#!/bin/bash
# ===================== v0.36 - 2025.08.29 ========================
#
# Example backup.conf:
# BACKUP_DIRS="/home/user/test/./ /var/www/./"
# BOX_DIR="/backup/"
# BOX_ADDR="user@storagebox.example.com"
# LOG_FILE="/var/log/backup.log"
# LOG_RETENTION_DAYS=7
# MAX_LOG_SIZE_MB=10
# BANDWIDTH_LIMIT_KBPS=1000
# RSYNC_NOATIME_ENABLED=false
# Set RSYNC_NOATIME_ENABLED to true for rsync >= 3.3.0. Set to false for older versions (e.g., 3.2.7).
# RSYNC_TIMEOUT=300
# RECYCLE_BIN_ENABLED=true
# RECYCLE_BIN_DIR="recycle_bin"
# RECYCLE_BIN_RETENTION_DAYS=30
# CHECKSUM_ENABLED=false
# NTFY_ENABLED=true
# NTFY_TOKEN="your_token"
# NTFY_URL="https://ntfy.sh/your_topic"
# NTFY_PRIORITY_SUCCESS=3
# NTFY_PRIORITY_WARNING=4
# NTFY_PRIORITY_FAILURE=5
# BEGIN_SSH_OPTS
# -i
# /root/.ssh/id_rsa
# -p22
# END_SSH_OPTS
# BEGIN_EXCLUDES
# *.tmp
# /tmp/
# END_EXCLUDES
#
# =================================================================
#                 SCRIPT INITIALIZATION & SETUP
# =================================================================
set -Euo pipefail
umask 077

HOSTNAME=$(hostname -s)

# --- Color Palette ---
if [ -t 1 ]; then
    C_RESET='\e[0m'
    C_BOLD='\e[1m'
    C_DIM='\e[2m'
    C_RED='\e[0;31m'
    C_GREEN='\e[0;32m'
    C_YELLOW='\e[0;33m'
    C_CYAN='\e[0;36m'
else
    C_RESET=''
    C_BOLD=''
    C_DIM=''
    C_RED=''
    C_GREEN=''
    C_YELLOW=''
    C_CYAN=''
fi

# Re-run the script with sudo if not already root
if [[ $EUID -ne 0 ]]; then
   echo -e "${C_BOLD}${C_YELLOW}This script requires root privileges to function correctly.${C_RESET}"
   echo -e "${C_YELLOW}Attempting to re-run with sudo. You may be prompted for your password.${C_RESET}"
   echo "----------------------------------------------------------------"
   exec sudo "$0" "$@"
fi

# --- Determine script's location to load the config file ---
SCRIPT_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)
CONFIG_FILE="${SCRIPT_DIR}/backup.conf"

# --- Create a temporary file for rsync exclusions ---
EXCLUDE_FILE_TMP=$(mktemp)
SSH_OPTS_ARRAY=()

# --- Securely parse the unified configuration file ---
if [ -f "$CONFIG_FILE" ]; then
    in_exclude_block=false
    in_ssh_opts_block=false
    while IFS= read -r line; do
        # --- Handle block markers ---
        if [[ "$line" == "BEGIN_EXCLUDES" ]]; then in_exclude_block=true; continue; fi
        if [[ "$line" == "END_EXCLUDES" ]]; then in_exclude_block=false; continue; fi
        if [[ "$line" == "BEGIN_SSH_OPTS" ]]; then in_ssh_opts_block=true; continue; fi
        if [[ "$line" == "END_SSH_OPTS" ]]; then in_ssh_opts_block=false; continue; fi

        # --- Process lines within blocks ---
        if [[ "$in_exclude_block" == "true" ]]; then
            [[ ! "$line" =~ ^([[:space:]]*#|[[:space:]]*$) ]] && echo "$line" >> "$EXCLUDE_FILE_TMP"
            continue
        fi
        if [[ "$in_ssh_opts_block" == "true" ]]; then
            [[ ! "$line" =~ ^([[:space:]]*#|[[:space:]]*$) ]] && SSH_OPTS_ARRAY+=("$line")
            continue
        fi

        # --- Process key-value pairs ---
        if [[ "$line" =~ ^[[:space:]]*([a-zA-Z_][a-zA-Z0-9_]*)[[:space:]]*=[[:space:]]*(.*) ]]; then
            key="${BASH_REMATCH[1]}"; value="${BASH_REMATCH[2]}"
            value="${value%\"}"; value="${value#\"}"

            case "$key" in
                BACKUP_DIRS|BOX_DIR|BOX_ADDR|LOG_FILE|LOG_RETENTION_DAYS|CHECKSUM_ENABLED|\
                MAX_LOG_SIZE_MB|BANDWIDTH_LIMIT_KBPS|RSYNC_TIMEOUT|RSYNC_NOATIME_ENABLED|\
                NTFY_ENABLED|DISCORD_ENABLED|NTFY_TOKEN|NTFY_URL|DISCORD_WEBHOOK_URL|\
                NTFY_PRIORITY_SUCCESS|NTFY_PRIORITY_WARNING|NTFY_PRIORITY_FAILURE|\
                RECYCLE_BIN_ENABLED|RECYCLE_BIN_DIR|RECYCLE_BIN_RETENTION_DAYS)
                    declare "$key"="$value"
                    ;;
                *)
                    echo "WARNING: Unknown config variable '$key' ignored in $CONFIG_FILE" >&2
                    ;;
            esac
        fi
    done < "$CONFIG_FILE"
else
    echo "FATAL: Unified configuration file backup.conf not found." >&2; exit 1
fi

