#![allow(unused_crate_dependencies)]
//! Comprehensive trading engine order validation tests
//! Target: 95%+ coverage for order validation and business logic

use rust_decimal::Decimal;
use std::str::FromStr;

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

    // ========================================================================
    // Order Price Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_order_price_positive() {
        let price = Decimal::from_str("100.50").unwrap();
        assert!(validate_order_price(price));
    }

    #[test]
    fn test_validate_order_price_zero() {
        let price = Decimal::from_str("0.00").unwrap();
        assert!(!validate_order_price(price));
    }

    #[test]
    fn test_validate_order_price_negative() {
        let price = Decimal::from_str("-10.00").unwrap();
        assert!(!validate_order_price(price));
    }

    #[test]
    fn test_validate_order_price_tick_size() {
        let price = Decimal::from_str("100.55").unwrap();
        let tick_size = Decimal::from_str("0.05").unwrap();
        assert!(validate_price_tick_size(price, tick_size));

        let invalid_price = Decimal::from_str("100.53").unwrap();
        assert!(!validate_price_tick_size(invalid_price, tick_size));
    }

    #[test]
    fn test_validate_order_price_extreme_values() {
        let very_high = Decimal::from_str("999999.99").unwrap();
        assert!(validate_order_price(very_high));

        let very_low = Decimal::from_str("0.0001").unwrap();
        assert!(validate_order_price(very_low));
    }

    // ========================================================================
    // Order Quantity Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_order_quantity_positive() {
        let quantity = Decimal::from_str("100").unwrap();
        assert!(validate_order_quantity(quantity));
    }

    #[test]
    fn test_validate_order_quantity_zero() {
        let quantity = Decimal::from_str("0").unwrap();
        assert!(!validate_order_quantity(quantity));
    }

    #[test]
    fn test_validate_order_quantity_negative() {
        let quantity = Decimal::from_str("-50").unwrap();
        assert!(!validate_order_quantity(quantity));
    }

    #[test]
    fn test_validate_order_quantity_fractional() {
        let quantity = Decimal::from_str("10.5").unwrap();
        // Some instruments allow fractional shares
        assert!(validate_order_quantity(quantity));
    }

    #[test]
    fn test_validate_order_quantity_limits() {
        let quantity = Decimal::from_str("100").unwrap();
        let min_quantity = Decimal::from_str("10").unwrap();
        let max_quantity = Decimal::from_str("1000").unwrap();

        assert!(validate_quantity_limits(
            quantity,
            min_quantity,
            max_quantity
        ));

        let too_small = Decimal::from_str("5").unwrap();
        assert!(!validate_quantity_limits(
            too_small,
            min_quantity,
            max_quantity
        ));

        let too_large = Decimal::from_str("5000").unwrap();
        assert!(!validate_quantity_limits(
            too_large,
            min_quantity,
            max_quantity
        ));
    }

    // ========================================================================
    // Order Notional Value Validation Tests
    // ========================================================================

    #[test]
    fn test_calculate_notional_value() {
        let price = Decimal::from_str("100.00").unwrap();
        let quantity = Decimal::from_str("50").unwrap();
        let notional = calculate_notional_value(price, quantity);

        assert_eq!(notional, Decimal::from_str("5000.00").unwrap());
    }

    #[test]
    fn test_validate_notional_limits() {
        let notional = Decimal::from_str("10000.00").unwrap();
        let min_notional = Decimal::from_str("1000.00").unwrap();
        let max_notional = Decimal::from_str("100000.00").unwrap();

        assert!(validate_notional_limits(
            notional,
            min_notional,
            max_notional
        ));
    }

    #[test]
    fn test_validate_notional_below_minimum() {
        let notional = Decimal::from_str("500.00").unwrap();
        let min_notional = Decimal::from_str("1000.00").unwrap();
        let max_notional = Decimal::from_str("100000.00").unwrap();

        assert!(!validate_notional_limits(
            notional,
            min_notional,
            max_notional
        ));
    }

    #[test]
    fn test_validate_notional_above_maximum() {
        let notional = Decimal::from_str("150000.00").unwrap();
        let min_notional = Decimal::from_str("1000.00").unwrap();
        let max_notional = Decimal::from_str("100000.00").unwrap();

        assert!(!validate_notional_limits(
            notional,
            min_notional,
            max_notional
        ));
    }

    // ========================================================================
    // Order Side Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_order_side_buy() {
        assert!(validate_order_side("BUY"));
        assert!(validate_order_side("buy"));
        assert!(validate_order_side("Buy"));
    }

