//! Tests for RegionManager - Multi-region orchestration
//! Following strict TDD: These are FAILING tests written FIRST

use rtx_platform::{
    PlatformConfig, PlatformError,
    error::RegionError,
    region::{CrossRegionOp, RegionConfig, RegionHealth, RegionManager},
};
use std::collections::HashMap;
use uuid::Uuid;

/// Create test configuration
fn create_test_config() -> PlatformConfig {
    let mut regions = HashMap::new();

    regions.insert(
        "us-east-1".to_string(),
        RegionConfig {
            id: "us-east-1".to_string(),
            name: "US East 1".to_string(),
            endpoint: "https://us-east-1.rustytorch.com".to_string(),
            capacity_limits: HashMap::from([
                ("gpu".to_string(), 1000),
                ("memory_gb".to_string(), 10000),
                ("storage_gb".to_string(), 100000),
            ]),
            availability_zone_count: 3,
            latency_targets_ms: HashMap::from([
                ("us-west-1".to_string(), 100),
                ("eu-west-1".to_string(), 150),
            ]),
        },
    );

    regions.insert(
        "us-west-1".to_string(),
        RegionConfig {
            id: "us-west-1".to_string(),
            name: "US West 1".to_string(),
            endpoint: "https://us-west-1.rustytorch.com".to_string(),
            capacity_limits: HashMap::from([
                ("gpu".to_string(), 800),
                ("memory_gb".to_string(), 8000),
                ("storage_gb".to_string(), 80000),
            ]),
            availability_zone_count: 3,
            latency_targets_ms: HashMap::from([
                ("us-east-1".to_string(), 100),
                ("eu-west-1".to_string(), 180),
            ]),
        },
    );

    regions.insert(
        "eu-west-1".to_string(),
        RegionConfig {
            id: "eu-west-1".to_string(),
            name: "EU West 1".to_string(),
            endpoint: "https://eu-west-1.rustytorch.com".to_string(),
            capacity_limits: HashMap::from([
                ("gpu".to_string(), 600),
                ("memory_gb".to_string(), 6000),
                ("storage_gb".to_string(), 60000),
            ]),
            availability_zone_count: 2,
            latency_targets_ms: HashMap::from([
                ("us-east-1".to_string(), 150),
                ("us-west-1".to_string(), 180),
            ]),
        },
    );

    PlatformConfig {
        database_url: "postgresql://test:test@localhost/test".to_string(),
        redis_urls: vec!["redis://localhost:6379".to_string()],
        kafka_brokers: vec!["localhost:9092".to_string()],
        metrics_endpoint: "http://localhost:9090".to_string(),
        regions,
        sla_targets: rtx_platform::slo::SlaTargets {
            availability_percentage: 99.95,
            max_latency_p50_ms: 100,
            max_latency_p99_ms: 500,
            max_latency_p999_ms: 2000,
            max_error_rate_percentage: 0.1,
            error_budget_burn_rate_threshold: 2.0,
            downtime_budget_minutes_per_month: 43.8,
        },
    }
}

#[tokio::test]
async fn test_region_manager_creation_and_initialization() {
    let config = create_test_config();

    // This test WILL FAIL initially - RegionManager doesn't exist yet
    let manager = RegionManager::new(&config)
        .await
        .expect("Failed to create RegionManager");

    // Verify all regions are registered
    assert_eq!(manager.get_region_count().await, 3);

    // Verify each region is properly configured
    let us_east = manager
        .get_region("us-east-1")
        .await
        .expect("us-east-1 not found");
    assert_eq!(us_east.id, "us-east-1");
    assert_eq!(us_east.availability_zone_count, 3);
    assert_eq!(us_east.capacity_limits.get("gpu"), Some(&1000));
}

#[tokio::test]
async fn test_region_health_monitoring() {
    let config = create_test_config();
    let mut manager = RegionManager::new(&config).await.unwrap();

    // Start health monitoring
    manager
        .start_health_monitoring()
        .await
        .expect("Failed to start health monitoring");

    // Wait for initial health checks
    tokio::time::sleep(tokio::time::Duration::from_millis(100)).await;

    // This test WILL FAIL - health monitoring not implemented
    let health = manager
        .get_region_health("us-east-1")
        .await
        .expect("Failed to get health");

    match health {
        RegionHealth::Healthy { uptime, .. } => {
            assert!(uptime > std::time::Duration::from_secs(0));
        }
        _ => panic!("Region should be healthy after startup"),
    }
}

#[tokio::test]
async fn test_cross_region_operation_coordination() {
    let config = create_test_config();
    let mut manager = RegionManager::new(&config).await.unwrap();
    manager.start().await.unwrap();

    let tenant_id = Uuid::new_v4();
    let operation_id = Uuid::new_v4();

    // Create a cross-region tensor operation
    let cross_region_op = CrossRegionOp {
        id: operation_id,
        tenant_id,
        source_region: "us-east-1".to_string(),
        target_regions: vec!["us-west-1".to_string(), "eu-west-1".to_string()],
        operation_type: "tensor_allreduce".to_string(),
        data_size_bytes: 1024 * 1024 * 100, // 100MB
        priority: 1,
        timeout_ms: 5000,
    };

    // This test WILL FAIL - cross-region coordination not implemented
    let result = manager
        .coordinate_cross_region_operation(cross_region_op)
        .await;
    assert!(result.is_ok());

    let coordination_result = result.unwrap();
    assert_eq!(coordination_result.operation_id, operation_id);
    assert!(coordination_result.latency_ms < 5000);
    assert_eq!(coordination_result.participating_regions.len(), 3);
}

