//! Foxhunt Critical Path Tests Library
//!
//! This library provides comprehensive integration tests for the Foxhunt HFT trading system.
//! It includes tests for performance, safety, reliability, and functional correctness across
//! all system components.
#![allow(missing_docs)] // Test fixtures don't require comprehensive documentation
#![allow(clippy::needless_update)] // Explicit struct update syntax for test clarity
#![allow(clippy::type_complexity)] // Complex types in test fixture builders
#![warn(missing_debug_implementations)]
#![warn(rust_2018_idioms)]
#![allow(unused_crate_dependencies)]

// Suppress unused crate dependency warnings for test-only crates
// In Rust 2018+, external crates are automatically available without explicit extern crate declarations

/// Load test environment variables from .env.test
///
/// Call this at the start of test modules that need database access
pub fn load_test_env() {
    use std::sync::Once;
    static INIT: Once = Once::new();

    INIT.call_once(|| {
        // Environment loading is optional - tests should work without .env files
        // Production deployments use Vault, not .env files
        let _ = std::env::var("DATABASE_URL");
    });
}

// Chaos engineering module
pub mod chaos;

// Test modules - external files (only enable working ones for now)
// test_common is now a separate crate in testing/test-common/
// pub mod framework;      // Temporarily disabled
pub mod helpers; // Re-enabled after fixing imports
                 // pub mod unit;           // Temporarily disabled - has dependency issues
                 // pub mod integration;    // Temporarily disabled - missing broker modules
                 // pub mod performance;    // Temporarily disabled - missing dependencies
                 // pub mod gpu;            // Temporarily disabled — GPU tests require CUDA
pub mod fixtures;
pub mod utils; // Re-enabled after fixing imports

// Performance utilities module
pub mod performance_utils {
    //! Performance testing utilities and benchmarks

    use std::future::Future;
    use std::time::{Duration, Instant};

    /// Maximum allowed latency for HFT operations in nanoseconds (50μs)
    pub const MAX_LATENCY_NANOS: u64 = 50_000; // 50μs
    /// Minimum required throughput for HFT operations (10k ops/sec)
    pub const MIN_THROUGHPUT_OPS_PER_SEC: u64 = 10_000; // 10k ops/sec

    /// Measure the execution time of a synchronous operation
    ///
    /// # Arguments
    /// * `operation` - The function to measure
    ///
    /// # Returns
    ///
    /// A tuple containing the operation result and execution duration
    pub fn measure_operation<F, R>(operation: F) -> (R, Duration)
    where
        F: FnOnce() -> R,
    {
        let start = Instant::now();
        let result = operation();
        let duration = start.elapsed();
        (result, duration)
    }

    /// Measure the execution time of an asynchronous operation
    ///
    /// # Arguments
    /// * `operation` - The async function to measure
    ///
    /// # Returns
    ///
    /// A tuple containing the operation result and execution duration
    pub async fn measure_async_operation<F, Fut, R>(operation: F) -> (R, Duration)
    where
        F: FnOnce() -> Fut,
        Fut: Future<Output = R>,
    {
        let start = Instant::now();
        let result = operation().await;
        let duration = start.elapsed();
        (result, duration)
    }

    /// Validate that a measured latency meets HFT requirements
    ///
    /// # Arguments
    /// * `duration` - The measured latency
    ///
    /// * `max_latency_us` - Maximum allowed latency in microseconds
    ///
    /// # Panics
    ///
    /// Panics if the latency exceeds the specified maximum
    pub fn assert_hft_latency(duration: Duration, max_latency_us: u64) {
        let micros = duration.as_micros() as u64;
        assert!(
            micros <= max_latency_us,
            "Latency {}μs exceeds HFT requirement of {}μs",
            micros,
            max_latency_us
        );
    }

    /// Validate that measured throughput meets HFT requirements
    ///
    /// # Arguments
    /// * `ops_per_sec` - Measured operations per second
    ///
    /// * `operation` - Name of the operation for error reporting
    ///
    /// # Panics
    ///
    /// Panics if throughput is below the minimum HFT requirement
    pub fn assert_hft_throughput(ops_per_sec: u64, operation: &str) {
        assert!(
            ops_per_sec >= MIN_THROUGHPUT_OPS_PER_SEC,
            "{} throughput {} ops/sec below HFT requirement of {} ops/sec",
            operation,
            ops_per_sec,
            MIN_THROUGHPUT_OPS_PER_SEC
        );
    }
}

