use std::collections::BTreeMap;

use chrono::NaiveDate;
use fidc_core::{
    FuturesAccountState, FuturesContractSpec, FuturesDirection, FuturesOrderIntent,
    FuturesPositionEffect, OrderStatus,
};

fn d(year: i32, month: u32, day: u32) -> NaiveDate {
    NaiveDate::from_ymd_opt(year, month, day).expect("valid date")
}

#[test]
fn futures_account_tracks_long_margin_pnl_and_settlement() {
    let spec = FuturesContractSpec::new(300.0, 0.12, 0.14);
    let mut account = FuturesAccountState::new(1_000_000.0);

    account.open("IF2501", FuturesDirection::Long, spec, 2, 4000.0, 12.0);
    account.mark_price("IF2501", FuturesDirection::Long, 4010.0);

    assert!((account.total_cash() - 999_988.0).abs() < 1e-6);
    assert!((account.margin() - 288_720.0).abs() < 1e-6);
    assert!((account.cash() - 711_268.0).abs() < 1e-6);
    assert!((account.position_equity() - 6_000.0).abs() < 1e-6);
    assert!((account.total_value() - 1_005_988.0).abs() < 1e-6);

    let settlement = BTreeMap::from([("IF2501".to_string(), 4020.0)]);
    let cash_delta = account.settle(&settlement);

    assert!((cash_delta - 12_000.0).abs() < 1e-6);
    assert!((account.total_cash() - 1_011_988.0).abs() < 1e-6);
    let position = account
        .position("IF2501", FuturesDirection::Long)
        .expect("long position");
    assert!((position.avg_price - 4020.0).abs() < 1e-6);
    assert!((position.equity()).abs() < 1e-6);
}

#[test]
fn futures_account_tracks_short_close_cash_delta() {
    let spec = FuturesContractSpec::new(10.0, 0.1, 0.2);
    let mut account = FuturesAccountState::new(100_000.0);

    account.open("RB2501", FuturesDirection::Short, spec, 5, 3500.0, 3.0);
    account.mark_price("RB2501", FuturesDirection::Short, 3480.0);
    assert!((account.margin() - 34_800.0).abs() < 1e-6);
    assert!((account.position_equity() - 1_000.0).abs() < 1e-6);

    let cash_delta = account
        .close("RB2501", FuturesDirection::Short, 2, 3470.0, 2.0)
        .expect("close short");

    assert!((cash_delta - 598.0).abs() < 1e-6);
    assert!((account.total_cash() - 100_595.0).abs() < 1e-6);
    let position = account
        .position("RB2501", FuturesDirection::Short)
        .expect("remaining short position");
    assert_eq!(position.quantity, 3);
    assert!((position.equity() - 900.0).abs() < 1e-6);
}

#[test]
fn futures_order_execution_splits_close_between_old_and_today_quantity() {
    let spec = FuturesContractSpec::new(300.0, 0.12, 0.12);
    let mut account = FuturesAccountState::new(1_000_000.0);

    account.open("IF2501", FuturesDirection::Long, spec, 3, 4000.0, 0.0);
    account.begin_trading_day();
    account.open("IF2501", FuturesDirection::Long, spec, 2, 4010.0, 0.0);

    let report = account.execute_order(
        d(2025, 1, 2),
        Some(10),
        FuturesOrderIntent::close(
            "IF2501",
            FuturesDirection::Long,
            FuturesPositionEffect::Close,
            spec,
            4,
            4020.0,
            4.0,
            "auto close",
        ),
    );

    assert_eq!(report.order_events.len(), 1);
    assert_eq!(report.order_events[0].status, OrderStatus::Filled);
    assert_eq!(report.fill_events[0].quantity, 4);
    assert!((report.fill_events[0].net_cash_flow - 19_196.0).abs() < 1e-6);
    let position = account
        .position("IF2501", FuturesDirection::Long)
        .expect("remaining long position");
    assert_eq!(position.quantity, 1);
    assert_eq!(position.old_quantity, 0);
    assert_eq!(position.today_quantity(), 1);
}

#[test]
fn futures_close_today_rejects_when_today_quantity_is_insufficient() {
    let spec = FuturesContractSpec::new(10.0, 0.1, 0.1);
    let mut account = FuturesAccountState::new(100_000.0);

    account.open("RB2501", FuturesDirection::Short, spec, 2, 3500.0, 0.0);
    account.begin_trading_day();

    let report = account.execute_order(
        d(2025, 1, 3),
        Some(11),
        FuturesOrderIntent::close(
            "RB2501",
            FuturesDirection::Short,
            FuturesPositionEffect::CloseToday,
            spec,
            1,
            3490.0,
            1.0,
            "close today without today position",
        ),
    );

    assert_eq!(report.order_events.len(), 1);
    assert_eq!(report.order_events[0].status, OrderStatus::Rejected);
    assert!(
        report.order_events[0]
            .reason
            .contains("close today quantity")
    );
    let position = account
        .position("RB2501", FuturesDirection::Short)
        .expect("short position unchanged");
    assert_eq!(position.quantity, 2);
    assert_eq!(position.old_quantity, 2);
}

#[test]
fn futures_open_order_rejects_when_margin_is_insufficient() {
    let spec = FuturesContractSpec::new(300.0, 0.2, 0.2);
    let mut account = FuturesAccountState::new(10_000.0);

    let report = account.execute_order(
        d(2025, 1, 6),
        Some(12),
        FuturesOrderIntent::open(
            "IF2501",
            FuturesDirection::Long,
            spec,
            1,
            4000.0,
            2.0,
            "oversized open",
        ),
    );

    assert_eq!(report.order_events.len(), 1);
    assert_eq!(report.order_events[0].status, OrderStatus::Rejected);
    assert!(
        report.order_events[0]
            .reason
            .contains("insufficient futures margin")
    );
    assert!(account.position("IF2501", FuturesDirection::Long).is_none());
    assert!((account.total_cash() - 10_000.0).abs() < 1e-6);
}