[[ "$(echo $choice | awk '{print tolower($0)}')" == "n" ]] && { echo -e "\nThe following update to Microsoft Edge (Beta) v$release_version will not be installed. Exiting updater..." ;
	log "DEBUG" "User opted out for updating from $current_version to $release_version. Exiting...(1)" "$log_file" ; exit 1 ; }
	echo
fi
log "DEBUG" "Confirmation has been given to proceed with the following update of Microsoft Edge (Beta) [v$release_version]." "$log_file"

# download the debian file
log "DEBUG" "Checking if the file is already downloaded to the system..." "$log_file"
if [[ ! -f "$tmp_path/$filename" ]] ; then
	log "DEBUG" "Downloading the latest release version [v$release_version], file: $filename (URL: $url)" "$log_file"
	echo "Downloading the following release file: $filename. This may take a moment..."
	wget_timed=$(\time --format "%x:%e" wget -a "$tmp_path/wget_dump.log" -O "$tmp_path/$filename" "$url" 2>&1)
	exit_code=$(echo $wget_timed | cut -d: -f1)
	[[ ! $exit_code -eq 0 ]] && { echo "There was an issue downloading the Debian version of Microsoft Edge (Beta)." \
		"Please check $logs_dir/updater.log, for more information. Exiting update..." ;
		log "DEBUG" "Encountered an issue with wget. Exiting...(6)" "$log_file" ; exit 6 ; }
	awk -v end=$(grep -n '^\s*$' "$tmp_path/wget_dump.log" | tr '\n' ' ' | cut -d: -f1) 'NR>1*0&&NR<1*end+1' "$tmp_path/wget_dump.log" >> "$log_file"
	log "DEBUG" "Download completed successfully in $(echo $wget_timed | cut -d' ' -f2)s, wget log below." "$log_file"
	printf "Download complete in $(echo $wget_timed | cut -d' ' -f2)s. Validating checksums..."
else
	log "DEBUG" "File already downloaded to system. Skipped download and verifying checksum..." "$log_file"
	printf "Latest Debian release file is downloaded to the system, skipping download. Validating checksums..."
fi

## verify the downloaded file 
if [[ "$(sha256sum "$tmp_path/$filename" | cut -d' ' -f1)" != "$(grep 'SHA256:.*' "$tmp_path/Release" | cut -d' ' -f2)" ]] ; then
	## automatically remove the file - :@Ethan: it's either corrupt or hazardous to the health of the system
	rm "$tmp_path/$filename"
	log "DEBUG" "Checksum (SHA256) failed and integrity of file lost. File has been removed as either corrupt or hazardous/dangerous. Exiting...(7)" "$log_file"
	echo -e "failed.\nThe checksum (SHA256) failed for some reason and removed either because it was corrupt or dangerous. Exiting updater...\n"
	exit 7
fi
echo "complete."


# unarchive the .deb file and extract data.tar.gz
log "DEBUG" "Unarchiving the downloaded DEB file ($tmp_path/$filename)..." "$log_file"
printf "Unzipping download..."
## use ar to unarchive .deb file
exit_code=$(ar vx "$tmp_path/$filename" --output "$tmp_path" >/dev/null 2>&1)
[[ ! $exit_code -eq 0 ]] && { echo -e "incomplete.\nThere was an issue unarchiving $filename. Exiting updater...\n" ;
	log "ERROR" "There was an issue when unarchiving $filename. Exiting...(8)" "$log_file" ; exit 8 ; }
log "DEBUG" "Successfully unarchived $filename, decompressing the data.tar.gz file..." "$log_file"
## extract data from data.tar.gz
exit_code=$(tar --overwrite -xvf "$tmp_path/data.tar.xz" --directory "$tmp_path" >>"$log_file" 2>&1)
[[ ! $exit_code -eq 0 ]] && { echo -e "incomplete.\nThere was an extracting data.tar.gz. Exiting updater...\n" ;
	log "ERROR" "There was an issue when decompressing data.tar.gz using tar -xvf. Exiting...(8)" "$tmp_path" ; exit 8 ; }
log "DEBUG" "Successfully extracted files from data.tar.gz." "$log_file"
echo "completed."
## etc/ directory only contains a cron daily directory, remove it
rm -r "$tmp_path/etc/"

# compress archive the currently installed version of Edge (Beta) for restoration on failure
## :@TODO: compress everything on the system for a backup. Remove it if installation of new version was successful
log "DEBUG" "Creating an archive gzip tarball of system /opt/ and /usr/ directories..." "$log_file"
printf "Installing new version to system. This may take a few minutes..."
exit_code=$(archive_system "microsoft/msedge-beta")
if [[ ! $exit_code -eq 0 ]] ; then
	### :@Ethan: there was an issue with creating an archive, should probably inform the user to make a decision (unless -y is set)
	echo -e "failed.\nThere was an issue creating a backup of the system. Exiting..."
	log "ERROR" "There was an issue creating a gzip tarball of the system. Exiting...($exit_code)" "$log_file"
	exit $exit_code
fi
log "DEBUG" "Successfully created an archive gzip tarball of the system. Safe to continue with installation." "$log_file"

### :@NOTE: used to terminate the program at a certain point for incremental testing of functionality recently added up to the point of this exit.
#exit 0

# install the new version to system
log "DEBUG" "Copying files to there appropriate location..." "$log_file"
exit_code=$(cp -r "$tmp_path/opt" "/" >>"$log_file" 2>&1)
[[ ! $exit_code -eq 0 ]] && { echo -e "failed.\nThere was an issue installing files to the system. Reverting to previous version..." ; 
	log "DEBUG" "There was an issue copying $tmp_path/opt/ file to system /opt/. Reverting system files and exiting...(9)" "$log_file" ; restore_files && exit 9 ; }
exit_code=$(cp -r "$tmp_path/usr" "/" >>"$log_file" 2>&1)
[[ ! $exit_code -eq 0 ]] && { echo -e "failed.\nThere was an issue installing files to the system. Reverting to previous version..." ; 
	log "DEBUG" "There was an issue copying $tmp_path/usr/ file to system /usr/. Reverting system files and exiting...(9)" "$log_file" ; restore_files && exit 9 ; }
log "DEBUG" "Successfully installed files to their appropriate location." "$log_file"
echo "installation complete."

## confirm the update was successful - try to restore system otherwise
## :@TODO: validate new version has successfully installed properly - exit 12
if [[ "$(microsoft-edge-beta --version | cut -d' ' -f3)" != "$release_version" ]] ; then
	log "ERROR" "There was an issue with the update and installation. Restoring to previous version..." "$log_file"
	printf "Update was unsuccessful. Restoring to previous version..."

	## attempt restoration of system
	return_code=$(restore_files "microsoft/msedge-beta")
	[[ $return_code -eq 12 ]] && { echo -e "failed.\nThere was an error trying to restore system files." \ 
		"Either there no back was made or another issue occurred. Consult $log_file for more information." ; exit $return_code ; }
	log "DEBUG" "System restoration was successful, safe to use; however, the update was still failed. Exiting...(11)" "$log_file"
	echo -e "completed. However, there was still an issue trying to update Microsoft Edge (Beta) to the latest version." \
		"Consult $log_file for more information. Exiting..."
	
	exit 11
fi

elapsed_time=$SECONDS
script_time="$(($elapsed_time / 60))m $(($elapsed_time % 60))s"
log "DEBUG" "Installation and update was successful (completed in: $script_time) and system can be cleaned up to remove any waste." "$log_file"
echo "Microsoft Edge (Beta) has been successfully updated to the latest version: v$release_version, in $script_time."