Note taking script with color output and validation

note.sh

#!/bin/bash

# Usage examples:
#   ./note.sh                     # Show all notes with numbers
#   ./note.sh "Buy milk"          # Add new note
#   ./note.sh "TODO: Fix bugs"    # Add todo note
#   ./note.sh -d 5               # Delete note number 5
#   ./note.sh -cl                # Clear all notes (with confirmation)
#   ./note.sh -h                 # Show this help message
#
# Validation rules:
#   - Note text cannot be empty
#   - Maximum note length is 80 characters
#   - Delete command (-d) requires a valid number
#   - Note text must be in quotes if it contains spaces

# Configuration
NOTES_FILE=~/notes/all.txt
NOTES_DIR=$(dirname "$NOTES_FILE")
MAX_NOTE_LENGTH=80
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# Function to print error message in red
print_error() {
    echo -e "${RED}Error: $1${NC}"
}

# Function to print success message in green
print_success() {
    echo -e "${GREEN}$1${NC}"
}

# Function to print warning message in yellow
print_warning() {
    echo -e "${YELLOW}$1${NC}"
}

# Function to show help message
show_help() {
    cat << EOF
Usage:
  ./note.sh                      Show all notes with numbers
  ./note.sh "Your note"          Add new note
  ./note.sh "TODO: something"    Add todo note
  ./note.sh -d NUMBER           Delete note by number
  ./note.sh -cl                 Clear all notes (with confirmation)
  ./note.sh -h                  Show this help message

Notes:
  - Maximum note length is $MAX_NOTE_LENGTH characters
  - Use quotes for notes with spaces
  - Notes are stored in $NOTES_FILE
EOF
}

# Function to clear all notes
clear_notes() {
    if [ ! -f "$NOTES_FILE" ]; then
        print_error "No notes file exists."
        exit 1
    fi
    
    local count=$(wc -l < "$NOTES_FILE")
    if [ "$count" -eq 0 ]; then
        print_warning "Notes file is already empty."
        exit 0
    fi

    print_warning "Are you sure you want to delete all $count notes? (y/N)"
    read -r response
    if [[ "$response" =~ ^[Yy]$ ]]; then
        : > "$NOTES_FILE"
        print_success "All notes have been cleared."
    else
        print_warning "Operation cancelled."
    fi
}

# Function to validate delete command argument
validate_delete_arg() {
    local number=$1
    if ! [[ "$number" =~ ^[0-9]+$ ]]; then
        print_error "Delete command requires a valid number"
        exit 1
    fi
}

# Function to validate note text
validate_note() {
    local note="$1"
    if [[ -z "$note" ]]; then
        print_error "Note text cannot be empty"
        exit 1
    fi
    
    if [[ ${#note} -gt $MAX_NOTE_LENGTH ]]; then
        print_error "Note is too long (max $MAX_NOTE_LENGTH characters)"
        exit 1
    fi
}

# Create notes directory if it doesn't exist
mkdir -p "$NOTES_DIR"

# Function to display notes with line numbers
display_notes() {
    if [ -f "$NOTES_FILE" ]; then
        nl -w2 -s'. ' "$NOTES_FILE"
    else
        print_error "No notes found."
    fi
}

# Function to delete a note by number
delete_note() {
    local line_number=$1
    validate_delete_arg "$line_number"
    
    if [ -f "$NOTES_FILE" ]; then
        # Check if line exists
        if [ "$line_number" -le "$(wc -l < "$NOTES_FILE")" ]; then
            # Create a temporary file for the deletion
            sed "${line_number}d" "$NOTES_FILE" > "$NOTES_DIR/temp.txt"
            mv "$NOTES_DIR/temp.txt" "$NOTES_FILE"
            print_success "Note $line_number deleted."
            display_notes
        else
            print_error "Note number $line_number not found."
            exit 1
        fi
    else
        print_error "No notes file exists."
        exit 1
    fi
}

# Main logic
if [[ -z "$1" ]]; then
    display_notes
elif [[ "$1" == "-h" ]]; then
    show_help
elif [[ "$1" == "-cl" ]]; then
    clear_notes
elif [[ "$1" == "-d" ]]; then
    if [[ -z "$2" ]]; then
        print_error "Delete command requires a note number"
        exit 1
    fi
    delete_note "$2"
else
    validate_note "$1"
    echo "$1" >> "$NOTES_FILE"
    print_success "Note added."
fi