//! Trading Flow Integration Tests
//!
//! Comprehensive integration tests for TLI Client ↔ Trading Service communication.
//! Tests end-to-end trading workflows including order submission, risk validation,
//! execution, and monitoring with performance benchmarks.
#![allow(unused_crate_dependencies)]

use std::collections::HashMap;
use std::sync::{Arc, atomic::{AtomicU64, Ordering}};
use std::time::{Duration, Instant};

use tokio::sync::{mpsc, RwLock, Mutex};
use tokio::time::timeout;
use uuid::Uuid;
use serde_json::json;

use tli::prelude::*;
// use risk::prelude::*; // REMOVED - prelude does not exist
use crate::fixtures::*;
use crate::mocks::*;

/// Trading flow integration test suite
pub struct TradingFlowTests {
    /// TLI client suite for testing
    client_suite: TliClientSuite,
    /// Mock trading service
    mock_trading_service: MockTradingService,
    /// PostgreSQL test database
    test_db: TestDatabase,
    /// Performance metrics collector
    metrics: Arc<PerformanceMetrics>,
    /// Test configuration
    config: IntegrationTestConfig,
}

/// Performance metrics for trading operations
#[derive(Debug, Default)]
pub struct PerformanceMetrics {
    /// Order submission latency measurements (nanoseconds)
    pub order_submission_latencies: RwLock<Vec<u64>>,
    /// Risk validation latency measurements (nanoseconds)
    pub risk_validation_latencies: RwLock<Vec<u64>>,
    /// Database persistence latency measurements (nanoseconds)
    pub database_latencies: RwLock<Vec<u64>>,
    /// Total throughput counter
    pub total_operations: AtomicU64,
    /// Error counter
    pub error_count: AtomicU64,
    /// Memory usage tracking
    pub memory_usage_mb: AtomicU64,
}

impl TradingFlowTests {
    /// Create new trading flow test suite
    pub async fn new(config: IntegrationTestConfig) -> TliResult<Self> {
        // Initialize test database
        let test_db = TestDatabase::new().await?;

        // Initialize mock trading service
        let mock_trading_service = MockTradingService::new().await?;

        // Create TLI client suite with test endpoints
        let client_suite = TliClientBuilder::new()
            .with_service_endpoint(
                "trading_service".to_string(),
                format!("http://localhost:{}", mock_trading_service.port())
            )
            .with_trading_config(TradingClientConfig {
                timeout_ms: config.request_timeout_ms,
                max_retry_attempts: config.max_retry_attempts,
                circuit_breaker_threshold: config.circuit_breaker_threshold,
                ..Default::default()
            })
            .build()
            .await?;

        Ok(Self {
            client_suite,
            mock_trading_service,
            test_db,
            metrics: Arc::new(PerformanceMetrics::default()),
            config,
        })
    }

    /// Test basic order submission flow
    pub async fn test_basic_order_submission(&self) -> TliResult<TestResult> {
        let mut test_result = TestResult::new("basic_order_submission");
        let start_time = Instant::now();

        // Create test order
        let order_request = SubmitOrderRequest {
            symbol: "AAPL".to_string(),
            side: OrderSide::Buy as i32,
            order_type: OrderType::Market as i32,
            quantity: 100.0,
            client_order_id: format!("test_order_{}", Uuid::new_v4()),
            metadata: HashMap::new(),
        };

        // Configure mock response
        self.mock_trading_service.configure_order_response(
            &order_request.client_order_id,
            SubmitOrderResponse {
                success: true,
                order_id: format!("order_{}", Uuid::new_v4()),
                message: "Order submitted successfully".to_string(),
                execution_time_ns: 15_000, // 15µs simulated execution time
            }
        ).await;

        // Measure order submission latency
        let submission_start = Instant::now();

        let response = match self.client_suite.trading_client {
            Some(ref client) => {
                timeout(
                    Duration::from_millis(self.config.request_timeout_ms),
                    client.submit_order(order_request.clone())
                ).await
            }
            None => {
                test_result.add_error("Trading client not available".to_string());
                return Ok(test_result);
            }
        };

        let submission_latency = submission_start.elapsed().as_nanos() as u64;

        // Record performance metrics
        self.metrics.order_submission_latencies.write().await.push(submission_latency);
        self.metrics.total_operations.fetch_add(1, Ordering::Relaxed);

