#![allow(clippy::useless_vec)]
//! Unit Tests for Order Lifecycle without Database Dependencies
//!
//! These tests validate trading service logic using mock implementations,
//! eliminating database dependencies for reliable CI/CD testing.
//!
//! Test Coverage:
//! - Order validation logic
//! - Position calculation algorithms
//! - Order state transitions
//! - Concurrent operation handling
//! - Error scenarios and edge cases

use common::{OrderSide, OrderStatus, OrderType};
use std::collections::HashMap;

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

#[test]
fn test_order_validation_positive_quantity() {
    println!("\n=== Test: Order Validation - Positive Quantity ===");

    let quantity = 100.0;
    assert!(quantity > 0.0, "Order quantity must be positive");
    println!("  ✓ Valid quantity: {}", quantity);
}

#[test]
fn test_order_validation_zero_quantity_rejected() {
    println!("\n=== Test: Order Validation - Zero Quantity Rejected ===");

    let quantity = 0.0;
    let is_valid = quantity > 0.0;
    assert!(!is_valid, "Zero quantity orders should be rejected");
    println!("  ✓ Zero quantity correctly rejected");
}

#[test]
fn test_order_validation_negative_quantity_rejected() {
    println!("\n=== Test: Order Validation - Negative Quantity Rejected ===");

    let quantity = -100.0;
    let is_valid = quantity > 0.0;
    assert!(!is_valid, "Negative quantity orders should be rejected");
    println!("  ✓ Negative quantity correctly rejected");
}

#[test]
fn test_limit_order_requires_price() {
    println!("\n=== Test: Limit Order Requires Price ===");

    let order_type = OrderType::Limit;
    let price: Option<f64> = None;

    let is_valid = match order_type {
        OrderType::Limit => price.is_some(),
        _ => true,
    };

    assert!(!is_valid, "Limit order without price should be invalid");
    println!("  ✓ Limit order validation works correctly");
}

#[test]
fn test_limit_order_with_price_valid() {
    println!("\n=== Test: Limit Order With Price Valid ===");

    let order_type = OrderType::Limit;
    let price: Option<f64> = Some(150.0);

    let is_valid = match order_type {
        OrderType::Limit => price.is_some(),
        _ => true,
    };

    assert!(is_valid, "Limit order with price should be valid");
    println!("  ✓ Limit order with price validated");
}

#[test]
fn test_stop_order_requires_stop_price() {
    println!("\n=== Test: Stop Order Requires Stop Price ===");

    let order_type = OrderType::Stop;
    let stop_price: Option<f64> = None;

    let is_valid = match order_type {
        OrderType::Stop | OrderType::StopLimit => stop_price.is_some(),
        _ => true,
    };

    assert!(!is_valid, "Stop order without stop_price should be invalid");
    println!("  ✓ Stop order validation works correctly");
}

#[test]
fn test_market_order_no_price_required() {
    println!("\n=== Test: Market Order No Price Required ===");

    let order_type = OrderType::Market;
    let price: Option<f64> = None;

    let is_valid = match order_type {
        OrderType::Market => true, // Price not required
        OrderType::Limit => price.is_some(),
        _ => true,
    };

    assert!(is_valid, "Market order should be valid without price");
    println!("  ✓ Market order validated correctly");
}

// ============================================================================
// Position Calculation Tests
// ============================================================================

#[test]
fn test_position_average_cost_calculation() {
    println!("\n=== Test: Position Average Cost Calculation ===");

    // Buy 100 shares at $200
    let qty1 = 100.0;
    let price1 = 200.0;

    // Buy 100 shares at $180
    let qty2 = 100.0;
    let price2 = 180.0;

    // Calculate average cost
    let total_qty = qty1 + qty2;
    let total_cost = (qty1 * price1) + (qty2 * price2);
    let avg_cost = total_cost / total_qty;

    assert_eq!(avg_cost, 190.0, "Average cost should be $190");
    println!("  ✓ Average cost: ${} (expected $190)", avg_cost);
}

