scope-bca-core 0.8.2

//! Order book health analysis and market summary.
//!
//! Provides configurable health checks for stablecoin market monitoring:
//! peg deviation, spread, bid/ask balance, level count, and depth thresholds.

use crate::display::format_large_number;
use std::ops::Bound;

use super::types::{
    BookSide, BookSource, ExecutionEstimate, HealthCheck, OrderBook, OrderBookLevel, Trade,
};
use serde::{Deserialize, Serialize};

/// Default peg target (USD stablecoins).
pub const DEFAULT_PEG_TARGET: f64 = 1.0;
/// Default peg range. The outlier band is this times [`PEG_OUTLIER_FACTOR`]
/// around the peg target.
pub const DEFAULT_PEG_RANGE: f64 = 0.001;
/// Default minimum valid levels per side.
pub const DEFAULT_MIN_LEVELS: usize = 10;
/// The quote currency of a book's pair label (`USDC/USDT` → `USDT`). Depths,
/// volumes and sizes are amounts in it, so labels name it (M2).
pub(crate) fn quote_of(pair: &str) -> String {
    crate::market::Pair::parse(pair)
        .quote
        .unwrap_or_else(|| "quote".to_string())
}

/// Default minimum in-band depth per side (quote, e.g. USDT).
pub const DEFAULT_MIN_DEPTH: f64 = 3000.0;
/// Default bid/ask ratio floor.
pub const DEFAULT_MIN_BID_ASK_RATIO: f64 = 0.2;
/// Default bid/ask ratio ceiling.
pub const DEFAULT_MAX_BID_ASK_RATIO: f64 = 5.0;
/// Default maximum best-bid/best-ask spread, in percent of mid price.
pub const DEFAULT_MAX_SPREAD_PCT: f64 = 3.0;
/// Default minimum depth of the top 3 valid levels per side (quote).
pub const DEFAULT_MIN_TOP3_DEPTH: f64 = 300.0;
/// Default minimum depth of the top 10 valid levels per side (quote).
pub const DEFAULT_MIN_TOP10_DEPTH: f64 = 2000.0;

/// Default half-width of the depth window for the depth-to-volume rule,
/// in percent of the mid price.
pub const DEFAULT_DEPTH_WINDOW_PCT: f64 = 2.0;
/// Default floor: depth within the window, in percent of 24h volume.
/// Below it the book is too thin for the volume traded (fail).
pub const DEFAULT_MIN_DEPTH_VOLUME_PCT: f64 = 5.0;
/// Default ceiling: above it the volume is low for the visible
/// liquidity (warning).
pub const DEFAULT_MAX_DEPTH_VOLUME_PCT: f64 = 10.0;

/// Default price step between levels of a synthetic AMM book, in percent.
pub const DEFAULT_AMM_STEP_PCT: f64 = 0.1;

/// Number of levels summed for the top-3 depth check.
pub const TOP3_LEVELS: usize = 3;
/// Number of levels summed for the top-10 depth check.
pub const TOP10_LEVELS: usize = 10;

pub use super::types::{BPS_PER_PERCENT, PERCENT_PER_RATIO};

/// The outlier band is `peg_range` times this, around the peg target.
pub const PEG_OUTLIER_FACTOR: f64 = 5.0;

/// Execution slippage above this many basis points is flagged as high.
pub const SLIPPAGE_WARN_BPS: f64 = 10.0;

/// Health check thresholds for order book validation.
///
/// Built-in defaults are the `DEFAULT_*` constants in this module. The
/// `market.health` section of the config file replaces any of them, and
/// [`HealthOverrides`] (CLI flags, web request fields) replaces the result.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(default)]
pub struct HealthThresholds {
    /// Peg target (e.g., 1.0 for USD stablecoins).
    pub peg_target: f64,
    /// Price range around the peg. The outlier band is this × [`PEG_OUTLIER_FACTOR`]:
    /// levels outside it are left out of depth and level counts. Best prices
    /// (best bid, best ask, mid, spread) still include them.
    pub peg_range: f64,
    /// Minimum valid levels (price > 0, quantity > 0) per side.
    pub min_levels: usize,
    /// Minimum in-band depth per side in quote terms (e.g., USDT).
    pub min_depth: f64,
    /// Bid/ask ratio below which to warn (bid side thin).
    pub min_bid_ask_ratio: f64,
    /// Bid/ask ratio above which to warn (ask side thin).
    pub max_bid_ask_ratio: f64,
    /// Maximum spread between best valid bid and ask, in percent of mid price.
    pub max_spread_pct: f64,
    /// Minimum depth of the top 3 valid levels per side (quote).
    pub min_top3_depth: f64,
    /// Minimum depth of the top 10 valid levels per side (quote).
    pub min_top10_depth: f64,
    /// Price step between levels of a synthetic AMM book, in percent.
    /// With 0.1%, top-3 and top-10 depth mean depth within ±0.3% and ±1%.
    pub amm_step_pct: f64,
    /// Half-width of the depth window for the depth-to-volume rule, in
    /// percent of the mid price.
    pub depth_window_pct: f64,
    /// Depth within the window, in percent of 24h volume: below this fails.
    pub min_depth_volume_pct: f64,
    /// Depth within the window, in percent of 24h volume: above this warns.
    pub max_depth_volume_pct: f64,
}

impl Default for HealthThresholds {
    fn default() -> Self {
        Self {
            peg_target: DEFAULT_PEG_TARGET,
            peg_range: DEFAULT_PEG_RANGE,
            min_levels: DEFAULT_MIN_LEVELS,
            min_depth: DEFAULT_MIN_DEPTH,
            min_bid_ask_ratio: DEFAULT_MIN_BID_ASK_RATIO,
            max_bid_ask_ratio: DEFAULT_MAX_BID_ASK_RATIO,
            max_spread_pct: DEFAULT_MAX_SPREAD_PCT,
            min_top3_depth: DEFAULT_MIN_TOP3_DEPTH,
            min_top10_depth: DEFAULT_MIN_TOP10_DEPTH,
            amm_step_pct: DEFAULT_AMM_STEP_PCT,
            depth_window_pct: DEFAULT_DEPTH_WINDOW_PCT,
            min_depth_volume_pct: DEFAULT_MIN_DEPTH_VOLUME_PCT,
            max_depth_volume_pct: DEFAULT_MAX_DEPTH_VOLUME_PCT,
        }
    }
}

/// Per-request threshold overrides. A `None` field keeps the base value.
#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
#[serde(default)]
pub struct HealthOverrides {
    /// Peg target. The web API sends this as `peg`.
    #[serde(alias = "peg")]
    pub peg_target: Option<f64>,
    pub peg_range: Option<f64>,
    pub min_levels: Option<usize>,
    pub min_depth: Option<f64>,
    pub min_bid_ask_ratio: Option<f64>,
    pub max_bid_ask_ratio: Option<f64>,
    pub max_spread_pct: Option<f64>,
    pub min_top3_depth: Option<f64>,
    pub min_top10_depth: Option<f64>,
    pub amm_step_pct: Option<f64>,
    pub depth_window_pct: Option<f64>,
    pub min_depth_volume_pct: Option<f64>,
    pub max_depth_volume_pct: Option<f64>,
}

impl HealthThresholds {
    /// The peg target and its bands.
    pub fn peg_bands(&self) -> PegBands {
        PegBands::new(self.peg_target, self.peg_range)
    }

    /// Returns a copy of `self` with each `Some` field in `o` applied.
    pub fn with_overrides(&self, o: &HealthOverrides) -> Self {
        Self {
            peg_target: o.peg_target.unwrap_or(self.peg_target),
            peg_range: o.peg_range.unwrap_or(self.peg_range),
            min_levels: o.min_levels.unwrap_or(self.min_levels),
            min_depth: o.min_depth.unwrap_or(self.min_depth),
            min_bid_ask_ratio: o.min_bid_ask_ratio.unwrap_or(self.min_bid_ask_ratio),
            max_bid_ask_ratio: o.max_bid_ask_ratio.unwrap_or(self.max_bid_ask_ratio),
            max_spread_pct: o.max_spread_pct.unwrap_or(self.max_spread_pct),
            min_top3_depth: o.min_top3_depth.unwrap_or(self.min_top3_depth),
            min_top10_depth: o.min_top10_depth.unwrap_or(self.min_top10_depth),
            amm_step_pct: o.amm_step_pct.unwrap_or(self.amm_step_pct),
            depth_window_pct: o.depth_window_pct.unwrap_or(self.depth_window_pct),
            min_depth_volume_pct: o.min_depth_volume_pct.unwrap_or(self.min_depth_volume_pct),
            max_depth_volume_pct: o.max_depth_volume_pct.unwrap_or(self.max_depth_volume_pct),
        }
    }
}