        // Validate response
        match response {
            Ok(Ok(response)) => {
                let resp = response.into_inner();
                test_result.add_assertion("Order submission successful", resp.success);
                test_result.add_assertion("Order ID provided", !resp.order_id.is_empty());
                test_result.add_assertion(
                    "Latency within HFT requirements",
                    submission_latency < self.config.max_latency_ns
                );

                // Verify database persistence
                let db_start = Instant::now();
                let order_persisted = self.test_db.verify_order_persisted(
                    &resp.order_id
                ).await.unwrap_or(false);
                let db_latency = db_start.elapsed().as_nanos() as u64;

                self.metrics.database_latencies.write().await.push(db_latency);
                test_result.add_assertion("Order persisted to database", order_persisted);
                test_result.add_assertion(
                    "Database latency acceptable",
                    db_latency < self.config.max_db_latency_ns
                );
            }
            Ok(Err(e)) => {
                test_result.add_error(format!("Order submission failed: {:?}", e));
                self.metrics.error_count.fetch_add(1, Ordering::Relaxed);
            }
            Err(_) => {
                test_result.add_error("Order submission timeout".to_string());
                self.metrics.error_count.fetch_add(1, Ordering::Relaxed);
            }
        }

        test_result.execution_time = start_time.elapsed();
        test_result.set_passed(test_result.errors.is_empty());
        Ok(test_result)
    }

    /// Test risk-integrated order submission with validation
    pub async fn test_risk_integrated_order_submission(&self) -> TliResult<TestResult> {
        let mut test_result = TestResult::new("risk_integrated_order_submission");
        let start_time = Instant::now();

        // Create high-risk order that should trigger risk checks
        let risky_order = SubmitOrderRequest {
            symbol: "AAPL".to_string(),
            side: OrderSide::Buy as i32,
            order_type: OrderType::Market as i32,
            quantity: 100_000.0, // Large quantity to trigger risk limits
            price: Some(200.0),   // High price
            client_order_id: format!("risky_order_{}", Uuid::new_v4()),
            metadata: HashMap::new(),
        };

        // Configure mock risk service to reject this order
        self.mock_trading_service.configure_risk_rejection(
            &risky_order.client_order_id,
            "Position limit exceeded: would result in 150% of max allowed position".to_string()
        ).await;

        // Submit order and measure risk validation latency
        let risk_start = Instant::now();

        let response = match self.client_suite.trading_client {
            Some(ref client) => {
                timeout(
                    Duration::from_millis(self.config.request_timeout_ms),
                    client.submit_order(risky_order.clone())
                ).await
            }
            None => {
                test_result.add_error("Trading client not available".to_string());
                return Ok(test_result);
            }
        };

        let risk_latency = risk_start.elapsed().as_nanos() as u64;
        self.metrics.risk_validation_latencies.write().await.push(risk_latency);

        // Validate risk rejection
        match response {
            Ok(Ok(response)) => {
                let resp = response.into_inner();
                test_result.add_assertion("Order correctly rejected", !resp.success);
                test_result.add_assertion("Risk reason provided", resp.message.contains("Position limit"));
                test_result.add_assertion(
                    "Risk validation latency acceptable",
                    risk_latency < self.config.max_risk_latency_ns
                );
            }
            Ok(Err(e)) => {
                test_result.add_error(format!("Unexpected error: {:?}", e));
            }
            Err(_) => {
                test_result.add_error("Risk validation timeout".to_string());
            }
        }

        test_result.execution_time = start_time.elapsed();
        test_result.set_passed(test_result.errors.is_empty());
        Ok(test_result)
    }

    /// Test order lifecycle with position tracking
    pub async fn test_order_lifecycle_with_position_tracking(&self) -> TliResult<TestResult> {
        let mut test_result = TestResult::new("order_lifecycle_position_tracking");
        let start_time = Instant::now();

        let order_id = format!("lifecycle_order_{}", Uuid::new_v4());

        // Create order
        let order_request = SubmitOrderRequest {
            symbol: "AAPL".to_string(),
            side: OrderSide::Buy as i32,
            order_type: OrderType::Limit as i32,
            quantity: 500.0,
            price: Some(150.0),
            client_order_id: order_id.clone(),
            metadata: HashMap::new(),
        };

        // Configure mock to simulate full order lifecycle
        self.mock_trading_service.configure_lifecycle_simulation(
            &order_id,
            vec![
                OrderStatus::Pending,
                OrderStatus::PartiallyFilled,
                OrderStatus::Filled
            ]
        ).await;