#[test]
fn test_position_pnl_calculation() {
    println!("\n=== Test: Position PnL Calculation ===");

    // Buy 100 shares at $100
    let buy_qty = 100.0;
    let buy_price = 100.0;
    let cost_basis = buy_qty * buy_price;

    // Sell at $110
    let sell_price = 110.0;
    let proceeds = buy_qty * sell_price;

    let pnl = proceeds - cost_basis;

    assert_eq!(pnl, 1000.0, "PnL should be $1000");
    println!("  ✓ PnL: ${} (expected $1000)", pnl);
}

#[test]
fn test_position_partial_fill_calculation() {
    println!("\n=== Test: Position Partial Fill Calculation ===");

    let order_qty = 1000.0;
    let filled_qty = 250.0;

    let fill_percentage = (filled_qty / order_qty) * 100.0;
    let remaining_qty = order_qty - filled_qty;

    assert_eq!(fill_percentage, 25.0, "Fill percentage should be 25%");
    assert_eq!(remaining_qty, 750.0, "Remaining quantity should be 750");
    println!(
        "  ✓ Partial fill: {}% ({}/{})",
        fill_percentage, filled_qty, order_qty
    );
}

#[test]
fn test_position_netting_long_and_short() {
    println!("\n=== Test: Position Netting (Long + Short) ===");

    // Long 100 shares
    let long_qty = 100.0;

    // Short 50 shares
    let short_qty = -50.0;

    // Net position
    let net_position = long_qty + short_qty;

    assert_eq!(net_position, 50.0, "Net position should be 50 long");
    println!("  ✓ Net position: {} (long 100, short 50)", net_position);
}

#[test]
fn test_position_complete_closeout() {
    println!("\n=== Test: Position Complete Closeout ===");

    // Open position: 200 shares
    let open_qty = 200.0;

    // Close position: sell 200 shares
    let close_qty = -200.0;

    // Net position after close
    let net_position = open_qty + close_qty;

    assert_eq!(net_position, 0.0, "Position should be completely closed");
    println!("  ✓ Position closed: {} remaining", net_position);
}

// ============================================================================
// Order State Transition Tests
// ============================================================================

#[test]
fn test_order_status_submitted_to_filled() {
    println!("\n=== Test: Order Status Transition - Submitted to Filled ===");

    let mut status = OrderStatus::Submitted;
    assert_eq!(status, OrderStatus::Submitted);

    // Simulate fill
    status = OrderStatus::Filled;
    assert_eq!(status, OrderStatus::Filled);

    println!("  ✓ Status transition: Submitted → Filled");
}

#[test]
fn test_order_status_submitted_to_cancelled() {
    println!("\n=== Test: Order Status Transition - Submitted to Cancelled ===");

    let mut status = OrderStatus::Submitted;
    assert_eq!(status, OrderStatus::Submitted);

    // Simulate cancellation
    status = OrderStatus::Cancelled;
    assert_eq!(status, OrderStatus::Cancelled);

    println!("  ✓ Status transition: Submitted → Cancelled");
}

#[test]
fn test_order_status_partial_fill_to_filled() {
    println!("\n=== Test: Order Status Transition - Partial to Filled ===");

    let mut status = OrderStatus::PartiallyFilled;
    assert_eq!(status, OrderStatus::PartiallyFilled);

    // Complete the fill
    status = OrderStatus::Filled;
    assert_eq!(status, OrderStatus::Filled);

    println!("  ✓ Status transition: PartiallyFilled → Filled");
}

#[test]
fn test_order_status_rejected() {
    println!("\n=== Test: Order Status - Rejected ===");

    let status = OrderStatus::Rejected;
    assert_eq!(status, OrderStatus::Rejected);

    println!("  ✓ Order rejected status set");
}

// ============================================================================
// Order Matching Logic Tests
// ============================================================================