/// Quote depth of the top eligible levels per side, summed once per book.
///
/// The health checks and the repeating-view series both read these values.
#[derive(Debug, Clone, Copy, Default, PartialEq)]
pub struct TopDepth {
    pub bid_top3: f64,
    pub bid_top10: f64,
    pub ask_top3: f64,
    pub ask_top10: f64,
}

impl TopDepth {
    /// Top-N depth over the eligible levels: valid and inside the band the
    /// peg bands give for each side.
    fn from_book(book: &OrderBook, bands: &PegBands) -> Self {
        let bid = |n| book.top_depth(BookSide::Bid, bands.eligible_band(BookSide::Bid), n);
        let ask = |n| book.top_depth(BookSide::Ask, bands.eligible_band(BookSide::Ask), n);
        Self {
            bid_top3: bid(TOP3_LEVELS),
            bid_top10: bid(TOP10_LEVELS),
            ask_top3: ask(TOP3_LEVELS),
            ask_top10: ask(TOP10_LEVELS),
        }
    }
}

/// Where a price sits relative to the peg.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum PegBand {
    /// Within `peg_range` of the target.
    OnPeg,
    /// Within the outlier band (`peg_range` × [`PEG_OUTLIER_FACTOR`]).
    Slight,
    /// Outside the outlier band.
    Off,
}

/// The peg target and the bands around it, from [`HealthThresholds`]. The
/// price colors, the peg verdict and the outlier filter all use these.
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct PegBands {
    target: f64,
    range: f64,
}

impl PegBands {
    pub fn new(target: f64, range: f64) -> Self {
        Self { target, range }
    }

    /// The peg target.
    pub fn target(&self) -> f64 {
        self.target
    }

    /// Half-width of the outlier band.
    pub fn outlier_width(&self) -> f64 {
        self.range * PEG_OUTLIER_FACTOR
    }

    /// Lowest and highest price inside the outlier band (both inclusive).
    pub fn outlier_band(&self) -> (f64, f64) {
        (
            self.target - self.outlier_width(),
            self.target + self.outlier_width(),
        )
    }

    /// The prices of one side that are eligible for depth and level counts:
    /// bids from the low end of the outlier band up, asks from the high end
    /// down. The far side of each book is cut; the near side is not.
    pub fn eligible_band(&self, side: BookSide) -> (Bound<f64>, Bound<f64>) {
        let (lo, hi) = self.outlier_band();
        match side {
            BookSide::Bid => (Bound::Included(lo), Bound::Unbounded),
            BookSide::Ask => (Bound::Unbounded, Bound::Included(hi)),
        }
    }

    /// Where `price` sits: on the peg (within `range`, inclusive), inside
    /// the outlier band (inclusive, like the filter), or outside it.
    pub fn classify(&self, price: f64) -> PegBand {
        let (lo, hi) = self.outlier_band();
        if (price - self.target).abs() <= self.range {
            PegBand::OnPeg
        } else if (lo..=hi).contains(&price) {
            PegBand::Slight
        } else {
            PegBand::Off
        }
    }
}

/// The verdict on the peg, from the mid price and the market's health.
/// [`MarketSummary::peg_status`] returns it; `scope insights` reads it and
/// words each status once. The market summary report shows the same facts
/// as its health checks.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum PegStatus {
    /// Mid on the peg and every health check passes.
    OnPeg,
    /// Mid on the peg, but a health check fails.
    BookUnhealthy,
    SlightDeviation,
    Deviation,
    /// There is no mid price: a side has no valid level.
    NoPrice,
}

/// Quote depth of valid levels within ±`window_pct`% of `mid`, both sides.
///
/// The second value is `true` when a side's last fetched level is still
/// inside the window: the book may continue past what was fetched, so the
/// depth is a lower bound.
fn depth_within(book: &OrderBook, mid: f64, window_pct: f64) -> (f64, bool) {
    let lo = mid * (1.0 - window_pct / PERCENT_PER_RATIO);
    let hi = mid * (1.0 + window_pct / PERCENT_PER_RATIO);
    let depth =
        book.depth_in_band(BookSide::Bid, lo..=hi) + book.depth_in_band(BookSide::Ask, lo..=hi);
    let ends_inside = |levels: &[OrderBookLevel]| {
        levels
            .iter()
            .rev()
            .find(|l| l.is_valid())
            .is_some_and(|l| l.price >= lo && l.price <= hi)
    };
    (depth, ends_inside(&book.bids) || ends_inside(&book.asks))
}

/// The depth-to-volume rule: depth within the window should be
/// `min..=max` percent of 24h volume. Below fails, above warns.
fn depth_volume_check(
    book: &OrderBook,
    thresholds: &HealthThresholds,
    volume_24h: Option<f64>,
) -> HealthCheck {
    let q = quote_of(&book.pair);
    let w = thresholds.depth_window_pct;
    let (lo, hi) = (
        thresholds.min_depth_volume_pct,
        thresholds.max_depth_volume_pct,
    );
    let (Some(volume), Some(mid)) = (volume_24h.filter(|v| *v > 0.0), book.mid_price()) else {
        return HealthCheck::NotApplicable(
            "Depth/volume: n/a (no 24h volume or mid price from this source)".to_string(),
        );
    };
    let (depth, truncated) = depth_within(book, mid, w);
    let pct = depth / volume * PERCENT_PER_RATIO;
    let at_least = if truncated { "≥" } else { "" };
    let msg = format!(
        "Depth/volume: {at_least}{pct:.1}% ({at_least}{depth:.0} / {volume:.0} {q} within ±{w}%; target {lo}–{hi}%)"
    );
    if pct > hi {
        // A lower bound above the ceiling is still above it.
        HealthCheck::Warn(msg)
    } else if pct < lo && truncated {
        HealthCheck::NotApplicable(format!(
            "{msg}; n/a: the book ends before ±{w}%, so the depth may be higher"
        ))
    } else if pct < lo {
        HealthCheck::Fail(msg)
    } else {
        HealthCheck::Pass(msg)
    }
}

/// Aggregated market summary with order book snapshot and health results.
#[derive(Debug, Clone)]
pub struct MarketSummary {
    /// Pair label (e.g., "USDC/USDT").
    pub pair: String,
    /// Where the order book came from.
    pub source: BookSource,
    /// Peg target.
    pub peg_target: f64,
    /// Peg range the summary was built with (see [`PegBands`]).
    pub peg_range: f64,
    /// Best valid bid. Not outlier-filtered: a depeg stays visible.
    pub best_bid: Option<f64>,
    /// Best valid ask. Not outlier-filtered.
    pub best_ask: Option<f64>,
    /// Mid of the best valid bid and ask. Not outlier-filtered.
    pub mid_price: Option<f64>,
    /// Absolute spread between the best valid bid and ask (not
    /// outlier-filtered). `None` for a
    /// synthetic AMM book or when a side has no valid level.
    pub spread: Option<f64>,
    /// The same spread in percent of the mid of those two levels.
    pub spread_pct: Option<f64>,
    /// Top-3 and top-10 depth per side, as the checks judge them.
    pub top_depth: TopDepth,
    /// 24h volume in quote (e.g. USDT) if available.
    pub volume_24h: Option<f64>,
    /// Execution estimate for 10k USDT buy (slippage).
    pub execution_10k_buy: Option<ExecutionEstimate>,
    /// Execution estimate for 10k USDT sell (slippage).
    pub execution_10k_sell: Option<ExecutionEstimate>,
    /// Eligible asks: valid levels inside the outlier band.
    pub asks: Vec<OrderBookLevel>,
    /// Eligible bids: valid levels inside the outlier band.
    pub bids: Vec<OrderBookLevel>,
    /// Count of ask levels excluded as outliers.
    pub ask_outliers: usize,
    /// Count of bid levels excluded as outliers.
    pub bid_outliers: usize,
    /// Ask depth (quote) within range.
    pub ask_depth: f64,
    /// Bid depth (quote) within range.
    pub bid_depth: f64,
    /// Health check results.
    pub checks: Vec<HealthCheck>,
    /// Overall healthy (no failures).
    pub healthy: bool,
    /// The bot-pattern advisory, once [`MarketSummary::check_bot_patterns`]
    /// ran. Its line is also in `checks`; it never fails the summary.
    pub bot_patterns: Option<super::patterns::BotPatterns>,
}

impl MarketSummary {
    /// Deviation of `price` from the peg target, in percent of the target.
    /// `None` when the peg target is not positive. The one definition: text,
    /// markdown, series and insights all call it.
    pub fn peg_deviation_pct(&self, price: f64) -> Option<f64> {
        (self.peg_target > 0.0)
            .then(|| (price - self.peg_target) / self.peg_target * PERCENT_PER_RATIO)
    }

    /// The same deviation in basis points.
    pub fn peg_deviation_bps(&self, price: f64) -> Option<f64> {
        self.peg_deviation_pct(price)
            .map(|pct| pct * BPS_PER_PERCENT)
    }