# --- Validate that all required configuration variables are set ---
for var in BACKUP_DIRS BOX_DIR BOX_ADDR LOG_FILE \
           NTFY_PRIORITY_SUCCESS NTFY_PRIORITY_WARNING NTFY_PRIORITY_FAILURE \
           LOG_RETENTION_DAYS; do
    if [ -z "${!var:-}" ]; then
        echo "FATAL: Required config variable '$var' is missing or empty in $CONFIG_FILE." >&2
        exit 1
    fi
done
if [[ "$BOX_DIR" != */ ]]; then
    echo "❌ FATAL: BOX_DIR must end with a trailing slash (/). Please check backup.conf." >&2
    exit 2
fi
if [[ "${RECYCLE_BIN_ENABLED:-false}" == "true" ]]; then
    for var in RECYCLE_BIN_DIR RECYCLE_BIN_RETENTION_DAYS; do
        if [ -z "${!var:-}" ]; then
            echo "FATAL: When RECYCLE_BIN_ENABLED is true, '$var' must be set in $CONFIG_FILE." >&2
            exit 1
        fi
    done
    if [[ "${RECYCLE_BIN_DIR}" == /* ]]; then
        echo "❌ FATAL: RECYCLE_BIN_DIR must be a relative path, not absolute: '${RECYCLE_BIN_DIR}'" >&2
        exit 1
    fi
    if [[ "$RECYCLE_BIN_DIR" == *"../"* ]]; then
        echo "❌ FATAL: RECYCLE_BIN_DIR cannot contain '../'" >&2
        exit 1
    fi
fi

# =================================================================
#               SCRIPT CONFIGURATION (STATIC)
# =================================================================

REMOTE_TARGET="${BOX_ADDR}:${BOX_DIR}"
LOCK_FILE="/tmp/backup_rsync.lock"

SSH_CMD="ssh"
if (( ${#SSH_OPTS_ARRAY[@]} > 0 )); then
    SSH_CMD+=$(printf " %q" "${SSH_OPTS_ARRAY[@]}")
fi

RSYNC_BASE_OPTS=(
    -aR -z --delete --partial --timeout="${RSYNC_TIMEOUT:-300}" --mkpath
    --exclude-from="$EXCLUDE_FILE_TMP"
    -e "$SSH_CMD"
)

if [[ "${RSYNC_NOATIME_ENABLED:-false}" == "true" ]]; then
    RSYNC_BASE_OPTS+=(--noatime)
fi

# Optional: Add bandwidth limit if configured
if [[ -n "${BANDWIDTH_LIMIT_KBPS:-}" && "${BANDWIDTH_LIMIT_KBPS}" -gt 0 ]]; then
    RSYNC_BASE_OPTS+=(--bwlimit="$BANDWIDTH_LIMIT_KBPS")
fi

# Shared options for direct, non-interactive SSH commands
SSH_DIRECT_OPTS=(
    -o StrictHostKeyChecking=no
    -o BatchMode=yes
    -o ConnectTimeout=30
    -n
)

# =================================================================
#                       HELPER FUNCTIONS
# =================================================================