        // Submit order
        let submit_response = match self.client_suite.trading_client {
            Some(ref client) => {
                let response = client.submit_order(order_request).await?;
                response.into_inner()
            },
            None => {
                test_result.add_error("Trading client not available".to_string());
                return Ok(test_result);
            }
        };
        
        test_result.add_assertion("Order submission successful", submit_response.success);

        // Monitor order status changes
        let mut status_updates = Vec::new();
        let mut position_updates = Vec::new();

        // Start monitoring streams
        if let Some(ref client) = self.client_suite.trading_client {
            let order_stream = client.subscribe_to_order_updates().await?;
            let position_stream = client.subscribe_to_position_updates().await?;

            // Collect updates for 5 seconds
            let monitor_duration = Duration::from_secs(5);
            let monitor_start = Instant::now();

            while monitor_start.elapsed() < monitor_duration {
                tokio::select! {
                    order_update = order_stream.recv() => {
                        if let Some(update) = order_update {
                            if update.order_id == submit_response.order_id {
                                status_updates.push(update);
                            }
                        }
                    }
                    position_update = position_stream.recv() => {
                        if let Some(update) = position_update {
                            if update.symbol == "AAPL" {
                                position_updates.push(update);
                            }
                        }
                    }
                    _ = tokio::time::sleep(Duration::from_millis(100)) => {
                        // Continue monitoring
                    }
                }
            }
        }

        // Validate lifecycle
        test_result.add_assertion("Received status updates", !status_updates.is_empty());
        test_result.add_assertion("Received position updates", !position_updates.is_empty());

        // Verify final state
        if let Some(final_status) = status_updates.last() {
            test_result.add_assertion("Order reached filled state", final_status.status == OrderStatus::Filled);
        }

        // Verify position tracking
        if let Some(final_position) = position_updates.last() {
            test_result.add_assertion("Position updated correctly", final_position.quantity == 500.0);
        }

        test_result.execution_time = start_time.elapsed();
        test_result.set_passed(test_result.errors.is_empty());
        Ok(test_result)
    }

    /// Test concurrent order submissions for throughput validation
    pub async fn test_concurrent_order_throughput(&self) -> TliResult<TestResult> {
        let mut test_result = TestResult::new("concurrent_order_throughput");
        let start_time = Instant::now();

        let num_concurrent_orders = self.config.concurrent_order_count;
        let mut handles = Vec::new();
        let metrics = Arc::clone(&self.metrics);

        // Submit multiple orders concurrently
        for i in 0..num_concurrent_orders {
            let client = match self.client_suite.trading_client {
                Some(ref c) => c.clone(),
                None => {
                    test_result.add_error("Trading client not available".to_string());
                    return Ok(test_result);
                }
            };

            let order_request = SubmitOrderRequest {
                symbol: "AAPL".to_string(),
                side: if i % 2 == 0 { OrderSide::Buy } else { OrderSide::Sell } as i32,
                order_type: OrderType::Market as i32,
                quantity: 100.0,
                client_order_id: format!("concurrent_order_{}_{}", i, Uuid::new_v4()),
                metadata: HashMap::new(),
            };

            let metrics_clone = Arc::clone(&metrics);

            let handle = tokio::spawn(async move {
                let start = Instant::now();
                let result = client.submit_order(order_request).await;
                let latency = start.elapsed().as_nanos() as u64;

                metrics_clone.order_submission_latencies.write().await.push(latency);
                metrics_clone.total_operations.fetch_add(1, Ordering::Relaxed);

                match result {
                    Ok(response) => {
                        let resp = response.into_inner();
                        resp.success
                    },
                    Err(_) => {
                        metrics_clone.error_count.fetch_add(1, Ordering::Relaxed);
                        false
                    }
                }
            });

            handles.push(handle);
        }

        // Wait for all orders to complete
        let mut successful_orders = 0;
        for handle in handles {
            if let Ok(success) = handle.await {
                if success {
                    successful_orders += 1;
                }
            }
        }

        let total_time = start_time.elapsed();
        let throughput = successful_orders as f64 / total_time.as_secs_f64();

        // Validate throughput requirements
        test_result.add_assertion(
            "Minimum successful orders",
            successful_orders >= (num_concurrent_orders * 9 / 10) // 90% success rate
        );

        test_result.add_assertion(
            "Throughput meets HFT requirements",
            throughput >= self.config.min_throughput_ops_per_sec
        );

        test_result.metadata.insert("throughput_ops_per_sec".to_string(), json!(throughput));
        test_result.metadata.insert("successful_orders".to_string(), json!(successful_orders));
        test_result.metadata.insert("total_orders".to_string(), json!(num_concurrent_orders));

        test_result.execution_time = total_time;
        test_result.set_passed(test_result.errors.is_empty());
        Ok(test_result)
    }