    /// The peg target and bands this summary was built with.
    pub fn peg_bands(&self) -> PegBands {
        PegBands::new(self.peg_target, self.peg_range)
    }

    /// The one peg verdict: market summary and insights both read it. A mid
    /// on the peg counts as healthy only when every health check passes.
    pub fn peg_status(&self) -> PegStatus {
        let Some(mid) = self.mid_price else {
            return PegStatus::NoPrice;
        };
        match self.peg_bands().classify(mid) {
            PegBand::Off => PegStatus::Deviation,
            PegBand::Slight => PegStatus::SlightDeviation,
            PegBand::OnPeg if self.healthy => PegStatus::OnPeg,
            PegBand::OnPeg => PegStatus::BookUnhealthy,
        }
    }

    /// Eligible ask levels: valid and inside the outlier band. The checks,
    /// the text report and the JSON all show this count.
    pub fn ask_levels(&self) -> usize {
        self.asks.len()
    }

    /// Eligible bid levels. See [`Self::ask_levels`].
    pub fn bid_levels(&self) -> usize {
        self.bids.len()
    }

    /// Build summary from order book; the peg is `thresholds.peg_target`.
    /// Optionally includes 24h volume (from venue ticker) and execution estimates for 10k USDT.
    pub fn from_order_book(
        book: &OrderBook,
        thresholds: &HealthThresholds,
        volume_24h: Option<f64>,
    ) -> Self {
        let q = quote_of(&book.pair);
        let peg_target = thresholds.peg_target;
        let bands = thresholds.peg_bands();

        // The eligible levels: valid, and inside the outlier band. The band
        // cuts the far side of each book, so a depeg stays visible.
        let (ask_band, bid_band) = (
            bands.eligible_band(BookSide::Ask),
            bands.eligible_band(BookSide::Bid),
        );
        let asks: Vec<OrderBookLevel> = book
            .valid_levels_in_band(BookSide::Ask, ask_band)
            .cloned()
            .collect();
        let bids: Vec<OrderBookLevel> = book
            .valid_levels_in_band(BookSide::Bid, bid_band)
            .cloned()
            .collect();

        let outliers =
            |side, eligible: usize| book.valid_levels_in_band(side, ..).count() - eligible;
        let ask_outliers = outliers(BookSide::Ask, asks.len());
        let bid_outliers = outliers(BookSide::Bid, bids.len());

        let ask_depth = book.depth_in_band(BookSide::Ask, ask_band);
        let bid_depth = book.depth_in_band(BookSide::Bid, bid_band);
        let top_depth = TopDepth::from_book(book, &bands);

        let mut checks = Vec::new();

        // Peg safety: sells below peg
        let below_peg: Vec<_> = asks.iter().filter(|a| a.price < peg_target).collect();
        if below_peg.is_empty() {
            checks.push(HealthCheck::Pass("No sells below peg".to_string()));
        } else {
            let usdt = below_peg.iter().map(|a| a.value()).sum::<f64>();
            checks.push(HealthCheck::Fail(format!(
                "{} sell(s) below peg ({:.0} {q})",
                below_peg.len(),
                usdt
            )));
        }

        // Bid/ask ratio
        let ratio = if ask_depth > 0.0 {
            bid_depth / ask_depth
        } else {
            0.0
        };
        if ratio < thresholds.min_bid_ask_ratio || ratio > thresholds.max_bid_ask_ratio {
            checks.push(HealthCheck::Fail(format!("Bid/Ask ratio: {:.2}x", ratio)));
        } else {
            checks.push(HealthCheck::Pass(format!("Bid/Ask ratio: {:.2}x", ratio)));
        }

        // A synthetic AMM book has no real level count or spread (#37).
        let amm = book.source == BookSource::SyntheticAmm;

        // Spread between best valid bid and best valid ask
        match (amm, book.spread_pct()) {
            (true, _) => checks.push(HealthCheck::NotApplicable(
                "Spread: n/a (synthetic AMM book; the real spread is the pool fee, \
                 which the data source does not report)"
                    .to_string(),
            )),
            (false, Some(spread_pct)) => {
                let msg = format!(
                    "Spread: {:.3}% (max {:.1}%)",
                    spread_pct, thresholds.max_spread_pct
                );
                if spread_pct > thresholds.max_spread_pct {
                    checks.push(HealthCheck::Fail(msg));
                } else {
                    checks.push(HealthCheck::Pass(msg));
                }
            }
            (false, None) => {
                checks.push(HealthCheck::Fail("Spread: no valid bid or ask".to_string()))
            }
        }

        // Bid levels
        if amm {
            checks.push(HealthCheck::NotApplicable(
                "Bid levels: n/a (synthetic AMM book; the step size sets the level count)"
                    .to_string(),
            ));
        } else if bids.len() < thresholds.min_levels {
            checks.push(HealthCheck::Fail(format!(
                "Bid levels: {} < {} minimum",
                bids.len(),
                thresholds.min_levels
            )));
        } else {
            checks.push(HealthCheck::Pass(format!(
                "Bid levels: {} (min {})",
                bids.len(),
                thresholds.min_levels
            )));
        }

        // Bid depth
        if bid_depth < thresholds.min_depth {
            checks.push(HealthCheck::Fail(format!(
                "Bid depth: {:.0} {q} < {:.0} {q} minimum",
                bid_depth, thresholds.min_depth
            )));
        } else {
            checks.push(HealthCheck::Pass(format!(
                "Bid depth: {:.0} {q} (min {:.0})",
                bid_depth, thresholds.min_depth
            )));
        }

        // Ask levels
        if amm {
            checks.push(HealthCheck::NotApplicable(
                "Ask levels: n/a (synthetic AMM book; the step size sets the level count)"
                    .to_string(),
            ));
        } else if asks.len() < thresholds.min_levels {
            checks.push(HealthCheck::Fail(format!(
                "Ask levels: {} < {} minimum",
                asks.len(),
                thresholds.min_levels
            )));
        } else {
            checks.push(HealthCheck::Pass(format!(
                "Ask levels: {} (min {})",
                asks.len(),
                thresholds.min_levels
            )));
        }

        // Ask depth
        if ask_depth < thresholds.min_depth {
            checks.push(HealthCheck::Fail(format!(
                "Ask depth: {:.0} {q} < {:.0} {q} minimum",
                ask_depth, thresholds.min_depth
            )));
        } else {
            checks.push(HealthCheck::Pass(format!(
                "Ask depth: {:.0} {q} (min {:.0})",
                ask_depth, thresholds.min_depth
            )));
        }

        // Top-N depth per side (valid levels, best first)
        for (side, top3, top10) in [
            ("Bid", top_depth.bid_top3, top_depth.bid_top10),
            ("Ask", top_depth.ask_top3, top_depth.ask_top10),
        ] {
            for (n, depth, min) in [
                (TOP3_LEVELS, top3, thresholds.min_top3_depth),
                (TOP10_LEVELS, top10, thresholds.min_top10_depth),
            ] {
                if depth < min {
                    checks.push(HealthCheck::Fail(format!(
                        "{side} top-{n} depth: {depth:.0} {q} < {min:.0} {q} minimum"
                    )));
                } else {
                    checks.push(HealthCheck::Pass(format!(
                        "{side} top-{n} depth: {depth:.0} {q} (min {min:.0})"
                    )));
                }
            }
        }

        checks.push(depth_volume_check(book, thresholds, volume_24h));

        // n/a checks (#37 decision A) and warnings do not count.
        let healthy = !checks.iter().any(|c| matches!(c, HealthCheck::Fail(_)));

        let execution_10k_buy = book.estimate_buy_execution(10_000.0);
        let execution_10k_sell = book.estimate_sell_execution(10_000.0);

        Self {
            pair: book.pair.clone(),
            source: book.source,
            peg_target,
            peg_range: thresholds.peg_range,
            best_bid: book.best_bid(),
            best_ask: book.best_ask(),
            mid_price: book.mid_price(),
            spread: book.spread(),
            spread_pct: book.spread_pct(),
            top_depth,
            volume_24h,
            execution_10k_buy,
            execution_10k_sell,
            asks,
            bids,
            ask_outliers,
            bid_outliers,
            ask_depth,
            bid_depth,
            checks,
            healthy,
            bot_patterns: None,
        }
    }

    /// Adds the bot-pattern advisory: repeated sizes, metronome timing and
    /// ping-pong in `trades` (the venue's recent tape, or why there is
    /// none), and ladder quotes in a real exchange book. A finding warns, so
    /// `healthy` does not change.
    pub fn check_bot_patterns(&mut self, trades: std::result::Result<&[Trade], &str>) {
        let book = (self.source == BookSource::Exchange)
            .then_some((self.bids.as_slice(), self.asks.as_slice()));
        let found = super::patterns::detect(trades, book);
        self.checks.push(found.check());
        self.bot_patterns = Some(found);
    }