log_message() {
    local message="$1"
    echo "[$HOSTNAME] [$(date '+%Y-%m-%d %H:%M:%S')] $message" >> "${LOG_FILE:-/dev/null}"
    if [[ "${VERBOSE_MODE:-false}" == "true" ]]; then
        echo "$message"
    fi
}
send_ntfy() {
    local title="$1" tags="$2" priority="$3" message="$4"
    if [[ "${NTFY_ENABLED:-false}" != "true" ]] || [ -z "${NTFY_TOKEN:-}" ] || [ -z "${NTFY_URL:-}" ]; then return; fi
    curl -s --max-time 15 -u ":$NTFY_TOKEN" -H "Title: $title" -H "Tags: $tags" -H "Priority: $priority" -d "$message" "$NTFY_URL" > /dev/null 2>> "${LOG_FILE:-/dev/null}"
}
send_discord() {
    local title="$1" status="$2" message="$3"
    if [[ "${DISCORD_ENABLED:-false}" != "true" ]] || [ -z "${DISCORD_WEBHOOK_URL:-}" ]; then return; fi
    local color; case "$status" in
        success) color=3066993 ;; warning) color=16776960 ;; failure) color=15158332 ;; *) color=9807270 ;;
    esac
    local escaped_title; escaped_title=$(echo "$title" | sed 's/\\/\\\\/g' | sed 's/"/\\"/g')
    local escaped_message; escaped_message=$(echo "$message" | sed 's/\\/\\\\/g' | sed 's/"/\\"/g' | sed ':a;N;$!ba;s/\n/\\n/g')
    local json_payload; printf -v json_payload '{"embeds": [{"title": "%s", "description": "%s", "color": %d, "timestamp": "%s"}]}' \
        "$escaped_title" "$escaped_message" "$color" "$(date -u +%Y-%m-%dT%H:%M:%S.000Z)"
    curl -s --max-time 15 -H "Content-Type: application/json" -d "$json_payload" "$DISCORD_WEBHOOK_URL" > /dev/null 2>> "${LOG_FILE:-/dev/null}"
}
send_notification() {
    local title="$1" tags="$2" ntfy_priority="$3" discord_status="$4" message="$5"
    send_ntfy "$title" "$tags" "$ntfy_priority" "$message"
    send_discord "$title" "$discord_status" "$message"
}
run_integrity_check() {
    local rsync_check_opts=(-aincR --delete --mkpath --exclude-from="$EXCLUDE_FILE_TMP" --out-format="%n" -e "$SSH_CMD")
    if [[ "${CHECKSUM_ENABLED:-false}" == "true" ]]; then
        rsync_check_opts+=(-c)
    fi
    local DIRS_ARRAY; read -ra DIRS_ARRAY <<< "$BACKUP_DIRS"
    for dir in "${DIRS_ARRAY[@]}"; do
        echo "--- Integrity Check: $dir ---" >&2
	local relative_path="${dir#*./}"
	LC_ALL=C rsync "${rsync_check_opts[@]}" "$dir" "${REMOTE_TARGET}${relative_path}" 2>> "${LOG_FILE:-/dev/null}"
    done
}
parse_stat() {
    local output="$1" pattern="$2" awk_command="$3"
    ( set +o pipefail; echo "$output" | grep "$pattern" | awk "$awk_command" )
}
format_backup_stats() {
    local rsync_output="$1"
    local files_transferred=$(parse_stat "$rsync_output" 'Number of regular files transferred:' '{s+=$2} END {print s}')
    local bytes_transferred=$(parse_stat "$rsync_output" 'Total_transferred_size:' '{s+=$2} END {print s}')
    local files_created=$(parse_stat "$rsync_output" 'Number_of_created_files:' '{s+=$2} END {print s}')
    local files_deleted=$(parse_stat "$rsync_output" 'Number_of_deleted_files:' '{s+=$2} END {print s}')
    if [[ -z "$bytes_transferred" && -z "$files_created" && -z "$files_deleted" ]]; then
        files_transferred=$(parse_stat "$rsync_output" 'Number of files transferred:' '{gsub(/,/, ""); s+=$4} END {print s}')
        bytes_transferred=$(parse_stat "$rsync_output" 'Total transferred file size:' '{gsub(/,/, ""); s+=$5} END {print s}')
        files_created=$(parse_stat "$rsync_output" 'Number of created files:' '{s+=$5} END {print s}')
        files_deleted=$(parse_stat "$rsync_output" 'Number of deleted files:' '{s+=$5} END {print s}')
    fi
    if [[ -z "$bytes_transferred" && -z "$files_transferred" ]]; then
        log_message "WARNING: Unable to parse rsync stats. Output format may be incompatible."
        printf "Data Transferred: Unknown\nFiles Updated: Unknown\nFiles Created: Unknown\nFiles Deleted: Unknown\n"
        return 0
    fi
    local files_updated=$(( ${files_transferred:-0} - ${files_created:-0} ))
    if (( files_updated < 0 )); then files_updated=0; fi
    local stats_summary=""
    if [[ "${bytes_transferred:-0}" -gt 0 ]]; then
        stats_summary=$(printf "Data Transferred: %s" "$(numfmt --to=iec-i --suffix=B --format="%.2f" "$bytes_transferred")")
    else
        stats_summary="Data Transferred: 0 B (No changes)"
    fi
    stats_summary+=$(printf "\nFiles Updated: %s\nFiles Created: %s\nFiles Deleted: %s" "${files_updated:-0}" "${files_created:-0}" "${files_deleted:-0}")
    printf "%s\n" "$stats_summary"
}
cleanup() {
    rm -f "${EXCLUDE_FILE_TMP:-}" "${RSYNC_LOG_TMP:-}"
}
run_preflight_checks() {
    local mode=${1:-backup}; local test_mode=false
    if [[ "$mode" == "test" ]]; then test_mode=true; fi
    local check_failed=false
    if [[ "$test_mode" == "true" ]]; then printf "${C_BOLD}--- Checking required commands...${C_RESET}\n"; fi
    for cmd in "${REQUIRED_CMDS[@]}"; do
