#!/usr/bin/env bash
[ -f functions.sh ] && source functions.sh

roll_dice() {
    local count=${1%[dD]*}
    local sides=${1#*[dD]}
    local i
    local total=0
    for i in $(seq $count) ; do
        local die=$(($RANDOM % $sides + 1))
        total=$((total + $die))
        if [[ $i -le 10 ]]; then
            if [[ $i -lt $count ]]; then
               echo -n "${die}, "
            else
                if [[ $count -gt 1 ]]; then
                    echo -n "and ${die} "
                else
                    echo -n "${die} "
                fi
            fi
        fi
    done
    if [[ $((count - 10)) -gt 1 ]]; then
        echo -n "and $((count - 10)) more dice "
    fi
    if [[ $((count - 10)) -eq 1 ]]; then
        echo -n "and 1 more die "
    fi
    echo "for a total of ${total}."
}

rollString="${3##* }"

# Validate roll string is provided
if [[ -z "$rollString" ]]; then
    msg "$2" "${1}: Usage is roll #d# (e.g., 2d6, 1d20)"
    exit 0
fi

# Validate roll string format
if ! [[ "$rollString" =~ ^[1-9][0-9]*[dD][1-9][0-9]*$ ]]; then
    msg "$2" "${1}: Invalid format. Usage: roll #d# where # is greater than 0 (e.g., 2d6, 1d20)"
    exit 0
fi

# Extract count and sides for validation
count=${rollString%[dD]*}
sides=${rollString#*[dD]}

# Validate reasonable limits to prevent abuse
if [[ $count -gt 1000 ]]; then
    msg "$2" "${1}: Maximum 1000 dice per roll."
    exit 0
fi

if [[ $sides -gt 1000 ]]; then
    msg "$2" "${1}: Maximum 1000 sides per die."
    exit 0
fi

msg "$2" "$(roll_dice ${rollString})"