    /// The one JSON shape for a summary. The web API and both CLI commands
    /// send these keys; each call site adds only its own wrapper keys
    /// (`run`, `venue`, `analytics`). `app.js` reads them, so the names are
    /// pinned. `bids`/`asks` are capped at 20 levels; the level counts stay
    /// exact.
    pub fn to_json(&self) -> serde_json::Value {
        let exec = |e: &ExecutionEstimate| {
            serde_json::json!({
                "notional_usdt": e.notional_usdt,
                "vwap": e.vwap,
                "slippage_bps": e.slippage_bps,
                "fillable": e.fillable,
            })
        };
        let levels = |ls: &[OrderBookLevel]| {
            ls.iter()
                .take(20)
                .map(|l| {
                    serde_json::json!({"price": l.price, "quantity": l.quantity, "value": l.value()})
                })
                .collect::<Vec<_>>()
        };
        serde_json::json!({
            "pair": self.pair,
            "quote": quote_of(&self.pair),
            "book_source": self.source,
            "peg_target": self.peg_target,
            "best_bid": self.best_bid,
            "best_ask": self.best_ask,
            "mid_price": self.mid_price,
            "spread": self.spread,
            "volume_24h": self.volume_24h,
            "bid_depth": self.bid_depth,
            "ask_depth": self.ask_depth,
            "bid_outliers": self.bid_outliers,
            "ask_outliers": self.ask_outliers,
            "bid_levels": self.bid_levels(),
            "ask_levels": self.ask_levels(),
            "healthy": self.healthy,
            "slippage_warn_bps": SLIPPAGE_WARN_BPS,
            "execution_10k_buy": self.execution_10k_buy.as_ref().map(exec),
            "execution_10k_sell": self.execution_10k_sell.as_ref().map(exec),
            "bids": levels(&self.bids),
            "asks": levels(&self.asks),
            "checks": &self.checks,
            "bot_patterns": &self.bot_patterns,
        })
    }

    /// A price as text, with its deviation from the peg when there is one.
    fn price_with_peg_deviation(&self, price: f64) -> String {
        use crate::display::terminal as t;
        let shown = t::format_price_peg(price, &self.peg_bands());
        match self.peg_deviation_pct(price) {
            Some(pct) => format!("{shown}  ({pct:+.3}%)"),
            None => shown,
        }
    }

    /// Format as human-readable text report.
    /// When `venue_or_chain` is provided, it is displayed in the header (e.g. binance, ethereum).
    pub fn format_text(&self, venue_or_chain: Option<&str>) -> String {
        self.format_text_with_tokens(venue_or_chain, &[])
    }

    /// [`Self::format_text`], with a line under the header for each of the
    /// pair's tokens: its network and contract on the venue.
    pub fn format_text_with_tokens(
        &self,
        venue_or_chain: Option<&str>,
        tokens: &[super::assets::TokenAddress],
    ) -> String {
        let q = quote_of(&self.pair);
        use crate::display::terminal as t;

        let mut out = String::new();

        let title = match venue_or_chain {
            Some(c) => format!("{} ({})", self.pair, c),
            None => self.pair.clone(),
        };
        out.push_str(&t::section_header(&title));
        out.push('\n');
        for token in tokens {
            let mut value = token.contract.clone().unwrap_or("native coin".into());
            if token.other_networks > 0 {
                value.push_str(&format!(" (+{} networks)", token.other_networks));
            }
            let label = format!("{} ({})", token.symbol, token.network);
            out.push_str(&t::kv_row(&label, &value));
            out.push('\n');
        }

        // Metrics subsection
        out.push_str(&t::subsection_header("Metrics"));
        out.push('\n');
        if let Some(c) = venue_or_chain {
            out.push_str(&t::kv_row("Venue", c));
            out.push('\n');
        }
        out.push_str(&t::kv_row("Book", self.source.label()));
        out.push('\n');
        // One precision for every price of this book (M3): the peg's.
        let d = crate::display::format::price_decimals(self.peg_target);
        out.push_str(&t::kv_row(
            "Peg Target",
            &format!("{:.d$}", self.peg_target),
        ));
        out.push('\n');

        if let Some(bb) = self.best_bid {
            out.push_str(&t::kv_row("Best Bid", &self.price_with_peg_deviation(bb)));
            out.push('\n');
        }
        if let Some(ba) = self.best_ask {
            out.push_str(&t::kv_row("Best Ask", &self.price_with_peg_deviation(ba)));
            out.push('\n');
        }
        if let Some(mid) = self.mid_price {
            out.push_str(&t::kv_row("Mid Price", &self.price_with_peg_deviation(mid)));
            out.push('\n');
        }
        if let (Some(spread), Some(pct)) = (self.spread, self.spread_pct) {
            out.push_str(&t::kv_row("Spread", &format!("{spread:.d$}  ({pct:.3}%)")));
            out.push('\n');
        }

        if self.ask_outliers + self.bid_outliers > 0 {
            out.push_str(&t::kv_row(
                "Note",
                "best prices include levels outside the peg band; depth and levels do not",
            ));
            out.push('\n');
        }

        if let Some(v) = self.volume_24h {
            // A synthetic DEX book's volume is its best pool's, not the
            // token's total over all pools (M1).
            let label = if self.source == BookSource::Exchange {
                "Volume (24h)"
            } else {
                "Volume (24h, best pool)"
            };
            out.push_str(&t::kv_row(
                label,
                &format!("{} {q}", format_large_number(v)),
            ));
            out.push('\n');
        }

        if let Some(e) = &self.execution_10k_buy {
            let msg = if e.fillable {
                format!("~{:.2} bps slippage", e.slippage_bps)
            } else {
                "insufficient liquidity".to_string()
            };
            out.push_str(&t::kv_row("Exec 10K buy", &msg));
            out.push('\n');
        }
        if let Some(e) = &self.execution_10k_sell {
            let msg = if e.fillable {
                format!("~{:.2} bps slippage", e.slippage_bps)
            } else {
                "insufficient liquidity".to_string()
            };
            out.push_str(&t::kv_row("Exec 10K sell", &msg));
            out.push('\n');
        }

        // Ask side
        let base_symbol = self.pair.split('/').next().unwrap_or("BASE");
        let ask_label = if self.ask_outliers > 0 {
            format!(
                "Ask Side — {} levels, {} {q} (+{} outliers excl.)",
                self.ask_levels(),
                format_large_number(self.ask_depth),
                self.ask_outliers
            )
        } else {
            format!(
                "Ask Side — {} levels, {} {q}",
                self.ask_levels(),
                format_large_number(self.ask_depth)
            )
        };
        out.push_str(&t::subsection_header(&ask_label));
        out.push('\n');
        for level in self.asks.iter().take(8) {
            out.push_str(&t::orderbook_level(
                level.price,
                level.quantity,
                base_symbol,
                level.value(),
                &q,
                &self.peg_bands(),
            ));
            out.push('\n');
        }
        if self.asks.len() > 8 {
            out.push_str(&t::blank_row());
            out.push_str(&format!("    ... +{} more levels\n", self.asks.len() - 8));
        }

        // Bid side
        let bid_label = if self.bid_outliers > 0 {
            format!(
                "Bid Side — {} levels, {} {q} (+{} outliers excl.)",
                self.bid_levels(),
                format_large_number(self.bid_depth),
                self.bid_outliers
            )
        } else {
            format!(
                "Bid Side — {} levels, {} {q}",
                self.bid_levels(),
                format_large_number(self.bid_depth)
            )
        };
        out.push_str(&t::subsection_header(&bid_label));
        out.push('\n');
        for level in self.bids.iter().take(8) {
            out.push_str(&t::orderbook_level(
                level.price,
                level.quantity,
                base_symbol,
                level.value(),
                &q,
                &self.peg_bands(),
            ));
            out.push('\n');
        }
        if self.bids.len() > 8 {
            out.push_str(&t::blank_row());
            out.push_str(&format!("    ... +{} more levels\n", self.bids.len() - 8));
        }

