foxhunt/crates/risk/tests/compliance_breach_detection_tests.rs

//! Comprehensive Compliance Breach Detection Tests
//! Target: +10% coverage for compliance validation edge cases
//!
//! Focus Areas:
//! - Threshold boundary conditions
//! - Multiple simultaneous violations
//! - Correlation between violations
//! - Time-sensitive compliance checks
//! - Regulatory exemption scenarios

#![allow(
    dead_code,
    unused_crate_dependencies,
    unused_variables,
    clippy::assign_op_pattern,
    clippy::indexing_slicing,
    clippy::useless_vec
)]

use chrono::{DateTime, Datelike, Duration, Timelike, Utc};
use common::types::Price;
use rust_decimal::prelude::ToPrimitive;
use rust_decimal::Decimal;

// Helper macro for creating Decimal values
macro_rules! dec {
    ($val:expr) => {
        Decimal::try_from($val).expect("Failed to create Decimal")
    };
}

/// Position limit structure for testing
#[derive(Debug, Clone)]
struct PositionLimit {
    instrument_id: String,
    max_position_size: Price,
    max_daily_turnover: Price,
    concentration_limit: Decimal,
    current_position: Price,
    daily_turnover: Price,
    portfolio_value: Price,
}

/// Compliance violation structure for testing
#[derive(Debug, Clone)]
struct ComplianceViolation {
    violation_type: String,
    severity: String,
    timestamp: DateTime<Utc>,
    instrument_id: String,
    exceeded_value: Price,
    limit_value: Price,
}

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

    #[tokio::test]
    async fn test_position_exactly_at_limit() {
        let limit = PositionLimit {
            instrument_id: "AAPL".to_owned(),
            max_position_size: Price::new(100000.0).unwrap(),
            max_daily_turnover: Price::new(500000.0).unwrap(),
            concentration_limit: dec!(0.10),
            current_position: Price::new(100000.0).unwrap(),
            daily_turnover: Price::new(250000.0).unwrap(),
            portfolio_value: Price::new(1000000.0).unwrap(),
        };

        // Exactly at limit should be allowed
        assert!(limit.current_position <= limit.max_position_size);

        // But any additional size would breach
        let additional_position = Price::new(1.0).unwrap();
        let new_position = limit.current_position + additional_position;
        assert!(new_position > limit.max_position_size);
    }

    #[tokio::test]
    async fn test_position_one_cent_below_limit() {
        let limit = PositionLimit {
            instrument_id: "MSFT".to_owned(),
            max_position_size: Price::new(100000.0).unwrap(),
            max_daily_turnover: Price::new(500000.0).unwrap(),
            concentration_limit: dec!(0.10),
            current_position: Price::new(99999.99).unwrap(),
            daily_turnover: Price::new(250000.0).unwrap(),
            portfolio_value: Price::new(1000000.0).unwrap(),
        };

        // Just under limit
        assert!(limit.current_position < limit.max_position_size);

        // Verify exact difference
        let headroom = limit.max_position_size - limit.current_position;
        assert_eq!(headroom, Price::new(0.01).unwrap());
    }

    #[tokio::test]
    async fn test_position_one_cent_over_limit() {
        let limit = PositionLimit {
            instrument_id: "GOOGL".to_owned(),
            max_position_size: Price::new(100000.0).unwrap(),
            max_daily_turnover: Price::new(500000.0).unwrap(),
            concentration_limit: dec!(0.10),
            current_position: Price::new(100000.01).unwrap(),
            daily_turnover: Price::new(250000.0).unwrap(),
            portfolio_value: Price::new(1000000.0).unwrap(),
        };

        // Just over limit - should trigger violation
        assert!(limit.current_position > limit.max_position_size);

        let excess = limit.current_position - limit.max_position_size;
        assert_eq!(excess, Price::new(0.01).unwrap());
    }

    #[tokio::test]
    async fn test_concentration_at_exact_limit() {
        let limit = PositionLimit {
            instrument_id: "TSLA".to_owned(),
            max_position_size: Price::new(100000.0).unwrap(),
            max_daily_turnover: Price::new(500000.0).unwrap(),
            concentration_limit: dec!(0.10), // 10% max
            current_position: Price::new(100000.0).unwrap(),
            daily_turnover: Price::new(250000.0).unwrap(),
            portfolio_value: Price::new(1000000.0).unwrap(),
        };

