bsv_wallet_cli/

broadcast_verify.rs

//! Post-broadcast verification — fail loudly when a broadcast was silently
//! dropped, and **never** when it was not.
//!
//! # Bug 1 — the silent data loss this module was built to close
//!
//! A `send` (CLI `send` or the served `/createAction` endpoint) delegates to
//! `Wallet::create_action`, which signs the tx and broadcasts it. For a
//! **monitor-less served wallet** (no chain monitor / chaintracks) the wallet
//! has never fetched merkle proofs for its *confirmed* ancestors, so the BEEF it
//! hands ARC carries the whole unconfirmed chain. ARC then charges the fee for
//! the **entire package** and rejects the tx with **error 465 "fee too low"**.
//!
//! In `bsv-wallet-toolbox-rs`, an ARC 465 is tagged `service_error = true`, so
//! `classify_broadcast_results` treats it as a *transient* `ServiceError`
//! (retryable) rather than a permanent `InvalidTx`. `create_action` therefore
//! returns `Ok` with a txid — a **phantom txid that never propagates**. The send
//! path reported success and exit 0 while the funds were never sent.
//!
//! # Bug 2 — the false negative this module *introduced* (fixed here)
//!
//! The first cut of this module polled a **hardcoded** source list and never
//! looked at which broadcaster the wallet had actually been configured to use.
//! It was plane-blind, and every one of its sources was marked authoritative for
//! absence. Three separate defects fell out of that:
//!
//! 1. **The plane that actually holds the answer was never asked.** A wallet in
//!    Arcade V2 mode (`ARC_MODE=arcade`) submits to the Arcade endpoint, and the
//!    verifier never queried it — so the one store that is *guaranteed* to have
//!    a record of our own submission contributed nothing.
//! 2. **`arc.gorillapool.io` was trusted for absence unconditionally.** It is a
//!    submission-scoped metamorph store, **not a chain index**: it answers 404
//!    for transactions that are mined with hundreds of thousands of
//!    confirmations. (Verified directly: `GET
//!    https://arc.gorillapool.io/v1/tx/<genesis coinbase txid>` → `404
//!    {"extraInfo":"transaction not found"}`.) Its 404 carries no information
//!    about a transaction it was never handed.
//! 3. **Only WhatsOnChain could ever vote `Present`, inside a ~7.5 s window.**
//!    So the verdict reduced to a coin flip on WoC's mempool-indexing latency.
//!
//! The module's own comment asserted that "ARC keeps recently submitted txs
//! queryable … so all default sources are authoritative here". That is true only
//! of the ARC instance you actually submitted to. That unchecked proposition was
//! the root cause: in the dHouse funder's entire history, all four `Rejected`
//! verdicts were **false negatives** — every one of those transactions was on
//! chain.
//!
//! # The model this module now implements
//!
//! Doctrine (`CLAUDE.md`): *"2xx is never success — truth = visible in our own
//! index / on chain"*; a **positive** answer may be trusted, an **absence** must
//! be chain-verified. Applied to the verifier itself: **absence from the wrong
//! plane is not truth.**
//!
//! * **Presence is trusted from anybody.** A 200 from any store means that store
//!   holds the transaction. A freshly-minted txid we just created cannot be
//!   known to a third party unless it really propagated. So any `Present` →
//!   `Confirmed`, immediately.
//! * **Absence is trusted from almost nobody.** See [`AbsenceAuthority`]: a 404
//!   is evidence only from the broadcaster we personally submitted through
//!   (scope) or from a real chain+mempool index after its indexing window has
//!   elapsed (time) — and we require **both** before declaring `Rejected`.
//! * **The broadcaster we used is consulted first**, so the happy path
//!   short-circuits to `Confirmed` on a single request.
//! * If we cannot satisfy that bar we return `Inconclusive`, and callers preserve
//!   prior behaviour — a down (or unidentifiable) confirmation service never
//!   turns a real send into a false failure.

use std::time::{Duration, Instant};

use bsv_wallet_toolbox::{services::ARCADE_V2_MAINNET, Chain};
use reqwest::Client;

/// Default number of probe rounds before an absence may become definitive.
///
/// # Why not the original 6 × 1500 ms (~7.5 s)?
///
/// 7.5 s was never defensible as a *mempool-index* window. It is plenty for the
/// broadcaster we submitted through — that store knows about our submission the
/// instant it 200s our POST — but an independent index like WhatsOnChain only
/// learns of the transaction once it propagates to WoC's own node and WoC's
/// mempool ingestion picks it up. Normally that is a few seconds; under network
/// load, a provider hiccup, or an ARC→network relay delay it is routinely tens
/// of seconds. Declaring "the funds were NOT sent" on a 7.5 s WoC miss is
/// declaring a verdict on indexing latency, and that is exactly how the four
/// observed false negatives happened.
///
/// 12 rounds × 2500 ms ≈ 27.5 s of wall clock gives the independent index a
/// realistic chance to catch up before its silence is treated as evidence.
///
/// The cost is paid **only by transactions that really are absent everywhere**:
/// the happy path returns on the very first probe of the broadcaster, and the
/// caller's spending lock is already released before verification runs, so a
/// longer window does not serialize anything.
const DEFAULT_ATTEMPTS: u32 = 12;
/// Default delay between probe rounds (ms). See [`DEFAULT_ATTEMPTS`].
const DEFAULT_DELAY_MS: u64 = 2500;
/// Per-request timeout for a single status probe. Deliberately shorter than the
/// inter-round delay so one slow source cannot stretch a round past the next.
const PROBE_TIMEOUT: Duration = Duration::from_secs(5);

