Add environment configuration file support to Tailscale installation and receiver scripts.

- Introduced an environment file for configuration at `/etc/default/tailscale-receive`, allowing users to customize settings such as target user, target directory, and logging level.
- Enhanced the installation script to create and backup the environment file, ensuring proper permissions and ownership.
- Updated the receiver script to read configuration values from the environment file, improving flexibility and user experience.
- Implemented preflight checks to validate directory permissions and existing installations, enhancing installation reliability.
- Improved error handling and logging throughout the scripts for better user feedback.

Author: 1999AZZAR

install.sh

@@ -34,6 +34,9 @@ DEST_SEND_SCRIPT_PATH="/usr/local/bin/tailscale-send.sh"
 SYS_KIO_SERVICEMENU_DIR="/usr/share/kio/servicemenus"
 SYS_KSERVICES5_SERVICEMENU_DIR="/usr/share/kservices5/ServiceMenus"
 
+# Environment file for configuration
+ENV_FILE_PATH="/etc/default/tailscale-receive"
+
 # --- Functions ---
 
 # Function to print a formatted header
@@ -73,25 +76,92 @@ are_scripts_installed() {
 backup_existing_config() {
   local backup_dir="/tmp/tailscale-receiver-backup-$(date +%Y%m%d-%H%M%S)"
   mkdir -p "$backup_dir"
-  
+
   if [ -f "$DEST_SCRIPT_PATH" ]; then
     cp "$DEST_SCRIPT_PATH" "$backup_dir/"
     echo "Backed up receiver script to $backup_dir/"
   fi
-  
+
   if [ -f "$DEST_SEND_SCRIPT_PATH" ]; then
     cp "$DEST_SEND_SCRIPT_PATH" "$backup_dir/"
     echo "Backed up sender script to $backup_dir/"
   fi
-  
+
   if [ -f "$SERVICE_FILE_PATH" ]; then
     cp "$SERVICE_FILE_PATH" "$backup_dir/"
     echo "Backed up service file to $backup_dir/"
   fi
-  
+
+  # Backup environment file if it exists
+  backup_environment_file
+
   echo "Backup created at: $backup_dir"
 }
 
+# Function to create environment file
+create_environment_file() {
+  local target_user="$1"
+  local target_dir="/home/$target_user/Downloads/tailscale"
+
+  print_header "Creating Environment Configuration File"
+
+  # Create directory if it doesn't exist
+  mkdir -p "$(dirname "$ENV_FILE_PATH")" || {
+    print_error_and_exit "Failed to create directory for environment file: $(dirname "$ENV_FILE_PATH")"
+  }
+
+  # Create environment file with proper permissions
+  cat > "$ENV_FILE_PATH" << EOF
+# Tailscale Receiver Configuration File
+# This file contains configuration for the tailscale-receive service
+# Generated by install.sh on $(date)
+
+# Target user for file ownership (required)
+TARGET_USER=$target_user
+
+# Target directory for received files (required)
+TARGET_DIR=$target_dir
+
+# Logging level: debug, info, warn, error
+LOG_LEVEL=info
+
+# Optional: Tailscale auth key for automatic authentication
+# Obtain from: https://login.tailscale.com/admin/settings/keys
+# TS_AUTHKEY=tskey-xxxxxxxxxxxxxxxxxx
+
+# Optional: Archive management settings
+# ARCHIVE_ENABLED=true
+# ARCHIVE_DAYS=14
+# ARCHIVE_DIR_NAME=archive
+
+# Optional: Notification settings
+# NOTIFY_TIMEOUT=10
+EOF
+
+  # Set proper permissions (root:root, 600)
+  chmod 600 "$ENV_FILE_PATH" || {
+    print_error_and_exit "Failed to set permissions on environment file: $ENV_FILE_PATH"
+  }
+
+  chown root:root "$ENV_FILE_PATH" || {
+    print_warning "Failed to set ownership on environment file (non-critical): $ENV_FILE_PATH"
+  }
+
+  print_success "Environment file created: $ENV_FILE_PATH"
+  echo "  📝 Edit this file to customize settings:"
+  echo "     sudo nano $ENV_FILE_PATH"
+  echo "  🔒 File permissions: $(stat -c '%a %U:%G' "$ENV_FILE_PATH")"
+}
+
+# Function to backup environment file if it exists (called from backup_existing_config)
+backup_environment_file() {
+  if [ -f "$ENV_FILE_PATH" ]; then
+    local backup_file="$backup_dir/$(basename "$ENV_FILE_PATH")"
+    cp "$ENV_FILE_PATH" "$backup_file"
+    echo "Backed up environment file to $backup_dir/"
+  fi
+}
+
 # Function to perform preflight checks
 preflight_checks() {
   echo "🔍 Performing preflight checks..."
@@ -173,11 +243,54 @@ preflight_checks() {
     echo "✅ GUI dialog tools available"
   fi
 