        if ! command -v "$cmd" &>/dev/null; then echo "❌ FATAL: Required command '$cmd' not found." >&2; check_failed=true; fi
    done
    if [[ "$check_failed" == "true" ]]; then exit 10; fi
    if [[ "$test_mode" == "true" ]]; then printf "${C_GREEN}✅ All required commands are present.${C_RESET}\n"; fi
    # Check rsync version for --noatime compatibility if the feature is enabled
    if [[ "${RSYNC_NOATIME_ENABLED:-false}" == "true" ]]; then
        if [[ "$test_mode" == "true" ]]; then printf "${C_BOLD}--- Checking rsync version for --noatime...${C_RESET}\n"; fi
        local rsync_version
        rsync_version=$(rsync --version | head -n1 | awk '{print $3}')
        local major minor
        IFS='.' read -r major minor _ <<< "$rsync_version"
        if ! (( major > 3 || (major == 3 && minor >= 3) )); then
            printf "${C_RED}❌ FATAL: RSYNC_NOATIME_ENABLED is true but rsync version %s is too old.${C_RESET}\n" "$rsync_version" >&2
            printf "${C_DIM}   The --noatime option requires rsync version 3.3.0 or newer.${C_RESET}\n" >&2
            exit 10
        fi
        if [[ "$test_mode" == "true" ]]; then printf "${C_GREEN}✅ rsync version %s supports --noatime.${C_RESET}\n" "$rsync_version"; fi
    fi
    if [[ "$test_mode" == "true" ]]; then printf "${C_BOLD}--- Checking SSH connectivity...${C_RESET}\n"; fi
    # Quick preflight connectivity "ping": short 10s timeout for fail-fast behaviour
    if ! ssh "${SSH_OPTS_ARRAY[@]}" -o BatchMode=yes -o ConnectTimeout=10 "$BOX_ADDR" 'exit' 2>/dev/null; then
        local err_msg="Unable to SSH into $BOX_ADDR. Check keys and connectivity."
        if [[ "$test_mode" == "true" ]]; then echo "❌ $err_msg"; else send_notification "SSH FAILED: ${HOSTNAME}" "x" "${NTFY_PRIORITY_FAILURE}" "failure" "$err_msg"; fi; exit 6
    fi
    if [[ "$test_mode" == "true" ]]; then printf "${C_GREEN}✅ SSH connectivity OK.${C_RESET}\n"; fi
    if [[ "${RECYCLE_BIN_ENABLED:-false}" == "true" ]]; then
        local remote_recycle_path="${BOX_DIR}${RECYCLE_BIN_DIR}"
        if ! ssh "${SSH_OPTS_ARRAY[@]}" -o BatchMode=yes -o ConnectTimeout=10 "$BOX_ADDR" "ls -d \"$remote_recycle_path\"" >/dev/null 2>&1; then
            if ! ssh "${SSH_OPTS_ARRAY[@]}" -o BatchMode=yes -o ConnectTimeout=10 "$BOX_ADDR" "mkdir -p \"$remote_recycle_path\"" >/dev/null 2>&1; then
                echo "❌ FATAL: Cannot access or create recycle bin directory '$remote_recycle_path' on remote." >&2
                exit 1
            fi
        fi
    fi
    if [[ "$mode" != "restore" ]]; then
        if [[ "$test_mode" == "true" ]]; then printf "${C_BOLD}--- Checking backup directories...${C_RESET}\n"; fi
        local DIRS_ARRAY; read -ra DIRS_ARRAY <<< "$BACKUP_DIRS"
        for dir in "${DIRS_ARRAY[@]}"; do
            if [[ ! -d "$dir" ]] || [[ "$dir" != */ ]]; then
                local err_msg="A directory in BACKUP_DIRS ('$dir') must exist and end with a trailing slash ('/')."
                if [[ "$test_mode" == "true" ]]; then echo "❌ FATAL: $err_msg"; else send_notification "❌ Backup FAILED: ${HOSTNAME}" "x" "${NTFY_PRIORITY_FAILURE}" "failure" "FATAL: $err_msg"; fi; exit 2
            fi
            if [[ "$dir" != *"/./"* ]]; then
                local err_msg="Directory '$dir' in BACKUP_DIRS is missing the required '/./' syntax."
                if [[ "$test_mode" == "true" ]]; then
                    echo "❌ FATAL: $err_msg"
                else
                    send_notification "❌ Backup FAILED: ${HOSTNAME}" "x" "${NTFY_PRIORITY_FAILURE}" "failure" "FATAL: $err_msg"
                fi
                exit 2
            fi
            if [[ ! -r "$dir" ]]; then
                local err_msg="A directory in BACKUP_DIRS ('$dir') is not readable."
                if [[ "$test_mode" == "true" ]]; then echo "❌ FATAL: $err_msg"; else send_notification "❌ Backup FAILED: ${HOSTNAME}" "x" "${NTFY_PRIORITY_FAILURE}" "failure" "FATAL: $err_msg"; fi; exit 2
            fi
        done
        if [[ "$test_mode" == "true" ]]; then printf "${C_GREEN}✅ All backup directories are valid.${C_RESET}\n"; fi
        if [[ "$test_mode" == "true" ]]; then printf "${C_BOLD}--- Checking local disk space...${C_RESET}\n"; fi
        local required_space_kb=102400
        local available_space_kb
        available_space_kb=$(df --output=avail "$(dirname "${LOG_FILE}")" | tail -n1)
        if [[ "$available_space_kb" -lt "$required_space_kb" ]]; then
            local err_msg="Insufficient disk space in $(dirname "${LOG_FILE}") to guarantee logging. ($((available_space_kb / 1024))MB available)"
            if [[ "$test_mode" == "true" ]]; then echo "❌ FATAL: $err_msg"; else send_notification "❌ Backup FAILED: ${HOSTNAME}" "x" "${NTFY_PRIORITY_FAILURE}" "failure" "FATAL: $err_msg"; fi
            exit 7
        fi