// Safety test modules
pub mod safety {
    //! Safety testing utilities for error-free operations

    /// Safe test result type
    pub type SafeTestResult<T> = Result<T, SafeTestError>;

    /// Safe test error types
    #[derive(Debug, Clone)]
    pub enum SafeTestError {
        /// Assertion failed with details
        AssertionFailed {
            /// Field that failed
            field: String,
            /// Expected value
            expected: String,
            /// Actual value
            actual: String,
        },
        /// Thread join operation failed
        ThreadJoinFailed {
            /// Type of thread that failed
            thread_type: String,
        },
        /// Operation timed out
        Timeout {
            /// Operation that timed out
            operation: String,
            /// Timeout duration in milliseconds
            timeout_ms: u64,
        },
        /// Calculation failed
        CalculationFailed {
            /// Operation that failed
            operation: String,
            /// Error details
            details: String,
        },
    }

    impl std::fmt::Display for SafeTestError {
        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
            match self {
                SafeTestError::AssertionFailed {
                    field,
                    expected,
                    actual,
                } => {
                    write!(
                        f,
                        "Assertion failed for {}: expected {}, got {}",
                        field, expected, actual
                    )
                },
                SafeTestError::ThreadJoinFailed { thread_type } => {
                    write!(f, "Thread join failed for: {}", thread_type)
                },
                SafeTestError::Timeout {
                    operation,
                    timeout_ms,
                } => {
                    write!(
                        f,
                        "Operation {} timed out after {}ms",
                        operation, timeout_ms
                    )
                },
                SafeTestError::CalculationFailed { operation, details } => {
                    write!(f, "Calculation failed for {}: {}", operation, details)
                },
            }
        }
    }

    impl std::error::Error for SafeTestError {}

    /// Safe assertion function that never panics
    pub fn safe_assert(
        condition: bool,
        field: &str,
        expected: &str,
        actual: impl std::fmt::Display,
    ) -> SafeTestResult<()> {
        if condition {
            Ok(())
        } else {
            Err(SafeTestError::AssertionFailed {
                field: field.to_string(),
                expected: expected.to_string(),
                actual: actual.to_string(),
            })
        }
    }

    /// Safe equality assertion
    pub fn safe_assert_eq<T: PartialEq + std::fmt::Debug>(
        actual: &T,
        expected: &T,
        field: &str,
    ) -> SafeTestResult<()> {
        if actual == expected {
            Ok(())
        } else {
            Err(SafeTestError::AssertionFailed {
                field: field.to_string(),
                expected: format!("{:?}", expected),
                actual: format!("{:?}", actual),
            })
        }
    }
}

// Mock implementations for testing
pub mod mocks {
    //! Mock implementations for testing purposes

    use rust_decimal::Decimal;
    use std::collections::HashMap;
    use std::sync::Arc;
    use tokio::sync::RwLock;

    /// Mock market data provider for testing
    ///
    /// Provides thread-safe mock market data with configurable prices
    /// for testing trading algorithms and market data processing.
    #[derive(Debug, Clone)]
    pub struct MockMarketDataProvider {
        /// Thread-safe storage for current prices by symbol
        pub prices: Arc<RwLock<HashMap<String, Decimal>>>,
    }

    impl MockMarketDataProvider {
        /// Create a new mock market data provider with default prices
        ///
        /// Initializes with BTCUSD at $50,000 and ETHUSD at $3,000
        pub fn new() -> Self {
            let mut prices = HashMap::new();
            prices.insert("BTCUSD".to_string(), Decimal::from(50000));
            prices.insert("ETHUSD".to_string(), Decimal::from(3000));

            Self {
                prices: Arc::new(RwLock::new(prices)),
            }
        }

        /// Set the current price for a trading symbol
        ///
        /// # Arguments
        /// * `symbol` - Trading symbol (e.g., "BTCUSD")
        ///
        /// * `price` - New price to set
        pub async fn set_price(&self, symbol: &str, price: Decimal) {
            let mut prices = self.prices.write().await;
            prices.insert(symbol.to_string(), price);
        }

