displaymanager - how to select and disable a monitor on macos

displaymanager.sh

#!/usr/bin/env bash

# Traps Ctrl+C to ensure the cursor is restored if the user aborts the script
trap 'tput cnorm; echo -e "\nAborted."; exit 1' INT

# 1. Alias Installation Check
if [[ "$1" != "--skip-install" ]]; then
    user_shell=$(basename "$SHELL")
    if [[ "$user_shell" == "zsh" ]]; then
        config_file="$HOME/.zshrc"
    elif [[ "$user_shell" == "bash" ]]; then
        config_file="$HOME/.bashrc"
    else
        config_file=""
    fi

    if [[ -n "$config_file" ]]; then
        touch "$config_file"
        if grep -q "alias displaymanager=" "$config_file"; then
            echo "The 'displaymanager' shortcut is already installed in your $config_file."
            read -r -p "Do you want to reinstall/update it? (y/n): " install_alias
        else
            echo "The 'displaymanager' shortcut is not installed."
            read -r -p "Do you want to install it in your $config_file? (y/n): " install_alias
        fi
        
        if [[ "$install_alias" =~ ^[yY]$ ]]; then
            sed -i '' '/alias displaymanager=/d' "$config_file"
            gist_url="https://gist.github.com/matheusmota/5b990e0bd8352a6562847d6c4c9b642f/raw"
            echo "alias displaymanager='bash <(curl -sL \"$gist_url\") --skip-install'" >> "$config_file"
            echo "Alias installed successfully! (It will be available in your next terminal session or after running: source $config_file)"
            echo "------------------------------"
        else
            echo "Alias installation skipped."
            echo "------------------------------"
        fi
    fi
fi

# 2. Checks if displayplacer is installed
if ! command -v displayplacer &> /dev/null; then
    echo "'displayplacer' was not found on your system."
    read -r -p "Do you want to install it now using Homebrew? (y/n): " install_choice
    if [[ "$install_choice" =~ ^[yY]$ ]]; then
        if ! command -v brew &> /dev/null; then
            echo "Error: Homebrew is not installed. Please install Homebrew first."
            exit 1
        fi
        echo "Installing displayplacer..."
        brew install displayplacer
    else
        echo "Installation cancelled. The script requires displayplacer to work."
        exit 1
    fi
fi

# 3. Interactive Menu Function
choose_option() {
    local prompt="$1"
    shift
    local options=("$@")
    local selected=0
    
    echo -e "\n\033[1;36m$prompt\033[0m" # Cyan bold color
    
    for _ in "${options[@]}"; do echo ""; done
    echo -en "\033[${#options[@]}A"
    
    tput civis # Hides cursor
    
    while true; do
        tput sc # Saves cursor position
        
        for i in "${!options[@]}"; do
            if [[ $i -eq $selected ]]; then
                echo -e "\033[32m ❯ ${options[$i]}\033[0m\033[K"
            else
                echo -e "   ${options[$i]}\033[K"
            fi
        done
        
        read -rsn1 key
        if [[ $key == $'\033' ]]; then
            read -rsn2 key2
            if [[ $key2 == '[A' ]]; then # Up arrow
                ((selected--))
                [[ $selected -lt 0 ]] && selected=$((${#options[@]} - 1))
            elif [[ $key2 == '[B' ]]; then # Down arrow
                ((selected++))
                [[ $selected -ge ${#options[@]} ]] && selected=0
            fi
        elif [[ $key == "" ]]; then # Enter key
            break
        fi
        
        tput rc 
    done
    
    tput cnorm 
    
    tput rc
    for _ in "${options[@]}"; do echo ""; done
    
    return $selected
}

# 4. Captures and parses monitor data with CACHE Memory
CACHE_FILE="$HOME/.displaymanager_cache"

cache_ids=()
cache_types=()
cache_res=()

if [[ -f "$CACHE_FILE" ]]; then
    while IFS="|" read -r c_id c_type c_res; do
        if [[ -n "$c_id" ]]; then
            cache_ids+=("$c_id")
            cache_types+=("$c_type")
            cache_res+=("$c_res")
        fi
    done < "$CACHE_FILE"
fi