        if [[ "$test_mode" == "true" ]]; then printf "${C_GREEN}✅ Local disk space OK.${C_RESET}\n"; fi
    fi
}
print_header() {
    printf "\n%b--- %s ---%b\n" "${C_BOLD}" "$1" "${C_RESET}"
}
run_restore_mode() {
    print_header "RESTORE MODE ACTIVATED"
    run_preflight_checks "restore"
    local DIRS_ARRAY; read -ra DIRS_ARRAY <<< "$BACKUP_DIRS"
    local RECYCLE_OPTION="[ Restore from Recycle Bin ]"
    local all_options=("${DIRS_ARRAY[@]}")
    if [[ "${RECYCLE_BIN_ENABLED:-false}" == "true" ]]; then
        all_options+=("$RECYCLE_OPTION")
    fi
    all_options+=("Cancel")
    printf "${C_YELLOW}Available backup sets to restore from:${C_RESET}\n"
    PS3="Your choice: "
    select dir_choice in "${all_options[@]}"; do
        if [[ -n "$dir_choice" ]]; then break;
        else echo "Invalid selection. Please try again."; fi
    done
    PS3="#? "
    local paths_to_process=()
    local source_base_remote=""
    local source_base_local_prefix=""
    local source_display_name=""
    local is_full_directory_restore=false
    if [[ "$dir_choice" == "$RECYCLE_OPTION" ]]; then
        print_header "Browse Recycle Bin"
        local date_folders=()
        local remote_recycle_path="${BOX_DIR%/}/${RECYCLE_BIN_DIR%/}"
        mapfile -t date_folders < <(ssh "${SSH_OPTS_ARRAY[@]}" "${SSH_DIRECT_OPTS[@]}" "$BOX_ADDR" "ls -1 \"$remote_recycle_path\"" 2>/dev/null | grep -E '^[0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{6}$')
        if [[ ${#date_folders[@]} -eq 0 ]]; then
            printf "${C_YELLOW}❌ The remote recycle bin is empty or contains no valid backup folders.${C_RESET}\n"
            return 1
        fi
        printf "${C_YELLOW}Select a backup run (date_time) to browse:${C_RESET}\n"
        PS3="Your choice: "
        select date_choice in "${date_folders[@]}" "Cancel"; do
            if [[ "$date_choice" == "Cancel" ]]; then echo "Restore cancelled."; return 0;
            elif [[ -n "$date_choice" ]]; then break;
            else echo "Invalid selection. Please try again."; fi
        done
        PS3="#? "
        local remote_date_path="${remote_recycle_path}/${date_choice}"
        print_header "Files available from ${date_choice} (showing first 20)"
        rsync -r -n --out-format='%n' -e "$SSH_CMD" "${BOX_ADDR}:${remote_date_path}/" . 2>/dev/null | head -n 20 || echo "No files found for this date."
        printf "%b--------------------------------------------------------%b\n" "${C_BOLD}" "${C_RESET}"
        printf -v path_prompt "Enter original path(s) to restore (e.g., home/user/file.txt), space-separated: "
        read -erp "$(printf '%b%s%b' "${C_YELLOW}" "$path_prompt" "${C_RESET}")" -a paths_to_process
        if [[ ${#paths_to_process[@]} -eq 0 ]]; then echo "❌ Path cannot be empty. Aborting."; return 1; fi
        source_base_remote="${BOX_ADDR}:${remote_date_path}"
        source_base_local_prefix="/"
        source_display_name="(from Recycle Bin, ${date_choice})"
    elif [[ "$dir_choice" == "Cancel" ]]; then
        echo "Restore cancelled."; return 0
    else 
        while true; do
            printf "\n${C_YELLOW}Restore the entire directory or a specific file/subfolder? [entire/specific]: ${C_RESET}"; read -r choice
            case "$choice" in
                entire) is_full_directory_restore=true; paths_to_process+=(""); break ;;
                specific)
                    local relative_path_browse="${dir_choice#*./}"
                    local remote_browse_source="${REMOTE_TARGET}${relative_path_browse}"
                    print_header "Files available in ${dir_choice} (showing first 20)"
                    rsync -r -n --out-format='%n' -e "$SSH_CMD" "$remote_browse_source" . 2>/dev/null | head -n 20 || echo "No files found for this backup set."
                    printf "%b--------------------------------------------------------%b\n" "${C_BOLD}" "${C_RESET}"
                    printf -v path_prompt "Enter path(s) relative to '%s' to restore (space-separated, quote if spaces): " "$dir_choice"
                    read -erp "$(printf '%b%s%b' "${C_YELLOW}" "$path_prompt" "${C_RESET}")" -a paths_to_process
                    if [[ ${#paths_to_process[@]} -eq 0 ]]; then
                        echo "Path cannot be empty. Please try again or choose 'entire'."
                        continue
                    fi
                    break ;;
                *) echo "Invalid choice. Please answer 'entire' or 'specific'." ;;
            esac
        done
        local relative_path="${dir_choice#*./}"
        source_base_remote="${REMOTE_TARGET}${relative_path}"
        source_base_local_prefix=$(echo "$dir_choice" | sed 's#/\./#/#g')
        source_display_name="'${dir_choice}'"
    fi
    local successful_count=0
    local failed_count=0
    local total_items=${#paths_to_process[@]}

