//! The exchange tab's spread panel, end to end from cached-record shape.
//!
//! `nigig-mpesa` and `nigig-pay` cache P2P adverts as `OfflineP2PDealRecord`
//! and previously rendered one line per exchange from the *first* one. These
//! tests drive the replacement through the same conversion the pages use, so
//! the strings asserted here are the strings that reach the labels.
//!
//! The record shape is mirrored rather than imported: `p2p-analyzer` must not
//! depend on `nigig-core`, and the field list is stable. A drift would show
//! up as a compile error in the apps, which both build in CI.

use p2p_analyzer::{analyse, render_panel, snapshot_from_deals, summary_line, DealInput};
use p2p_core::QualityFilter;

/// Build the input the pages build, from the fields the cache holds.
fn cached(
    exchange: &str,
    advertiser: &str,
    side: &str,
    price: f64,
    completion_rate: f64,
    trades_count: u32,
) -> DealInput {
    DealInput {
        exchange: exchange.into(),
        advertiser: advertiser.into(),
        // Exactly what the pages do: the stored `side` is the tradeType the
        // page *requested*, so "BUY" means an advert we can buy from.
        we_buy: side.eq_ignore_ascii_case("BUY"),
        crypto: "USDT".into(),
        fiat: "KES".into(),
        price,
        available_amount: 5_000.0,
        min_order: 1_000.0,
        max_order: 200_000.0,
        payment_methods: vec!["BANK".into()],
        completion_rate,
        trades_count,
    }
}

fn report(deals: &[DealInput]) -> p2p_analyzer::SpreadReport {
    let snap = snapshot_from_deals(deals, "Binance P2P", "KES", "USDT", 0);
    analyse(&snap, &QualityFilter::default(), 0)
}

/// The headline case: a real spread, rendered for the card.
#[test]
fn a_two_sided_cache_renders_a_spread_card() {
    let deals = vec![
        cached("Binance P2P", "BennyBoss", "BUY", 129.92, 99.7, 4798),
        cached("Binance P2P", "Twin_traders00", "SELL", 130.30, 99.0, 500),
    ];
    let panel = render_panel(&report(&deals), 150);

    assert_eq!(panel.headline, "USDT KES spread +0.29%");
    assert!(panel.buy_line.contains("BennyBoss"));
    assert!(panel.buy_line.contains("4798 orders"));
    assert!(panel.sell_line.contains("Twin_traders00"));
    assert!(panel.window_line.starts_with("Fillable"));
    // 29 bps is under the 150 bps display threshold.
    assert!(!panel.actionable);
}

/// What the page showed before, and what it shows now.
#[test]
fn the_summary_line_reports_a_spread_rather_than_one_adverts_price() {
    let deals = vec![
        cached("Binance P2P", "BennyBoss", "BUY", 129.92, 99.7, 4798),
        cached("Binance P2P", "Twin_traders00", "SELL", 130.30, 99.0, 500),
    ];
    let line = summary_line("Binance P2P", &report(&deals));
    assert_eq!(line, "Binance P2P: buy 129.92 / sell 130.3 KES = +0.29%");
}

/// The defect the quality filter exists to prevent, through the real path.
#[test]
fn the_three_order_outlier_does_not_set_the_headline_price() {
    // Reproduces the live KES book: the best-priced sell advert had three
    // completed trades. The page's old "first cached deal" line would have
    // shown it, and a naive best-price scan reads it as a 3.6% opportunity.
    let deals = vec![
        cached("Binance P2P", "BennyBoss", "BUY", 129.92, 99.7, 4798),
        cached("Binance P2P", "tiero", "SELL", 134.60, 100.0, 3),
        cached("Binance P2P", "Twin_traders00", "SELL", 130.30, 99.0, 500),
    ];
    let r = report(&deals);

    assert_eq!(r.best_sell.as_ref().unwrap().advertiser, "Twin_traders00");
    assert_eq!(r.gross_bps, Some(29));

    let panel = render_panel(&r, 150);
    assert!(
        !panel.headline.contains("3."),
        "the outlier's spread leaked into the card"
    );
    assert!(panel.excluded_line.contains("1 advert excluded"));
}