        // Health checks
        out.push_str(&t::subsection_header("Health Checks"));
        out.push('\n');
        for check in &self.checks {
            out.push_str(&check.render_text());
            out.push('\n');
        }
        out.push_str(&t::blank_row());
        out.push('\n');
        out.push_str(&t::status_line(self.healthy));
        out.push('\n');
        out.push_str(&t::section_footer());
        out.push('\n');

        out
    }

    /// The one markdown rendering of a summary: metric table with peg
    /// deviations, then the health checks. `market summary --report` wraps it
    /// in a report header; token-health appends it to its own report. Missing
    /// prices show as `-`; the venue line and the checks section appear only
    /// when there is something to show.
    pub fn format_markdown(&self, venue: Option<&str>) -> String {
        let q = quote_of(&self.pair);
        let d = crate::display::format::price_decimals(self.peg_target);
        let with_deviation = |price: f64| match self.peg_deviation_pct(price) {
            Some(pct) => format!("{price:.d$} ({pct:+.3}%)"),
            None => format!("{price:.d$}"),
        };
        let bid_ask_or_dash =
            |price: Option<f64>| price.map(with_deviation).unwrap_or_else(|| "-".to_string());
        let price_or_dash = |price: Option<f64>| {
            price
                .map(|p| format!("{p:.d$}"))
                .unwrap_or_else(|| "-".to_string())
        };
        let exec_or_dash = |e: &Option<ExecutionEstimate>| {
            e.as_ref()
                .map(|e| {
                    if e.fillable {
                        format!("{:.2} bps", e.slippage_bps)
                    } else {
                        "insufficient".to_string()
                    }
                })
                .unwrap_or_else(|| "-".to_string())
        };

        let mut md = String::new();
        if let Some(v) = venue {
            md.push_str(&format!("**Venue:** {v}  \n\n"));
        }
        md.push_str("| Metric | Value |\n|--------|-------|\n");
        md.push_str(&format!("| Peg Target | {:.d$} |\n", self.peg_target));
        md.push_str(&format!("| Book | {} |\n", self.source.label()));
        md.push_str(&format!(
            "| Best Bid | {} |\n",
            bid_ask_or_dash(self.best_bid)
        ));
        md.push_str(&format!(
            "| Best Ask | {} |\n",
            bid_ask_or_dash(self.best_ask)
        ));
        md.push_str(&format!(
            "| Mid Price | {} |\n",
            price_or_dash(self.mid_price)
        ));
        md.push_str(&format!("| Spread | {} |\n", price_or_dash(self.spread)));
        if let Some(v) = self.volume_24h {
            md.push_str(&format!("| Volume (24h) | {v:.0} {q} |\n"));
        }
        md.push_str(&format!(
            "| 10k Buy Slippage | {} |\n",
            exec_or_dash(&self.execution_10k_buy)
        ));
        md.push_str(&format!(
            "| 10k Sell Slippage | {} |\n",
            exec_or_dash(&self.execution_10k_sell)
        ));
        md.push_str(&format!("| Bid Depth | {:.0} |\n", self.bid_depth));
        md.push_str(&format!("| Ask Depth | {:.0} |\n", self.ask_depth));
        md.push_str(&format!(
            "| Healthy | {} |\n",
            if self.healthy { "✓" } else { "✗" }
        ));

        if !self.checks.is_empty() {
            md.push_str("\n**Health Checks:**\n");
            for check in &self.checks {
                md.push_str(&format!("- {} {}\n", check.icon(), check.message()));
            }
        }
        md
    }
}

// =============================================================================
// Tests
// =============================================================================

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

    /// Side of `qtys.len()` levels stepping away from `start` by `step` per level.
    fn side(start: f64, step: f64, qtys: &[f64]) -> Vec<OrderBookLevel> {
        qtys.iter()
            .enumerate()
            .map(|(i, &quantity)| OrderBookLevel {
                price: start + step * i as f64,
                quantity,
            })
            .collect()
    }

    /// Book that passes every default check: 10 levels × 400 per side near peg.
    fn healthy_book() -> OrderBook {
        OrderBook {
            pair: "USDC/USDT".to_string(),
            source: crate::market::types::BookSource::Exchange,
            bids: side(0.9999, -0.0001, &[400.0; 10]),
            asks: side(1.0001, 0.0001, &[400.0; 10]),
        }
    }

    fn summarize(book: &OrderBook) -> MarketSummary {
        MarketSummary::from_order_book(book, &HealthThresholds::default(), None)
    }

    fn failed(summary: &MarketSummary) -> Vec<String> {
        summary
            .checks
            .iter()
            .filter_map(|c| match c {
                HealthCheck::Fail(m) => Some(m.clone()),
                HealthCheck::Pass(_) | HealthCheck::NotApplicable(_) | HealthCheck::Warn(_) => None,
            })
            .collect()
    }

    // ---- Depth-to-volume rule ----

    /// `healthy_book` plus one level per side beyond ±2%, so the book does
    /// not end inside the depth window.
    fn deep_book() -> OrderBook {
        let mut b = healthy_book();
        b.bids.push(OrderBookLevel {
            price: 0.97,
            quantity: 100.0,
        });
        b.asks.push(OrderBookLevel {
            price: 1.03,
            quantity: 100.0,
        });
        b
    }

    /// Depth within ±2% of mid for `deep_book` (the far levels are outside).
    fn deep_window_depth() -> f64 {
        let b = healthy_book();
        b.bids
            .iter()
            .chain(&b.asks)
            .map(OrderBookLevel::value)
            .sum()
    }

    fn with_volume(book: &OrderBook, volume: Option<f64>) -> MarketSummary {
        MarketSummary::from_order_book(book, &HealthThresholds::default(), volume)
    }

    fn depth_volume(s: &MarketSummary) -> &HealthCheck {
        let found = status_of(s, "Depth/volume");
        assert_eq!(found.len(), 1, "{:?}", s.checks);
        found[0]
    }

    #[test]
    fn test_depth_volume_below_floor_fails() {
        // 4% of volume is visible: too thin for the volume traded.
        let s = with_volume(&deep_book(), Some(deep_window_depth() / 0.04));
        assert!(
            matches!(depth_volume(&s), HealthCheck::Fail(_)),
            "{:?}",
            depth_volume(&s)
        );
        assert!(!s.healthy);
    }

    #[test]
    fn test_depth_volume_at_floor_passes() {
        let s = with_volume(&deep_book(), Some(deep_window_depth() / 0.05));
        assert!(
            matches!(depth_volume(&s), HealthCheck::Pass(_)),
            "{:?}",
            depth_volume(&s)
        );
        assert!(s.healthy, "{:?}", s.checks);
    }

    #[test]
    fn test_depth_volume_above_ceiling_warns_but_stays_healthy() {
        // 12%: visible liquidity is high for the volume. A warning only.
        let s = with_volume(&deep_book(), Some(deep_window_depth() / 0.12));
        let c = depth_volume(&s);
        assert!(matches!(c, HealthCheck::Warn(_)), "{c:?}");
        assert!(c.message().contains("12.0%"), "{c:?}");
        assert!(s.healthy, "a warning must not make the book unhealthy");
    }

    #[test]
    fn test_depth_volume_without_volume_is_not_applicable() {
        let s = with_volume(&deep_book(), None);
        assert!(matches!(depth_volume(&s), HealthCheck::NotApplicable(_)));
        let s = with_volume(&deep_book(), Some(0.0));
        assert!(matches!(depth_volume(&s), HealthCheck::NotApplicable(_)));
    }

    #[test]
    fn test_truncated_book_below_floor_is_not_applicable() {
        // healthy_book ends inside ±2%: the real depth may be higher, so a
        // floor failure would not be conclusive.
        let s = with_volume(&healthy_book(), Some(deep_window_depth() / 0.01));
        let c = depth_volume(&s);
        assert!(matches!(c, HealthCheck::NotApplicable(_)), "{c:?}");
        assert!(c.message().contains('≥'), "{c:?}");
    }

    #[test]
    fn test_truncated_book_above_ceiling_still_warns() {
        let s = with_volume(&healthy_book(), Some(deep_window_depth() / 0.30));
        let c = depth_volume(&s);
        assert!(matches!(c, HealthCheck::Warn(_)), "{c:?}");
        assert!(c.message().contains("≥30.0%"), "{c:?}");
    }

    #[test]
    fn test_depth_volume_thresholds_are_overridable() {
        let t = HealthThresholds {
            min_depth_volume_pct: 1.0,
            max_depth_volume_pct: 50.0,
            ..HealthThresholds::default()
        };
        let s = MarketSummary::from_order_book(&deep_book(), &t, Some(deep_window_depth() / 0.12));
        assert!(matches!(depth_volume(&s), HealthCheck::Pass(_)));
    }

    // ---- Display: every check shows its value and limit ----

    #[test]
    fn test_passing_level_and_depth_checks_are_shown_with_limits() {
        let s = summarize(&healthy_book());
        for prefix in [
            "Bid levels",
            "Ask levels",
            "Bid depth",
            "Ask depth",
            "Bid top-3 depth",
            "Ask top-10 depth",
        ] {
            let found = status_of(&s, prefix);
            assert_eq!(found.len(), 1, "{prefix}: {:?}", s.checks);
            assert!(
                matches!(found[0], HealthCheck::Pass(_)),
                "{prefix}: {:?}",
                found[0]
            );
            assert!(
                found[0].message().contains("(min "),
                "{prefix}: {:?}",
                found[0]
            );
        }
    }

