appInstaller-v1.0

#!/bin/bash

################################################################
# BASIC SCRIPT CONFIGURATION
################################################################

# Declare app name as shown in finder and dont add .app to the end)
applicationName=""
# Declare the latest version hosted in CDN
latestVersion=""
# Declare the Mosyle CDN variable/CDN URL of the package file
cdn=""
# Declare the SHA-256 hash of the package file
sha256=""
# Declare path of app
appFilePath="/Applications/$applicationName.app"

# Array of files to be deleted/uninstalled. Use this application to find residual files: https://freemacsoft.net/appcleaner/
filesToDelete=(
    "/Applications/$applicationName"
)

##########################################################################################################################################
######################################################### ADVANCED OPTIONS BELOW #########################################################
##########################################################################################################################################

################################################################
# DIRECTORIES
################################################################

# Declare tmp folder
temporaryFolderPath="/tmp"
# Declare name of the downloaded installer
temporaryFileName="/${applicationName}-$(date +%s).pkg"
# Declare the directory for the parent log folder
logDirectory="/private/var/log/.apaIT"
# Declare the name of the log file
logFileName="${applicationName}_${latestVersion}_updater.log"
# Declare the path for the plist that contains the string that represents the version number
installedVersion=$(defaults read "$appFilePath/Contents/Info.plist" CFBundleShortVersionString 2>/dev/null || echo "null")


################################################################
# COMMANDS
################################################################

# Curl command used throught the script. https://ss64.com/osx/curl.html
callCurl="$( curl -s -S -L -k "$cdn" -o "${temporaryFolderPath}""${temporaryFileName}" ) 2>&1"
# Means by which SHA256 is determined. https://ss64.com/osx/shasum.html
shaCheck="$( shasum -a 256 "${temporaryFolderPath}""${temporaryFileName}" | awk '{print $1}' )"

################################################################
# FUNCTIONS
################################################################

# Function to iniciate the log
logStart() {
    local datestamp
    datestamp=$(date +"%Y-%m-%d %H:%M:%S")
    echo "Session started @ $datestamp" | tee -a "$logDirectory/$logFileName"
}

# Function to update the log
logMessage() {
    local timestamp
    timestamp=$(date +"%H:%M:%S")
    echo "[$timestamp] $1" | tee -a "$logDirectory/$logFileName"
}

# Function to handle end of log
logEnd() {
    echo "----------" >> "$logDirectory/$logFileName"
}

# Function to handle script errors
handleError() {
    local error_message=$1
    logMessage "ERROR: $error_message"
    logEnd
    exit 1
}

# Function to handle successful completion of the script
handleSuccess() {
    logMessage "Installation of $applicationName v$latestVersion complete."
    logEnd
    exit 0
}

# Function to delete files, given an array of paths
deleteFiles() {
    local timestamp
    timestamp=$(date +"%H:%M:%S")
    local filesToDelete=("$@")
    for file in "${filesToDelete[@]}"; do
        if [[ -e "$file" ]]; then
            rm -rf "$file"
            echo "[$timestamp] Deleted file: $file" >> "$logDirectory/$logFileName"
        fi
    done
}

################################################################
# SCRIPT START
################################################################

# Check if the log directory exists or create it
[[ -d "$logDirectory" ]] || mkdir -p "$logDirectory"

logStart

if [[ -e "$appFilePath" ]]; then
    
    if [[ "$installedVersion" = "$latestVersion" ]]; then
        logMessage "$applicationName ($installedVersion) is installed. This device is up to date."
        logEnd
        exit 0
    elif [[ "$installedVersion" = "null" ]]; then
        logMessage "Device is reporting OS version: $(sw_vers -productVersion)"
        logMessage "$applicationName appears to be installed but is malformed/corrupted. The \$installedVersion variable can not be found. Reinstallation is needed."
        logMessage "Beginning download..."

        if curl_output="$callCurl 2>&1"; then
            logMessage "Download complete. Checking SHA-256..."
            
            if [[ "$sha256" == "$shaCheck" ]]; then
                logMessage "SHA-256 is valid. Uninstalling old version ($installedVersion)."
                deleteFiles "${filesToDelete[@]}"
                logMessage "Uninstallation successful. Beginning install of old version ($latestVersion)."
                installer -pkg "${temporaryFolderPath}${temporaryFileName}" -target / | while read -r line; do logMessage "$line" ; done
                handleSuccess
            else
                logMessage "ERROR: SHA-256 does not match. Exiting..."
                logMessage "Expected SHA-256: $sha256"
                logMessage "Downloaded SHA-256: $($shaCheck | awk '{print $1}')"
                handleError "SHA-256 verification failed."
            fi
        else
            handleError "Curl command failed. > $curl_output"
        fi
    elif [[ "$installedVersion" < "$latestVersion" ]]; then
        logMessage "Device is reporting OS version: $(sw_vers -productVersion)"
        logMessage "$applicationName is installed but NOT up to date. Installed version: $installedVersion, CDN Version: $latestVersion."
        logMessage "Beginning download..."
        
        if curl_output="$callCurl 2>&1"; then
            logMessage "Download complete. Checking SHA-256..."
            
            if [[ "$sha256" == "$shaCheck" ]]; then
                logMessage "SHA-256 is valid. Uninstalling old version ($installedVersion)."
                deleteFiles "${filesToDelete[@]}"
                logMessage "Uninstallation successful. Beginning install of old version ($latestVersion)."
                installer -pkg "${temporaryFolderPath}${temporaryFileName}" -target / | while read -r line; do logMessage "$line" ; done
                handleSuccess
            else
                logMessage "Expected SHA-256: $sha256"
                logMessage "Downloaded SHA-256: $($shaCheck | awk '{print $1}')"
                handleError "SHA-256 verification failed."
            fi
        else
            handleError "Curl command failed. > $curl_output"
        fi
    elif [[ "$installedVersion" > "$latestVersion" ]]; then
        logMessage "Device is reporting OS version: $(sw_vers -productVersion)"
        logMessage "WEIRD!!! Installed version (v$installedVersion) is newer than CDN version (v$latestVersion)."
        handleSuccess
    else
        logMessage "Device is reporting OS version: $(sw_vers -productVersion)"
        handleError "Unable to determine installed version: ($installedVersion)"
    fi
else
    logMessage "$applicationName is not installed."
    logMessage "Device is reporting OS version: $(sw_vers -productVersion)"
    logMessage "Beginning download..."

    if curl_output="$callCurl 2>&1"; then
        logMessage "Download complete. Checking SHA-256..."
        
        if [[ "$sha256" == "$shaCheck" ]]; then
            logMessage "SHA-256 is valid. Beginning install."
            installer -pkg "${temporaryFolderPath}${temporaryFileName}" -target / | while read -r line; do logMessage "$line" ; done
            handleSuccess
        else
            logMessage "ERROR: SHA-256 does not match. Exiting..."
            logMessage "Expected SHA-256: $sha256"
            logMessage "Downloaded SHA-256: $($shaCheck | awk '{print $1}')"
            handleError "SHA-256 verification failed."
        fi
    else
        handleError "Curl command failed. > $curl_output"
    fi
fi