#!/bin/bash
#
# Script Name: AppBackup-restic.sh
# Description:
#   Creates a backup of a web application and optionally its MySQL database.
#   The script archives the application home directory and uploads the backup
#   either to a remote SFTP server or to a Backblaze B2 repository using Restic,
#   depending on the host on which it is executed.
#
# Usage:
#   AppBackup-restic.sh --appname <name> --appuser <user> [--apppassword <password>]
#
# Author: Charlie Silverman
# Version: 1.7
#
# Revision History:
#   1.0 - Initial version.
#   1.1 - Added logging to file.
#   1.2 - Added strict error handling, input validation, and FQDN support.
#   1.3 - Added trap-based error logging and improved operational visibility.
#   1.4 - Added application-specific log files, interrupt handling,
#         and enhanced logging.
#   1.5 - Added command-line help.
#   1.6 - Replaced positional parameters with named command-line options
#         and added support for short/long option formats.
#   1.7 - Added email delivery of current execution log on success,
#         failure, or interruption.
#

set -o errexit
set -o nounset
set -o pipefail

#------------------------------------------------------------------------------
# Help Function
#------------------------------------------------------------------------------

show_help() {

cat << EOF

AppBackup-restic.sh v1.7

DESCRIPTION
    Creates a backup of a web application's files and optionally its
    MySQL database. The backup is uploaded either via SFTP or Restic,
    depending on the host.

USAGE

    AppBackup-restic.sh --appname <name> --appuser <user>
                        [--apppassword <password>]

OPTIONS

    -a, --appname <name>
        Name of the application and MySQL database.
        Required.

    -u, --appuser <user>
        Linux account that owns the application files.
        Required.

    -p, --apppassword <password>
        MySQL password and SFTP password (if applicable).
        Optional.

    -h, --help
        Display this help and exit.

EXAMPLES

    AppBackup-restic.sh \
        --appname KISNetManager \
        --appuser kisuser \
        --apppassword MySecurePassword

    AppBackup-restic.sh \
        -a CustomerPortal \
        -u portaluser

LOG FILES

    Historical Log:
        /tmp/AppBackup-<ApplicationName>.log

    Current Run Log:
        /tmp/AppBackup-<ApplicationName>-YYYYMMDD_HHMMSS.log

EMAIL NOTIFICATIONS

    Current execution logs are emailed to:

        ackitsme3@gmail.com

    Success, failure, and interruption events each generate
    a separate email.

AUTHOR

    Charlie Silverman

VERSION

    1.7

EOF

}

#------------------------------------------------------------------------------
# Process Command Line Arguments
#------------------------------------------------------------------------------

AppName=""
AppUser=""
AppPassword=""

while [[ $# -gt 0 ]]; do

    case "$1" in

        -a|--appname)
            AppName="$2"
            shift 2
            ;;

        --appname=*)
            AppName="${1#*=}"
            shift
            ;;

        -u|--appuser)
            AppUser="$2"
            shift 2
            ;;

        --appuser=*)
            AppUser="${1#*=}"
            shift
            ;;

        -p|--apppassword)
            AppPassword="$2"
            shift 2
            ;;

        --apppassword=*)
            AppPassword="${1#*=}"
            shift
            ;;

        -h|--help)
            show_help
            exit 0
            ;;

        *)
            echo "ERROR: Unknown option '$1'"
            echo
            show_help
            exit 1
            ;;

    esac

done

#------------------------------------------------------------------------------
# Validate Required Parameters
#------------------------------------------------------------------------------

if [[ -z "$AppName" || -z "$AppUser" ]]; then
    echo "ERROR: --appname and --appuser are required."
    echo
    show_help
    exit 1
fi

#------------------------------------------------------------------------------
# Runtime Variables
#------------------------------------------------------------------------------

DATE=$(date "+%Y%m%d_%H%M%S")
HOSTNAME_FQDN="$(hostname -f)"

SAFE_APPNAME=$(echo "$AppName" | tr -cs '[:alnum:]_-' '_')

LOGFILE="/tmp/AppBackup-${SAFE_APPNAME}.log"
RUNLOG="/tmp/AppBackup-${SAFE_APPNAME}-${DATE}.log"

touch "$RUNLOG"

#------------------------------------------------------------------------------
# Logging Function
#------------------------------------------------------------------------------

log() {

    local msg

    msg="$(date '+%Y-%m-%d %H:%M:%S') [$$] $1"

    echo "$msg" | tee -a "$RUNLOG"
}

#------------------------------------------------------------------------------
# Email Function
#------------------------------------------------------------------------------

send_email_log() {

    local subject="$1"

    if command -v mailx >/dev/null 2>&1; then

        mailx -s "$subject" ackitsme3@gmail.com < "$RUNLOG"

    elif command -v mail >/dev/null 2>&1; then

        mail -s "$subject" ackitsme3@gmail.com < "$RUNLOG"

    else

        log "WARNING: mailx/mail command not found. Email not sent."