    // ---- #37: synthetic AMM books ----

    fn amm_summary(base_reserve: f64) -> MarketSummary {
        let pair = crate::chains::DexPair {
            dex_name: "Uniswap V2".into(),
            pair_address: "0xpool".into(),
            base_token: "USDC".into(),
            quote_token: "USDT".into(),
            price_usd: 1.0,
            volume_24h: 0.0,
            liquidity_usd: 2.0 * base_reserve,
            liquidity_base: Some(base_reserve),
            price_change_24h: 0.0,
            buys_24h: 0,
            sells_24h: 0,
            buys_6h: 0,
            sells_6h: 0,
            buys_1h: 0,
            sells_1h: 0,
            pair_created_at: None,
            url: None,
        };
        let t = HealthThresholds::default();
        let book =
            super::super::analytics::order_book_from_analytics("ethereum", &pair, "USDC", &t);
        MarketSummary::from_order_book(&book, &t, None)
    }

    fn status_of<'a>(s: &'a MarketSummary, prefix: &str) -> Vec<&'a HealthCheck> {
        s.checks
            .iter()
            .filter(|c| c.message().starts_with(prefix))
            .collect()
    }

    #[test]
    fn test_amm_levels_and_spread_are_not_applicable_and_shown() {
        // #37 decision A: n/a checks are always shown and never fail.
        let s = amm_summary(10_000_000.0);
        assert_eq!(s.source, BookSource::SyntheticAmm);
        let spread = status_of(&s, "Spread");
        assert_eq!(spread.len(), 1);
        assert!(matches!(spread[0], HealthCheck::NotApplicable(_)));
        for side in ["Bid levels", "Ask levels"] {
            let c = status_of(&s, side);
            assert_eq!(c.len(), 1, "{} must always be shown", side);
            assert!(matches!(c[0], HealthCheck::NotApplicable(_)), "{}", side);
        }
    }

    #[test]
    fn test_deep_amm_pool_can_be_healthy() {
        // 10M base at $1: ±0.5% band depth ≈ 25k per side, top-3 ≈ 15k,
        // top-10 ≈ 50k. Every applicable rule passes.
        let s = amm_summary(10_000_000.0);
        assert!(s.healthy, "{:?}", failed(&s));
    }

    #[test]
    fn test_shallow_amm_pool_fails_the_depth_rules() {
        // 1,000 base at $1: band depth ≈ 2.5 USDT per side.
        let s = amm_summary(1_000.0);
        assert!(!s.healthy);
        let f = failed(&s);
        assert!(f.iter().any(|m| m.starts_with("Bid depth")), "{:?}", f);
        assert!(
            f.iter().any(|m| m.starts_with("Ask top-3 depth")),
            "{:?}",
            f
        );
        assert!(
            f.iter().any(|m| m.starts_with("Bid top-10 depth")),
            "{:?}",
            f
        );
    }

    #[test]
    fn test_exchange_book_rules_are_unchanged() {
        // The AMM n/a rules (levels, spread) apply to synthetic AMM books
        // only. Depth/volume is n/a here for another reason: no volume.
        let s = summarize(&healthy_book());
        assert_eq!(s.source, BookSource::Exchange);
        assert!(
            s.checks
                .iter()
                .filter(|c| !c.message().starts_with("Depth/volume"))
                .all(|c| !matches!(c, HealthCheck::NotApplicable(_))),
            "{:?}",
            s.checks
        );
    }

    #[test]
    fn test_book_source_labels_and_json_names() {
        // JSON consumers match on these names; the labels name the source
        // in text and markdown reports.
        for (src, json, label) in [
            (BookSource::Exchange, "exchange", "exchange order book"),
            (
                BookSource::SyntheticAmm,
                "synthetic_amm",
                "synthetic (AMM curve x·y=k)",
            ),
            (
                BookSource::SyntheticEstimate,
                "synthetic_estimate",
                "synthetic estimate (pool reserves not reported)",
            ),
        ] {
            assert_eq!(serde_json::to_value(src).unwrap(), serde_json::json!(json));
            assert_eq!(src.label(), label);
        }
        assert_eq!(BookSource::default(), BookSource::Exchange);
        let na = HealthCheck::NotApplicable("x".into());
        assert_eq!((na.icon(), na.status(), na.message()), ("–", "n/a", "x"));
    }

    #[test]
    fn test_check_json_shape_includes_na() {
        // JSON consumers (the web UI among them) match on these strings.
        let v = serde_json::to_value(HealthCheck::NotApplicable("x".into())).unwrap();
        assert_eq!(v, serde_json::json!({"status": "n/a", "message": "x"}));
        let v = serde_json::to_value(HealthCheck::Fail("y".into())).unwrap();
        assert_eq!(v, serde_json::json!({"status": "fail", "message": "y"}));
    }

    #[test]
    fn test_to_json_shape_is_the_one_the_web_and_cli_share() {
        // app.js reads these keys; the CLI JSON adds only `run` and `venue`.
        let s = MarketSummary::from_order_book(
            &healthy_book(),
            &HealthThresholds::default(),
            Some(50_000.0),
        );
        let v = s.to_json();
        for key in [
            "pair",
            "book_source",
            "peg_target",
            "best_bid",
            "best_ask",
            "mid_price",
            "spread",
            "volume_24h",
            "bid_depth",
            "ask_depth",
            "bid_outliers",
            "ask_outliers",
            "bid_levels",
            "ask_levels",
            "healthy",
            "slippage_warn_bps",
            "execution_10k_buy",
            "execution_10k_sell",
            "bids",
            "asks",
            "checks",
        ] {
            assert!(v.get(key).is_some(), "missing key {key}");
        }
        assert_eq!(v["pair"], "USDC/USDT");
        assert_eq!(v["book_source"], "exchange");
        assert_eq!(v["slippage_warn_bps"], SLIPPAGE_WARN_BPS);
        assert_eq!(v["bid_levels"], 10);
        let buy = &v["execution_10k_buy"];
        for key in ["notional_usdt", "vwap", "slippage_bps", "fillable"] {
            assert!(buy.get(key).is_some(), "missing exec key {key}");
        }
        let level = &v["bids"][0];
        for key in ["price", "quantity", "value"] {
            assert!(level.get(key).is_some(), "missing level key {key}");
        }
    }

    #[test]
    fn test_to_json_caps_levels_at_twenty_but_counts_all() {
        let mut book = healthy_book();
        book.bids = side(0.9999, -0.0001, &[400.0; 25]);
        let s = summarize(&book);
        let v = s.to_json();
        assert_eq!(v["bids"].as_array().unwrap().len(), 20);
        assert_eq!(v["bid_levels"], 25);
    }

    #[test]
    fn test_format_markdown_table_with_deviations_and_checks() {
        let s = MarketSummary::from_order_book(
            &healthy_book(),
            &HealthThresholds::default(),
            Some(50_000.0),
        );
        let md = s.format_markdown(Some("binance"));
        assert!(md.contains("**Venue:** binance"), "{md}");
        // One precision for the book: the peg's (6 decimals near a USD peg).
        assert!(md.contains("| Peg Target | 1.000000 |"), "{md}");
        // Best prices carry their peg deviation; mid and spread do not.
        assert!(md.contains("0.999900 (-0.010%)"), "{md}");
        assert!(md.contains("1.000100 (+0.010%)"), "{md}");
        assert!(md.contains("| Mid Price | 1.000000 |"), "{md}");
        assert!(md.contains("| Volume (24h) | 50000 USDT |"), "{md}");
        assert!(md.contains("| Healthy | ✓ |"), "{md}");
        assert!(md.contains("**Health Checks:**"), "{md}");
        assert!(md.contains("- ✓ No sells below peg"), "{md}");

        let md = s.format_markdown(None);
        assert!(!md.contains("**Venue:**"), "{md}");
    }

    #[test]
    fn test_format_markdown_dashes_and_unhealthy_icon() {
        let mut s = summarize(&healthy_book());
        s.best_bid = None;
        s.best_ask = None;
        s.mid_price = None;
        s.spread = None;
        s.volume_24h = None;
        s.healthy = false;
        s.checks = vec![];
        let md = s.format_markdown(None);
        assert!(md.contains("| Best Bid | - |"), "{md}");
        assert!(!md.contains("Volume (24h)"), "{md}");
        assert!(md.contains("| Healthy | ✗ |"), "{md}");
        // No checks, no section.
        assert!(!md.contains("Health Checks:"), "{md}");
    }

    #[test]
    fn test_text_report_names_the_book_source() {
        // The report wraps at terminal_width().
        let _lock = crate::display::terminal::width_lock();
        let s = amm_summary(10_000_000.0);
        let text = s.format_text(Some("eth"));
        assert!(text.contains("synthetic (AMM curve x·y=k)"), "{}", text);
        assert!(text.contains("– "), "n/a rows use the dash icon: {}", text);
    }

    #[test]
    fn test_market_summary_from_order_book() {
        let summary = summarize(&healthy_book());

        assert!(summary.healthy, "{:?}", failed(&summary));
        assert_eq!(summary.bids.len(), 10);
        assert_eq!(summary.asks.len(), 10);
        assert!(summary.bid_depth > 3000.0);
        assert!(summary.ask_depth > 3000.0);
    }

