/**
 * Test class: Verify object pool manager functionality
 * @author chuyang
 * @version 1.0
 */
public class ConnectionPoolTest {

	public ConnectionPoolManager m_ConnectionPoolManager;

	public ConnectionPoolTest(){

	}

	@Override
	public void finalize() throws Throwable {

	}
	/**
	 * Main test method
	 * @param args
	 */
	public static void main(String[] args) {
		System.out.println("=== Start Object Pool Manager Test ===");
		
		// 1. Test initializing connection pool
		System.out.println("\n1. Initialize connection pool");
		ConnectionPoolManager poolManager = new ConnectionPoolManager(2, 5, "jdbc:mysql://localhost:3306/testdb");
		System.out.println(poolManager.getPoolStatus());
		
		// 2. Test borrowing connections
		System.out.println("\n2. Test borrowing connections");
		DatabaseConnection conn1 = poolManager.borrowConnection();
		DatabaseConnection conn2 = poolManager.borrowConnection();
		DatabaseConnection conn3 = poolManager.borrowConnection(); // Should create new connection
		System.out.println(poolManager.getPoolStatus());
		
		// 3. Test returning connections
		System.out.println("\n3. Test returning connections");
		poolManager.returnConnection(conn1);
		System.out.println(poolManager.getPoolStatus());
		
		// 4. Test reusing connections
		System.out.println("\n4. Test reusing connections");
		DatabaseConnection conn4 = poolManager.borrowConnection(); // Should reuse just returned connection
		System.out.println("Reused connection ID: " + conn4.getConnectionId());
		System.out.println(poolManager.getPoolStatus());
		
		// 5. Test pool full condition
		System.out.println("\n5. Test pool full condition");
		DatabaseConnection conn5 = poolManager.borrowConnection(); // Create 4th connection
		DatabaseConnection conn6 = poolManager.borrowConnection(); // Create 5th connection (reach max capacity)
		DatabaseConnection conn7 = poolManager.borrowConnection(); // Should return null as pool is full
		System.out.println("Result of borrowing beyond max capacity: " + (conn7 == null ? "Pool is full, cannot borrow more connections" : "Successfully borrowed connection"));
		System.out.println(poolManager.getPoolStatus());
		
		// 6. Test shrinking pool
		System.out.println("\n6. Test shrinking pool");
		// Return some connections for shrinking
		poolManager.returnConnection(conn2);
		poolManager.returnConnection(conn3);
		poolManager.returnConnection(conn5);
		poolManager.returnConnection(conn6);
		System.out.println("Before shrink " + poolManager.getPoolStatus());
		poolManager.shrinkPool();
		System.out.println("After shrink " + poolManager.getPoolStatus());
		
		// 7. Test thread safety (simple test)
		System.out.println("\n7. Simple thread safety test");
		ConnectionPoolManager threadTestPool = new ConnectionPoolManager(3, 10, "jdbc:mysql://localhost:3306/testdb");
		
		// Create several threads to borrow and return connections simultaneously
		Thread[] threads = new Thread[5];
		for (int i = 0; i < threads.length; i++) {
			final int threadId = i;
			threads[i] = new Thread(() -> {
				try {
					System.out.println("Thread " + threadId + " borrowing connection");
					DatabaseConnection conn = threadTestPool.borrowConnection();
					if (conn != null) {
						System.out.println("Thread " + threadId + " got connection: " + conn.getConnectionId());
						// Simulate using connection
						Thread.sleep(200);
						threadTestPool.returnConnection(conn);
						System.out.println("Thread " + threadId + " returned connection: " + conn.getConnectionId());
					}
				} catch (Exception e) {
					e.printStackTrace();
				}
			});
			threads[i].start();
		}
		
		// Wait for all threads to complete
		for (Thread thread : threads) {
			try {
				thread.join();
			} catch (InterruptedException e) {
				Thread.currentThread().interrupt();
			}
		}
		
		System.out.println("\nAfter thread test " + threadTestPool.getPoolStatus());
		
		// 8. Test DatabaseConnection clone functionality
		System.out.println("\n8. Test connection clone functionality");
		DatabaseConnection originalConn = new DatabaseConnection("original-clone-test", "jdbc:mysql://localhost:3306/clonedb");
		DatabaseConnection clonedConn = originalConn.clone();
		System.out.println("Original connection ID: " + originalConn.getConnectionId());
		System.out.println("Cloned connection ID: " + clonedConn.getConnectionId());
		System.out.println("Cloned connection URL: " + clonedConn.getDatabaseUrl());
		
		System.out.println("\n=== Object Pool Manager Test Completed ===");
	}
}