        // Calculate actual concentration
        let concentration = limit.current_position.to_decimal().unwrap()
            / limit.portfolio_value.to_decimal().unwrap();

        assert_eq!(concentration, limit.concentration_limit);
    }

    #[tokio::test]
    async fn test_fractional_position_limits() {
        // Test with crypto fractional positions
        let limit = PositionLimit {
            instrument_id: "BTC-USD".to_owned(),
            max_position_size: Price::new(450000.0).unwrap(),
            max_daily_turnover: Price::new(2000000.0).unwrap(),
            concentration_limit: dec!(0.15),
            current_position: Price::new(449999.9999).unwrap(),
            daily_turnover: Price::new(1500000.0).unwrap(),
            portfolio_value: Price::new(3000000.0).unwrap(),
        };

        // Fractional amounts just under limit
        assert!(limit.current_position < limit.max_position_size);

        let headroom = limit.max_position_size - limit.current_position;
        assert!(headroom < Price::new(1.0).unwrap());
    }
}

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

    #[tokio::test]
    async fn test_multiple_limit_breaches_single_order() {
        let limit = PositionLimit {
            instrument_id: "AMZN".to_owned(),
            max_position_size: Price::new(100000.0).unwrap(),
            max_daily_turnover: Price::new(500000.0).unwrap(),
            concentration_limit: dec!(0.10),
            current_position: Price::new(150000.0).unwrap(), // Breach 1
            daily_turnover: Price::new(600000.0).unwrap(),   // Breach 2
            portfolio_value: Price::new(1000000.0).unwrap(),
        };

        let mut violations = Vec::new();

        // Check position limit
        if limit.current_position > limit.max_position_size {
            violations.push(ComplianceViolation {
                violation_type: "Position Limit".to_owned(),
                severity: "High".to_owned(),
                timestamp: Utc::now(),
                instrument_id: limit.instrument_id.clone(),
                exceeded_value: limit.current_position,
                limit_value: limit.max_position_size,
            });
        }

        // Check daily turnover limit
        if limit.daily_turnover > limit.max_daily_turnover {
            violations.push(ComplianceViolation {
                violation_type: "Daily Turnover".to_owned(),
                severity: "Medium".to_owned(),
                timestamp: Utc::now(),
                instrument_id: limit.instrument_id.clone(),
                exceeded_value: limit.daily_turnover,
                limit_value: limit.max_daily_turnover,
            });
        }

        // Check concentration
        let concentration = limit.current_position.to_decimal().unwrap()
            / limit.portfolio_value.to_decimal().unwrap();
        if concentration > limit.concentration_limit {
            violations.push(ComplianceViolation {
                violation_type: "Concentration Risk".to_owned(),
                severity: "Medium".to_owned(),
                timestamp: Utc::now(),
                instrument_id: limit.instrument_id.clone(),
                exceeded_value: Price::new(concentration.to_f64().unwrap_or(0.0)).unwrap(),
                limit_value: Price::new(limit.concentration_limit.to_f64().unwrap_or(0.0)).unwrap(),
            });
        }

        // Should have at least 2 violations
        assert!(violations.len() >= 2);
    }

    #[tokio::test]
    async fn test_cascading_violations() {
        // Primary violation triggers secondary checks
        let mut violations = Vec::new();

        // 1. Daily loss limit breach
        let current_loss = Price::new(-25000.0).unwrap();
        let max_daily_loss = Price::new(-20000.0).unwrap();

        if current_loss < max_daily_loss {
            violations.push(ComplianceViolation {
                violation_type: "Daily Loss Limit".to_owned(),
                severity: "Critical".to_owned(),
                timestamp: Utc::now(),
                instrument_id: "PORTFOLIO".to_owned(),
                exceeded_value: current_loss,
                limit_value: max_daily_loss,
            });

            // 2. This triggers risk budget check
            violations.push(ComplianceViolation {
                violation_type: "Risk Budget Exceeded".to_owned(),
                severity: "High".to_owned(),
                timestamp: Utc::now() + Duration::milliseconds(10),
                instrument_id: "PORTFOLIO".to_owned(),
                exceeded_value: current_loss,
                limit_value: max_daily_loss,
            });

            // 3. Which triggers VaR limit check
            violations.push(ComplianceViolation {
                violation_type: "Portfolio VaR Breach".to_owned(),
                severity: "High".to_owned(),
                timestamp: Utc::now() + Duration::milliseconds(20),
                instrument_id: "PORTFOLIO".to_owned(),
                exceeded_value: Price::new(30000.0).unwrap(),
                limit_value: Price::new(25000.0).unwrap(),
            });
        }

        assert_eq!(violations.len(), 3);

        // Violations should be time-ordered
        for i in 1..violations.len() {
            assert!(violations[i].timestamp > violations[i - 1].timestamp);
        }
    }

