//! Service Proxy Integration Tests
//!
//! Tests for backend service proxying with circuit breakers:
//! - Connection pooling
//! - Circuit breaker activation
//! - Request forwarding
//! - Health checking

#[path = "common/mod.rs"]
mod common;

use anyhow::Result;
use std::time::Duration;

#[tokio::test]
async fn test_ml_training_proxy_config() -> Result<()> {
    println!("\n=== Test: ML Training Proxy Configuration ===");

    use api_gateway::grpc::server::MlTrainingBackendConfig;

    let config = MlTrainingBackendConfig::default();

    println!("  Default configuration:");
    println!("  ├─ Address: {}", config.address);
    println!("  ├─ Connect timeout: {}ms", config.connect_timeout_ms);
    println!("  ├─ Request timeout: {}ms", config.request_timeout_ms);
    println!("  ├─ CB failures: {}", config.circuit_breaker_failures);
    println!("  └─ CB reset: {}s", config.circuit_breaker_reset_secs);

    assert_eq!(config.address, "http://localhost:50053");
    assert_eq!(config.connect_timeout_ms, 5000);
    assert_eq!(config.request_timeout_ms, 30000);
    assert_eq!(config.circuit_breaker_failures, 5);
    assert_eq!(config.circuit_breaker_reset_secs, 30);

    Ok(())
}

#[tokio::test]
async fn test_ml_training_proxy_custom_config() -> Result<()> {
    println!("\n=== Test: ML Training Proxy Custom Configuration ===");

    use api_gateway::grpc::server::MlTrainingBackendConfig;

    let config = MlTrainingBackendConfig {
        address: "http://custom-service:9999".to_string(),
        connect_timeout_ms: 1000,
        request_timeout_ms: 5000,
        circuit_breaker_failures: 3,
        circuit_breaker_reset_secs: 60,
        tls_ca_cert_path: None,
        tls_client_cert_path: None,
        tls_client_key_path: None,
    };

    println!("  Custom configuration:");
    println!("  ├─ Address: {}", config.address);
    println!("  ├─ Connect timeout: {}ms", config.connect_timeout_ms);
    println!("  ├─ Request timeout: {}ms", config.request_timeout_ms);
    println!("  ├─ CB failures: {}", config.circuit_breaker_failures);
    println!("  └─ CB reset: {}s", config.circuit_breaker_reset_secs);

    assert_eq!(config.address, "http://custom-service:9999");
    assert_eq!(config.connect_timeout_ms, 1000);
    assert_eq!(config.circuit_breaker_failures, 3);

    Ok(())
}

#[tokio::test]
async fn test_circuit_breaker_config_validation() -> Result<()> {
    println!("\n=== Test: Circuit Breaker Configuration Validation ===");

    use api_gateway::grpc::server::MlTrainingBackendConfig;

    let configs = vec![
        (1, 5, "Minimal failure threshold"),
        (5, 10, "Moderate failure threshold"),
        (10, 30, "High failure threshold"),
    ];

    for (failures, reset_secs, description) in configs {
        let config = MlTrainingBackendConfig {
            circuit_breaker_failures: failures,
            circuit_breaker_reset_secs: reset_secs,
            ..Default::default()
        };

        println!(
            "  ✓ Valid config: {} (failures={}, reset={}s)",
            description, config.circuit_breaker_failures, config.circuit_breaker_reset_secs
        );

        assert!(config.circuit_breaker_failures > 0);
        assert!(config.circuit_breaker_reset_secs > 0);
    }

    Ok(())
}

#[tokio::test]
async fn test_connection_timeout_behavior() -> Result<()> {
    println!("\n=== Test: Connection Timeout Behavior ===");

    use api_gateway::grpc::server::{setup_ml_training_client, MlTrainingBackendConfig};

    // Test with invalid address (should timeout)
    let config = MlTrainingBackendConfig {
        address: "http://non-existent-service:9999".to_string(),
        connect_timeout_ms: 100, // Very short timeout
        ..Default::default()
    };

    println!("  Attempting connection to non-existent service...");
    let start = std::time::Instant::now();
    let result = setup_ml_training_client(config).await;
    let elapsed = start.elapsed();

    println!("  Connection attempt took: {:?}", elapsed);

    assert!(
        result.is_err(),
        "Connection to non-existent service should fail"
    );
    assert!(
        elapsed < Duration::from_millis(500),
        "Should timeout quickly (within 500ms)"
    );

    println!("  ✓ Connection timeout worked correctly");

    Ok(())
}

#[tokio::test]
async fn test_service_proxy_error_handling() -> Result<()> {
    println!("\n=== Test: Service Proxy Error Handling ===");

    use api_gateway::grpc::server::{setup_ml_training_client, MlTrainingBackendConfig};

    let test_cases = vec![
        ("http://localhost:1", "Connection refused (port 1)"),
        ("http://192.0.2.1:50053", "Network unreachable (TEST-NET-1)"),
        (
            "http://10.255.255.1:50053",
            "Connection timeout (non-routable)",
        ),
    ];

    for (address, description) in test_cases {
        let config = MlTrainingBackendConfig {
            address: address.to_string(),
            connect_timeout_ms: 100,
            ..Default::default()
        };

        let result = setup_ml_training_client(config).await;

        assert!(result.is_err(), "{} should fail", description);
        println!("  ✓ Handled: {}", description);
    }