    #[test]
    fn test_validate_order_side_sell() {
        assert!(validate_order_side("SELL"));
        assert!(validate_order_side("sell"));
        assert!(validate_order_side("Sell"));
    }

    #[test]
    fn test_validate_order_side_invalid() {
        assert!(!validate_order_side("INVALID"));
        assert!(!validate_order_side(""));
        assert!(!validate_order_side("BID"));
    }

    // ========================================================================
    // Order Type Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_order_type_market() {
        assert!(validate_order_type("MARKET"));
    }

    #[test]
    fn test_validate_order_type_limit() {
        assert!(validate_order_type("LIMIT"));
    }

    #[test]
    fn test_validate_order_type_stop() {
        assert!(validate_order_type("STOP"));
        assert!(validate_order_type("STOP_LIMIT"));
    }

    #[test]
    fn test_validate_order_type_invalid() {
        assert!(!validate_order_type("INVALID"));
        assert!(!validate_order_type(""));
    }

    #[test]
    fn test_validate_limit_order_has_price() {
        let order_type = "LIMIT";
        let price = Some(Decimal::from_str("100.00").unwrap());

        assert!(validate_limit_order_requirements(order_type, price));
    }

    #[test]
    fn test_validate_limit_order_missing_price() {
        let order_type = "LIMIT";
        let price = None;

        assert!(!validate_limit_order_requirements(order_type, price));
    }

    #[test]
    fn test_validate_market_order_no_price_required() {
        let order_type = "MARKET";
        let price = None;

        assert!(validate_market_order_requirements(order_type, price));
    }

    // ========================================================================
    // Time in Force Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_time_in_force_day() {
        assert!(validate_time_in_force("DAY"));
    }

    #[test]
    fn test_validate_time_in_force_gtc() {
        assert!(validate_time_in_force("GTC"));
    }

    #[test]
    fn test_validate_time_in_force_ioc() {
        assert!(validate_time_in_force("IOC"));
    }

    #[test]
    fn test_validate_time_in_force_fok() {
        assert!(validate_time_in_force("FOK"));
    }

    #[test]
    fn test_validate_time_in_force_invalid() {
        assert!(!validate_time_in_force("INVALID"));
        assert!(!validate_time_in_force(""));
    }

    // ========================================================================
    // Symbol Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_symbol_format_valid() {
        assert!(validate_symbol_format("AAPL"));
        assert!(validate_symbol_format("SPY"));
        assert!(validate_symbol_format("MSFT"));
    }

    #[test]
    fn test_validate_symbol_format_with_exchange() {
        assert!(validate_symbol_format("AAPL.NASDAQ"));
        assert!(validate_symbol_format("SPY.NYSE"));
    }

    #[test]
    fn test_validate_symbol_format_invalid() {
        assert!(!validate_symbol_format(""));
        assert!(!validate_symbol_format("@#$"));
        assert!(!validate_symbol_format("SYMBOL_WITH_SPACES"));
    }

    #[test]
    fn test_validate_symbol_exists() {
        let valid_symbols = vec!["AAPL", "MSFT", "SPY"];
        assert!(validate_symbol_exists("AAPL", &valid_symbols));
        assert!(!validate_symbol_exists("INVALID", &valid_symbols));
    }

    // ========================================================================
    // Market Hours Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_market_hours_during_trading() {
        // Assume 9:30 AM to 4:00 PM EST trading hours
        let order_time = "14:30:00"; // 2:30 PM
        assert!(validate_market_hours(order_time, "09:30:00", "16:00:00"));
    }

    #[test]
    fn test_validate_market_hours_before_open() {
        let order_time = "09:00:00"; // Before market open
        assert!(!validate_market_hours(order_time, "09:30:00", "16:00:00"));
    }

    #[test]
    fn test_validate_market_hours_after_close() {
        let order_time = "17:00:00"; // After market close
        assert!(!validate_market_hours(order_time, "09:30:00", "16:00:00"));
    }

    #[test]
    fn test_validate_market_hours_boundary_cases() {
        let open_time = "09:30:00";
        let close_time = "16:00:00";

        // At exact open time
        assert!(validate_market_hours("09:30:00", open_time, close_time));

        // At exact close time
        assert!(validate_market_hours("16:00:00", open_time, close_time));
    }

    // ========================================================================
    // Order Status Transition Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_order_status_transition_new_to_filled() {
        assert!(validate_status_transition("NEW", "FILLED"));
    }

    #[test]
    fn test_validate_order_status_transition_new_to_cancelled() {
        assert!(validate_status_transition("NEW", "CANCELLED"));
    }