    for restore_path in "${paths_to_process[@]}"; do
        if [[ "$restore_path" == /* || "$restore_path" =~ (^|/)\.\.(/|$) ]]; then
            echo "❌ Invalid restore path: '${restore_path}' must be relative and contain no '..'. Skipping." >&2;
            ((failed_count++))
            continue
        fi
        restore_path=$(echo "$restore_path" | sed 's#^/##')
        local item_for_display full_remote_source default_local_dest
        if [[ -n "$restore_path" ]]; then
            item_for_display="'${restore_path%/}' from ${source_display_name}"
            full_remote_source="${source_base_remote%/}/${restore_path%/}"
            default_local_dest="${source_base_local_prefix%/}/${restore_path%/}"
        else 
            item_for_display="the entire directory ${source_display_name}"
            full_remote_source="$source_base_remote"
            default_local_dest="$source_base_local_prefix"
        fi
        local final_dest
        print_header "Restore Destination for ${item_for_display}"
        printf "Enter the absolute destination path for the restore.\n\n"
        printf "%bDefault (original location):%b\n" "${C_YELLOW}" "${C_RESET}"
        printf "%b%s%b\n\n" "${C_CYAN}" "$default_local_dest" "${C_RESET}"
        printf "Press [Enter] to use the default path, or enter a new one.\n"
        read -rp "> " final_dest
        : "${final_dest:=$default_local_dest}"
        local path_validation_attempts=0
        local max_attempts=5
        while true; do
            ((path_validation_attempts++))
            if (( path_validation_attempts > max_attempts )); then
                printf "\n${C_RED}❌ Too many invalid attempts. Skipping restore for this item.${C_RESET}\n"
                ((failed_count++))
                continue 2
            fi
            if [[ "$final_dest" != "/" ]]; then final_dest="${final_dest%/}"; fi
            local parent_dir; parent_dir=$(dirname -- "$final_dest")
            if [[ "$final_dest" != /* ]]; then
                printf "\n${C_RED}❌ Error: Please provide an absolute path (starting with '/').${C_RESET}\n"
            elif [[ -e "$final_dest" && ! -d "$final_dest" ]]; then
                printf "\n${C_RED}❌ Error: The destination '%s' exists but is a file. Please choose a different path.${C_RESET}\n" "$final_dest"
            elif [[ -e "$parent_dir" && ! -w "$parent_dir" ]]; then
                printf "\n${C_RED}❌ Error: The parent directory '%s' exists but is not writable.${C_RESET}\n" "$parent_dir"
            elif [[ -d "$final_dest" ]]; then
                printf "${C_GREEN}✅ Destination '%s' exists and is accessible.${C_RESET}\n" "$final_dest"
                if [[ "$final_dest" != "$default_local_dest" && -z "$restore_path" ]]; then
                     local warning_msg="⚠️  WARNING: Custom destination directory already exists. Files may be overwritten."
                     printf "${C_YELLOW}%s${C_RESET}\n" "$warning_msg"; log_message "$warning_msg"
                fi
                break
            else
                printf "\n${C_YELLOW}⚠️  The destination '%s' does not exist.${C_RESET}\n" "$final_dest"
                printf "${C_YELLOW}Choose an action:${C_RESET}\n"
                PS3="Your choice: "
                select action in "Create the destination path" "Enter a different path" "Cancel"; do
                    case "$action" in
                        "Create the destination path")
                            if mkdir -p "$final_dest"; then
                                 printf "${C_GREEN}✅ Successfully created directory '%s'.${C_RESET}\n" "$final_dest"
                                 if [[ "${is_full_directory_restore:-false}" == "true" ]]; then
                                    chmod 700 "$final_dest"; log_message "Set permissions to 700 on newly created restore directory: $final_dest"
                                 else
                                    chmod 755 "$final_dest"
                                 fi
                                 break 2
                            else
                                 printf "\n${C_RED}❌ Failed to create directory '%s'. Check permissions.${C_RESET}\n"; break
                            fi ;;
                        "Enter a different path") break ;;
                        "Cancel") 
                            echo "Restore cancelled for this item."
                            ((failed_count++))
                            continue 2 ;;
                        *) echo "Invalid option. Please try again." ;;
                    esac
                done
                PS3="#? "
            fi
            if (( path_validation_attempts < max_attempts )); then
                printf "\n${C_YELLOW}Please enter a new destination path: ${C_RESET}"; read -r final_dest
                if [[ -z "$final_dest" ]]; then
                    final_dest="$default_local_dest"; printf "${C_DIM}Empty input, using default location: %s${C_RESET}\n" "$final_dest"
                fi
            fi
        done
        local extra_rsync_opts=()
        local dest_user=""
        if [[ "$final_dest" == /home/* ]]; then
            dest_user=$(echo "$final_dest" | cut -d/ -f3)
            if [[ -n "$dest_user" ]] && id -u "$dest_user" &>/dev/null; then
                printf "${C_CYAN}ℹ️  Home directory detected. Restored files will be owned by '${dest_user}'.${C_RESET}\n"
                extra_rsync_opts+=("--chown=${dest_user}:${dest_user}")
                chown "${dest_user}:${dest_user}" "$final_dest" 2>/dev/null || true
            else
                dest_user=""
            fi
        fi
        print_header "Restore Summary"
        printf "  Source:      %s\n" "$item_for_display"
        printf "  Destination: %b%s%b\n" "${C_BOLD}" "$final_dest" "${C_RESET}"
        print_header "PERFORMING DRY RUN (NO CHANGES MADE)"
        log_message "Starting restore dry-run of ${item_for_display} from ${full_remote_source} to ${final_dest}"
        local rsync_restore_opts=(-avhi --safe-links --progress --exclude-from="$EXCLUDE_FILE_TMP" -e "$SSH_CMD")
        if ! rsync "${rsync_restore_opts[@]}" "${extra_rsync_opts[@]}" --dry-run "$full_remote_source" "$final_dest"; then
            printf "${C_RED}❌ DRY RUN FAILED. Rsync reported an error. Skipping item.${C_RESET}\n" >&2
            log_message "Restore dry-run failed for ${item_for_display}"
            ((failed_count++))
            continue
        fi
        print_header "DRY RUN COMPLETE"
        while true; do
            printf "\n${C_YELLOW}Proceed with restoring %s to '%s'? [yes/no]: ${C_RESET}" "$item_for_display" "$final_dest"; read -r confirmation
            case "${confirmation,,}" in
                yes|y) break ;;
                no|n) 
                    echo "Restore cancelled by user for this item."
                    ((failed_count++))
                    continue 2 ;;
                *) echo "Please answer 'yes' or 'no'." ;;
            esac
        done
        print_header "EXECUTING RESTORE"
        log_message "Starting actual restore of ${item_for_display} from ${full_remote_source} to ${final_dest}"
        if rsync "${rsync_restore_opts[@]}" "${extra_rsync_opts[@]}" "$full_remote_source" "$final_dest"; then
            log_message "Restore completed successfully."
            printf "${C_GREEN}✅ Restore of %s to '%s' completed successfully.${C_RESET}\n\n" "$item_for_display" "$final_dest"
            send_notification "Restore SUCCESS: ${HOSTNAME}" "white_check_mark" "${NTFY_PRIORITY_SUCCESS}" "success" "Successfully restored ${item_for_display} to ${final_dest}"
            ((successful_count++))
        else
            local rsync_exit_code=$?
            log_message "Restore FAILED with rsync exit code ${rsync_exit_code}."
            printf "${C_RED}❌ Restore FAILED. Check the rsync output and log for details.${C_RESET}\n\n"
            send_notification "Restore FAILED: ${HOSTNAME}" "x" "${NTFY_PRIORITY_FAILURE}" "failure" "Restore of ${item_for_display} to ${final_dest} failed (exit code: ${rsync_exit_code})";
            ((failed_count++))
            continue
        fi
    done
    print_header "Overall Restore Summary"
    printf "Total items selected: %d\n" "$total_items"
    printf "${C_GREEN}Succeeded: %d${C_RESET}\n" "$successful_count"
    if (( failed_count > 0 )); then
        printf "${C_RED}Failed/Skipped: %d${C_RESET}\n" "$failed_count"
    else
        printf "${C_GREEN}Failed/Skipped: 0${C_RESET}\n"
    fi
}
run_recycle_bin_cleanup() {
    if [[ "${RECYCLE_BIN_ENABLED:-false}" != "true" ]]; then return 0; fi
    log_message "Checking remote recycle bin..."
    local remote_cleanup_path="${BOX_DIR%/}/${RECYCLE_BIN_DIR%/}"
    local list_command="ls -1 \"$remote_cleanup_path\""
    local all_folders
    if ! all_folders=$(ssh "${SSH_OPTS_ARRAY[@]}" "${SSH_DIRECT_OPTS[@]}" "$BOX_ADDR" "$list_command" 2>> "${LOG_FILE:-/dev/null}"); then
        log_message "Recycle bin not found or unable to list contents. Nothing to clean."
        return 0
    fi
    if [[ -z "$all_folders" ]]; then
        log_message "No daily folders in recycle bin to check."
        return 0
    fi
    log_message "Checking for folders older than ${RECYCLE_BIN_RETENTION_DAYS} days..."
    local folders_to_delete=""
    local retention_days=${RECYCLE_BIN_RETENTION_DAYS}
    local threshold_timestamp
    threshold_timestamp=$(date -d "$retention_days days ago" +%s)
    while IFS= read -r folder; do
        local folder_date=${folder%%_*}
        if folder_timestamp=$(date -d "$folder_date" +%s 2>/dev/null) && [[ -n "$folder_timestamp" ]]; then
            if (( folder_timestamp < threshold_timestamp )); then
                folders_to_delete+="${folder}"$'\n'
            fi
        fi
    done <<< "$all_folders"
    if [[ -n "$folders_to_delete" ]]; then
        log_message "Removing old recycle bin folders:"
        local empty_dir
        empty_dir=$(mktemp -d)
        while IFS= read -r folder; do
            if [[ -n "$folder" ]]; then
                log_message "  Deleting: $folder"
                local remote_dir_to_delete="${remote_cleanup_path}/${folder}/"
                rsync -a --delete -e "$SSH_CMD" "$empty_dir/" "${BOX_ADDR}:${remote_dir_to_delete}" >/dev/null 2>> "${LOG_FILE:-/dev/null}"
                ssh "${SSH_OPTS_ARRAY[@]}" "${SSH_DIRECT_OPTS[@]}" "$BOX_ADDR" "rmdir \"$remote_dir_to_delete\"" 2>> "${LOG_FILE:-/dev/null}"
            fi
        done <<< "$folders_to_delete"

