#!/bin/bash

# Global Configuration
SCRIPT_PATH="/home/litespeed/mb-backups/backup_all.sh"
LOG_FILE="/home/litespeed/mb-backups/logs/cron_check.log"
CRON_SCHEDULE="0 0 * * *"

# Slack Webhook URL (optional)
SLACK_WEBHOOK_URL="https://hooks.slack.com/services/your/webhook/url"

# Email Notification (optional)
EMAIL="your_email@example.com"

# Helper functions
log_message() {
    local level="$1"
    local message="$2"
    echo "[$(date)] [$level] $message" | tee -a "$LOG_FILE"
}

send_notification() {
    local message="$1"
    if [ -n "$SLACK_WEBHOOK_URL" ]; then
        curl -X POST -H 'Content-type: application/json' \
            --data "{\"text\":\"$message\"}" "$SLACK_WEBHOOK_URL"
        log_message "INFO" "Slack notification sent."
    fi

    if [ -n "$EMAIL" ]; then
        echo "$message" | mail -s "Backup Script Notification" "$EMAIL"
        log_message "INFO" "Email notification sent."
    fi
}

check_cron_service() {
    if ! systemctl is-active --quiet crond; then
        log_message "ERROR" "Cron service is not running. Attempting to restart..."
        sudo systemctl start crond && log_message "INFO" "Cron service restarted successfully." || {
            log_message "ERROR" "Failed to restart cron service."
            exit 1
        }
    fi
}

install_cronnext() {
    log_message "INFO" "Checking for 'cronnext' tool..."
    if ! command -v cronnext &> /dev/null; then
        log_message "WARNING" "'cronnext' tool not found. Attempting to install..."
        if command -v pip &> /dev/null; then
            pip install cronnext && log_message "INFO" "'cronnext' installed successfully." || {
                log_message "ERROR" "Failed to install 'cronnext'. Please install it manually."
                send_notification "Cronnext installation failed. Please check the server configuration."
                exit 1
            }
        else
            log_message "ERROR" "'pip' is not installed. Unable to install 'cronnext'."
            send_notification "Pip is missing; unable to install Cronnext. Please investigate."
            exit 1
        fi
    else
        log_message "INFO" "'cronnext' is already installed."
    fi
}

check_and_repair_cron() {
    log_message "INFO" "Checking for existing cron job for $SCRIPT_PATH..."
    local existing_job
    existing_job=$(crontab -l 2>/dev/null | grep -F "$SCRIPT_PATH")

    if [ -z "$existing_job" ]; then
        log_message "WARNING" "Automated backups are NOT enabled. Attempting to re-add cron job..."
        (crontab -l 2>/dev/null; echo "$CRON_SCHEDULE SHELL=/bin/bash PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin RESTIC_PASSWORD=\"YourResticPassword\" $SCRIPT_PATH > /home/litespeed/mb-backups/logs/auto/backup.log 2>&1") | crontab - && \
            log_message "INFO" "Cron job re-added successfully." || \
            log_message "ERROR" "Failed to add cron job."
    else
        log_message "INFO" "Automated backups are already enabled with the following schedule:"
        echo "$existing_job" | awk '{print "Schedule: " $1, $2, $3, $4, $5}' | tee -a "$LOG_FILE"
    fi
}

calculate_next_run_fallback() {
    local cron_schedule="$1"
    case "$cron_schedule" in
        "0 * * * *") # Hourly
            date -d "+1 hour" "+%Y-%m-%d %H:00:00"
            ;;
        "0 0 * * *") # Daily at midnight
            date -d "tomorrow 00:00" "+%Y-%m-%d %H:%M:%S"
            ;;
        "0 0 * * 0") # Weekly at midnight on Sunday
            date -d "next sunday 00:00" "+%Y-%m-%d %H:%M:%S"
            ;;
        "*/15 * * * *") # Every 15 minutes
            date -d "15 minutes" "+%Y-%m-%d %H:%M:%S"
            ;;
        *) # Unsupported schedules
            log_message "ERROR" "Unsupported schedule for fallback: $cron_schedule"
            echo "Unsupported schedule"
            ;;
    esac
}

display_next_run() {
    log_message "INFO" "Calculating next run time for the cron job..."
    install_cronnext

    local next_run
    next_run=$(cronnext "$CRON_SCHEDULE" 2>/dev/null)

    if [ -n "$next_run" ]; then
        log_message "INFO" "Next scheduled run time: $next_run"
    else
        log_message "WARNING" "Failed to calculate next run time using 'cronnext'. Falling back to manual calculation..."
        next_run=$(calculate_next_run_fallback "$CRON_SCHEDULE")
        if [ "$next_run" == "Unsupported schedule" ]; then
            send_notification "Failed to calculate next run time: unsupported schedule $CRON_SCHEDULE."
        else
            log_message "INFO" "Next scheduled run time (fallback): $next_run"
        fi
    fi
}

# Main Execution
log_message "INFO" "Starting backup schedule verification script..."
check_cron_service
check_and_repair_cron
display_next_run

log_message "INFO" "Backup schedule verification completed successfully."