#!/bin/bash

# Check for arguments and set variables
if [ "$#" -lt 2 ] || [ "$#" -gt 3 ]; then
    echo "Usage: $0 {FOLDER} YYYY_MM_DD YYYY_MM_DD"
    exit 1
fi

# Set folder path
if [ "$#" -eq 3 ]; then
    TARGET_DIR="$1"
    START_DATE="$2"
    END_DATE="$3"
else
    TARGET_DIR="."
    START_DATE="$1"
    END_DATE="$2"
fi

# Ensure the target directory exists
mkdir -p "$TARGET_DIR"

# Convert input dates to YYYY-MM-DD format for `date` compatibility
START_DATE=$(echo "$START_DATE" | sed 's/_/-/g')
END_DATE=$(echo "$END_DATE" | sed 's/_/-/g')

# Loop through dates and create folders
current_date="$START_DATE"
while [[ "$current_date" < "$END_DATE" ]] || [[ "$current_date" == "$END_DATE" ]]; do
    # Format date as YYYY_MM_DD
    formatted_date=$(date -d "$current_date" +"%Y_%m_%d")
    
    # Create folder with the formatted date
    mkdir -p "$TARGET_DIR/$formatted_date"
    
    # Increment date by one day
    current_date=$(date -I -d "$current_date + 1 day")
done

echo "Folders created from ${START_DATE//-/_} to ${END_DATE//-/_} in $TARGET_DIR."