/// Outcome of verifying that a just-broadcast tx actually reached the network.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum BroadcastVerification {
    /// At least one source confirms the tx exists (accepted / seen / mined).
    Confirmed,
    /// Both the broadcaster we actually submitted through **and** an independent
    /// chain index affirmatively report the tx absent after the full probe
    /// window, and no source reports it present — the broadcast was silently
    /// dropped (classic ARC 465 fee-too-low on a deep unconfirmed BEEF).
    /// The funds were NOT sent.
    Rejected,
    /// No source could give an answer that clears the evidence bar. Callers must
    /// NOT treat this as a failure (avoids false negatives when the confirmation
    /// service is unreachable, or when only the *wrong* plane reports absence).
    Inconclusive,
}

impl BroadcastVerification {
    /// Map a verification into a `Result`, failing loudly only on a definitive
    /// `Rejected`. `Confirmed` and `Inconclusive` are both treated as "proceed".
    pub fn into_send_result(self, txid: &str) -> anyhow::Result<()> {
        match self {
            BroadcastVerification::Rejected => Err(anyhow::anyhow!(
                "broadcast rejected: transaction {txid} is absent from BOTH the broadcaster \
                 it was submitted to AND an independent chain index, after the full probe \
                 window. The broadcaster dropped it — most likely error 465 \"fee too low\", \
                 because a monitor-less wallet presented a deep unconfirmed BEEF and ARC \
                 charged the fee for the whole unconfirmed package. The funds were NOT sent. \
                 Fetch merkle proofs for the confirmed ancestors (run `bsv-wallet tick` with \
                 CHAINTRACKS_URL set) or fund from a confirmed UTXO, then retry."
            )),
            BroadcastVerification::Confirmed | BroadcastVerification::Inconclusive => Ok(()),
        }
    }
}

/// Presence of a txid according to a single source.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum Presence {
    /// Source has the tx (HTTP 200).
    Present,
    /// Source definitively does not have the tx (HTTP 404 from a real handler).
    Absent,
    /// Source could not give a definitive answer (auth error, 5xx, network
    /// error, or a 404 that looks like "no such route" rather than "no such tx").
    Unknown,
}

/// What a source's **absence** (404) answer is worth.
///
/// Presence is trusted from every source; absence is a different question
/// entirely, and the answer depends on *why* that store would be expected to
/// hold the transaction.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum AbsenceAuthority {
    /// **Worthless.** A submission-scoped store we did *not* submit to.
    ///
    /// ARC/metamorph instances index what was handed to *them*. They are not
    /// chain indexes: `arc.gorillapool.io` returns 404 for the Bitcoin genesis
    /// coinbase, a transaction with ~960,000 confirmations. A 404 from such a
    /// store tells us only that *it* never received the transaction — which is
    /// the expected answer whenever we broadcast somewhere else. These sources
    /// are kept purely as extra chances to observe `Present`.
    None,

    /// **Scope-authoritative.** This is the broadcaster we personally submitted
    /// through, so it *must* have a record of our own submission.
    ///
    /// This is the only store whose silence is meaningful immediately rather
    /// than eventually. It is still not sufficient on its own:
    ///   * in Arcade mode the toolbox keeps classic ARC as a failover provider,
    ///     so the transaction may legitimately have gone out through the other
    ///     provider and be unknown to the primary; and
    ///   * a misconfigured base URL turns "no such route" into a 404 that is
    ///     indistinguishable from "no such transaction" at the status-code level
    ///     (Arcade V2 answers `GET /tx/{txid}` with `application/json
    ///     {"error":"transaction not found"}` but answers the *wrong* path
    ///     `GET /v1/tx/{txid}` with `text/plain "404 page not found"`).
    ///
    /// Hence the content-type guard in [`probe`] and the conjunction below.
    Broadcaster,

    /// **Time-authoritative.** An independent chain + mempool index (WhatsOnChain).
    ///
    /// Unlike a metamorph store this really does index the whole chain, so its
    /// 404 is about the transaction and not about scope. Its weakness is
    /// *latency*, not coverage: mempool ingestion lags acceptance. So its
    /// absence counts only from the **final** probe round, after the window in
    /// [`DEFAULT_ATTEMPTS`] has elapsed.
    ChainIndex,
}

/// Absence votes gathered during one probe round, grouped by authority class.
///
/// A `Rejected` verdict requires the **conjunction**: the plane we submitted
/// through has no record of our submission *and* an independent chain index
/// still cannot see the transaction after the full window. Either one alone has
/// a mundane innocent explanation (provider failover; indexing lag), and acting
/// on either one alone is precisely what produced four false "funds were NOT
/// sent" reports on transactions that were on chain.
///
/// Consequence, stated honestly: a wallet whose broadcaster cannot be probed
/// (e.g. classic TAAL ARC with no API key, which answers 401 → `Unknown`) can
/// never reach `Rejected`. That is the intended trade. A missed drop is caught
/// downstream — the transaction simply never mines and the unfail canary
/// reconciles it — whereas a false `Rejected` reports lost funds that were not
/// lost, which is the more expensive error by far.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
struct AbsenceVotes {
    /// The broadcaster we submitted through answered 404.
    broadcaster: bool,
    /// An independent chain index answered 404.
    chain_index: bool,
}

impl AbsenceVotes {
    fn record(&mut self, authority: AbsenceAuthority) {
        match authority {
            AbsenceAuthority::Broadcaster => self.broadcaster = true,
            AbsenceAuthority::ChainIndex => self.chain_index = true,
            // A store we did not submit to has no opinion about absence.
            AbsenceAuthority::None => {}
        }
    }