    /// Test circuit breaker functionality
    pub async fn test_circuit_breaker_activation(&self) -> TliResult<TestResult> {
        let mut test_result = TestResult::new("circuit_breaker_activation");
        let start_time = Instant::now();

        // Configure mock to fail multiple consecutive requests
        self.mock_trading_service.configure_failure_sequence(10).await;

        let mut consecutive_failures = 0;
        let max_attempts = 15;

        // Submit orders until circuit breaker activates
        for i in 0..max_attempts {
            let order_request = SubmitOrderRequest {
                symbol: "AAPL".to_string(),
                side: OrderSide::Buy as i32,
                order_type: OrderType::Market as i32,
                quantity: 100.0,
                client_order_id: format!("cb_test_order_{}", i),
                metadata: HashMap::new(),
            };

            let response = match self.client_suite.trading_client {
                Some(ref client) => client.submit_order(order_request).await,
                None => {
                    test_result.add_error("Trading client not available".to_string());
                    return Ok(test_result);
                }
            };

            match response {
                Ok(response) => {
                    let resp = response.into_inner();
                    if !resp.success {
                        consecutive_failures += 1;
                        if consecutive_failures >= self.config.circuit_breaker_threshold {
                            test_result.add_assertion("Circuit breaker activated", true);
                            break;
                        }
                    } else {
                        consecutive_failures = 0; // Reset on success
                    }
                }
                Err(TliError::CircuitBreakerOpen) => {
                    test_result.add_assertion("Circuit breaker properly triggered", true);
                    break;
                }
                Err(_) => {
                    // Handle other errors
                    consecutive_failures += 1;
                }
            }
        }

        // Verify circuit breaker status
        if let Some(ref client) = self.client_suite.trading_client {
            let response = client.get_circuit_breaker_status().await?;
            let status = response.into_inner();
            test_result.add_assertion("Circuit breaker status available", status.is_open);
        }

        test_result.execution_time = start_time.elapsed();
        test_result.set_passed(test_result.errors.is_empty());
        Ok(test_result)
    }

    /// Test emergency stop functionality
    pub async fn test_emergency_stop(&self) -> TliResult<TestResult> {
        let mut test_result = TestResult::new("emergency_stop");
        let start_time = Instant::now();

        // Submit initial order to ensure system is active
        let order_request = SubmitOrderRequest {
            symbol: "AAPL".to_string(),
            side: OrderSide::Buy as i32,
            order_type: OrderType::Market as i32,
            quantity: 100.0,
            client_order_id: format!("pre_stop_order_{}", Uuid::new_v4()),
            metadata: HashMap::new(),
        };

        if let Some(ref client) = self.client_suite.trading_client {
            let response = client.submit_order(order_request).await?;
            let initial_response = response.into_inner();
            test_result.add_assertion("Initial order successful", initial_response.success);

            // Trigger emergency stop
            let response = client.trigger_emergency_stop("Integration test emergency stop").await?;
            let stop_result = response.into_inner();
            test_result.add_assertion("Emergency stop triggered successfully", stop_result.success);

            // Wait for stop to propagate
            tokio::time::sleep(Duration::from_millis(100)).await;

            // Attempt to submit order after emergency stop
            let post_stop_order = SubmitOrderRequest {
                symbol: "AAPL".to_string(),
                side: OrderSide::Buy as i32,
                order_type: OrderType::Market as i32,
                quantity: 100.0,
                client_order_id: format!("post_stop_order_{}", Uuid::new_v4()),
                metadata: HashMap::new(),
            };

            let post_stop_response = client.submit_order(post_stop_order).await;
            
            match post_stop_response {
                Ok(response) => {
                    let resp = response.into_inner();
                    test_result.add_assertion("Order rejected after emergency stop", !resp.success);
                    test_result.add_assertion("Emergency stop message provided",
                        resp.message.contains("emergency") || resp.message.contains("stopped"));
                }
                Err(TliError::TradingHalted) => {
                    test_result.add_assertion("Trading halted error received", true);
                }
                Err(e) => {
                    test_result.add_error(format!("Unexpected error after emergency stop: {:?}", e));
                }
            }