    #[test]
    fn test_peg_comes_from_thresholds() {
        // Asks at 1.0001+ are below a 1.01 peg, so the peg check must fail.
        // Before, callers passed a literal 1.0 and --peg had no effect.
        let thresholds = HealthThresholds {
            peg_target: 1.01,
            peg_range: 0.01,
            ..HealthThresholds::default()
        };
        let summary = MarketSummary::from_order_book(&healthy_book(), &thresholds, None);
        assert_eq!(summary.peg_target, 1.01);
        assert!(
            failed(&summary).iter().any(|m| m.contains("below peg")),
            "{:?}",
            failed(&summary)
        );
    }

    #[test]
    fn test_default_criteria_values() {
        // Pins the agreed "healthy" spec so a silent default change fails here.
        let t = HealthThresholds::default();
        assert_eq!(t.min_levels, 10);
        assert_eq!(t.max_spread_pct, 3.0);
        assert_eq!(t.min_top3_depth, 300.0);
        assert_eq!(t.min_top10_depth, 2000.0);
        assert_eq!(t.min_depth, 3000.0);
        // Depth within ±2% of mid should be 5–10% of 24h volume.
        assert_eq!(t.depth_window_pct, 2.0);
        assert_eq!(t.min_depth_volume_pct, 5.0);
        assert_eq!(t.max_depth_volume_pct, 10.0);
    }

    #[test]
    fn test_nine_levels_is_unhealthy() {
        let mut book = healthy_book();
        // Keep total depth high so only the level-count rule can fail.
        book.bids = side(0.9999, -0.0001, &[1000.0; 9]);
        let summary = summarize(&book);
        assert!(!summary.healthy);
        assert_eq!(failed(&summary), vec!["Bid levels: 9 < 10 minimum"]);
    }

    #[test]
    fn test_zero_quantity_level_is_not_valid() {
        let mut book = healthy_book();
        book.asks[9].quantity = 0.0;
        book.asks.push(OrderBookLevel {
            price: 1.0011,
            quantity: 0.0,
        });
        let summary = summarize(&book);
        assert!(
            failed(&summary).contains(&"Ask levels: 9 < 10 minimum".to_string()),
            "{:?}",
            failed(&summary)
        );
    }

    #[test]
    fn test_spread_over_three_percent_is_unhealthy() {
        let mut book = healthy_book();
        // Best ask 1.0400 vs best bid 0.9999: ~3.94% of mid.
        book.asks = side(1.04, 0.0001, &[400.0; 10]);
        let summary = summarize(&book);
        assert!(!summary.healthy);
        assert!(
            failed(&summary).iter().any(|m| m.starts_with("Spread:")),
            "{:?}",
            failed(&summary)
        );
    }

    #[test]
    fn test_spread_under_three_percent_passes_spread_check() {
        let mut book = healthy_book();
        // Best ask 1.0200 vs best bid 0.9999: ~1.98% of mid.
        book.asks = side(1.02, 0.0001, &[400.0; 10]);
        let summary = summarize(&book);
        assert!(
            !failed(&summary).iter().any(|m| m.starts_with("Spread:")),
            "{:?}",
            failed(&summary)
        );
    }

    #[test]
    fn test_thin_top3_is_unhealthy_even_with_deep_book() {
        let mut book = healthy_book();
        // Top 3 hold ~150 USDT; levels 4-10 hold 3500, so only top-3 fails.
        let mut qtys = vec![50.0; 3];
        qtys.extend([500.0; 7]);
        book.bids = side(0.9999, -0.0001, &qtys);
        let summary = summarize(&book);
        assert_eq!(
            failed(&summary),
            vec!["Bid top-3 depth: 150 USDT < 300 USDT minimum"]
        );
    }

    #[test]
    fn test_top10_counts_only_first_ten_levels() {
        let mut book = healthy_book();
        // First 10 levels hold ~1500; level 11 adds 2000 so total depth passes.
        let mut qtys = vec![150.0; 10];
        qtys.push(2000.0);
        book.asks = side(1.0001, 0.0001, &qtys);
        let summary = summarize(&book);
        assert!(summary.ask_depth >= 3000.0);
        let fails = failed(&summary);
        assert_eq!(fails.len(), 1, "{fails:?}");
        assert!(fails[0].starts_with("Ask top-10 depth:"), "{fails:?}");
    }

    #[test]
    fn test_format_text_with_chain() {
        let book = OrderBook {
            pair: "USDC/USDT".to_string(),
            source: crate::market::types::BookSource::Exchange,
            bids: vec![OrderBookLevel {
                price: 1.0,
                quantity: 100.0,
            }],
            asks: vec![OrderBookLevel {
                price: 1.0,
                quantity: 100.0,
            }],
        };
        let summary = MarketSummary::from_order_book(&book, &HealthThresholds::default(), None);
        let out = summary.format_text(Some("biconomy"));
        assert!(out.contains("biconomy"));
        assert!(out.contains("Venue"));
    }

    #[test]
    fn test_format_text_without_chain() {
        let book = OrderBook {
            pair: "X/Y".to_string(),
            source: crate::market::types::BookSource::Exchange,
            bids: vec![OrderBookLevel {
                price: 1.0,
                quantity: 10.0,
            }],
            asks: vec![],
        };
        let summary = MarketSummary::from_order_book(&book, &HealthThresholds::default(), None);
        let out = summary.format_text(None);
        assert!(out.contains("X/Y"));
        assert!(!out.contains("Venue"));
    }

    #[test]
    fn test_health_check_sells_below_peg() {
        let book = OrderBook {
            pair: "USDC/USDT".to_string(),
            source: crate::market::types::BookSource::Exchange,
            bids: vec![OrderBookLevel {
                price: 0.9995,
                quantity: 1000.0,
            }],
            asks: vec![
                OrderBookLevel {
                    price: 0.9990,
                    quantity: 100.0,
                }, // below peg
                OrderBookLevel {
                    price: 1.0001,
                    quantity: 500.0,
                },
            ],
        };

        let summary = MarketSummary::from_order_book(&book, &HealthThresholds::default(), None);

        assert!(!summary.healthy);
        let has_fail = summary
            .checks
            .iter()
            .any(|c| matches!(c, HealthCheck::Fail(m) if m.contains("sell")));
        assert!(has_fail);
    }

    #[test]
    fn test_token_lines_sit_under_the_header() {
        // The reader must see which tokens the venue's symbols are.
        let book = OrderBook {
            pair: "USDN/USDT".to_string(),
            source: BookSource::Exchange,
            bids: vec![OrderBookLevel {
                price: 0.9999,
                quantity: 1000.0,
            }],
            asks: vec![OrderBookLevel {
                price: 1.0001,
                quantity: 1000.0,
            }],
        };
        let summary = MarketSummary::from_order_book(&book, &HealthThresholds::default(), None);
        let tokens = [
            super::super::assets::TokenAddress {
                symbol: "USDN".into(),
                network: "ETH".into(),
                contract: Some("0xeC747DAf41A4Ca4ebE72356592F8301924132907".into()),
                other_networks: 0,
            },
            super::super::assets::TokenAddress {
                symbol: "USDT".into(),
                network: "ETH".into(),
                contract: Some("0xdAC17F958D2ee523a2206206994597C13D831ec7".into()),
                other_networks: 7,
            },
        ];
        let out = summary.format_text_with_tokens(Some("weex"), &tokens);
        // Under the header and above the metrics, one unwrapped line each
        // with the full address.
        let at = |needle: &str| {
            out.lines()
                .position(|l| l.contains(needle))
                .unwrap_or_else(|| panic!("no {needle:?} in {out}"))
        };
        let header = at("USDN/USDT (weex)");
        let base = at("USDN (ETH)        0xeC747DAf41A4Ca4ebE72356592F8301924132907");
        let quote =
            at("USDT (ETH)        0xdAC17F958D2ee523a2206206994597C13D831ec7 (+7 networks)");
        assert_eq!((base, quote), (header + 1, header + 2), "{out}");
        assert!(at("Metrics") > quote, "{out}");
        assert_eq!(
            summary.format_text(Some("weex")),
            summary.format_text_with_tokens(Some("weex"), &[])
        );
    }

    #[test]
    fn test_format_text_with_volume_and_spread() {
        let book = OrderBook {
            pair: "USDC/USDT".to_string(),
            source: crate::market::types::BookSource::Exchange,
            bids: vec![
                OrderBookLevel {
                    price: 0.9999,
                    quantity: 1000.0,
                },
                OrderBookLevel {
                    price: 0.9998,
                    quantity: 1000.0,
                },
            ],
            asks: vec![
                OrderBookLevel {
                    price: 1.0001,
                    quantity: 1000.0,
                },
                OrderBookLevel {
                    price: 1.0002,
                    quantity: 1000.0,
                },
            ],
        };
        let summary =
            MarketSummary::from_order_book(&book, &HealthThresholds::default(), Some(50_000.0));
        let out = summary.format_text(Some("binance"));
        // Text output is read on screen: large figures are shortened (the
        // markdown and JSON reports keep the full value).
        let volume = out.lines().find(|l| l.contains("Volume (24h)")).unwrap();
        assert!(volume.ends_with("50.00K USDT"), "{volume}");
        assert!(out.contains("Ask Side — 2 levels, 2.00K USDT"), "{out}");
        assert!(out.contains("Spread"));
    }

