Few bash UI functions.

bash-ui.sh

#!/bin/bash

# ============================================
# UI Library - User Interface Functions
# No dependencies - pure output/input
# ============================================

# Color codes
readonly COLOR_RESET='\033[0m'
readonly COLOR_RED='\033[0;31m'
readonly COLOR_GREEN='\033[0;32m'
readonly COLOR_YELLOW='\033[1;33m'
readonly COLOR_BLUE='\033[0;34m'
readonly COLOR_CYAN='\033[0;36m'

# ============================================
# Output Functions
# ============================================

lib_print_info() {
    local message="$1"
    echo -e "${COLOR_BLUE}[INFO]${COLOR_RESET} $message"
}

lib_print_success() {
    local message="$1"
    echo -e "${COLOR_GREEN}[SUCCESS]${COLOR_RESET} $message"
}

lib_print_warn() {
    local message="$1"
    echo -e "${COLOR_YELLOW}[WARN]${COLOR_RESET} $message" >&2
}

lib_print_error() {
    local message="$1"
    local exit_code="${2:-}"
    echo -e "${COLOR_RED}[ERROR]${COLOR_RESET} $message" >&2
    
    if [[ -n "$exit_code" ]]; then
        exit "$exit_code"
    fi
}

lib_print_step() {
    local step="$1"
    local message="$2"
    echo -e "\n${COLOR_CYAN}==>${COLOR_RESET} ${COLOR_GREEN}Step $step:${COLOR_RESET} $message\n"
}

lib_print_header() {
    local message="$1"
    local line=$(printf '=%.0s' {1..60})
    echo -e "\n${COLOR_CYAN}$line${COLOR_RESET}"
    echo -e "${COLOR_CYAN}$message${COLOR_RESET}"
    echo -e "${COLOR_CYAN}$line${COLOR_RESET}\n"
}

# ============================================
# Input Functions
# ============================================

lib_prompt_yes_no() {
    local prompt="$1"
    local default="${2:-n}"  # Default to 'n' if not specified
    local response
    
    if [[ "$default" == "y" ]]; then
        prompt="$prompt [Y/n]: "
    else
        prompt="$prompt [y/N]: "
    fi
    
    while true; do
        read -rp "$prompt" response
        response="${response:-$default}"  # Use default if empty
        response=$(echo "$response" | tr '[:upper:]' '[:lower:]')
        
        case "$response" in
            y|yes)
                return 0
                ;;
            n|no)
                return 1
                ;;
            *)
                lib_print_warn "Please answer 'y' or 'n'"
                ;;
        esac
    done
}

lib_prompt_input() {
    local prompt="$1"
    local default="$2"
    local response
    
    if [[ -n "$default" ]]; then
        read -rp "$prompt [$default]: " response
        echo "${response:-$default}"
    else
        read -rp "$prompt: " response
        echo "$response"
    fi
}

lib_prompt_select() {
    local prompt="$1"
    shift
    local options=("$@")
    local choice
    
    echo "$prompt"
    for i in "${!options[@]}"; do
        echo "  $((i+1))) ${options[$i]}"
    done
    
    while true; do
        read -rp "Enter selection [1-${#options[@]}]: " choice
        
        if [[ "$choice" =~ ^[0-9]+$ ]] && \
           [[ "$choice" -ge 1 ]] && \
           [[ "$choice" -le "${#options[@]}" ]]; then
            echo "${options[$((choice-1))]}"
            return 0
        else
            lib_print_warn "Invalid selection. Please enter a number between 1 and ${#options[@]}"
        fi
    done
}

lib_prompt_confirm_destructive() {
    local action="$1"
    local target="$2"
    
    lib_print_warn "DESTRUCTIVE OPERATION"
    lib_print_warn "Action: $action"
    lib_print_warn "Target: $target"
    lib_print_warn "This operation CANNOT be undone!"
    echo ""
    
    if ! lib_prompt_yes_no "Are you absolutely sure you want to proceed?" "n"; then
        lib_print_info "Operation cancelled by user"
        return 1
    fi
    
    # Double confirmation for extra safety
    lib_print_warn "Type 'yes' to confirm (not just 'y'):"
    local confirmation
    read -rp "> " confirmation
    
    if [[ "$confirmation" != "yes" ]]; then
        lib_print_info "Operation cancelled"
        return 1
    fi
    
    return 0
}

# ============================================
# Progress Functions
# ============================================

lib_spinner() {
    local pid=$1
    local message="${2:-Processing}"
    local delay=0.1
    local spinstr='|/-\'
    
    echo -n "$message "
    while kill -0 "$pid" 2>/dev/null; do
        local temp=${spinstr#?}
        printf "[%c]" "$spinstr"
        spinstr=$temp${spinstr%"$temp"}
        sleep $delay
        printf "\b\b\b"
    done
    printf "\b\b\b   \b\b\b"
}

lib_progress_bar() {
    local current=$1
    local total=$2
    local width=50
    local percentage=$((current * 100 / total))
    local filled=$((width * current / total))
    local empty=$((width - filled))
    
    printf "\rProgress: ["
    printf "%${filled}s" | tr ' ' '='
    printf "%${empty}s" | tr ' ' '-'
    printf "] %3d%%" "$percentage"
    
    if [[ $current -eq $total ]]; then
        echo ""
    fi
}

# ============================================
# Formatting Functions
# ============================================

lib_format_size() {
    local size_bytes=$1
    local units=("B" "KB" "MB" "GB" "TB")
    local unit_index=0
    local size=$size_bytes
    
    while [[ $size -gt 1024 && $unit_index -lt 4 ]]; do
        size=$((size / 1024))
        ((unit_index++))
    done
    
    echo "${size}${units[$unit_index]}"
}

lib_format_list() {
    local title="$1"
    shift
    local items=("$@")
    
    echo "$title:"
    for item in "${items[@]}"; do
        echo "  • $item"
    done
}

lib_print_key_value() {
    local key="$1"
    local value="$2"
    printf "  %-25s : %s\n" "$key" "$value"
}

# ============================================
# Validation Helper (display only)
# ============================================

lib_display_validation_error() {
    local field="$1"
    local error="$2"
    lib_print_error "Validation failed for '$field': $error"
}

# ============================================
# Box Drawing
# ============================================

lib_print_box() {
    local message="$1"
    local length=${#message}
    local border=$(printf '─%.0s' $(seq 1 $((length + 2))))
    
    echo "┌${border}┐"
    echo "│ ${message} │"
    echo "└${border}┘"
}

lib_print_summary() {
    local title="$1"
    shift
    local items=("$@")
    
    lib_print_box "$title"
    for item in "${items[@]}"; do
        echo "  $item"
    done
    echo ""
}