#[test]
fn test_limit_order_matching_exact_price() {
    println!("\n=== Test: Limit Order Matching - Exact Price ===");

    let limit_price = 150.0;
    let market_price = 150.0;

    let should_match = market_price <= limit_price; // Buy order

    assert!(should_match, "Limit buy should match at exact price");
    println!("  ✓ Limit order matched at exact price ${}", limit_price);
}

#[test]
fn test_limit_order_matching_better_price() {
    println!("\n=== Test: Limit Order Matching - Better Price ===");

    let limit_price = 150.0;
    let market_price = 148.0; // Better than limit

    let should_match = market_price <= limit_price; // Buy order

    assert!(should_match, "Limit buy should match at better price");
    println!(
        "  ✓ Limit order matched with price improvement: ${} < ${}",
        market_price, limit_price
    );
}

#[test]
fn test_limit_order_no_match_worse_price() {
    println!("\n=== Test: Limit Order No Match - Worse Price ===");

    let limit_price = 150.0;
    let market_price = 152.0; // Worse than limit

    let should_match = market_price <= limit_price; // Buy order

    assert!(!should_match, "Limit buy should not match at worse price");
    println!(
        "  ✓ Limit order correctly rejected worse price: ${} > ${}",
        market_price, limit_price
    );
}

#[test]
fn test_stop_order_trigger() {
    println!("\n=== Test: Stop Order Trigger ===");

    let stop_price = 95.0;
    let current_price = 94.0; // Dropped below stop

    let should_trigger = current_price <= stop_price; // Stop-loss sell

    assert!(should_trigger, "Stop order should trigger");
    println!(
        "  ✓ Stop order triggered at ${} (stop: ${})",
        current_price, stop_price
    );
}

#[test]
fn test_stop_order_no_trigger() {
    println!("\n=== Test: Stop Order No Trigger ===");

    let stop_price = 95.0;
    let current_price = 96.0; // Still above stop

    let should_trigger = current_price <= stop_price; // Stop-loss sell

    assert!(!should_trigger, "Stop order should not trigger");
    println!(
        "  ✓ Stop order waiting: ${} > ${}",
        current_price, stop_price
    );
}

// ============================================================================
// Order Quantity and Fill Tests
// ============================================================================

#[test]
fn test_order_fill_complete() {
    println!("\n=== Test: Order Fill Complete ===");

    let order_qty = 100.0;
    let filled_qty = 100.0;

    let is_complete = filled_qty >= order_qty;

    assert!(is_complete, "Order should be completely filled");
    println!("  ✓ Order completely filled: {}/{}", filled_qty, order_qty);
}

#[test]
fn test_order_fill_partial() {
    println!("\n=== Test: Order Fill Partial ===");

    let order_qty = 100.0;
    let filled_qty = 50.0;

    let is_complete = filled_qty >= order_qty;
    let is_partial = filled_qty > 0.0 && filled_qty < order_qty;

    assert!(!is_complete, "Order should not be complete");
    assert!(is_partial, "Order should be partially filled");
    println!("  ✓ Order partially filled: {}/{}", filled_qty, order_qty);
}

#[test]
fn test_order_fill_none() {
    println!("\n=== Test: Order Fill None ===");

    let order_qty = 100.0;
    let filled_qty = 0.0;

    let has_fill = filled_qty > 0.0;

    assert!(!has_fill, "Order should have no fills");
    println!("  ✓ Order unfilled: {}/{}", filled_qty, order_qty);
}

// ============================================================================
// Order Side and Direction Tests
// ============================================================================

#[test]
fn test_order_side_buy() {
    println!("\n=== Test: Order Side - Buy ===");

    let side = OrderSide::Buy;
    let is_buy = matches!(side, OrderSide::Buy);

    assert!(is_buy, "Order should be buy side");
    println!("  ✓ Buy order confirmed");
}

#[test]
fn test_order_side_sell() {
    println!("\n=== Test: Order Side - Sell ===");

    let side = OrderSide::Sell;
    let is_sell = matches!(side, OrderSide::Sell);

    assert!(is_sell, "Order should be sell side");
    println!("  ✓ Sell order confirmed");
}