update_cache() {
    local new_id="$1"
    local new_type="$2"
    local new_res="$3"
    local found=false
    
    for i in "${!cache_ids[@]}"; do
        if [[ "${cache_ids[$i]}" == "$new_id" ]]; then
            cache_types[$i]="$new_type"
            cache_res[$i]="$new_res"
            found=true
            break
        fi
    done
    
    if [[ "$found" == "false" ]]; then
        cache_ids+=("$new_id")
        cache_types+=("$new_type")
        cache_res+=("$new_res")
    fi
}

active_ids=()
current_id=""
current_type=""
current_res=""
current_enabled=""

# Reads displayplacer output line by line securely
while IFS= read -r raw_line; do
    # Clears any hidden carriage returns from macOS output
    line="${raw_line//$'\r'/}"
    
    if [[ "$line" == Persistent\ screen\ id:\ * ]]; then
        if [[ -n "$current_id" ]]; then
            update_cache "$current_id" "$current_type" "$current_res"
            if [[ "$current_enabled" == "true" ]]; then
                active_ids+=("$current_id")
            fi
        fi
        current_id="${line#Persistent screen id: }"
        # STRIP ALL HIDDEN WHITESPACES to avoid corrupted UUIDs
        current_id="${current_id//[[:space:]]/}"
        
        current_type="Unknown"
        current_res="Unknown"
        current_enabled="Unknown"
    elif [[ "$line" == Type:\ * ]]; then
        current_type="${line#Type: }"
    elif [[ "$line" == Resolution:\ * ]]; then
        current_res="${line#Resolution: }"
        current_res="${current_res//[[:space:]]/}"
    elif [[ "$line" == Enabled:\ * ]]; then
        current_enabled="${line#Enabled: }"
        current_enabled="${current_enabled//[[:space:]]/}"
    fi
done <<< "$(displayplacer list)"

# Catches the last monitor block
if [[ -n "$current_id" ]]; then
    update_cache "$current_id" "$current_type" "$current_res"
    if [[ "$current_enabled" == "true" ]]; then
        active_ids+=("$current_id")
    fi
fi

# Saves sanitized data to cache
> "$CACHE_FILE"
for i in "${!cache_ids[@]}"; do
    echo "${cache_ids[$i]}|${cache_types[$i]}|${cache_res[$i]}" >> "$CACHE_FILE"
done

ids=()
displays=()

for i in "${!cache_ids[@]}"; do
    c_id="${cache_ids[$i]}"
    ids+=("$c_id")
    
    is_active=false
    for act_id in "${active_ids[@]}"; do
        if [[ "$act_id" == "$c_id" ]]; then
            is_active=true
            break
        fi
    done
    
    if $is_active; then
        state_text="ON"
    else
        state_text="OFF"
    fi
    
    displays+=("${cache_types[$i]} [Res: ${cache_res[$i]}] - Status: $state_text")
done

if [ ${#ids[@]} -eq 0 ]; then
    echo "No monitors found or an error occurred while reading displays."
    exit 1
fi

displays+=("Exit")

# 5. Main Execution Loop
while true; do
    choose_option "Select a monitor to manage:" "${displays[@]}"
    monitor_idx=$?
    
    if [[ $monitor_idx -eq $((${#displays[@]} - 1)) ]]; then
        echo "Exiting..."
        exit 0
    fi
    
    selected_id="${ids[$monitor_idx]}"
    
    # Sub-menu for action
    choose_option "Action for ${cache_types[$monitor_idx]}:" "Enable (Turn on)" "Disable (Turn off)" "Back"
    action_idx=$?
    
    if [[ $action_idx -eq 0 ]]; then
        echo -e "Enabling monitor..."
        displayplacer "id:$selected_id enabled:true"
        break
    elif [[ $action_idx -eq 1 ]]; then
        echo -e "Disabling monitor..."
        displayplacer "id:$selected_id enabled:false"
        break
    elif [[ $action_idx -eq 2 ]]; then
        continue
    fi
done

echo -e "Command executed successfully!"