import os
import sys
from google import genai
from google.genai import types

def main():
    # When API keys are disabled by organizational policy, we must authenticate using
    # Google Cloud Application Default Credentials (ADC) via the Gemini Enterprise Agent Platform (Vertex AI) API.
    
    # Check for GCP project configuration
    project_id = os.environ.get("GOOGLE_CLOUD_PROJECT")
    location = os.environ.get("GOOGLE_CLOUD_LOCATION", "us-central1")
    
    if not project_id:
        print("Error: GOOGLE_CLOUD_PROJECT environment variable is not set.", file=sys.stderr)
        print("Please configure your GCP project using one of the following methods:", file=sys.stderr)
        print("\nMethod 1: Set the environment variable directly:", file=sys.stderr)
        print("  export GOOGLE_CLOUD_PROJECT=\"your-gcp-project-id\"", file=sys.stderr)
        print("\nMethod 2: Authenticate using gcloud CLI Application Default Credentials (ADC):", file=sys.stderr)
        print("  gcloud auth application-default login", file=sys.stderr)
        print("  gcloud config set project your-gcp-project-id", file=sys.stderr)
        sys.exit(1)

    print("Initializing Gemini Client via Gemini Enterprise Agent Platform (Vertex AI) using Application Default Credentials (ADC)...")
    print(f"Project ID: {project_id}")
    print(f"Location:   {location}")
    print("-" * 50)

    try:
        # Initialize the Client for Gemini Enterprise Agent Platform (Vertex AI) using Application Default Credentials (ADC).
        # Setting vertexai=True routes the request through the Gemini Enterprise Agent Platform (Vertex AI Agent Engine).
        client = genai.Client(
            vertexai=True,
            project=project_id,
            location=location
        )
    except Exception as e:
        print(f"Failed to initialize client: {e}", file=sys.stderr)
        print("Please ensure you have run 'gcloud auth application-default login'", file=sys.stderr)
        sys.exit(1)

    # Use the gemini-3.5-flash model, which offers frontier-level reasoning,
    # coding capability, and agentic workflows.
    model_name = "gemini-2.5-flash"

    # Prepare a simple text prompt
    prompt = "Explain the concept of containerization in three simple sentences."

    print(f"\nSending prompt to model '{model_name}':")
    print(f"\"{prompt}\"")
    print("-" * 50)

    try:
        # Send the prompt to Gemini Enterprise Agent Platform (Vertex AI) and get the response
        response = client.models.generate_content(
            model=model_name,
            contents=prompt,
        )

        # Print the response text
        print("Response received:")
        print(response.text)
        print("-" * 50)

    except Exception as e:
        print(f"An error occurred while generating content: {e}", file=sys.stderr)
        print("\nTroubleshooting tips:", file=sys.stderr)
        print("1. Ensure Gemini Enterprise Agent Platform (Vertex AI) API ('aiplatform.googleapis.com') is enabled in your project.", file=sys.stderr)
        print("2. Ensure your authenticated identity has the \"Gemini Enterprise Agent Platform User\" (\"Vertex AI User\") role (roles/aiplatform.user).", file=sys.stderr)
        sys.exit(1)

    # Example 2: Sending a prompt with configuration options (temperature, etc.)
    prompt_config = "Describe three advantages of microservices architecture."
    print(f"\nSending prompt with configuration to model '{model_name}':")
    print(f"\"{prompt_config}\"")
    print("-" * 50)

    try:
        response_config = client.models.generate_content(
            model=model_name,
            contents=prompt_config,
            config=types.GenerateContentConfig(
                temperature=0.2,       # Lower temperature means more deterministic responses
                max_output_tokens=300, # Limit the response length
            )
        )
        print("Response received (with config):")
        print(response_config.text)
        print("-" * 50)

    except Exception as e:
        print(f"An error occurred: {e}", file=sys.stderr)
        sys.exit(1)

if __name__ == "__main__":
    main()