#!/usr/bin/env bash

# I shamefully used ChatGPT to generate this. My brain just is not suited to
# coming up with that regex on my own and I didn't have much luck searching
# the web for helpful material.

# Function to convert a string to snake_case
to_snake_case() {
    local input="$1"
    local snake_case
    snake_case=$(echo "$input" | sed -E 's/[[:space:]]+/_/g; s/([a-z])([A-Z])/\1_\2/g; s/[^a-zA-Z0-9_]+/_/g; s/__+/_/g; s/^_+|_+$//g' | tr '[:upper:]' '[:lower:]')
    echo "$snake_case"
}

# Check if the file name is provided as an argument
if [ -z "$1" ]; then
    echo "Usage: $0 <file-name>"
    exit 1
fi

# Get the file name from the argument
file_name="$1"

# Extract the directory, base name, and extension
dir=$(dirname "$file_name")
base_name=$(basename "$file_name")
extension="${base_name##*.}"
base_name="${base_name%.*}"

# Convert the base name to snake_case
snake_case_base_name=$(to_snake_case "$base_name")

# Construct the new file name
if [ "$base_name" == "$extension" ]; then
    new_file_name="$dir/$snake_case_base_name"
else
    new_file_name="$dir/$snake_case_base_name.$extension"
fi

# Rename the file
mv "$file_name" "$new_file_name"

echo "File renamed to: $new_file_name"