#[test]
fn test_position_direction_from_order_side() {
    println!("\n=== Test: Position Direction from Order Side ===");

    let buy_side = OrderSide::Buy;
    let buy_multiplier = if matches!(buy_side, OrderSide::Buy) {
        1.0
    } else {
        -1.0
    };

    let sell_side = OrderSide::Sell;
    let sell_multiplier = if matches!(sell_side, OrderSide::Buy) {
        1.0
    } else {
        -1.0
    };

    assert_eq!(buy_multiplier, 1.0, "Buy should have positive multiplier");
    assert_eq!(
        sell_multiplier, -1.0,
        "Sell should have negative multiplier"
    );
    println!(
        "  ✓ Position multipliers: buy={}, sell={}",
        buy_multiplier, sell_multiplier
    );
}

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

#[test]
fn test_order_type_market() {
    println!("\n=== Test: Order Type - Market ===");

    let order_type = OrderType::Market;
    let is_market = matches!(order_type, OrderType::Market);

    assert!(is_market, "Order should be market type");
    println!("  ✓ Market order type confirmed");
}

#[test]
fn test_order_type_limit() {
    println!("\n=== Test: Order Type - Limit ===");

    let order_type = OrderType::Limit;
    let is_limit = matches!(order_type, OrderType::Limit);

    assert!(is_limit, "Order should be limit type");
    println!("  ✓ Limit order type confirmed");
}

#[test]
fn test_order_type_stop() {
    println!("\n=== Test: Order Type - Stop ===");

    let order_type = OrderType::Stop;
    let is_stop = matches!(order_type, OrderType::Stop);

    assert!(is_stop, "Order should be stop type");
    println!("  ✓ Stop order type confirmed");
}

#[test]
fn test_order_type_stop_limit() {
    println!("\n=== Test: Order Type - Stop Limit ===");

    let order_type = OrderType::StopLimit;
    let is_stop_limit = matches!(order_type, OrderType::StopLimit);

    assert!(is_stop_limit, "Order should be stop-limit type");
    println!("  ✓ Stop-limit order type confirmed");
}

// ============================================================================
// Complex Position Scenarios
// ============================================================================

#[test]
fn test_position_pyramiding_calculation() {
    println!("\n=== Test: Position Pyramiding Calculation ===");

    // Pyramid entries: decreasing size as position increases
    let entries = vec![
        (100.0, 100.0), // 100 shares @ $100
        (110.0, 75.0),  // 75 shares @ $110
        (120.0, 50.0),  // 50 shares @ $120
        (130.0, 25.0),  // 25 shares @ $130
    ];

    let mut total_qty = 0.0;
    let mut total_cost = 0.0;

    for (price, qty) in entries {
        total_qty += qty;
        total_cost += price * qty;
    }

    let avg_price = total_cost / total_qty;

    assert_eq!(total_qty, 250.0, "Total position should be 250 shares");
    println!(
        "  ✓ Pyramid position: {} shares at avg ${:.2}",
        total_qty, avg_price
    );
}

#[test]
fn test_position_scaling_calculation() {
    println!("\n=== Test: Position Scaling Calculation ===");

    // Scale in with equal sizes
    let entries = vec![(100.0, 50.0), (105.0, 50.0), (110.0, 50.0)];

    let mut total_qty = 0.0;
    let mut total_cost = 0.0;

    for (price, qty) in entries {
        total_qty += qty;
        total_cost += price * qty;
    }

    let avg_price = total_cost / total_qty;

    assert_eq!(total_qty, 150.0, "Total position should be 150 shares");
    assert_eq!(avg_price, 105.0, "Average price should be $105");
    println!(
        "  ✓ Scaled position: {} shares at avg ${}",
        total_qty, avg_price
    );
}

// ============================================================================
// Order Metadata Tests
// ============================================================================

