#!/usr/bin/env bash


    ## ## ## ## ## ## ## ## ## ## ## ## ## ##
   ##                                       ##
  ##            restic-backup.sh             ##
 ##                                           ##
 ##    Simple script to help setup and run    ##
  ##       periodic Restic backup jobs       ##
   ##                                       ##
    ## ## ## ## ## ## ## ## ## ## ## ## ## ##


##
## Information
##

NAME="restic-backup.sh"
VERSION="0.2.0"
AUTHOR="david@socialnerds.org"
LICENSE="MIT"
DESCRIPTION="A simple script to help setup and run periodic Restic backup jobs."
WEBSITE="https://git.socialnerds.org/david/scripts"
CHANGELOG=("[2023-10-26][v0.2.0] Complete rewrite"
           "[2022-01-01][v0.1.0] Initial version")

##
## Configuration
##

EXECUTABLE="$(basename $0)"
LIBRARIES="lib.sh"
DEPENDENCIES="basename dirname readlink tr head chmod curl restic"
REQUIRE_ROOT=0

# Files
PASSWORD="$HOME/.restic-password"
REPOSITORY="$HOME/.restic-repository"
HEALTHCHECKS="$HOME/.restic-healthchecks"

# Build the Restic command
RESTIC_BINARY="$(command -v restic)"
RESTIC_OPTIONS="-q"
RESTIC_COMMAND="$RESTIC_BINARY --password-file $PASSWORD --repository-file $REPOSITORY $RESTIC_OPTIONS"

# How many snapshots should be kept?
SNAPSHOTS=32


##
## Functions
##

# Print help information
function print_help() {
  printf "%s\n\n%s\n%b\n\n%s\n  %-15s %s\n  %-15s %s\n  %-15s %s\n  %-15s %s\n  %-15s %s\n" \
         "$DESCRIPTION" "Usage:" "$LIB_BOLD$EXECUTABLE <options> <path or Restic keyword>$LIB_CLEAR" "Options:" \
         "-c, --checks" "Enable Healthchecks" \
         "-h, --help" "Print help screen and exit" \
         "-i, --info" "Print script information and exit" \
         "-v, --verbose" "More verbose output" \
         "-q, --quiet" "No output except errors (overrides -v)"
}


##
## Preflight
##

# Load BASH libraries
SCRIPT_PATH=$(readlink -f "$0")
SCRIPT_DIR=$(dirname "$SCRIPT_PATH")
for LIBRARY in $LIBRARIES; do
  if [[ -r "$SCRIPT_DIR/$LIBRARY" ]]; then
    #echo "Loading library file [$SCRIPT_DIR/$LIBRARY]"
    source "$SCRIPT_DIR/$LIBRARY"
  else
    echo "Error: Cannot load library file [$SCRIPT_DIR/$LIBRARY]"
    exit 1
  fi
done

# Check for root privileges
if ! lib_amiroot && [[ $REQUIRE_ROOT -eq 1 ]]; then
  lib_print "!You need to have root privileges"
  exit 1
fi

# Check for dependencies
MISSING_COMMANDS=$(lib_missing_commands $DEPENDENCIES)
if [ -n "$MISSING_COMMANDS" ]; then
  lib_print "!One or more commands missing [$MISSING_COMMANDS]"
  lib_print "Try installing them with your package manager"
  exit 1
fi


##
## Liftoff
##

while [[ "$1" =~ ^- && ! "$1" == "--" ]]; do
  case $1 in
    -c|--checks)
      C=1
      ;;
    -h|--help)
      H=1
      ;;
    -i|--info)
      I=1
      ;;
    -v|--verbose)
      V=1
      ;;
    -q|--quiet)
      Q=1
      ;;
    *)
      lib_print "!Unknown option [$1]"
      lib_print "Try --help or -h for available options"
      exit 1
      ;;
  esac
  shift
done

if [[ "$1" == '--' ]]; then
  shift
fi

if [[ $I -eq 1 ]]; then
  lib_print_info
  exit 0
elif [[ $H -eq 1 ]]; then
  print_help
  exit 0
fi

if [[ -z "$1" ]]; then
  print_help
  exit 0
else
  # Generate a new password file if it is missing or empty
  if [[ ! -s $PASSWORD ]]; then
    lib_gen_string 32 > $PASSWORD
    chmod 600 $PASSWORD
    lib_print "New password file generated since it did not exist or was empty [$PASSWORD]"
  fi