    #[test]
    fn test_format_text_with_outliers_and_many_levels() {
        // Book with levels outside peg range (peg_range*5 = 0.005) -> outliers
        // price_lo=0.995, price_hi=1.005 - asks above 1.005 excluded
        let mut asks: Vec<OrderBookLevel> = (0..12)
            .map(|i| OrderBookLevel {
                price: 1.0 + 0.0001 * (i + 1) as f64, // 1.0001 .. 1.0012
                quantity: 500.0,
            })
            .collect();
        asks.push(OrderBookLevel {
            price: 1.01, // outlier
            quantity: 100.0,
        });
        let book = OrderBook {
            pair: "USDC/USDT".to_string(),
            source: crate::market::types::BookSource::Exchange,
            bids: vec![
                OrderBookLevel {
                    price: 0.9999,
                    quantity: 600.0,
                },
                OrderBookLevel {
                    price: 0.9998,
                    quantity: 600.0,
                },
                OrderBookLevel {
                    price: 0.9997,
                    quantity: 600.0,
                },
                OrderBookLevel {
                    price: 0.9996,
                    quantity: 600.0,
                },
                OrderBookLevel {
                    price: 0.9995,
                    quantity: 600.0,
                },
                OrderBookLevel {
                    price: 0.9994,
                    quantity: 600.0,
                },
            ],
            asks,
        };
        let summary = MarketSummary::from_order_book(&book, &HealthThresholds::default(), None);
        let out = summary.format_text(None);
        assert!(
            out.contains("outliers excl.") || summary.ask_outliers > 0 || summary.bid_outliers > 0
        );
        assert!(out.contains("... +")); // truncation for > 8 levels
    }

    #[test]
    fn test_format_text_execution_fillable() {
        // Sufficient liquidity for 10k buy/sell -> fillable
        let book = OrderBook {
            pair: "USDC/USDT".to_string(),
            source: crate::market::types::BookSource::Exchange,
            bids: vec![OrderBookLevel {
                price: 0.9999,
                quantity: 20_000.0,
            }],
            asks: vec![OrderBookLevel {
                price: 1.0001,
                quantity: 20_000.0,
            }],
        };
        let summary = MarketSummary::from_order_book(&book, &HealthThresholds::default(), None);
        let out = summary.format_text(Some("cex"));
        assert!(out.contains("Exec 10K buy"));
        assert!(out.contains("Exec 10K sell"));
        assert!(out.contains("slippage") || out.contains("insufficient"));
    }

    #[test]
    fn test_format_text_bid_outliers_and_many_bid_levels() {
        // Many bid levels + bid outlier → covers lines 328-330, 354-355
        let mut bids: Vec<OrderBookLevel> = (0..12)
            .map(|i| OrderBookLevel {
                price: 1.0 - 0.0001 * (i + 1) as f64,
                quantity: 500.0,
            })
            .collect();
        bids.push(OrderBookLevel {
            price: 0.98, // bid outlier far below peg
            quantity: 100.0,
        });
        let book = OrderBook {
            pair: "USDC/USDT".to_string(),
            source: crate::market::types::BookSource::Exchange,
            bids,
            asks: vec![
                OrderBookLevel {
                    price: 1.0001,
                    quantity: 600.0,
                },
                OrderBookLevel {
                    price: 1.0002,
                    quantity: 600.0,
                },
            ],
        };
        let summary = MarketSummary::from_order_book(&book, &HealthThresholds::default(), None);
        let out = summary.format_text(None);
        assert!(summary.bid_outliers > 0);
        assert!(out.contains("outliers excl."));
        assert!(out.contains("... +"));
    }

    // ---- One eligible-levels set ----

    #[test]
    fn test_top_depth_never_exceeds_in_band_depth_with_far_outliers() {
        // One level at the peg, then a huge level far below it.
        let mut bids = side(0.9999, 0.0, &[100.0]);
        bids.extend(side(0.5, 0.0, &[100_000.0]));
        let b = OrderBook {
            bids,
            ..healthy_book()
        };
        let s = summarize(&b);
        assert_eq!(s.top_depth.bid_top3, s.bid_depth);
        assert!(s.top_depth.bid_top10 <= s.bid_depth);
        assert!((s.bid_depth - 99.99).abs() < 1e-9);
        // The whole-book depth keeps its own name and its own value.
        assert!((b.total_depth(BookSide::Bid) - 50_099.99).abs() < 1e-9);
        assert_eq!(s.bid_outliers, 1);
    }

    #[test]
    fn test_shown_level_count_equals_the_checked_one() {
        // 8 valid asks in the band, 3 outliers at 1.01, one invalid ask.
        let mut asks = side(1.0001, 0.0001, &[400.0; 8]);
        asks.extend(side(1.01, 0.001, &[400.0; 3]));
        asks.push(OrderBookLevel {
            price: 1.0002,
            quantity: 0.0,
        });
        let s = summarize(&OrderBook {
            asks,
            ..healthy_book()
        });
        assert_eq!(s.ask_levels(), 8);
        assert_eq!(s.ask_outliers, 3);
        assert!(failed(&s).contains(&"Ask levels: 8 < 10 minimum".to_string()));
        assert!(s.format_text(None).contains("Ask Side — 8 levels"));
    }

    #[test]
    fn test_a_zero_quantity_level_is_not_a_sell_below_peg() {
        let mut asks = healthy_book().asks;
        asks.insert(
            0,
            OrderBookLevel {
                price: 0.9999,
                quantity: 0.0,
            },
        );
        let s = summarize(&OrderBook {
            asks,
            ..healthy_book()
        });
        assert!(!failed(&s).iter().any(|m| m.contains("below peg")));
    }

    // ---- Peg verdict ----

    #[test]
    fn test_peg_status_follows_the_mid_and_the_health_checks() {
        let s = summarize(&healthy_book());
        assert_eq!(s.peg_status(), PegStatus::OnPeg);
        let mut unhealthy = s.clone();
        unhealthy.healthy = false;
        assert_eq!(unhealthy.peg_status(), PegStatus::BookUnhealthy);
        let mut off = s.clone();
        off.mid_price = Some(0.9);
        assert_eq!(off.peg_status(), PegStatus::Deviation);
        off.mid_price = None;
        assert_eq!(off.peg_status(), PegStatus::NoPrice);
    }

    #[test]
    fn test_peg_bands_come_from_the_thresholds() {
        let bands = HealthThresholds {
            peg_target: 0.5,
            peg_range: 0.002,
            ..HealthThresholds::default()
        }
        .peg_bands();
        assert_eq!(bands.classify(0.5015), PegBand::OnPeg);
        assert_eq!(bands.classify(0.505), PegBand::Slight);
        assert_eq!(bands.classify(0.52), PegBand::Off);
        assert_eq!(bands.outlier_band(), (0.49, 0.51));
    }

    #[test]
    fn test_slight_deviation_is_between_the_peg_range_and_the_outlier_band() {
        let mut s = summarize(&healthy_book());
        s.mid_price = Some(1.003);
        assert_eq!(s.peg_status(), PegStatus::SlightDeviation);
    }

    #[test]
    fn test_peg_band_edges_are_inclusive_like_the_outlier_filter() {
        let bands = PegBands::new(1.0, 0.25);
        // Exactly on the range edge is on the peg; exactly on the band edge
        // is inside the band, the same prices the level filter keeps.
        assert_eq!(bands.classify(1.25), PegBand::OnPeg);
        assert_eq!(bands.classify(2.25), PegBand::Slight);
        assert_eq!(bands.classify(2.26), PegBand::Off);
        let book = OrderBook {
            asks: vec![OrderBookLevel {
                price: 2.25,
                quantity: 1.0,
            }],
            ..healthy_book()
        };
        assert_eq!(
            book.valid_levels_in_band(BookSide::Ask, bands.eligible_band(BookSide::Ask))
                .count(),
            1
        );
    }

    #[test]
    fn test_text_report_notes_that_best_prices_include_outlier_levels() {
        let mut asks = healthy_book().asks;
        asks.push(OrderBookLevel {
            price: 1.5,
            quantity: 10.0,
        });
        let with_outlier = summarize(&OrderBook {
            asks,
            ..healthy_book()
        });
        assert!(
            with_outlier
                .format_text(None)
                .contains("best prices include")
        );
        assert!(
            !summarize(&healthy_book())
                .format_text(None)
                .contains("best prices include")
        );
    }
}