#! /bin/bash

set -euo pipefail

DEFAULT_BASE="$HOME/doc/drafts/adhoc"

bar() {
    local -r len="${1:-80}" # 1st arg or 80.
    local -r char="${2:--}" # 2nd arg or a dash.

    seq -s "$char" "$len" | sed -E 's/[0-9]+//g'
}

main() {
    local -r base="${1:-$DEFAULT_BASE}"

    local -r title_given='Untitled'
    local -r title_lower=$(echo "$title_given" | tr '[:upper:]' '[:lower:]')
    local -r title_lower_dashed=$(echo "$title_lower" | sed 's/\s\+/-/g')
    local -r timestamp="$(date --iso-8601=ns)"
    local -r file="${base}/${timestamp}--${title_lower_dashed}.md"

    mkdir -p "$base"
    if [[ ! -a "$file" ]]
    then
        touch "$file"
        {
            echo "$title_given"
            bar 80 '='
            echo "started: $timestamp"
            printf '\n\n'
        } > "$file"
    fi
    echo "$file"
}

main "$@"