#!/bin/bash
#
# Fix DropboxHelperInstaller
#
# Revised - 2025.09.15
#
# This script fixes issues with Dropbox displaying prompts for administrator privileges
# after installation. It extracts the Dropbox Helper Tool installer from each Dropbox
# installation to ensure compatibility and proper authorization.
#
# The script:
#
# 1. Validates Dropbox application exists and contains the helper installer
# 2. Creates the DropboxHelperTools directory if needed
# 3. Extracts the helper installer with proper permissions
# 4. Sets SUID permissions for elevated privilege operations
#
# Copyright (c) 2025 University of Utah, Marriott Library, Client Platform Services.
# All Rights Reserved.
#
# Permission to use, copy, modify, and distribute this software and
# its documentation for any purpose and without fee is hereby granted,
# provided that the above copyright notice appears in all copies and
# that both that copyright notice and this permission notice appear
# in supporting documentation, and that the name of The University
# of Utah not be used in advertising or publicity pertaining to
# distribution of the software without specific, written prior
# permission. This software is supplied as is without expressed or
# implied warranties of any kind.

set -euo pipefail  # Exit on error, undefined vars, pipe failures

##################################
# Global Variables
##################################

readonly SCRIPT_NAME="$(basename "$0")"
readonly LOG_PREFIX="$(date '+%Y-%m-%d %H:%M:%S') - ${SCRIPT_NAME}"

# Dropbox paths - configurable section
readonly DROPBOX_APP_PATH="/Applications/Dropbox.app"
readonly DROPBOX_HELPER_INSTALLER_SOURCE_PATH="${DROPBOX_APP_PATH}/Contents/Resources/DropboxHelperInstaller.tgz"
readonly DROPBOX_HELPER_TOOLS_TARGET_DIR_PATH="/Library/DropboxHelperTools"
readonly DROPBOX_HELPER_INSTALLER_TARGET_PATH="${DROPBOX_HELPER_TOOLS_TARGET_DIR_PATH}/DropboxHelperInstaller"

##################################
# Functions
##################################

# Logging function
log()
{
    local level="$1"
    shift
    echo "${LOG_PREFIX} - ${level}: $*"
}

# Validate Dropbox application exists and is properly installed
validate_dropbox_installation()
{
    log "INFO" "Validating Dropbox installation..."
    
    if [[ ! -d "$DROPBOX_APP_PATH" ]]; then
        log "ERROR" "Dropbox application not found at: $DROPBOX_APP_PATH"
        log "ERROR" "Please install Dropbox before running this script"
        return 1
    fi
    
    if [[ ! -f "$DROPBOX_HELPER_INSTALLER_SOURCE_PATH" ]]; then
        log "ERROR" "DropboxHelperInstaller.tgz not found in Dropbox bundle"
        log "ERROR" "Expected location: $DROPBOX_HELPER_INSTALLER_SOURCE_PATH"
        log "ERROR" "This may indicate a corrupted or incomplete Dropbox installation"
        return 1
    fi
    
    # Verify the tar file is valid
    if ! tar -tzf "$DROPBOX_HELPER_INSTALLER_SOURCE_PATH" >/dev/null 2>&1; then
        log "ERROR" "DropboxHelperInstaller.tgz appears to be corrupted"
        return 1
    fi
    
    log "SUCCESS" "Dropbox installation validated successfully"
    return 0
}

# Create target directory with proper permissions
create_target_directory()
{
    log "INFO" "Creating DropboxHelperTools directory..."
    
    if [[ ! -d "$DROPBOX_HELPER_TOOLS_TARGET_DIR_PATH" ]]; then
        if mkdir -p "$DROPBOX_HELPER_TOOLS_TARGET_DIR_PATH"; then
            log "SUCCESS" "Created directory: $DROPBOX_HELPER_TOOLS_TARGET_DIR_PATH"
        else
            log "ERROR" "Failed to create directory: $DROPBOX_HELPER_TOOLS_TARGET_DIR_PATH"
            return 1
        fi
    else
        log "INFO" "Directory already exists: $DROPBOX_HELPER_TOOLS_TARGET_DIR_PATH"
    fi
    
    return 0
}

# Extract the helper installer
extract_helper_installer()
{
    log "INFO" "Extracting DropboxHelperInstaller from Dropbox bundle..."
    