/// An entirely unfillable book must not read as an opportunity.
#[test]
fn a_book_where_every_seller_fails_the_filter_says_so() {
    // The honest state of the captured KES book at the default floor: the
    // sell side had order counts of 3, 48, 25, 2 and 0.
    let deals = vec![
        cached("Binance P2P", "BennyBoss", "BUY", 129.92, 99.7, 4798),
        cached("Binance P2P", "tiero", "SELL", 134.60, 100.0, 3),
        cached("Binance P2P", "fougoumba1", "SELL", 130.23, 66.7, 2),
        cached("Binance P2P", "Axchange01", "SELL", 130.00, 0.0, 0),
    ];
    let r = report(&deals);

    assert!(
        r.best_buy.is_some(),
        "the buy side had established merchants"
    );
    assert!(r.best_sell.is_none());
    assert_eq!(r.net_bps, None);

    let panel = render_panel(&r, 150);
    assert!(panel.headline.contains("no spread from qualifying adverts"));
    assert!(panel.sell_line.is_empty());
    assert!(!panel.actionable);

    let line = summary_line("Binance P2P", &r);
    assert!(line.contains("below the quality floor"), "{line}");
}

/// An empty cache is a state, not a failure.
#[test]
fn an_empty_cache_reads_as_empty_rather_than_as_zero() {
    let r = report(&[]);
    let panel = render_panel(&r, 150);
    assert!(panel.headline.contains("no adverts on either side"));
    assert!(panel.buy_line.is_empty());
    assert!(panel.window_line.is_empty());
    assert_eq!(
        summary_line("Bybit P2P", &r),
        "Bybit P2P: no KES adverts cached"
    );
}

/// The page caches several exchanges into one list; they must not be mixed.
#[test]
fn a_binance_buy_is_never_paired_with_a_bybit_sell() {
    // Both exist in the same cached vector. A spread between them is not a
    // trade anyone can execute in one place.
    let deals = vec![
        cached("Binance P2P", "BennyBoss", "BUY", 129.92, 99.7, 4798),
        cached("Bybit P2P", "bybit_seller", "SELL", 140.00, 99.0, 900),
    ];
    let r = report(&deals);
    assert!(
        r.best_sell.is_none(),
        "a cross-exchange pair produced a phantom spread"
    );
}

/// The inversion trap, asserted at the boundary the pages cross.
#[test]
fn the_stored_side_string_maps_to_our_action_not_the_advertisers() {
    let buy = cached("Binance P2P", "x", "BUY", 129.92, 99.0, 500);
    let sell = cached("Binance P2P", "y", "SELL", 130.30, 99.0, 500);
    assert!(buy.we_buy, "a stored BUY is an advert we can buy from");
    assert!(!sell.we_buy);

    // And the resulting spread is positive, which it would not be if the
    // two were swapped.
    let r = report(&[buy, sell]);
    assert!(r.gross_bps.unwrap() > 0);
}

/// A wide spread with no overlapping limits is the trap the card must show.
#[test]
fn limits_that_do_not_overlap_are_called_out_rather_than_hidden() {
    let mut buy = cached("Binance P2P", "small", "BUY", 129.92, 99.0, 500);
    buy.max_order = 13_000.0;
    let mut sell = cached("Binance P2P", "large", "SELL", 130.30, 99.0, 500);
    sell.min_order = 71_000.0;

    let r = report(&[buy, sell]);
    let panel = render_panel(&r, 20);

    assert!(
        panel.headline.contains("+0.29%"),
        "the price spread looks fine"
    );
    assert_eq!(
        panel.window_line,
        "Limits do not overlap — no fillable amount"
    );
    assert!(summary_line("Binance P2P", &r).contains("limits do not overlap"));
}

/// Prices arrive as f64 from the page's JSON reader; they must not drift.
#[test]
fn a_cached_f64_price_survives_into_the_rendered_string_exactly() {
    // 129.92_f64 is not exactly 129.92. If the conversion scaled the float
    // directly it could land a unit low and render as 129.919999.
    let deals = vec![
        cached("Binance P2P", "a", "BUY", 129.92, 99.0, 500),
        cached("Binance P2P", "b", "SELL", 130.30, 99.0, 500),
    ];
    let panel = render_panel(&report(&deals), 150);
    assert!(panel.buy_line.contains("129.92"), "{}", panel.buy_line);
    assert!(!panel.buy_line.contains("129.919"), "{}", panel.buy_line);
    assert!(panel.sell_line.contains("130.3"), "{}", panel.sell_line);
}