#!/bin/bash

# Directory where Systemd files will be stored
SYSTEMD_DIR="/etc/systemd/system"

# Path to the crontab file
CRONTAB_FILE="/etc/crontab"

# Function to convert cron syntax to Systemd OnCalendar syntax
convert_cron_to_systemd_timer() {
    minute="$1"
    hour="$2"
    day_of_month="$3"
    month="$4"
    day_of_week="$5"

    echo "$month-$day_of_month *-$day_of_week $hour:$minute:00"
}

# Main function
process_crontab() {
    while read -r line; do
        # Skip comments, empty lines, and lines with environment variables
        if [[ "$line" =~ ^# ]] || [[ -z "$line" ]] || [[ "$line" =~ ^[A-Za-z_]+= ]]; then
            continue
        fi

        # Check if the line has at least 6 fields for the time specs and the command
        fields=($line)
        if [[ ${#fields[@]} -lt 6 ]]; then
            continue
        fi

        # Parse the line (first part is the time specs, last part is the command)
        minute="${fields[0]}"
        hour="${fields[1]}"
        day_of_month="${fields[2]}"
        month="${fields[3]}"
        day_of_week="${fields[4]}"
        command="${fields[@]:5}"

        # Create a timer name based on the command
        timer_name=$(basename "$command" | sed 's/\..*//')

        # Create the Systemd .service file
        echo "[Unit]
Description=Run $command from cron

[Service]
ExecStart=$command
" > "$SYSTEMD_DIR/$timer_name.service"

        # Create the Systemd .timer file
        calendar=$(convert_cron_to_systemd_timer "$minute" "$hour" "$day_of_month" "$month" "$day_of_week")
        echo "[Unit]
Description=Timer for $timer_name

[Timer]
OnCalendar=$calendar
Persistent=true

[Install]
WantedBy=timers.target
" > "$SYSTEMD_DIR/$timer_name.timer"

        # Enable and start the timer
        systemctl enable "$timer_name.timer"
        systemctl start "$timer_name.timer"

        echo "Created and started $timer_name.timer"
    done < "$CRONTAB_FILE"
}

# Execution
process_crontab