    fi
}

#------------------------------------------------------------------------------
# Error Handling
#------------------------------------------------------------------------------

error_handler() {

    local exit_code=$?
    local line_number=$1

    log "ERROR: Backup failed on line ${line_number} with exit code ${exit_code}"

    send_email_log \
        "FAILED: AppBackup ${AppName} (${HOSTNAME_FQDN})"

    exit "${exit_code}"
}

interrupt_handler() {

    log "ERROR: Backup interrupted by signal"

    send_email_log \
        "INTERRUPTED: AppBackup ${AppName} (${HOSTNAME_FQDN})"

    exit 1
}

trap 'error_handler $LINENO' ERR
trap interrupt_handler SIGINT SIGTERM

#------------------------------------------------------------------------------
# Startup Logging
#------------------------------------------------------------------------------

log "================================================================="
log "Starting backup job"
log "Application: $AppName"
log "Application User: $AppUser"
log "Host: $HOSTNAME_FQDN"
log "Historical Log: $LOGFILE"
log "Run Log: $RUNLOG"
log "================================================================="

#------------------------------------------------------------------------------
# Restic Repository Configuration
#------------------------------------------------------------------------------

export RESTIC_REPOSITORY="s3:https://s3.us-west-004.backblazeb2.com/ackitsbucket/docker"
export RESTIC_PASSWORD_FILE="/root/.restic-password"

#------------------------------------------------------------------------------
# Host Specific Configuration
#------------------------------------------------------------------------------

HostPrefix=""

if [[ "$HOSTNAME_FQDN" == "ackitserver.ackcentuate.com" ]]; then

    if [[ "$AppName" == "KISNetManager" ]]; then
        HostPrefix="dev-"
    fi

fi

ArchiveFile="${AppName}-${DATE}.tar.bz2"

#------------------------------------------------------------------------------
# Prepare Backup Workspace
#------------------------------------------------------------------------------

log "Changing to backup directory"

cd /home/Backups

#------------------------------------------------------------------------------
# Database Backup
#------------------------------------------------------------------------------

if [[ -n "$AppPassword" ]]; then

    log "Creating MySQL database backup"

    mkdir -p "/home/${AppUser}/SQLBackup"

    mysqldump \
        -u "$AppUser" \
        --password="$AppPassword" \
        "$AppName" \
        > "/home/${AppUser}/SQLBackup/${AppName}.sqldump"

    log "MySQL dump completed successfully"

else

    log "Database password not supplied. Skipping MySQL backup."

fi

#------------------------------------------------------------------------------
# Remove Previous Backup Archives
#------------------------------------------------------------------------------

log "Removing previous backup archives"

rm -f /home/Backups/"${AppName}"*.tar.bz* 2>/dev/null || true
rm -f /home/Backups/"${HostPrefix}${AppName}"*.tar.bz* 2>/dev/null || true

#------------------------------------------------------------------------------
# Create Archive
#------------------------------------------------------------------------------

log "Creating archive ${HostPrefix}${ArchiveFile}"

tar cjf \
    "/home/Backups/${HostPrefix}${ArchiveFile}" \
    "/home/${AppUser}/"

log "Archive created successfully"

#------------------------------------------------------------------------------
# Upload Backup
#------------------------------------------------------------------------------

if [[ "$HOSTNAME_FQDN" != "ackitserver.ackcentuate.com" ]]; then

    if [[ -z "$AppPassword" ]]; then
        log "ERROR: SFTP upload requires --apppassword"
        exit 1
    fi

    log "Uploading archive via SFTP"

    lftp "sftp://${AppUser}:${AppPassword}@webbuilder.ackcentuate.com" -e \
        "cd /home/Backups; put /home/Backups/${HostPrefix}${ArchiveFile}; bye"

    log "SFTP upload completed successfully"

else

    log "Loading Restic environment"

    source /root/.restic-env

    log "Starting Restic backup"

    restic backup "/home/${AppUser}/" \
        --tag apache \
        --tag website \
        --tag "$AppName" \
        --tag "$HOSTNAME_FQDN" \
        >> "$RUNLOG" 2>&1

    log "Restic backup completed successfully"

fi

#------------------------------------------------------------------------------
# Cleanup
#------------------------------------------------------------------------------

if [[ -n "$AppPassword" ]]; then

    log "Removing temporary SQL backup files"

    rm -rf "/home/${AppUser}/SQLBackup"

fi

#------------------------------------------------------------------------------
# Completion
#------------------------------------------------------------------------------

log "Backup completed successfully"
log "Application: $AppName"
log "Archive: ${HostPrefix}${ArchiveFile}"
log "Host: $HOSTNAME_FQDN"
log "================================================================="

#------------------------------------------------------------------------------
# Append Current Run Log To Historical Log
#------------------------------------------------------------------------------

cat "$RUNLOG" >> "$LOGFILE"

#------------------------------------------------------------------------------
# Email Current Run Log
#------------------------------------------------------------------------------

send_email_log \
    "SUCCESS: AppBackup ${AppName} (${HOSTNAME_FQDN})"

#------------------------------------------------------------------------------
# Cleanup Run Log
#------------------------------------------------------------------------------

rm -f "$RUNLOG"

exit 0