+  # Check if target directories are writable (simulate what the script will do)
+  local test_user
+  if [[ -n "${TARGET_USER:-}" ]]; then
+    test_user="$TARGET_USER"
+  elif [[ -n "${SUDO_USER:-}" ]]; then
+    test_user="$SUDO_USER"
+  else
+    test_user="root"
+  fi
+
+  if id "$test_user" &>/dev/null; then
+    local test_dir="/home/$test_user/Downloads"
+    if [[ -d "$test_dir" ]]; then
+      if [[ -w "$test_dir" ]]; then
+        echo "✅ Target directory structure looks good: $test_dir"
+      else
+        echo "⚠️  WARNING: Target directory not writable: $test_dir"
+        echo "   The service may fail to create the tailscale subdirectory."
+        echo "   Check permissions: ls -ld $test_dir"
+        ((issues_found++))
+      fi
+    else
+      echo "⚠️  WARNING: Downloads directory doesn't exist: $test_dir"
+      echo "   It will be created during installation."
+    fi
+  fi
+
+  # Check for existing installation
+  if [ -f "$SERVICE_FILE_PATH" ] || [ -f "$DEST_SCRIPT_PATH" ] || [ -f "$ENV_FILE_PATH" ]; then
+    echo "ℹ️  Existing installation detected."
+    echo "   A backup will be created during installation."
+  fi
+
+  # Check available disk space
+  local available_space
+  available_space=$(df /usr/local | awk 'NR==2 {print int($4/1024)}')  # KB to MB
+  if [[ $available_space -lt 50 ]]; then
+    echo "⚠️  WARNING: Low disk space available: ${available_space}MB"
+    echo "   At least 50MB recommended for installation and logs."
+    ((issues_found++))
+  fi
+
   # Summary
   if [ $issues_found -eq 0 ]; then
     echo "✅ All preflight checks passed!"
   else
-    echo "⚠️  Some optional checks failed, but installation can proceed."
+    echo "⚠️  $issues_found issue(s) found. Review warnings above."
+    echo "   Installation can proceed but may have limited functionality."
   fi
 
   echo ""
@@ -277,22 +390,15 @@ get_target_user() {
 create_receiver_script() {
   local target_user="$1"
   local target_dir="/home/$target_user/Downloads/tailscale"
-  
+
   # Create the target directory and set ownership
   mkdir -p "$target_dir"
   chown "$target_user:$target_user" "$target_dir"
-  
-  # Read the source script and replace the configuration
-  local script_content
-  script_content=$(cat "$SOURCE_SCRIPT")
-  
-  # Replace the configuration section
-  script_content=$(echo "$script_content" | sed "s|TARGET_DIR=.*|TARGET_DIR=\"$target_dir/\"|")
-  script_content=$(echo "$script_content" | sed "s|FIX_OWNER=.*|FIX_OWNER=\"$target_user\"|")
-  
-  # Write the configured script
-  echo "$script_content" > "$DEST_SCRIPT_PATH"
-  chmod +x "$DEST_SCRIPT_PATH"
+
+  # Copy the script without modification (configuration via environment file)
+  install -m 0755 "$SOURCE_SCRIPT" "$DEST_SCRIPT_PATH" || {
+    print_error_and_exit "Failed to install receiver script to '$DEST_SCRIPT_PATH'"
+  }
 }
 
