rfsn

#!/bin/bash

set -euo pipefail

# `Right File System Naming` renames files and directories to have a
# standardised way `for me =)` to name stuff.

# Dependencies:
# mv

# NOTE: There is no correlation that DT made a video about this.
#
# NOTE: Was planning to call it `rn`, but the last thing that I want is to
# mistyped with `rm` :/.

# -------------------------------- Functions -------------------------------- #

Usage()
{
    while read -r; do
        printf '%s\n' "$REPLY"
    done <<-EOF
Usage: rfsn [OPTS] FILES_OR_DIRS

  -h, --help                 - Display this help information.
  -f, --force                - Force the file renaming (default). Overrides '-i'
  -H, --force-hyphen         - Replaces ' ' and '_' with '-'.
  -i, --interactive          - Prompts before any action.
  -U, --force-underscore     - Replaces ' ' and '-' with '_'.

The use of '--' to ignore proceeding options is supported.
	EOF
}

Err()
{
    printf "Err: %s\n" "$2" 1>&2
    # shellcheck disable=2086
    (($1 > 0)) && exit $1
}

# ----------------------------- Input Processing ----------------------------- #

(($# == 0)) && Err 1 "Arguments(s) required."

Sep="-"
ForceHyphen=false
ForceUnderscore=false
Interactive=false
Force=true

while [[ -n $1 ]]; do
    case $1 in
        --) break ;;
        --help | -h)
            Usage
            exit 0
            ;;
        --force | -f)
            Force=true
            ;;
        --force-hyphen | -H)
            Sep="-"
            ForceHyphen=true
            ;;
        --interactive | -i)
            Interactive=true
            Force=false
            ;;
        --force-underscore | -U)
            Sep="_"
            ForceUnderscore=true
            ;;
        -*) Err 1 "Incorrect option(s) specified." ;;
        *) break ;;
    esac
    shift
done

# ----------------------------------- Main ----------------------------------- #

# Based from get_valid_filename @ https://github.com/django/django/blob/main/django/utils/text.py
for Argument in "$@"; do
    Source=$Argument
    ArgumentDir=${Argument%/*}

    BaseName=${Argument##*/}
    BaseName=${BaseName,,}
    BaseName=${BaseName/" "/$Sep}
    BaseName=${BaseName/":"/$Sep}

    if [[ $ForceHyphen == true ]]; then
        BaseName=${BaseName/"-"/$Sep}
    elif [[ $ForceUnderscore == true ]]; then
        BaseName=${BaseName/"_"/$Sep}
    fi

    BaseName=${BaseName//[^a-z0-9._-]/}
    Destination="$ArgumentDir/$BaseName"

    [[ -z $BaseName ]] || [[ $BaseName == "." ]] || [[ $BaseName == ".." ]] \
        && Err 1 "Could not derive file name from '$BaseName'."

    if [[ $Force == false ]] && [[ $Interactive == true ]]; then
        read -rp "Are you sure that you want to rename $Source to $Destination? (y/N) "

        [[ $REPLY =~ ^[Yy] ]] || return 0
    fi

    # Using `-i` just in case.
    mv -i "$Source" "$Destination"
done