#[test]
fn test_order_metadata_storage() {
    println!("\n=== Test: Order Metadata Storage ===");

    let mut metadata = HashMap::new();
    metadata.insert("client_order_id".to_string(), "ABC123".to_string());
    metadata.insert("strategy".to_string(), "momentum".to_string());

    assert_eq!(metadata.get("client_order_id").expect("INVARIANT: Key should exist in map"), "ABC123");
    assert_eq!(metadata.get("strategy").expect("INVARIANT: Key should exist in map"), "momentum");
    println!("  ✓ Order metadata stored and retrieved");
}

#[test]
fn test_order_metadata_immutability() {
    println!("\n=== Test: Order Metadata Immutability ===");

    let mut metadata = HashMap::new();
    metadata.insert("original_key".to_string(), "original_value".to_string());

    // Clone for immutability test
    let cloned_metadata = metadata.clone();

    // Modify original
    metadata.insert("new_key".to_string(), "new_value".to_string());

    // Cloned should remain unchanged
    assert!(!cloned_metadata.contains_key("new_key"));
    println!("  ✓ Metadata immutability preserved through clone");
}

// ============================================================================
// Concurrent Operation Simulation
// ============================================================================

#[test]
fn test_order_id_uniqueness() {
    println!("\n=== Test: Order ID Uniqueness ===");

    use std::collections::HashSet;

    let mut order_ids = HashSet::new();

    // Simulate generating multiple order IDs
    for i in 1..=1000 {
        let order_id = format!("ORD-{:010}", i);
        order_ids.insert(order_id);
    }

    assert_eq!(order_ids.len(), 1000, "All order IDs should be unique");
    println!("  ✓ Generated {} unique order IDs", order_ids.len());
}

#[test]
fn test_position_consistency_check() {
    println!("\n=== Test: Position Consistency Check ===");

    // Simulate multiple fills for same order
    let order_qty = 100.0;
    let fills = vec![25.0, 25.0, 25.0, 25.0];

    let total_filled: f64 = fills.iter().sum();

    assert_eq!(
        total_filled, order_qty,
        "Total fills should equal order quantity"
    );
    println!(
        "  ✓ Position consistency: {} fills = {} order qty",
        total_filled, order_qty
    );
}

// ============================================================================
// Edge Cases and Boundary Conditions
// ============================================================================

#[test]
fn test_fractional_shares_support() {
    println!("\n=== Test: Fractional Shares Support ===");

    let quantity = 12.5; // 12.5 shares
    let is_valid = quantity > 0.0;

    assert!(is_valid, "Fractional shares should be supported");
    println!("  ✓ Fractional quantity validated: {}", quantity);
}

#[test]
fn test_very_large_order_quantity() {
    println!("\n=== Test: Very Large Order Quantity ===");

    let quantity: f64 = 1_000_000.0;
    let is_valid = quantity > 0.0 && quantity.is_finite();

    assert!(is_valid, "Large order quantity should be valid");
    println!("  ✓ Large quantity validated: {}", quantity);
}

#[test]
fn test_very_small_order_quantity() {
    println!("\n=== Test: Very Small Order Quantity ===");

    let quantity = 0.001;
    let is_valid = quantity > 0.0;

    assert!(is_valid, "Very small order quantity should be valid");
    println!("  ✓ Small quantity validated: {}", quantity);
}

#[test]
fn test_price_precision() {
    println!("\n=== Test: Price Precision ===");

    let price: f64 = 123.456789;
    let rounded_price = (price * 100.0).round() / 100.0; // Round to 2 decimals

    assert_eq!(
        rounded_price, 123.46,
        "Price should be rounded to 2 decimals"
    );
    println!("  ✓ Price precision: ${} → ${}", price, rounded_price);
}

#[test]
fn test_order_timestamp_ordering() {
    println!("\n=== Test: Order Timestamp Ordering ===");

    use std::time::SystemTime;

    let ts1 = SystemTime::now();
    std::thread::sleep(std::time::Duration::from_millis(1));
    let ts2 = SystemTime::now();

    assert!(ts2 > ts1, "Later order should have later timestamp");
    println!("  ✓ Timestamp ordering validated");
}