  # Generate a new repo file if it is missing or empty
  if [[ ! -s $REPOSITORY ]]; then
    echo -n "Repository URL: "; read -r INPUT
    echo $INPUT > $REPOSITORY
    chmod 600 $REPOSITORY
    lib_print "New repository file generated since it did not exist or was empty [$REPOSITORY]"
  fi

  # Generate a new healthchecks file if it is missing or empty
  if [[ ! -s $HEALTHCHECKS ]] && [[ $C -eq 1 ]]; then
    echo -n "Healthchecks URL: "; read -r INPUT
    if [[ -n "$INPUT" ]]; then
      echo "$INPUT" > $HEALTHCHECKS
      chmod 600 $HEALTHCHECKS
      lib_print "New healthchecks file generated [$HEALTHCHECKS]"
    fi
  fi

  # Initialize a new repo if the URL has no config file
  if ! $($RESTIC_COMMAND snapshots >/dev/null 2>&1); then
    if ! $($RESTIC_COMMAND init >/dev/null 2>&1); then
	  lib_print "!A problem occured while initializing a new repository"
      exit 1
    fi
    lib_print "New repository initialized"
  fi

  # Run the Restic repository check
  if ! $($RESTIC_COMMAND check >/dev/null 2>&1); then
    lib_print "!Repository check failed"
    exit 1
  fi

  if [[ "$1" =~ ^/ && -r "$1" ]]; then
    # Signal Healthchecks start if enabled
    if [[ "$C" -eq 1 ]]; then
      HEALTHCHECKS_URL=$(cat $HEALTHCHECKS)
      curl -fsS -m 10 --retry 5 -o /dev/null $HEALTHCHECKS_URL/start
    fi
    # Run the actual backup
    if ! $($RESTIC_COMMAND backup --one-file-system ${@:2} "$1" >/dev/null 2>&1); then
      lib_print "!Something went wrong while running backup [$1]"
      # Signal Healthchecks fail if enabled
      if [[ "$C" -eq 1 ]]; then
        curl -fsS -m 10 --retry 5 -o /dev/null $HEALTHCHECKS_URL/fail >/dev/null 2>&1
      fi
      exit 1
    fi
    # Delete old snapshots
    if ! $($RESTIC_COMMAND forget --keep-last $SNAPSHOTS --path "$1" --prune >/dev/null 2>&1); then
      lib_print "!Something went wrong while deleting old snapshots [$1]"
      # Signal Healthchecks fail if enabled
      if [[ "$C" -eq 1 ]]; then
        curl -fsS -m 10 --retry 5 -o /dev/null $HEALTHCHECKS_URL/fail >/dev/null 2>&1
      fi
      exit 1
    fi
    # Signal Healthchecks success if enabled
    if [[ "$C" -eq 1 ]]; then
      curl -fsS -m 10 --retry 5 -o /dev/null $HEALTHCHECKS_URL >/dev/null 2>&1
    fi
  elif [[ "$1" =~ ^(backup|cache|cat|check|copy|diff|dump|find|forget|generate|help|init|key|list|ls|migrate|mount|prune|recover|repair|restore|rewrite|snapshots|stats|tag|unlock|version)$ ]]; then
    # Wrapper mode
    $RESTIC_COMMAND $@
  else
    lib_print "!The given path must be absolute and readable [$1]"
    lib_print "Or you can try a Restic keyword directly for wrapper mode"
	exit 1
  fi
fi


##
## Here be dragons
##

exit 0