    /// Absence is definitive only when both authority classes agree.
    fn is_definitive(self) -> bool {
        self.broadcaster && self.chain_index
    }
}

/// The broadcast plane the wallet is configured to submit through.
///
/// This mirrors `services_env::services_options_from_env` — the ONE place that
/// decides which broadcaster the wallet uses — so the verifier asks the same
/// endpoint the transaction was actually handed to.
#[derive(Debug, Clone, PartialEq, Eq)]
enum BroadcastPlane {
    /// Arcade V2 (`ARC_MODE=arcade` / `ARCADE=1`).
    ///
    /// Status endpoint is `GET {base}/tx/{txid}` — **no `/v1` prefix**. Verified
    /// two ways: `ArcadeV2Provider::get_tx_status` in `bsv-wallet-toolbox-rs`
    /// builds `format!("{}/tx/{}", self.url, txid)`, and the live endpoint
    /// answers that path with `application/json {"error":"transaction not
    /// found"}` while `/v1/tx/{txid}` answers `text/plain "404 page not found"`
    /// (i.e. the `/v1` path does not exist and its 404 is a routing artifact).
    /// Keyless: Arcade's status read needs no `Authorization` header.
    ArcadeV2 { base: String },
    /// Classic ARC. Status endpoint is `GET {base}/v1/tx/{txid}`, matching
    /// `ArcProvider::get_tx_status` in the toolbox.
    ClassicArc { base: String },
}

impl BroadcastPlane {
    /// Resolve the plane from explicit inputs (pure — unit-testable).
    ///
    /// `arcade_mode` and `arc_url` are read from the same env vars that
    /// `services_env` reads, so the verifier cannot drift from the broadcaster.
    fn resolve(chain: Chain, arcade_mode: bool, arc_url: Option<String>) -> Self {
        let arc_url = arc_url
            .map(|s| s.trim().to_string())
            .filter(|s| !s.is_empty());
        if arcade_mode {
            BroadcastPlane::ArcadeV2 {
                base: normalize_base(&arc_url.unwrap_or_else(|| ARCADE_V2_MAINNET.to_string())),
            }
        } else {
            BroadcastPlane::ClassicArc {
                base: normalize_base(&arc_url.unwrap_or_else(|| taal_arc_url(chain).to_string())),
            }
        }
    }

    fn from_env(chain: Chain) -> Self {
        Self::resolve(
            chain,
            crate::services_env::arcade_mode_enabled(),
            std::env::var("ARC_URL").ok(),
        )
    }

    fn base(&self) -> &str {
        match self {
            BroadcastPlane::ArcadeV2 { base } | BroadcastPlane::ClassicArc { base } => base,
        }
    }

    fn name(&self) -> &'static str {
        match self {
            BroadcastPlane::ArcadeV2 { .. } => "broadcaster(arcade-v2)",
            BroadcastPlane::ClassicArc { .. } => "broadcaster(arc)",
        }
    }

    /// URL template with the literal `{txid}` placeholder.
    fn status_template(&self) -> String {
        match self {
            // Arcade V2: `/tx/{txid}`. `/v1/tx/{txid}` is NOT a route there.
            BroadcastPlane::ArcadeV2 { base } => format!("{base}/tx/{{txid}}"),
            // Classic ARC: `/v1/tx/{txid}`.
            BroadcastPlane::ClassicArc { base } => format!("{base}/v1/tx/{{txid}}"),
        }
    }
}

/// A network endpoint we can ask "do you know this txid?".
#[derive(Clone, Debug)]
struct StatusSource {
    /// Human-readable name (diagnostics only).
    name: &'static str,
    /// URL template containing the literal `{txid}` placeholder.
    url_template: String,
    /// Full `Authorization` header value, if the endpoint needs one.
    auth: Option<String>,
    /// What this source's 404 is worth. See [`AbsenceAuthority`].
    absence: AbsenceAuthority,
}

/// Build the ordered source list for a plane (pure — unit-testable).
///
/// Ordering is load-bearing: **index 0 is always the broadcaster we submitted
/// through**, because it is both the fastest and the most authoritative answer
/// available, and `verify` returns on the first `Present`.
fn build_sources(
    chain: Chain,
    plane: &BroadcastPlane,
    taal_key: Option<String>,
) -> Vec<StatusSource> {
    let mut sources = vec![StatusSource {
        name: plane.name(),
        url_template: plane.status_template(),
        // Arcade's status read is keyless; classic ARC (TAAL) wants the key.
        auth: match plane {
            BroadcastPlane::ArcadeV2 { .. } => None,
            BroadcastPlane::ClassicArc { .. } => taal_key.clone(),
        },
        absence: AbsenceAuthority::Broadcaster,
    }];

    // The independent chain + mempool index. Keyless, reliable 200/404, and the
    // only source here that indexes the chain rather than its own inbox.
    sources.push(StatusSource {
        name: "whatsonchain",
        url_template: format!("{}/tx/hash/{{txid}}", woc_base(chain)),
        auth: None,
        absence: AbsenceAuthority::ChainIndex,
    });