        /// Get the current price for a trading symbol
        ///
        /// # Arguments
        /// * `symbol` - Trading symbol to look up
        ///
        /// # Returns
        /// * `Some(Decimal)` - Current price if symbol exists
        ///
        /// * `None` - If symbol is not found
        pub async fn get_price(&self, symbol: &str) -> Option<Decimal> {
            let prices = self.prices.read().await;
            prices.get(symbol).copied()
        }
    }

    impl Default for MockMarketDataProvider {
        fn default() -> Self {
            Self::new()
        }
    }
}

// Test configuration
pub mod config {
    //! Test configuration utilities

    use rust_decimal::Decimal;

    /// Configuration settings for test execution
    ///
    /// Centralizes test configuration including capital, symbols, timeouts,
    /// and other parameters that affect test behavior.
    #[derive(Debug, Clone)]
    pub struct TestConfig {
        /// Starting capital amount for trading tests
        pub initial_capital: Decimal,
        /// List of trading symbols to use in tests
        pub test_symbols: Vec<String>,
        /// Whether to enable detailed logging during tests
        pub enable_logging: bool,
        /// Maximum time allowed for test execution in seconds
        pub timeout_seconds: u64,
        /// Maximum number of retry attempts for flaky tests
        pub max_retries: u32,
    }

    impl Default for TestConfig {
        fn default() -> Self {
            Self {
                initial_capital: Decimal::from(100000),
                test_symbols: vec!["BTCUSD".to_string(), "ETHUSD".to_string()],
                enable_logging: false,
                timeout_seconds: 30,
                max_retries: 3,
            }
        }
    }

    /// Load test configuration from environment variables
    ///
    /// Reads configuration from environment variables with sensible defaults:
    /// - TEST_INITIAL_CAPITAL: Starting capital (default: 100,000)
    ///
    /// - TEST_SYMBOLS: Comma-separated symbols (default: "BTCUSD,ETHUSD")
    /// - TEST_ENABLE_LOGGING: Enable logging (default: false)
    ///
    /// - TEST_TIMEOUT_SECONDS: Test timeout (default: 30)
    /// - TEST_MAX_RETRIES: Maximum retries (default: 3)
    ///
    /// # Returns
    ///
    /// TestConfig with values from environment or defaults
    pub fn load_test_config() -> TestConfig {
        TestConfig {
            initial_capital: std::env::var("TEST_INITIAL_CAPITAL")
                .ok()
                .and_then(|s| s.parse::<i64>().ok())
                .map(Decimal::from)
                .unwrap_or(Decimal::from(100000)),
            test_symbols: std::env::var("TEST_SYMBOLS")
                .unwrap_or_else(|_| "BTCUSD,ETHUSD".to_string())
                .split(',')
                .map(|s| s.trim().to_string())
                .collect(),
            enable_logging: std::env::var("TEST_ENABLE_LOGGING")
                .map(|s| s.to_lowercase() == "true")
                .unwrap_or(false),
            timeout_seconds: std::env::var("TEST_TIMEOUT_SECONDS")
                .ok()
                .and_then(|s| s.parse().ok())
                .unwrap_or(30),
            max_retries: std::env::var("TEST_MAX_RETRIES")
                .ok()
                .and_then(|s| s.parse().ok())
                .unwrap_or(3),
        }
    }
}

// Utility functions moved to utils/ module to avoid conflicts

/// Generate a unique test ID for test identification
///
/// Creates a monotonically increasing test ID using an atomic counter.
///
/// This is useful for distinguishing between multiple test runs.
///
/// # Returns
///
/// A string in the format "TEST_{counter}"
pub fn generate_test_id() -> String {
    use std::sync::atomic::{AtomicU64, Ordering};
    static COUNTER: AtomicU64 = AtomicU64::new(1);
    format!("TEST_{}", COUNTER.fetch_add(1, Ordering::SeqCst))
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::config::TestConfig;
    use crate::mocks::MockMarketDataProvider;
    use rust_decimal::Decimal;

    #[test]
    fn test_lib_imports() {
        // Test that all imports work correctly
        let _config = TestConfig::default();
        let _id = generate_test_id();
        assert!(!_id.is_empty());
    }

    #[tokio::test]
    async fn test_async_utils() {
        // Test async utilities
        let provider = MockMarketDataProvider::new();
        provider.set_price("TESTUSD", Decimal::from(12345)).await;
        let price = provider.get_price("TESTUSD").await;
        assert_eq!(price, Some(Decimal::from(12345)));
    }
}