#[tokio::test]
async fn test_region_failover_mechanism() {
    let config = create_test_config();
    let mut manager = RegionManager::new(&config).await.unwrap();
    manager.start().await.unwrap();

    let tenant_id = Uuid::new_v4();

    // Initially schedule operation in us-east-1
    let operation_req = manager.create_operation_request(
        tenant_id,
        "us-east-1",
        "model_inference",
        1024 * 1024 * 50, // 50MB
    );

    let initial_assignment = manager
        .schedule_operation(operation_req)
        .await
        .expect("Failed to schedule operation");
    assert_eq!(initial_assignment.assigned_region, "us-east-1");

    // Simulate us-east-1 failure
    manager
        .mark_region_unavailable("us-east-1", "simulated_failure")
        .await
        .expect("Failed to mark region unavailable");

    // This test WILL FAIL - failover mechanism not implemented
    let failover_req = manager.create_operation_request(
        tenant_id,
        "us-east-1", // Request same region
        "model_inference",
        1024 * 1024 * 50,
    );

    let failover_assignment = manager
        .schedule_operation(failover_req)
        .await
        .expect("Failed to handle failover");

    // Should be automatically redirected to available region
    assert_ne!(failover_assignment.assigned_region, "us-east-1");
    assert!(
        failover_assignment.assigned_region == "us-west-1"
            || failover_assignment.assigned_region == "eu-west-1"
    );
    assert!(failover_assignment.is_failover);
}

#[tokio::test]
async fn test_region_capacity_management() {
    let config = create_test_config();
    let mut manager = RegionManager::new(&config).await.unwrap();
    manager.start().await.unwrap();

    let tenant_id = Uuid::new_v4();

    // Check initial capacity
    let initial_capacity = manager
        .get_region_capacity("us-east-1")
        .await
        .expect("Failed to get initial capacity");
    assert_eq!(initial_capacity.total_gpu, 1000);
    assert_eq!(initial_capacity.available_gpu, 1000);

    // Reserve significant capacity
    let reservation = manager
        .reserve_capacity(
            "us-east-1",
            tenant_id,
            HashMap::from([("gpu".to_string(), 800), ("memory_gb".to_string(), 8000)]),
        )
        .await
        .expect("Failed to reserve capacity");

    // This test WILL FAIL - capacity management not implemented
    let updated_capacity = manager.get_region_capacity("us-east-1").await.unwrap();
    assert_eq!(updated_capacity.available_gpu, 200);
    assert_eq!(updated_capacity.reserved_gpu, 800);

    // Try to over-reserve - should fail
    let over_reservation_result = manager
        .reserve_capacity(
            "us-east-1",
            Uuid::new_v4(),
            HashMap::from([("gpu".to_string(), 300)]), // Only 200 available
        )
        .await;

    assert!(matches!(
        over_reservation_result,
        Err(PlatformError::Region(RegionError::CapacityExhausted { .. }))
    ));
}

#[tokio::test]
async fn test_region_latency_optimization() {
    let config = create_test_config();
    let mut manager = RegionManager::new(&config).await.unwrap();
    manager.start().await.unwrap();

    let tenant_id = Uuid::new_v4();

    // Request operation with latency constraints
    let latency_sensitive_req = manager.create_latency_sensitive_request(
        tenant_id,
        vec!["us-east-1".to_string(), "us-west-1".to_string()],
        100, // Max 100ms latency between regions
        "distributed_training",
        1024 * 1024 * 200, // 200MB
    );

    // This test WILL FAIL - latency optimization not implemented
    let assignment = manager
        .optimize_for_latency(latency_sensitive_req)
        .await
        .expect("Failed to optimize for latency");

    // Verify latency constraints are met
    assert!(assignment.max_inter_region_latency_ms <= 100);
    assert!(
        assignment
            .participating_regions
            .contains(&"us-east-1".to_string())
    );
    assert!(
        assignment
            .participating_regions
            .contains(&"us-west-1".to_string())
    );

    // Verify optimal region selection based on latency matrix
    let latency_matrix = assignment.latency_matrix;
    for (source, targets) in latency_matrix {
        for (target, latency) in targets {
            if assignment.participating_regions.contains(&source)
                && assignment.participating_regions.contains(&target)
            {
                assert!(latency <= 100.0);
            }
        }
    }
}

#[tokio::test]
async fn test_region_data_locality_optimization() {
    let config = create_test_config();
    let mut manager = RegionManager::new(&config).await.unwrap();
    manager.start().await.unwrap();

    let tenant_id = Uuid::new_v4();

    // Simulate data already present in specific regions
    manager
        .register_data_locality(
            tenant_id,
            "dataset_123".to_string(),
            vec!["us-east-1".to_string(), "eu-west-1".to_string()],
            1024 * 1024 * 1024, // 1GB dataset
        )
        .await
        .expect("Failed to register data locality");

    // Request operation that needs this dataset
    let data_local_req = manager.create_data_locality_request(
        tenant_id,
        "dataset_123".to_string(),
        "model_training",
        vec!["gpu".to_string()],
        100, // Need 100 GPUs
    );

    // This test WILL FAIL - data locality optimization not implemented
    let assignment = manager
        .optimize_for_data_locality(data_local_req)
        .await
        .expect("Failed to optimize for data locality");

    // Should prefer regions where data already exists
    assert!(assignment.assigned_region == "us-east-1" || assignment.assigned_region == "eu-west-1");
    assert_eq!(assignment.data_transfer_required, false);
    assert_eq!(assignment.estimated_data_transfer_time_ms, 0);
}