            // Verify emergency stop status
            let response = client.get_trading_status().await?;
            let status = response.into_inner();
            test_result.add_assertion("Trading status shows emergency stop", status.emergency_stop_active);
        }

        test_result.execution_time = start_time.elapsed();
        test_result.set_passed(test_result.errors.is_empty());
        Ok(test_result)
    }

    /// Run complete trading flow test suite
    pub async fn run_complete_suite(&self) -> TliResult<TestSuite> {
        let mut suite = TestSuite::new("trading_flow_integration");
        let suite_start = Instant::now();

        // Run all test cases
        let tests = vec![
            self.test_basic_order_submission().await?,
            self.test_risk_integrated_order_submission().await?,
            self.test_order_lifecycle_with_position_tracking().await?,
            self.test_concurrent_order_throughput().await?,
            self.test_circuit_breaker_activation().await?,
            self.test_emergency_stop().await?,
        ];

        for test in tests {
            suite.add_test_result(test);
        }

        // Generate performance summary
        let metrics = self.generate_performance_summary().await;
        suite.metadata.insert("performance_metrics".to_string(), json!(metrics));

        suite.execution_time = suite_start.elapsed();
        suite.set_passed(suite.passed_tests >= suite.total_tests * 80 / 100); // 80% pass rate

        Ok(suite)
    }

    /// Generate comprehensive performance summary
    async fn generate_performance_summary(&self) -> serde_json::Value {
        let order_latencies = self.metrics.order_submission_latencies.read().await;
        let risk_latencies = self.metrics.risk_validation_latencies.read().await;
        let db_latencies = self.metrics.database_latencies.read().await;

        let order_stats = calculate_latency_stats(&order_latencies);
        let risk_stats = calculate_latency_stats(&risk_latencies);
        let db_stats = calculate_latency_stats(&db_latencies);

        json!({
            "order_submission": {
                "count": order_latencies.len(),
                "avg_ns": order_stats.avg,
                "p50_ns": order_stats.p50,
                "p95_ns": order_stats.p95,
                "p99_ns": order_stats.p99,
                "max_ns": order_stats.max
            },
            "risk_validation": {
                "count": risk_latencies.len(),
                "avg_ns": risk_stats.avg,
                "p50_ns": risk_stats.p50,
                "p95_ns": risk_stats.p95,
                "p99_ns": risk_stats.p99,
                "max_ns": risk_stats.max
            },
            "database_operations": {
                "count": db_latencies.len(),
                "avg_ns": db_stats.avg,
                "p50_ns": db_stats.p50,
                "p95_ns": db_stats.p95,
                "p99_ns": db_stats.p99,
                "max_ns": db_stats.max
            },
            "total_operations": self.metrics.total_operations.load(Ordering::Relaxed),
            "error_count": self.metrics.error_count.load(Ordering::Relaxed),
            "memory_usage_mb": self.metrics.memory_usage_mb.load(Ordering::Relaxed)
        })
    }
}

/// Calculate latency statistics from measurements
fn calculate_latency_stats(latencies: &[u64]) -> LatencyStats {
    if latencies.is_empty() {
        return LatencyStats::default();
    }

    let mut sorted = latencies.to_vec();
    sorted.sort_unstable();

    let len = sorted.len();
    let avg = sorted.iter().sum::<u64>() / len as u64;
    let p50 = sorted[len * 50 / 100];
    let p95 = sorted[len * 95 / 100];
    let p99 = sorted[len * 99 / 100];
    let max = sorted[len - 1];

    LatencyStats { avg, p50, p95, p99, max }
}

/// Latency statistics structure
#[derive(Debug, Default)]
struct LatencyStats {
    avg: u64,
    p50: u64,
    p95: u64,
    p99: u64,
    max: u64,
}

#[cfg(test)]
mod tests {
    use super::*;

    #[tokio::test]
    async fn test_trading_flow_integration() {
        let config = IntegrationTestConfig::default();
        let tests = TradingFlowTests::new(config).await.unwrap();
        let results = tests.run_complete_suite().await.unwrap();

        println!("Trading Flow Integration Test Results:");
        println!("Passed: {}/{}", results.passed_tests, results.total_tests);
        println!("Execution time: {:?}", results.execution_time);

        // Print performance metrics
        if let Some(metrics) = results.metadata.get("performance_metrics") {
            println!("Performance Metrics: {}", serde_json::to_string_pretty(metrics).unwrap());
        }

        assert!(results.passed, "Trading flow integration tests should pass");
    }
}