    // Third-party ARC stores: extra chances to observe `Present`, never a vote
    // for absence (see AbsenceAuthority::None). Skipped when they *are* the
    // broadcaster — that row is already at index 0 with real authority.
    if let Some(gp) = gorillapool_arc_url(chain) {
        if normalize_base(gp) != plane.base() {
            sources.push(StatusSource {
                name: "arc-gorillapool",
                url_template: format!("{gp}/v1/tx/{{txid}}"),
                auth: None,
                absence: AbsenceAuthority::None,
            });
        }
    }
    // TAAL only when we hold a key — keyless it answers 401 (`Unknown`), which
    // is pure latency for zero information.
    if let Some(key) = taal_key {
        let taal = taal_arc_url(chain);
        if normalize_base(taal) != plane.base() {
            sources.push(StatusSource {
                name: "arc-taal",
                url_template: format!("{taal}/v1/tx/{{txid}}"),
                auth: Some(key),
                absence: AbsenceAuthority::None,
            });
        }
    }

    sources
}

/// Verifies that a broadcast tx actually reached the network.
///
/// Cheap to clone (shares the reqwest connection pool). Built once and shared
/// via an axum extension on the served path, or per-command on the CLI path.
#[derive(Clone)]
pub struct BroadcastVerifier {
    client: Client,
    sources: Vec<StatusSource>,
    attempts: u32,
    delay: Duration,
    /// When false (env opt-out) `verify` short-circuits to `Inconclusive`.
    enabled: bool,
}

impl BroadcastVerifier {
    /// Build a verifier for `chain`, reading the broadcast plane and optional
    /// overrides from the env:
    /// - `ARC_MODE=arcade` / `ARCADE=1` + `ARC_URL` select the plane probed first.
    /// - `BSV_WALLET_SKIP_BROADCAST_VERIFY=1` disables verification entirely.
    /// - `BSV_WALLET_BROADCAST_VERIFY_ATTEMPTS` overrides the probe-round count.
    /// - `BSV_WALLET_BROADCAST_VERIFY_DELAY_MS` overrides the inter-round delay.
    /// - `TAAL_API_KEY` / `MAIN_TAAL_API_KEY` authenticate the TAAL ARC probe.
    pub fn from_env(chain: Chain) -> Self {
        let enabled = !env_truthy("BSV_WALLET_SKIP_BROADCAST_VERIFY");
        let attempts = std::env::var("BSV_WALLET_BROADCAST_VERIFY_ATTEMPTS")
            .ok()
            .and_then(|v| v.parse::<u32>().ok())
            .filter(|n| *n > 0)
            .unwrap_or(DEFAULT_ATTEMPTS);
        let delay_ms = std::env::var("BSV_WALLET_BROADCAST_VERIFY_DELAY_MS")
            .ok()
            .and_then(|v| v.parse::<u64>().ok())
            .unwrap_or(DEFAULT_DELAY_MS);

        // TAAL ARC uses a raw `Authorization: <key>` header (no "Bearer " prefix).
        let taal_key = std::env::var("TAAL_API_KEY")
            .ok()
            .filter(|k| !k.is_empty())
            .or_else(|| {
                std::env::var("MAIN_TAAL_API_KEY")
                    .ok()
                    .filter(|k| !k.is_empty())
            });

        let plane = BroadcastPlane::from_env(chain);
        tracing::debug!(plane = ?plane, "broadcast verifier plane");

        Self {
            client: Client::new(),
            sources: build_sources(chain, &plane, taal_key),
            attempts,
            delay: Duration::from_millis(delay_ms),
            enabled,
        }
    }

    /// Wall-clock ceiling for the absence determination. A source that hangs
    /// must not be able to stretch the window without bound, so rounds stop once
    /// the nominal window (plus one probe timeout of slack) has elapsed.
    fn absence_window(&self) -> Duration {
        self.delay * self.attempts.saturating_sub(1) + PROBE_TIMEOUT
    }

    /// Probe the network for `txid`, returning as soon as any source reports it
    /// present, otherwise after the full probe window.
    pub async fn verify(&self, txid: &str) -> BroadcastVerification {
        if !self.enabled || self.sources.is_empty() {
            return BroadcastVerification::Inconclusive;
        }

        let deadline = Instant::now() + self.absence_window();
        // Votes from the LAST COMPLETED round. Using the last round (rather than
        // any round) is what makes the chain-index vote time-authoritative: its
        // silence only counts once the indexing window has actually elapsed.
        let mut last_votes: Option<AbsenceVotes> = None;

        for attempt in 0..self.attempts {
            let mut votes = AbsenceVotes::default();
            for src in &self.sources {
                match probe(&self.client, src, txid).await {
                    // Doctrine: a positive answer may be trusted from any source.
                    // A txid we minted moments ago cannot be known to a third
                    // party unless it genuinely propagated.
                    Presence::Present => return BroadcastVerification::Confirmed,
                    Presence::Absent => votes.record(src.absence),
                    Presence::Unknown => {}
                }
            }
            last_votes = Some(votes);

            if attempt + 1 < self.attempts {
                if Instant::now() >= deadline {
                    // Slow sources already consumed the window; further rounds
                    // would only extend the caller's wait, not the evidence.
                    break;
                }
                tokio::time::sleep(self.delay).await;
            }
        }

        match last_votes {
            Some(v) if v.is_definitive() => BroadcastVerification::Rejected,
            _ => BroadcastVerification::Inconclusive,
        }
    }
}