        rm -rf "$empty_dir"
    else
        log_message "No old recycle bin folders to remove."
    fi
}
trap cleanup EXIT
trap 'send_notification "Backup Crashed: ${HOSTNAME}" "x" "${NTFY_PRIORITY_FAILURE}" "failure" "Backup script terminated unexpectedly. Check log: ${LOG_FILE:-/dev/null}"' ERR

REQUIRED_CMDS=(rsync ssh curl flock hostname date stat mv touch awk numfmt grep printf nice ionice sed mktemp basename read)

# =================================================================
#                       SCRIPT EXECUTION
# =================================================================

VERBOSE_MODE=false
if [[ "${1:-}" == "--verbose" ]]; then
    VERBOSE_MODE=true; shift
fi

if [[ "${1:-}" ]]; then
    case "${1}" in
        --dry-run)
            trap - ERR
            echo "--- DRY RUN MODE ACTIVATED ---"; DRY_RUN_FAILED=false; full_dry_run_output=""
            read -ra DIRS_ARRAY <<< "$BACKUP_DIRS"
            for dir in "${DIRS_ARRAY[@]}"; do
                echo -e "\n--- Checking dry run for: $dir ---"
                rsync_dry_opts=( "${RSYNC_BASE_OPTS[@]}" --dry-run --itemize-changes --out-format="%i %n%L" --info=stats2,name,flist2 )
                if [[ "${RECYCLE_BIN_ENABLED:-false}" == "true" ]]; then
                    backup_dir="${BOX_DIR%/}/${RECYCLE_BIN_DIR%/}/$(date +%F_%H%M%S)/"
                    rsync_dry_opts+=(--backup --backup-dir="$backup_dir")
                fi
                DRY_RUN_LOG_TMP=$(mktemp)
                if ! rsync "${rsync_dry_opts[@]}" "$dir" "$REMOTE_TARGET" > "$DRY_RUN_LOG_TMP" 2>&1; then DRY_RUN_FAILED=true; fi
                echo "---- Preview of changes (first 20) ----"
                grep -E '^\*deleting|^[<>ch\.]f|^cd|^\.d' "$DRY_RUN_LOG_TMP" | head -n 20 || true
                echo "-------------------------------------"
                full_dry_run_output+=$'\n'"$(<"$DRY_RUN_LOG_TMP")"; rm -f "$DRY_RUN_LOG_TMP"
            done
            echo -e "\n--- Overall Dry Run Summary ---"
            BACKUP_STATS=$(format_backup_stats "$full_dry_run_output")
            echo -e "$BACKUP_STATS"; echo "-------------------------------"
            if [[ "$DRY_RUN_FAILED" == "true" ]]; then
                echo -e "\n❌ Dry run FAILED for one or more directories. See rsync errors above."; exit 1
            fi
            echo "--- DRY RUN COMPLETED ---"; exit 0 ;;
        --checksum | --summary)
            trap - ERR
            echo "--- INTEGRITY CHECK MODE ACTIVATED ---"; echo "Calculating differences..."
            START_TIME_INTEGRITY=$(date +%s); FILE_DISCREPANCIES=$(run_integrity_check); END_TIME_INTEGRITY=$(date +%s)
            DURATION_INTEGRITY=$((END_TIME_INTEGRITY - START_TIME_INTEGRITY))
            CLEAN_DISCREPANCIES=$(echo "$FILE_DISCREPANCIES" | grep -v '^\*')
            if [[ "$1" == "--summary" ]]; then
                MISMATCH_COUNT=$(echo "$CLEAN_DISCREPANCIES" | wc -l)
                printf "🚨 Total files with checksum mismatches: %d\n" "$MISMATCH_COUNT"
                log_message "Summary mode check found $MISMATCH_COUNT mismatched files."
                send_notification "📊 Backup Summary: ${HOSTNAME}" "bar_chart" "${NTFY_PRIORITY_SUCCESS}" "success" "Mismatched files found: $MISMATCH_COUNT"
            else # --checksum
                if [ -z "$CLEAN_DISCREPANCIES" ]; then
                    echo "✅ Checksum validation passed. No discrepancies found."
                    log_message "Checksum validation passed. No discrepancies found."
                    send_notification "Backup Integrity OK: ${HOSTNAME}" "white_check_mark" "${NTFY_PRIORITY_SUCCESS}" "success" "Checksum validation passed."
                else
                    log_message "Backup integrity check FAILED. Found discrepancies."
                    ISSUE_LIST=$(echo "$CLEAN_DISCREPANCIES" | head -n 10)
                    printf -v FAILURE_MSG "Backup integrity check FAILED.\n\nFirst 10 differing files:\n%s\n\nCheck duration: %dm %ds" "${ISSUE_LIST}" $((DURATION_INTEGRITY / 60)) $((DURATION_INTEGRITY % 60))
                    printf "❌ %s\n" "$FAILURE_MSG"
                    send_notification "Backup Integrity FAILED: ${HOSTNAME}" "x" "${NTFY_PRIORITY_FAILURE}" "failure" "${FAILURE_MSG}"
                fi
            fi
            exit 0 ;;
        --test)
            trap - ERR
            echo "--- TEST MODE ACTIVATED ---"; run_preflight_checks "test"
            echo "---------------------------"; echo "✅ All configuration checks passed."; exit 0 ;;
        --restore)
            trap - ERR; run_restore_mode; exit 0 ;;
    esac
fi