    #[tokio::test]
    async fn test_violation_severity_escalation() {
        let base_limit = Price::new(100000.0).unwrap();
        let test_cases = vec![
            (Price::new(105000.0).unwrap(), "Low"),      // 5% breach
            (Price::new(112000.0).unwrap(), "Medium"),   // 12% breach
            (Price::new(130000.0).unwrap(), "High"),     // 30% breach
            (Price::new(160000.0).unwrap(), "Critical"), // 60% breach
        ];

        for (current_value, expected_severity) in test_cases {
            let breach_percentage = (current_value - base_limit).to_decimal().unwrap()
                / base_limit.to_decimal().unwrap()
                * dec!(100.0);

            let severity = if breach_percentage > dec!(50.0) {
                "Critical"
            } else if breach_percentage > dec!(25.0) {
                "High"
            } else if breach_percentage > dec!(10.0) {
                "Medium"
            } else {
                "Low"
            };

            assert_eq!(severity, expected_severity);
        }
    }
}

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

    #[tokio::test]
    async fn test_intraday_limit_reset() {
        // Daily turnover should reset at market open
        let market_open = Utc::now()
            .date_naive()
            .and_hms_opt(9, 30, 0)
            .unwrap()
            .and_utc();

        let before_open = market_open - Duration::minutes(30);
        let after_open = market_open + Duration::minutes(30);

        // Turnover accumulated before open
        let _pre_open_turnover = Price::new(400000.0).unwrap();

        // Should reset after open
        let is_new_trading_day = after_open.date_naive() != before_open.date_naive()
            || (after_open.hour() == 9 && after_open.minute() >= 30);

        assert!(is_new_trading_day);
    }

    #[tokio::test]
    async fn test_end_of_day_position_check() {
        // Some limits only apply at EOD
        let market_close = Utc::now()
            .date_naive()
            .and_hms_opt(16, 0, 0)
            .unwrap()
            .and_utc();

        let check_time = market_close + Duration::minutes(5);

        let is_after_close = check_time.hour() >= 16;

        if is_after_close {
            // Enforce overnight position limits (typically stricter)
            let intraday_limit = Price::new(200000.0).unwrap();
            let overnight_limit = Price::new(100000.0).unwrap();

            assert!(overnight_limit < intraday_limit);
        }
    }

    #[tokio::test]
    async fn test_settlement_period_restrictions() {
        // T+2 settlement - restrictions during settlement
        let trade_date = Utc::now();
        let settlement_date = trade_date + Duration::days(2);

        let days_until_settlement = (settlement_date - trade_date).num_days();

        assert_eq!(days_until_settlement, 2);

        // During settlement, may have restrictions on new orders
        let in_settlement_period = days_until_settlement > 0;
        assert!(in_settlement_period);
    }

    #[tokio::test]
    async fn test_weekend_position_limits() {
        // Stricter limits for weekend exposure
        let current_time = Utc::now();
        let is_friday_afternoon = current_time.date_naive().weekday().num_days_from_monday() == 4
            && current_time.hour() >= 14;

        if is_friday_afternoon {
            // Apply weekend position limits (more conservative)
            let weekday_limit = Price::new(200000.0).unwrap();
            let weekend_limit = Price::new(150000.0).unwrap();

            assert!(weekend_limit < weekday_limit);
        }
    }
}

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

    #[tokio::test]
    async fn test_qualified_institutional_buyer_exemption() {
        // QIB status provides exemption from certain limits
        let is_qib = true;
        let base_limit = Price::new(100000.0).unwrap();

        let effective_limit = if is_qib {
            (base_limit * 5.0).unwrap() // 5x multiplier for QIBs
        } else {
            base_limit
        };

        assert_eq!(effective_limit, Price::new(500000.0).unwrap());
    }

    #[tokio::test]
    async fn test_hedging_exemption() {
        // Bona fide hedging transactions exempt from position limits
        let is_hedge = true;
        let position_size = Price::new(500000.0).unwrap();
        let standard_limit = Price::new(100000.0).unwrap();

        let is_compliant = if is_hedge {
            true // Exempt from position limits
        } else {
            position_size <= standard_limit
        };

        assert!(is_compliant);
    }

    #[tokio::test]
    async fn test_temporary_exemption_expiration() {
        let exemption_granted = Utc::now() - Duration::hours(25);
        let exemption_duration = Duration::hours(24);
        let exemption_expires = exemption_granted + exemption_duration;

        let is_exemption_active = Utc::now() <= exemption_expires;

        // Exemption has expired
        assert!(!is_exemption_active);

        // Should revert to standard limits
        let standard_limit = Price::new(100000.0).unwrap();
        let position = Price::new(150000.0).unwrap();

        let is_violation = position > standard_limit;
        assert!(is_violation);
    }

    #[tokio::test]
    async fn test_cross_border_exemption() {
        // Some jurisdictions exempt from certain regulations
        let is_foreign_account = true;
        let is_us_regulation = true;

        let requires_compliance = !is_foreign_account || !is_us_regulation;

        if !requires_compliance {
            // Exempt from U.S. specific regulations
            assert!(!is_foreign_account || !is_us_regulation);
        }
    }
}