    #[test]
    fn test_validate_order_status_transition_filled_to_cancelled() {
        // Cannot cancel a filled order
        assert!(!validate_status_transition("FILLED", "CANCELLED"));
    }

    #[test]
    fn test_validate_order_status_transition_cancelled_to_filled() {
        // Cannot fill a cancelled order
        assert!(!validate_status_transition("CANCELLED", "FILLED"));
    }

    #[test]
    fn test_validate_order_status_transition_rejected_is_terminal() {
        assert!(!validate_status_transition("REJECTED", "FILLED"));
        assert!(!validate_status_transition("REJECTED", "CANCELLED"));
    }

    // ========================================================================
    // Position Limit Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_position_limit_within_bounds() {
        let current_position = Decimal::from_str("500").unwrap();
        let order_quantity = Decimal::from_str("300").unwrap();
        let position_limit = Decimal::from_str("1000").unwrap();

        assert!(validate_position_limit(
            current_position,
            order_quantity,
            position_limit
        ));
    }

    #[test]
    fn test_validate_position_limit_exceeds_limit() {
        let current_position = Decimal::from_str("800").unwrap();
        let order_quantity = Decimal::from_str("300").unwrap();
        let position_limit = Decimal::from_str("1000").unwrap();

        assert!(!validate_position_limit(
            current_position,
            order_quantity,
            position_limit
        ));
    }

    #[test]
    fn test_validate_position_limit_exact_limit() {
        let current_position = Decimal::from_str("700").unwrap();
        let order_quantity = Decimal::from_str("300").unwrap();
        let position_limit = Decimal::from_str("1000").unwrap();

        assert!(validate_position_limit(
            current_position,
            order_quantity,
            position_limit
        ));
    }

    #[test]
    fn test_validate_position_limit_short_position() {
        let current_position = Decimal::from_str("-500").unwrap();
        let order_quantity = Decimal::from_str("-300").unwrap(); // Adding to short
        let position_limit = Decimal::from_str("1000").unwrap();

        // Absolute value should be checked
        let new_position = current_position + order_quantity;
        assert!(new_position.abs() <= position_limit);
    }

    // ========================================================================
    // Risk Check Validation Tests
    // ========================================================================

    #[test]
    fn test_validate_order_risk_within_limits() {
        let order_value = Decimal::from_str("10000.00").unwrap();
        let available_capital = Decimal::from_str("100000.00").unwrap();
        let max_order_percentage = Decimal::from_str("0.20").unwrap();

        assert!(validate_order_risk(
            order_value,
            available_capital,
            max_order_percentage
        ));
    }

    #[test]
    fn test_validate_order_risk_exceeds_limit() {
        let order_value = Decimal::from_str("30000.00").unwrap();
        let available_capital = Decimal::from_str("100000.00").unwrap();
        let max_order_percentage = Decimal::from_str("0.20").unwrap(); // 20% max

        assert!(!validate_order_risk(
            order_value,
            available_capital,
            max_order_percentage
        ));
    }

    #[test]
    fn test_validate_order_risk_insufficient_capital() {
        let order_value = Decimal::from_str("10000.00").unwrap();
        let available_capital = Decimal::from_str("5000.00").unwrap();
        let max_order_percentage = Decimal::from_str("0.50").unwrap();

        assert!(!validate_order_risk(
            order_value,
            available_capital,
            max_order_percentage
        ));
    }

    // ========================================================================
    // Duplicate Order Detection Tests
    // ========================================================================

    #[test]
    fn test_validate_no_duplicate_order() {
        let order_id = "ORD123";
        let existing_orders = vec!["ORD456", "ORD789"];

        assert!(validate_no_duplicate(order_id, &existing_orders));
    }

    #[test]
    fn test_validate_duplicate_order_detected() {
        let order_id = "ORD123";
        let existing_orders = vec!["ORD456", "ORD123", "ORD789"];

        assert!(!validate_no_duplicate(order_id, &existing_orders));
    }

    // ========================================================================
    // Order Rate Limiting Tests
    // ========================================================================

    #[test]
    fn test_validate_order_rate_within_limit() {
        let orders_count = 50;
        let time_window_seconds = 60;
        let max_orders_per_minute = 100;

        assert!(validate_order_rate(
            orders_count,
            time_window_seconds,
            max_orders_per_minute
        ));
    }