/// Probe a single source for a txid's presence.
async fn probe(client: &Client, src: &StatusSource, txid: &str) -> Presence {
    let url = src.url_template.replace("{txid}", txid);
    let mut req = client.get(&url).timeout(PROBE_TIMEOUT);
    if let Some(auth) = &src.auth {
        req = req.header("Authorization", auth);
    }
    match req.send().await {
        Ok(resp) => {
            let status = resp.status().as_u16();
            match status {
                200 => Presence::Present,
                404 => {
                    // A 404 has two very different meanings: "I have no such
                    // transaction" (a real answer from the ARC/Arcade handler,
                    // always a JSON problem document) and "I have no such route"
                    // (a misconfigured base URL — Go/edge routers answer
                    // `text/plain "404 page not found"`). Only the former is
                    // evidence, and only for a source whose absence we would act
                    // on. Downgrading the routing artifact to `Unknown` keeps a
                    // typo in `ARC_URL` from being reported as lost funds.
                    if src.absence == AbsenceAuthority::Broadcaster && !is_json(&resp) {
                        tracing::debug!(
                            source = src.name,
                            url = %url,
                            "broadcaster 404 is not a JSON tx-status body — treating as \
                             route-not-found (check ARC_URL / path shape), not absence"
                        );
                        return Presence::Unknown;
                    }
                    Presence::Absent
                }
                other => {
                    tracing::debug!(
                        source = src.name,
                        status = other,
                        "broadcast probe inconclusive"
                    );
                    Presence::Unknown
                }
            }
        }
        Err(e) => {
            tracing::debug!(source = src.name, error = %e, "broadcast probe request failed");
            Presence::Unknown
        }
    }
}

/// Whether a response carries a JSON body (the shape every ARC/Arcade status
/// handler returns, including for "transaction not found").
fn is_json(resp: &reqwest::Response) -> bool {
    resp.headers()
        .get(reqwest::header::CONTENT_TYPE)
        .and_then(|v| v.to_str().ok())
        .map(|ct| ct.to_ascii_lowercase().contains("json"))
        .unwrap_or(false)
}

fn normalize_base(url: &str) -> String {
    url.trim().trim_end_matches('/').to_string()
}

fn taal_arc_url(chain: Chain) -> &'static str {
    match chain {
        Chain::Main => "https://arc.taal.com",
        Chain::Test => "https://arc-test.taal.com",
    }
}

fn gorillapool_arc_url(chain: Chain) -> Option<&'static str> {
    match chain {
        Chain::Main => Some("https://arc.gorillapool.io"),
        // GorillaPool testnet ARC is not commonly used; omit it.
        Chain::Test => None,
    }
}

fn woc_base(chain: Chain) -> &'static str {
    match chain {
        Chain::Main => "https://api.whatsonchain.com/v1/bsv/main",
        Chain::Test => "https://api.whatsonchain.com/v1/bsv/test",
    }
}

fn env_truthy(key: &str) -> bool {
    std::env::var(key)
        .map(|v| {
            let v = v.trim().to_ascii_lowercase();
            v == "1" || v == "true" || v == "yes" || v == "on"
        })
        .unwrap_or(false)
}

#[cfg(test)]
mod tests {
    use super::*;
    use axum::http::StatusCode;
    use axum::routing::get;
    use axum::Router;
    use std::net::SocketAddr;

    // ---- synthetic values only (never a real txid / URL from any wallet) ----
    const TXID: &str = "0000000000000000000000000000000000000000000000000000000000000001";
    const SYNTHETIC_ARCADE: &str = "https://arcade.invalid";
    const SYNTHETIC_ARC: &str = "https://arc.invalid";
    const SYNTHETIC_KEY: &str = "test-key-not-a-real-credential";

    // =====================================================================
    // Source selection: which plane do we ask, and with what path shape?
    // =====================================================================

    #[test]
    fn arcade_plane_uses_bare_tx_path_not_v1() {
        // Arcade V2's status route is `/tx/{txid}`. `/v1/tx/{txid}` is not a
        // route on Arcade at all (it answers with the router's text/plain 404),
        // which would have made every Arcade tx look "absent".
        let plane = BroadcastPlane::resolve(
            Chain::Main,
            /* arcade_mode */ true,
            Some(SYNTHETIC_ARCADE.to_string()),
        );
        assert_eq!(
            plane.status_template(),
            format!("{SYNTHETIC_ARCADE}/tx/{{txid}}")
        );
        assert!(
            !plane.status_template().contains("/v1/"),
            "Arcade V2 must NOT be probed on the classic ARC /v1 path"
        );
    }

    #[test]
    fn classic_arc_plane_uses_v1_tx_path() {
        let plane = BroadcastPlane::resolve(
            Chain::Main,
            /* arcade_mode */ false,
            Some(SYNTHETIC_ARC.to_string()),
        );
        assert_eq!(
            plane.status_template(),
            format!("{SYNTHETIC_ARC}/v1/tx/{{txid}}")
        );
    }

    #[test]
    fn arcade_mode_defaults_to_the_arcade_endpoint_when_arc_url_is_unset() {
        let plane = BroadcastPlane::resolve(Chain::Main, true, None);
        assert_eq!(plane.base(), ARCADE_V2_MAINNET.trim_end_matches('/'));
    }

