alarm

#!/bin/bash

# Function to calculate the next occurrence of a given weekday
next_weekday() {
    target_day=$(date -d "$1" +%u)  # Convert weekday to a number (1=Monday, 7=Sunday)
    current_day=$(date +%u)  # Get current day of the week

    if (( target_day >= current_day )); then
        # If the target day is today or later this week
        days_to_add=$((target_day - current_day))
    else
        # If the target day is earlier in the week, schedule for next week
        days_to_add=$((7 - current_day + target_day))
    fi
    date -d "+$days_to_add day" +"%Y-%m-%d"
}

# Function to print usage/help message
alarm_print_help() {
    echo "Usage: alarm [DATE] [TIME] [MESSAGE]"
    echo "Sets an alarm using the 'at' command and displays a toast notification."
    echo
    echo "Arguments:"
    echo "  DATE     Optional. Date in 'yyyy-mm-dd' format or a weekday abbreviation (e.g., MON, TUE)."
    echo "           If a weekday is provided, the alarm will be set for the first next occurrence of that weekday."
    echo "  TIME     Time in 'HH:MM' format or '+<minutes>' format."
    echo "           - 'HH:MM': Sets the alarm at the specified time."
    echo "           - '+<minutes>': Sets the alarm after the specified number of minutes."
    echo "  MESSAGE  Optional. Custom message to display with the alarm."
    echo
    echo "Examples:"
    echo "  alarm 15:30 \"Meeting starts now!\""
    echo "  alarm +10 \"Take a break!\""
    echo "  alarm MON 08:00 \"Monday morning alarm!\""
    echo "  alarm 2024-10-20 07:00 \"Important event!\""
    echo "  alarm -help          Displays this help message."
}

alarm() {
    # Display help if no arguments are provided or if '-help' is called
    if [[ $# -eq 0 || $1 == "-help" ]]; then
        alarm_print_help
        return 0
    fi

    # Check if "at" is installed
    if ! command -v at &> /dev/null; then
        echo "'at' command not found. Attempting to install..."
        if ! sudo apt-get install -y at; then
            echo "Failed to install 'at'. Please re-run the script with sudo permissions."
            return 1
        fi
    fi

    # Check if "atd" is running and start it if not
    if ! pgrep -x "atd" > /dev/null; then
        echo "'atd' service is not running. Attempting to start it..."
        if ! sudo service atd start; then
            echo "Failed to start 'atd' service. Please check your system configuration."
            return 1
        fi
    fi

    # Locate the full path of the "toast" command
    toast_path=$(whereis -b toast | awk '{print $2}')
    if [[ -z "$toast_path" ]]; then
        echo "Could not find 'toast'. Make sure it is installed and available."
        return 1
    fi

    # Handle date or weekday input
    if [[ $1 =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}$ ]]; then
        # If the input is in yyyy-mm-dd format
        alarm_date=$1
    elif [[ $1 =~ ^(MON|TUE|WED|THU|FRI|SAT|SUN)$ ]]; then
        # If the input is a weekday abbreviation
        alarm_date=$(next_weekday "$1")
    fi

    # Shift the arguments if a date or weekday was provided
    if [[ -n "$alarm_date" ]]; then
        shift
    fi

    # Handle different time formats
    if [[ $1 =~ ^[\+]?[0-9]+$ ]]; then
        # Extract the number of minutes (remove the "+")
        minutes_from_now=${1#+}

        if [[ -n "$alarm_date" ]]; then
            echo "\"$toast_path\" alarm \"${2:-It is now $minutes_from_now minutes from now on $alarm_date!}\"" | at $alarm_date now + $minutes_from_now minutes
        else
            echo "\"$toast_path\" alarm \"${2:-It is now $minutes_from_now minutes from now!}\"" | at now + $minutes_from_now minutes
        fi
        echo "Alarm set for $minutes_from_now minutes from now."
    elif [[ $1 =~ ^([0-1]?[0-9]|2[0-3]):([0-5][0-9])$ ]]; then
        # If the user passed a time in HH:MM format, pass it directly to 'at'
        if [[ -n "$alarm_date" ]]; then
            echo "\"$toast_path\" alarm \"${2:-It is now $1 on $alarm_date!}\"" | at $1 $alarm_date
        else
            echo "\"$toast_path\" alarm \"${2:-It is now $1!}\"" | at $1
        fi
        echo "Alarm set for $1."
    else
        echo "Please provide time in hh:mm format, +<minutes> format, or a valid date or weekday."
        return 1
    fi
}