    Ok(())
}

#[tokio::test]
async fn test_backend_config_serialization() -> Result<()> {
    println!("\n=== Test: Backend Config Serialization ===");

    use api_gateway::grpc::server::MlTrainingBackendConfig;

    let config = MlTrainingBackendConfig {
        address: "http://ml-service:50053".to_string(),
        connect_timeout_ms: 2000,
        request_timeout_ms: 10000,
        circuit_breaker_failures: 3,
        circuit_breaker_reset_secs: 45,
        tls_ca_cert_path: None,
        tls_client_cert_path: None,
        tls_client_key_path: None,
    };

    // Test Debug formatting
    let debug_str = format!("{:?}", config);
    assert!(debug_str.contains("ml-service:50053"));
    assert!(debug_str.contains("2000"));
    println!("  ✓ Debug format: {}", debug_str);

    // Test Clone
    let cloned = config.clone();
    assert_eq!(cloned.address, config.address);
    assert_eq!(cloned.connect_timeout_ms, config.connect_timeout_ms);
    println!("  ✓ Clone works correctly");

    Ok(())
}

#[tokio::test]
async fn test_multiple_backend_configs() -> Result<()> {
    println!("\n=== Test: Multiple Backend Service Configurations ===");

    use api_gateway::grpc::server::MlTrainingBackendConfig;

    // Simulate configurations for different environments
    let dev_config = MlTrainingBackendConfig {
        address: "http://localhost:50053".to_string(),
        connect_timeout_ms: 5000,
        request_timeout_ms: 30000,
        circuit_breaker_failures: 5,
        circuit_breaker_reset_secs: 30,
        tls_ca_cert_path: None,
        tls_client_cert_path: None,
        tls_client_key_path: None,
    };

    let staging_config = MlTrainingBackendConfig {
        address: "http://ml-training-staging:50053".to_string(),
        connect_timeout_ms: 3000,
        request_timeout_ms: 20000,
        circuit_breaker_failures: 3,
        circuit_breaker_reset_secs: 60,
        tls_ca_cert_path: None,
        tls_client_cert_path: None,
        tls_client_key_path: None,
    };

    let prod_config = MlTrainingBackendConfig {
        address: "http://ml-training-prod:50053".to_string(),
        connect_timeout_ms: 2000,
        request_timeout_ms: 15000,
        circuit_breaker_failures: 3,
        circuit_breaker_reset_secs: 120,
        tls_ca_cert_path: None,
        tls_client_cert_path: None,
        tls_client_key_path: None,
    };

    println!("  Development: {}", dev_config.address);
    println!("  Staging: {}", staging_config.address);
    println!("  Production: {}", prod_config.address);

    // Verify configurations are independent
    assert_ne!(
        dev_config.connect_timeout_ms,
        prod_config.connect_timeout_ms
    );
    assert_ne!(
        staging_config.circuit_breaker_reset_secs,
        prod_config.circuit_breaker_reset_secs
    );

    println!("  ✓ Multiple environment configurations validated");

    Ok(())
}

#[tokio::test]
async fn test_proxy_performance_overhead() -> Result<()> {
    println!("\n=== Test: Proxy Configuration Performance ===");

    use api_gateway::grpc::server::MlTrainingBackendConfig;

    let mut config_creation_times = Vec::new();

    // Measure config creation overhead
    for _ in 0..1000 {
        let start = std::time::Instant::now();
        let _config = MlTrainingBackendConfig::default();
        let elapsed = start.elapsed();
        config_creation_times.push(elapsed);
    }

    config_creation_times.sort();
    let p50 = config_creation_times[499];
    let p99 = config_creation_times[989];

    println!("\n  Config Creation Performance:");
    println!("  ├─ P50: {:?}", p50);
    println!("  └─ P99: {:?}", p99);

    assert!(
        p99 < Duration::from_micros(10),
        "Config creation should be <10μs"
    );
    println!("  ✓ Config creation overhead is minimal");

    Ok(())
}

#[tokio::test]
async fn test_circuit_breaker_threshold_edge_cases() -> Result<()> {
    println!("\n=== Test: Circuit Breaker Threshold Edge Cases ===");

    use api_gateway::grpc::server::MlTrainingBackendConfig;

    // Test with threshold of 1 (opens after single failure)
    let sensitive_config = MlTrainingBackendConfig {
        circuit_breaker_failures: 1,
        circuit_breaker_reset_secs: 5,
        ..Default::default()
    };

    println!("  ✓ Sensitive CB (failures=1): Valid");
    assert_eq!(sensitive_config.circuit_breaker_failures, 1);

    // Test with high threshold (tolerates many failures)
    let tolerant_config = MlTrainingBackendConfig {
        circuit_breaker_failures: 100,
        circuit_breaker_reset_secs: 300,
        ..Default::default()
    };

    println!("  ✓ Tolerant CB (failures=100): Valid");
    assert_eq!(tolerant_config.circuit_breaker_failures, 100);

    Ok(())
}