    #[test]
    fn classic_mode_defaults_to_taal_and_respects_chain() {
        assert_eq!(
            BroadcastPlane::resolve(Chain::Main, false, None).base(),
            "https://arc.taal.com"
        );
        assert_eq!(
            BroadcastPlane::resolve(Chain::Test, false, None).base(),
            "https://arc-test.taal.com"
        );
    }

    #[test]
    fn empty_arc_url_falls_back_to_the_default_rather_than_an_empty_base() {
        let plane = BroadcastPlane::resolve(Chain::Main, true, Some("   ".to_string()));
        assert_eq!(plane.base(), ARCADE_V2_MAINNET.trim_end_matches('/'));
    }

    #[test]
    fn trailing_slash_in_arc_url_does_not_produce_a_double_slash() {
        let plane = BroadcastPlane::resolve(
            Chain::Main,
            true,
            Some(format!("{SYNTHETIC_ARCADE}/").to_string()),
        );
        assert_eq!(
            plane.status_template(),
            format!("{SYNTHETIC_ARCADE}/tx/{{txid}}")
        );
    }

    #[test]
    fn the_broadcaster_we_used_is_always_the_first_source_consulted() {
        // This is the whole point of the fix: the plane that actually holds the
        // answer must be asked FIRST, in both modes.
        for plane in [
            BroadcastPlane::resolve(Chain::Main, true, Some(SYNTHETIC_ARCADE.to_string())),
            BroadcastPlane::resolve(Chain::Main, false, Some(SYNTHETIC_ARC.to_string())),
        ] {
            let sources = build_sources(Chain::Main, &plane, None);
            assert_eq!(sources[0].absence, AbsenceAuthority::Broadcaster);
            assert!(
                sources[0].url_template.starts_with(plane.base()),
                "source 0 ({}) must be the configured broadcaster {}",
                sources[0].url_template,
                plane.base()
            );
        }
    }

    #[test]
    fn arcade_broadcaster_probe_is_keyless_even_when_a_taal_key_exists() {
        let plane = BroadcastPlane::resolve(Chain::Main, true, Some(SYNTHETIC_ARCADE.to_string()));
        let sources = build_sources(Chain::Main, &plane, Some(SYNTHETIC_KEY.to_string()));
        assert!(sources[0].auth.is_none());
    }

    #[test]
    fn classic_broadcaster_probe_carries_the_taal_key_when_present() {
        let plane = BroadcastPlane::resolve(Chain::Main, false, None);
        let sources = build_sources(Chain::Main, &plane, Some(SYNTHETIC_KEY.to_string()));
        assert_eq!(sources[0].auth.as_deref(), Some(SYNTHETIC_KEY));
    }

    #[test]
    fn keyless_taal_is_not_probed_at_all() {
        // Without a key TAAL answers 401 → Unknown: pure latency, zero signal.
        let plane = BroadcastPlane::resolve(Chain::Main, true, Some(SYNTHETIC_ARCADE.to_string()));
        let sources = build_sources(Chain::Main, &plane, None);
        assert!(!sources.iter().any(|s| s.name == "arc-taal"));
    }

    #[test]
    fn a_store_is_never_listed_twice_when_it_is_also_the_broadcaster() {
        // Broadcasting through GorillaPool in classic mode must not add a second
        // (presence-only) GorillaPool row.
        let plane = BroadcastPlane::resolve(
            Chain::Main,
            false,
            Some("https://arc.gorillapool.io".to_string()),
        );
        let sources = build_sources(Chain::Main, &plane, None);
        let gp_rows: Vec<_> = sources
            .iter()
            .filter(|s| s.url_template.contains("arc.gorillapool.io"))
            .collect();
        assert_eq!(gp_rows.len(), 1);
        assert_eq!(gp_rows[0].absence, AbsenceAuthority::Broadcaster);
    }

    // =====================================================================
    // Absence authority: whose 404 may be believed, and when?
    // =====================================================================

    #[test]
    fn a_third_party_arc_store_is_never_authoritative_for_absence() {
        // arc.gorillapool.io 404s for the genesis coinbase (~960k confirmations).
        // It is a submission-scoped metamorph store, not a chain index: when we
        // broadcast through Arcade, its 404 is the EXPECTED answer and carries
        // no information. Marking it authoritative caused false "funds not sent".
        let plane = BroadcastPlane::resolve(Chain::Main, true, Some(SYNTHETIC_ARCADE.to_string()));
        let sources = build_sources(Chain::Main, &plane, Some(SYNTHETIC_KEY.to_string()));
        for s in sources.iter().filter(|s| s.name.starts_with("arc-")) {
            assert_eq!(
                s.absence,
                AbsenceAuthority::None,
                "{} is not the broadcaster; its absence must carry no weight",
                s.name
            );
        }
    }

    #[test]
    fn whatsonchain_is_the_chain_index_authority() {
        let plane = BroadcastPlane::resolve(Chain::Main, true, Some(SYNTHETIC_ARCADE.to_string()));
        let sources = build_sources(Chain::Main, &plane, None);
        let woc = sources.iter().find(|s| s.name == "whatsonchain").unwrap();
        assert_eq!(woc.absence, AbsenceAuthority::ChainIndex);
    }