    # Remove existing installer if present (force fresh extraction)
    if [[ -f "$DROPBOX_HELPER_INSTALLER_TARGET_PATH" ]]; then
        log "INFO" "Removing existing installer for fresh extraction"
        rm -f "$DROPBOX_HELPER_INSTALLER_TARGET_PATH"
    fi
    
    # Extract without verbose output to reduce log noise
    if tar -zxf "$DROPBOX_HELPER_INSTALLER_SOURCE_PATH" -C "$DROPBOX_HELPER_TOOLS_TARGET_DIR_PATH"; then
        log "SUCCESS" "Successfully extracted DropboxHelperInstaller"
    else
        log "ERROR" "Failed to extract DropboxHelperInstaller"
        return 1
    fi
    
    # Verify extraction was successful
    if [[ ! -f "$DROPBOX_HELPER_INSTALLER_TARGET_PATH" ]]; then
        log "ERROR" "DropboxHelperInstaller not found after extraction"
        log "ERROR" "Expected location: $DROPBOX_HELPER_INSTALLER_TARGET_PATH"
        return 1
    fi
    
    return 0
}

# Set proper permissions on the helper installer
set_permissions()
{
    log "INFO" "Setting proper permissions on DropboxHelperInstaller..."
    
    # Set ownership to root:wheel for both directory and installer
    if chown root:wheel "$DROPBOX_HELPER_TOOLS_TARGET_DIR_PATH" "$DROPBOX_HELPER_INSTALLER_TARGET_PATH"; then
        log "SUCCESS" "Set ownership to root:wheel"
    else
        log "ERROR" "Failed to set ownership"
        return 1
    fi
    
    # Set SUID permissions (04511)
    # 0 = no special modes for group/others
    # 4 = SUID (set user ID on execution)
    # 5 = read + execute for owner
    # 1 = execute only for group
    # 1 = execute only for others
    
    if chmod 04511 "$DROPBOX_HELPER_INSTALLER_TARGET_PATH"; then
        log "SUCCESS" "Set installer permissions to 04511 (SUID enabled)"
    else
        log "ERROR" "Failed to set installer permissions"
        return 1
    fi
    
    # Verify permissions were set correctly
    local perms
    perms=$(stat -f "%Sp %u:%g" "$DROPBOX_HELPER_INSTALLER_TARGET_PATH" 2>/dev/null || echo "unknown")
    log "INFO" "Final permissions: $perms"
    
    return 0
}

# Verify the installation was successful
verify_installation()
{
    log "INFO" "Verifying DropboxHelperInstaller installation..."
    
    # Check file exists and is executable
    if [[ ! -x "$DROPBOX_HELPER_INSTALLER_TARGET_PATH" ]]; then
        log "ERROR" "DropboxHelperInstaller is not executable"
        return 1
    fi
    
    # Check SUID bit is set
    if [[ ! -u "$DROPBOX_HELPER_INSTALLER_TARGET_PATH" ]]; then
        log "ERROR" "SUID bit not set on DropboxHelperInstaller"
        return 1
    fi
    
    # Check ownership
    local owner
    owner=$(stat -f "%u:%g" "$DROPBOX_HELPER_INSTALLER_TARGET_PATH" 2>/dev/null || echo "unknown")
    if [[ "$owner" != "0:0" ]]; then
        log "ERROR" "Incorrect ownership on DropboxHelperInstaller (expected 0:0, got $owner)"
        return 1
    fi
    
    log "SUCCESS" "DropboxHelperInstaller installation verified successfully"
    return 0
}

##################################
# Main Execution
##################################

main()
{
    log "INFO" "=== Starting Dropbox Helper Installer Fix ==="
    log "INFO" "Script version: 2025.09.15"
    log "INFO" "Running as: $(whoami)"
    
    # Validate we're running as root
    if [[ $EUID -ne 0 ]]; then
        log "ERROR" "This script must be run as root (required for SUID permissions)"
        log "ERROR" "Please run with sudo or as root user"
        exit 1
    fi
    
    # Execute main steps
    if ! validate_dropbox_installation; then
        exit 1
    fi
    
    if ! create_target_directory; then
        exit 1
    fi
    
    if ! extract_helper_installer; then
        exit 1
    fi
    
    if ! set_permissions; then
        exit 1
    fi
    
    if ! verify_installation; then
        exit 1
    fi
    
    log "SUCCESS" "=== Dropbox Helper Installer Fix Completed Successfully ==="
    log "INFO" "Dropbox should no longer prompt for administrator privileges"
    
    exit 0
}

# Execute main function
main "$@"