 # Function to show interactive setup wizard
@@ -424,13 +530,15 @@ fi
 # 6. Create and configure the receiver script
 echo "➡️  Installing the receiver script..."
 create_receiver_script "$TARGET_USER"
-print_success "Receiver script installed to '$DEST_SCRIPT_PATH' (configured for user: $TARGET_USER)."
+print_success "Receiver script installed to '$DEST_SCRIPT_PATH'."
 
-# 7. Copy and set permissions for the sender script (for Dolphin context menu)
+# 6. Create environment configuration file
+create_environment_file "$TARGET_USER"
+
+# 7. Install the sender script (for Dolphin context menu)
 if [ -f "$SEND_SOURCE_SCRIPT" ]; then
   echo "➡️  Installing the sender script..."
-  cp "$SEND_SOURCE_SCRIPT" "$DEST_SEND_SCRIPT_PATH" || print_error_and_exit "Failed to copy script to '$DEST_SEND_SCRIPT_PATH'."
-  chmod +x "$DEST_SEND_SCRIPT_PATH" || print_error_and_exit "Failed to make sender script executable."
+  install -m 0755 "$SEND_SOURCE_SCRIPT" "$DEST_SEND_SCRIPT_PATH" || print_error_and_exit "Failed to install sender script to '$DEST_SEND_SCRIPT_PATH'."
   print_success "Sender script installed to '$DEST_SEND_SCRIPT_PATH'."
 else
   echo "⚠️  Sender script '$SEND_SOURCE_SCRIPT' not found. Skipping send integration."
@@ -449,6 +557,7 @@ Wants=network-online.target
 Type=simple
 User=root
 Group=root
+EnvironmentFile=-$ENV_FILE_PATH
 ExecStart=$DEST_SCRIPT_PATH
 Restart=on-failure
 RestartSec=15s
@@ -483,7 +592,7 @@ if [ -f "$DEST_SEND_SCRIPT_PATH" ]; then
   echo "➡️  Installing Dolphin service menu..."
   mkdir -p "$SYS_KIO_SERVICEMENU_DIR" "$SYS_KSERVICES5_SERVICEMENU_DIR"
 
-  # Write a single .desktop content
+  # Create desktop service menu file
   DESKTOP_CONTENT='[Desktop Entry]
 Type=Service
 X-KDE-ServiceTypes=KonqPopupMenu/Plugin
@@ -496,8 +605,14 @@ Icon=network-workgroup
 Exec=/usr/local/bin/tailscale-send.sh %F
 '
 
-  echo "$DESKTOP_CONTENT" > "$SYS_KIO_SERVICEMENU_DIR/tailscale-send.desktop" || print_error_and_exit "Failed to write service menu (.kio)."
-  echo "$DESKTOP_CONTENT" > "$SYS_KSERVICES5_SERVICEMENU_DIR/tailscale-send.desktop" || print_error_and_exit "Failed to write service menu (kservices5)."
+  # Create temporary file and install it
+  TMP_DESKTOP_FILE=$(mktemp) || print_error_and_exit "Failed to create temporary file for desktop menu."
+  echo "$DESKTOP_CONTENT" > "$TMP_DESKTOP_FILE" || print_error_and_exit "Failed to write desktop content to temporary file."
+
+  install -m 0644 "$TMP_DESKTOP_FILE" "$SYS_KIO_SERVICEMENU_DIR/tailscale-send.desktop" || print_error_and_exit "Failed to install service menu (.kio)."
+  install -m 0644 "$TMP_DESKTOP_FILE" "$SYS_KSERVICES5_SERVICEMENU_DIR/tailscale-send.desktop" || print_error_and_exit "Failed to install service menu (kservices5)."
+
+  rm -f "$TMP_DESKTOP_FILE"
   print_success "Dolphin service menu installed."
 
   # Rebuild KDE service cache if tools exist