    #[test]
    fn absence_is_definitive_only_when_broadcaster_and_chain_index_agree() {
        let mut none = AbsenceVotes::default();
        assert!(!none.is_definitive(), "no votes is not evidence");

        // A store we did not submit to voting absent changes nothing.
        none.record(AbsenceAuthority::None);
        assert!(!none.is_definitive());

        let mut broadcaster_only = AbsenceVotes::default();
        broadcaster_only.record(AbsenceAuthority::Broadcaster);
        assert!(
            !broadcaster_only.is_definitive(),
            "the primary may 404 while the tx went out through the failover provider"
        );

        let mut index_only = AbsenceVotes::default();
        index_only.record(AbsenceAuthority::ChainIndex);
        assert!(
            !index_only.is_definitive(),
            "a chain index can simply be lagging its mempool ingestion"
        );

        let mut both = AbsenceVotes::default();
        both.record(AbsenceAuthority::Broadcaster);
        both.record(AbsenceAuthority::ChainIndex);
        assert!(both.is_definitive());
    }

    // =====================================================================
    // End-to-end verdicts against local mock sources.
    // =====================================================================

    /// Local mock answering every status path (`/tx/{txid}` and `/v1/tx/{txid}`)
    /// with `code`. Returns the base URL (`http://127.0.0.1:PORT`).
    async fn mock_status_server(code: StatusCode) -> String {
        mock_status_server_ct(code, Some("application/json")).await
    }

    /// As [`mock_status_server`], with an explicit `Content-Type` (or none).
    async fn mock_status_server_ct(code: StatusCode, content_type: Option<&'static str>) -> String {
        let handler = move || async move {
            let mut resp = axum::response::Response::new(axum::body::Body::from("{}"));
            *resp.status_mut() = code;
            if let Some(ct) = content_type {
                resp.headers_mut()
                    .insert(reqwest::header::CONTENT_TYPE.as_str(), ct.parse().unwrap());
            } else {
                resp.headers_mut()
                    .remove(reqwest::header::CONTENT_TYPE.as_str());
            }
            resp
        };
        let app = Router::new()
            .route("/tx/{txid}", get(handler))
            .route("/v1/tx/{txid}", get(handler))
            .route("/tx/hash/{txid}", get(handler));
        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
        let addr: SocketAddr = listener.local_addr().unwrap();
        tokio::spawn(async move {
            axum::serve(listener, app).await.ok();
        });
        format!("http://{}", addr)
    }

    fn source(name: &'static str, base: &str, absence: AbsenceAuthority) -> StatusSource {
        StatusSource {
            name,
            url_template: format!("{base}/tx/{{txid}}"),
            auth: None,
            absence,
        }
    }

    /// Verifier over an explicit source list (fast: 2 rounds, no delay).
    fn verifier_with(sources: Vec<StatusSource>) -> BroadcastVerifier {
        BroadcastVerifier {
            client: Client::new(),
            sources,
            attempts: 2,
            delay: Duration::from_millis(0),
            enabled: true,
        }
    }

    #[tokio::test]
    async fn rejected_when_broadcaster_and_chain_index_both_report_absent() {
        // The original purpose of the module (ARC 465 fee-too-low) still fires:
        // the plane we submitted to has no record AND the chain index cannot see
        // it after the window.
        let base = mock_status_server(StatusCode::NOT_FOUND).await;
        let verifier = verifier_with(vec![
            source("broadcaster", &base, AbsenceAuthority::Broadcaster),
            source("chain-index", &base, AbsenceAuthority::ChainIndex),
        ]);

        let outcome = verifier.verify(TXID).await;
        assert_eq!(outcome, BroadcastVerification::Rejected);
        assert!(
            outcome.into_send_result(TXID).is_err(),
            "a Rejected verification must map to Err so the send fails loudly"
        );
    }

    #[tokio::test]
    async fn the_false_negative_that_motivated_this_fix_is_now_inconclusive() {
        // Exactly the observed regression: the broadcaster we used is never
        // asked (or is unreachable), a third-party ARC store 404s because we
        // never submitted to it, and the chain index has not indexed the mempool
        // entry yet. Old code: Rejected ("the funds were NOT sent"). Every such
        // transaction was actually on chain.
        let absent = mock_status_server(StatusCode::NOT_FOUND).await;
        let verifier = verifier_with(vec![
            // Broadcaster unreachable → Unknown, not a vote.
            source(
                "broadcaster",
                "http://127.0.0.1:1",
                AbsenceAuthority::Broadcaster,
            ),
            source("chain-index", &absent, AbsenceAuthority::ChainIndex),
            source("arc-third-party", &absent, AbsenceAuthority::None),
        ]);
        assert_eq!(
            verifier.verify(TXID).await,
            BroadcastVerification::Inconclusive
        );
    }

    #[tokio::test]
    async fn third_party_absence_alone_never_rejects() {
        let base = mock_status_server(StatusCode::NOT_FOUND).await;
        let verifier = verifier_with(vec![
            source("arc-third-party-a", &base, AbsenceAuthority::None),
            source("arc-third-party-b", &base, AbsenceAuthority::None),
        ]);
        assert_eq!(
            verifier.verify(TXID).await,
            BroadcastVerification::Inconclusive
        );
    }