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

    #[tokio::test]
    async fn test_correlated_position_concentration() {
        // Multiple positions in same sector should aggregate
        let tech_positions = vec![
            ("AAPL", Price::new(40000.0).unwrap()),
            ("MSFT", Price::new(35000.0).unwrap()),
            ("GOOGL", Price::new(30000.0).unwrap()),
        ];

        let mut total_tech_exposure = Price::ZERO;
        for (_, value) in &tech_positions {
            total_tech_exposure = total_tech_exposure + *value;
        }

        let portfolio_value = Price::new(1000000.0).unwrap();
        let sector_limit = dec!(0.15); // 15% max per sector

        let sector_concentration =
            total_tech_exposure.to_decimal().unwrap() / portfolio_value.to_decimal().unwrap();

        // Tech sector is over-concentrated
        assert!(sector_concentration > sector_limit);
    }

    #[tokio::test]
    async fn test_leveraged_position_correlation() {
        // Leveraged and unleveraged positions on same underlying
        let spy_long = Price::new(100000.0).unwrap();
        let spy_3x_long = Price::new(50000.0).unwrap();

        // Effective exposure considering leverage (multiply by 3.0 as f64)
        let effective_spy_exposure = spy_long + (spy_3x_long * 3.0).unwrap();

        let exposure_limit = Price::new(200000.0).unwrap();

        // Combined exposure exceeds limit
        assert!(effective_spy_exposure > exposure_limit);
    }

    #[tokio::test]
    async fn test_derivatives_underlying_correlation() {
        // Options and stock on same underlying
        let stock_position = Price::new(100000.0).unwrap();
        let option_delta_exposure = Price::new(60000.0).unwrap(); // Delta-adjusted
        let futures_exposure = Price::new(50000.0).unwrap();

        let total_underlying_exposure = stock_position + option_delta_exposure + futures_exposure;

        let combined_limit = Price::new(150000.0).unwrap();

        // Total exposure exceeds limit
        assert!(total_underlying_exposure > combined_limit);
    }
}

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

    #[tokio::test]
    async fn test_wash_sale_detection() {
        // Sell at loss, rebuy within 30 days
        let sale_date = Utc::now() - Duration::days(15);
        let purchase_date = Utc::now();

        let days_between = (purchase_date - sale_date).num_days();

        let is_wash_sale = days_between <= 30;
        assert!(is_wash_sale);

        // Loss disallowed for tax purposes
    }

    #[tokio::test]
    async fn test_pattern_day_trader_detection() {
        // 4+ day trades in 5 business days
        let day_trades = vec![
            Utc::now() - Duration::days(4),
            Utc::now() - Duration::days(3),
            Utc::now() - Duration::days(2),
            Utc::now() - Duration::days(1),
        ];

        let is_pattern_day_trader = day_trades.len() >= 4;
        assert!(is_pattern_day_trader);

        // Requires $25,000 minimum equity
        let min_equity_required = Price::new(25000.0).unwrap();
        let current_equity = Price::new(20000.0).unwrap();

        let is_compliant = current_equity >= min_equity_required;
        assert!(!is_compliant);
    }

    #[tokio::test]
    async fn test_short_sale_restriction_uptick_rule() {
        // Cannot short on downtick during circuit breaker
        let circuit_breaker_triggered = true;
        let is_uptick = false;

        let can_short = if circuit_breaker_triggered {
            is_uptick // Must be on uptick
        } else {
            true // No restriction
        };

        assert!(!can_short);
    }

    #[tokio::test]
    async fn test_margin_call_calculation() {
        let account_equity = Price::new(50000.0).unwrap();
        let margin_debt = Price::new(80000.0).unwrap();

        let margin_ratio = margin_debt.to_decimal().unwrap() / account_equity.to_decimal().unwrap();

        let maintenance_margin = dec!(0.25); // 25% minimum
        let current_margin = dec!(1.0)
            - (margin_debt.to_decimal().unwrap()
                / (account_equity + margin_debt).to_decimal().unwrap());

        let is_margin_call = current_margin < maintenance_margin;
        assert!(is_margin_call);

        // Calculate required deposit
        let required_equity = margin_debt.to_decimal().unwrap() / (dec!(1.0) - maintenance_margin);
        let deposit_amount = required_equity - account_equity.to_decimal().unwrap();
        let deposit_required = if let Some(deposit_f64) = deposit_amount.to_f64() {
            Price::new(deposit_f64).unwrap()
        } else {
            Price::ZERO
        };

        assert!(deposit_required > Price::ZERO);
    }
}