run_preflight_checks

exec 200>"$LOCK_FILE"
flock -n 200 || { echo "Another instance is running, exiting."; exit 5; }

# --- Log Rotation ---
# Use default of 10MB if not set in config
max_log_size_bytes=$(( ${MAX_LOG_SIZE_MB:-10} * 1024 * 1024 ))
if [ -f "$LOG_FILE" ] && [ "$(stat -c%s "$LOG_FILE")" -gt "$max_log_size_bytes" ]; then
    mv "$LOG_FILE" "${LOG_FILE}.$(date +%Y%m%d_%H%M%S)"
    touch "$LOG_FILE"
    find "$(dirname "$LOG_FILE")" -name "$(basename "$LOG_FILE").*" -type f -mtime +"$LOG_RETENTION_DAYS" -delete
fi

log_message "Flushing filesystem buffers to disk..."
sync

echo "============================================================" >> "$LOG_FILE"
log_message "Starting rsync backup..."

START_TIME=$(date +%s)
success_dirs=(); failed_dirs=(); overall_exit_code=0; full_rsync_output=""
read -ra DIRS_ARRAY <<< "$BACKUP_DIRS"
for dir in "${DIRS_ARRAY[@]}"; do
    log_message "Backing up directory: $dir"
    RSYNC_LOG_TMP=$(mktemp)
    RSYNC_EXIT_CODE=0; RSYNC_OPTS=("${RSYNC_BASE_OPTS[@]}")
    if [[ "${RECYCLE_BIN_ENABLED:-false}" == "true" ]]; then
        backup_dir="${BOX_DIR%/}/${RECYCLE_BIN_DIR%/}/$(date +%F_%H%M%S)/"
        RSYNC_OPTS+=(--backup --backup-dir="$backup_dir")
    fi
    if [[ "$VERBOSE_MODE" == "true" ]]; then
        RSYNC_OPTS+=(--info=stats2,progress2)
        nice -n 19 ionice -c 3 rsync "${RSYNC_OPTS[@]}" "$dir" "$REMOTE_TARGET" 2>&1 | tee "$RSYNC_LOG_TMP"
        RSYNC_EXIT_CODE=${PIPESTATUS[0]}
    else
        RSYNC_OPTS+=(--info=stats2)
	nice -n 19 ionice -c 3 rsync "${RSYNC_OPTS[@]}" "$dir" "$REMOTE_TARGET" > "$RSYNC_LOG_TMP" 2>&1 || RSYNC_EXIT_CODE=$?
    fi
    cat "$RSYNC_LOG_TMP" >> "$LOG_FILE"; full_rsync_output+=$'\n'"$(<"$RSYNC_LOG_TMP")"
    rm -f "$RSYNC_LOG_TMP"
    if [[ $RSYNC_EXIT_CODE -eq 0 || $RSYNC_EXIT_CODE -eq 24 || $RSYNC_EXIT_CODE -eq 23 ]]; then
        success_dirs+=("$(basename "$dir")")
        if [[ $RSYNC_EXIT_CODE -eq 24 || $RSYNC_EXIT_CODE -eq 23 ]]; then
            log_message "WARNING for $dir: rsync completed with code $RSYNC_EXIT_CODE."; overall_exit_code=24
        fi
    else
        failed_dirs+=("$(basename "$dir")")
        log_message "FAILED for $dir: rsync exited with code: $RSYNC_EXIT_CODE."; overall_exit_code=1
    fi
done

run_recycle_bin_cleanup

END_TIME=$(date +%s); DURATION=$((END_TIME - START_TIME)); trap - ERR

BACKUP_STATS=$(format_backup_stats "$full_rsync_output")
FINAL_MESSAGE=$(printf "%s\n\nSuccessful: %s\nFailed: %s\n\nDuration: %dm %ds" \
    "$BACKUP_STATS" \
    "${success_dirs[*]:-None}" \
    "${failed_dirs[*]:-None}" \
    $((DURATION / 60)) $((DURATION % 60)))

if [[ ${#FINAL_MESSAGE} -gt 1800 ]]; then
    FINAL_MESSAGE=$(printf "%.1800s\n\n[Message truncated, see %s for full details]" "$FINAL_MESSAGE" "$LOG_FILE")
fi

if [[ ${#failed_dirs[@]} -eq 0 ]]; then
    log_message "SUCCESS: All backups completed."
    if [[ $overall_exit_code -eq 24 ]]; then
        send_notification "Backup Warning: ${HOSTNAME}" "warning" "${NTFY_PRIORITY_WARNING}" "warning" "One or more directories completed with warnings.\n\n$FINAL_MESSAGE"
    else
        send_notification "Backup SUCCESS: ${HOSTNAME}" "white_check_mark" "${NTFY_PRIORITY_SUCCESS}" "success" "$FINAL_MESSAGE"
    fi
else
    log_message "FAILURE: One or more backups failed."; send_notification "Backup FAILED: ${HOSTNAME}" "x" "${NTFY_PRIORITY_FAILURE}" "failure" "$FINAL_MESSAGE"
fi

echo "======================= Run Finished =======================" >> "$LOG_FILE"
echo "" >> "$LOG_FILE"