    #[tokio::test]
    async fn broadcaster_absence_alone_never_rejects() {
        // The toolbox keeps a failover provider behind the primary, so the tx
        // may legitimately have gone out through the other plane.
        let absent = mock_status_server(StatusCode::NOT_FOUND).await;
        let verifier = verifier_with(vec![
            source("broadcaster", &absent, AbsenceAuthority::Broadcaster),
            // Chain index unreachable → Unknown.
            source(
                "chain-index",
                "http://127.0.0.1:1",
                AbsenceAuthority::ChainIndex,
            ),
        ]);
        assert_eq!(
            verifier.verify(TXID).await,
            BroadcastVerification::Inconclusive
        );
    }

    #[tokio::test]
    async fn chain_index_absence_alone_never_rejects() {
        let absent = mock_status_server(StatusCode::NOT_FOUND).await;
        let verifier = verifier_with(vec![
            // Broadcaster answers 401 (keyless TAAL) → Unknown.
            source("broadcaster", &absent, AbsenceAuthority::Broadcaster),
            source("chain-index", &absent, AbsenceAuthority::ChainIndex),
        ]);
        // Sanity: with both absent it WOULD reject...
        assert_eq!(verifier.verify(TXID).await, BroadcastVerification::Rejected);

        // ...but with the broadcaster unreachable, the chain index alone must not.
        let unauth = mock_status_server(StatusCode::UNAUTHORIZED).await;
        let verifier = verifier_with(vec![
            source("broadcaster", &unauth, AbsenceAuthority::Broadcaster),
            source("chain-index", &absent, AbsenceAuthority::ChainIndex),
        ]);
        assert_eq!(
            verifier.verify(TXID).await,
            BroadcastVerification::Inconclusive
        );
    }

    #[tokio::test]
    async fn presence_from_any_source_confirms_even_when_others_say_absent() {
        // Doctrine: a positive answer may be trusted; an absence may not.
        let present = mock_status_server(StatusCode::OK).await;
        let absent = mock_status_server(StatusCode::NOT_FOUND).await;
        let verifier = verifier_with(vec![
            source("broadcaster", &absent, AbsenceAuthority::Broadcaster),
            source("chain-index", &absent, AbsenceAuthority::ChainIndex),
            source("arc-third-party", &present, AbsenceAuthority::None),
        ]);
        let outcome = verifier.verify(TXID).await;
        assert_eq!(outcome, BroadcastVerification::Confirmed);
        assert!(outcome.into_send_result(TXID).is_ok());
    }

    #[tokio::test]
    async fn confirmed_broadcast_succeeds() {
        let base = mock_status_server(StatusCode::OK).await;
        let verifier = verifier_with(vec![source(
            "broadcaster",
            &base,
            AbsenceAuthority::Broadcaster,
        )]);
        let outcome = verifier.verify(TXID).await;
        assert_eq!(outcome, BroadcastVerification::Confirmed);
        assert!(outcome.into_send_result(TXID).is_ok());
    }

    #[tokio::test]
    async fn unreachable_source_is_inconclusive_not_a_failure() {
        // 503 from every probe → we cannot confirm either way → Inconclusive,
        // which must NOT be a failure (no false negatives when the service is down).
        let base = mock_status_server(StatusCode::SERVICE_UNAVAILABLE).await;
        let verifier = verifier_with(vec![
            source("broadcaster", &base, AbsenceAuthority::Broadcaster),
            source("chain-index", &base, AbsenceAuthority::ChainIndex),
        ]);
        let outcome = verifier.verify(TXID).await;
        assert_eq!(outcome, BroadcastVerification::Inconclusive);
        assert!(outcome.into_send_result(TXID).is_ok());
    }

    #[tokio::test]
    async fn a_routing_404_from_the_broadcaster_is_not_absence() {
        // A wrong base URL / path shape yields `text/plain "404 page not found"`.
        // That must never be read as "the funds were NOT sent".
        let text_404 = mock_status_server_ct(StatusCode::NOT_FOUND, Some("text/plain")).await;
        let json_404 = mock_status_server(StatusCode::NOT_FOUND).await;
        let verifier = verifier_with(vec![
            source("broadcaster", &text_404, AbsenceAuthority::Broadcaster),
            source("chain-index", &json_404, AbsenceAuthority::ChainIndex),
        ]);
        assert_eq!(
            verifier.verify(TXID).await,
            BroadcastVerification::Inconclusive
        );
    }

    #[tokio::test]
    async fn disabled_verifier_is_inconclusive() {
        let base = mock_status_server(StatusCode::NOT_FOUND).await;
        let mut verifier = verifier_with(vec![
            source("broadcaster", &base, AbsenceAuthority::Broadcaster),
            source("chain-index", &base, AbsenceAuthority::ChainIndex),
        ]);
        verifier.enabled = false;
        assert_eq!(
            verifier.verify(TXID).await,
            BroadcastVerification::Inconclusive
        );
    }

    #[test]
    fn absence_window_is_bounded_and_reflects_the_configured_rounds() {
        let v = BroadcastVerifier {
            client: Client::new(),
            sources: vec![],
            attempts: DEFAULT_ATTEMPTS,
            delay: Duration::from_millis(DEFAULT_DELAY_MS),
            enabled: true,
        };
        // 11 gaps × 2.5s + 5s slack — long enough for a real mempool index to
        // catch up, and hard-bounded so a hung source cannot extend it.
        assert_eq!(
            v.absence_window(),
            Duration::from_millis(27_500) + PROBE_TIMEOUT
        );
    }
}