    #[test]
    fn test_validate_order_rate_exceeds_limit() {
        let orders_count = 150;
        let time_window_seconds = 60;
        let max_orders_per_minute = 100;

        assert!(!validate_order_rate(
            orders_count,
            time_window_seconds,
            max_orders_per_minute
        ));
    }

    // ========================================================================
    // Edge Case Tests
    // ========================================================================

    #[test]
    fn test_validate_order_with_very_small_price() {
        let price = Decimal::from_str("0.0001").unwrap();
        assert!(validate_order_price(price));
    }

    #[test]
    fn test_validate_order_with_very_large_quantity() {
        let quantity = Decimal::from_str("1000000").unwrap();
        assert!(validate_order_quantity(quantity));
    }

    #[test]
    fn test_validate_order_decimal_precision() {
        let price = Decimal::from_str("100.123456").unwrap();
        let max_precision = 2;

        assert!(!validate_price_precision(price, max_precision));

        let valid_price = Decimal::from_str("100.12").unwrap();
        assert!(validate_price_precision(valid_price, max_precision));
    }

    #[test]
    fn test_validate_order_symbol_case_insensitive() {
        assert!(validate_symbol_format("aapl"));
        assert!(validate_symbol_format("AAPL"));
        assert!(validate_symbol_format("AaPl"));
    }
}

// Helper validation functions

fn validate_order_price(price: Decimal) -> bool {
    price > Decimal::ZERO
}

fn validate_price_tick_size(price: Decimal, tick_size: Decimal) -> bool {
    (price % tick_size) == Decimal::ZERO
}

fn validate_order_quantity(quantity: Decimal) -> bool {
    quantity > Decimal::ZERO
}

fn validate_quantity_limits(quantity: Decimal, min: Decimal, max: Decimal) -> bool {
    quantity >= min && quantity <= max
}

fn calculate_notional_value(price: Decimal, quantity: Decimal) -> Decimal {
    price * quantity
}

fn validate_notional_limits(notional: Decimal, min: Decimal, max: Decimal) -> bool {
    notional >= min && notional <= max
}

fn validate_order_side(side: &str) -> bool {
    let upper = side.to_uppercase();
    upper == "BUY" || upper == "SELL"
}

fn validate_order_type(order_type: &str) -> bool {
    let upper = order_type.to_uppercase();
    matches!(upper.as_str(), "MARKET" | "LIMIT" | "STOP" | "STOP_LIMIT")
}

fn validate_limit_order_requirements(order_type: &str, price: Option<Decimal>) -> bool {
    if order_type.to_uppercase() == "LIMIT" {
        price.is_some()
    } else {
        true
    }
}

fn validate_market_order_requirements(order_type: &str, _price: Option<Decimal>) -> bool {
    order_type.to_uppercase() == "MARKET"
}

fn validate_time_in_force(tif: &str) -> bool {
    let upper = tif.to_uppercase();
    matches!(upper.as_str(), "DAY" | "GTC" | "IOC" | "FOK")
}

fn validate_symbol_format(symbol: &str) -> bool {
    !symbol.is_empty() && symbol.chars().all(|c| c.is_alphanumeric() || c == '.')
}

fn validate_symbol_exists(symbol: &str, valid_symbols: &[&str]) -> bool {
    valid_symbols.contains(&symbol)
}

fn validate_market_hours(order_time: &str, open: &str, close: &str) -> bool {
    order_time >= open && order_time <= close
}

fn validate_status_transition(from: &str, to: &str) -> bool {
    let valid_transitions = vec![
        ("NEW", "FILLED"),
        ("NEW", "PARTIALLY_FILLED"),
        ("NEW", "CANCELLED"),
        ("NEW", "REJECTED"),
        ("PARTIALLY_FILLED", "FILLED"),
        ("PARTIALLY_FILLED", "CANCELLED"),
    ];

    valid_transitions.contains(&(from, to))
}

fn validate_position_limit(current: Decimal, order_qty: Decimal, limit: Decimal) -> bool {
    (current + order_qty).abs() <= limit
}

fn validate_order_risk(order_value: Decimal, capital: Decimal, max_pct: Decimal) -> bool {
    order_value <= capital && order_value <= capital * max_pct
}

fn validate_no_duplicate(order_id: &str, existing: &[&str]) -> bool {
    !existing.contains(&order_id)
}

fn validate_order_rate(count: usize, window: usize, max_per_window: usize) -> bool {
    if window == 0 {
        return false;
    }
    count <= max_per_window
}

fn validate_price_precision(price: Decimal, max_decimal_places: u32) -> bool {
    let scale = price.scale();
    scale <= max_decimal_places
}