//! Router-coverage CSRF test.
//!
//! Enumerates every mutating route registered through `CsrfRouter` (via the
//! manifest harvested at registration time, `makenotwork::csrf::route_manifest`)
//! and asserts the whole-router CSRF invariant in one place — instead of relying
//! on per-route tests, or on an audit, to notice a route that drifted.
//!
//! Why this exists: CSRF has surfaced in nearly every audit run because the
//! protection is enforced opt-in across ~350 per-route posture declarations plus
//! a multi-branch middleware. Each run an adversarial reader finds a different
//! site that drifted (route registration, the auto-posture pre-auth branch, a
//! mis-declared skip). This test converts "did every route get protected?" from
//! a code-reading exercise into a CI assertion that fails the moment a route
//! drifts.

use crate::harness::TestHarness;
use makenotwork::csrf::{route_manifest, ManifestPosture};

/// Auto-posture paths where an *outer* layer (e.g. the access gate) rejects the
/// test user with a non-403 status before the per-route CSRF layer runs, so the
/// strict `== 403` assertion below does not apply. Each entry must name the
/// layer that rejects it. The request is still refused — just not by the CSRF
/// layer — so excluding it does not weaken the security claim. Keep this list
/// short and justified; an unexplained entry is a smell.
const REJECTED_BEFORE_CSRF_LAYER: &[&str] = &[
    // (populated empirically — see test output if this list is wrong)
];

// CHRONIC A′ (the pre-auth CSRF gap) is CLOSED as of 2026-06-15: `validate_auto`
// no longer skips token validation for logged-out callers, and the
// posture-independent `origin_gate` (layered on the whole `CsrfRouter` tree in
// `finalize`) rejects positively cross-site mutations. There is no longer a
// tracked-gap allowlist; `forgot_password_rejects_preauth_tokenless_post` below
// pins the fix. If a new pre-auth gap is ever knowingly accepted, reintroduce a
// justified allowlist + a test that flips when it closes (see git history for
// the prior `KNOWN_PREAUTH_CSRF_GAPS` forcing-function pattern).

/// Core coverage assertion: every Auto-posture route rejects an authenticated
/// request that carries no CSRF token. This catches a route that lost its auto
/// validation layer (the #18-class regression) across the whole router at once.
#[tokio::test]
async fn every_auto_route_rejects_authenticated_tokenless_mutation() {
    let mut h = TestHarness::new().await;
    // Log in a user so requests clear the access gate and reach the per-route
    // CSRF layer. The client tracks the session cookie; `request_with_headers`
    // deliberately does NOT inject a CSRF token, so each request is
    // authenticated-but-tokenless.
    h.signup("csrfcov", "csrfcov@example.com", "password123").await;

    let manifest = route_manifest();
    let auto_routes: Vec<_> = manifest
        .iter()
        .filter(|e| e.posture == ManifestPosture::Auto)
        .collect();
    assert!(
        auto_routes.len() > 50,
        "manifest looks empty/broken: {} auto of {} total routes",
        auto_routes.len(),
        manifest.len()
    );

    // Each manifest path may register any mutating method (single-method
    // helpers like `put_csrf`, or multi-method `with_csrf(get().post())`); the
    // manifest keys by path, not method. So probe the four mutating methods and
    // require that the one the route actually handles is rejected with 403. A
    // method the route does not handle returns 405 (the auto layer does not wrap
    // the method-not-allowed fallback) — that is not a CSRF result, so we move
    // on. The client IP is rotated every request so the per-IP rate limiter
    // (an outer layer that would 429 before the CSRF layer) never trips.
    let mut ip_counter: u32 = 0;
    let mut next_ip = |h: &mut TestHarness| {
        ip_counter += 1;
        h.client
            .set_forwarded_ip(&format!("10.50.{}.{}", (ip_counter / 256) % 256, ip_counter % 256));
    };

    let mut failures = Vec::new();
    for entry in &auto_routes {
        if REJECTED_BEFORE_CSRF_LAYER.contains(&entry.path.as_str()) {
            continue;
        }
        // Authenticated session + no CSRF token + no form content-type:
        // `validate_auto` must return 403 (Forbidden) before the handler runs.
        // Path params in the manifest (e.g. `/api/items/{id}`) still match the
        // route pattern, and validation rejects before any param is parsed.
        let mut outcome: Option<(&str, u16)> = None;
        for method in ["POST", "PUT", "PATCH", "DELETE"] {
            next_ip(&mut h);
            let resp = h
                .client
                .request_with_headers(method, &entry.path, None, &[])
                .await;
            let code = resp.status.as_u16();
            if code == 403 {
                outcome = Some((method, code));
                break;
            }
            if code != 405 {
                // The route handled this method but did NOT reject — the real
                // (and only interesting) failure case.
                outcome = Some((method, code));
                break;
            }
            // 405: route doesn't handle this method; try the next one.
        }
        match outcome {
            Some((_, 403)) => {}
            Some((method, code)) => failures.push(format!("{} [{method}] -> {code}", entry.path)),
            None => failures.push(format!("{} -> all methods 405 (no mutating method?)", entry.path)),
        }
    }

    assert!(
        failures.is_empty(),
        "{} Auto route(s) did NOT reject a tokenless authenticated request (CSRF \
         layer missing/bypassed). If a route is legitimately refused earlier by \
         an outer layer, add it to REJECTED_BEFORE_CSRF_LAYER with a reason:\n{}",
        failures.len(),
        failures.join("\n")
    );
}

/// Manifest sanity: it is populated, the posture mix is plausible, and every
/// opt-out (Manual/Skip) carries a documented justification at its call site.
#[tokio::test]
async fn csrf_manifest_is_populated_and_optouts_are_justified() {
    let _h = TestHarness::new().await; // building the app populates the manifest
    let manifest = route_manifest();

    let count = |p: ManifestPosture| manifest.iter().filter(|e| e.posture == p).count();
    let (auto, manual, skip) = (
        count(ManifestPosture::Auto),
        count(ManifestPosture::Manual),
        count(ManifestPosture::Skip),
    );
    eprintln!(
        "CSRF manifest: {auto} auto, {manual} manual, {skip} skip, {} total",
        manifest.len()
    );

    assert!(manifest.len() > 100, "manifest too small: {}", manifest.len());
    assert!(auto > 50, "expected many Auto routes, got {auto}");

    for e in &manifest {
        if matches!(e.posture, ManifestPosture::Manual | ManifestPosture::Skip) {
            assert!(
                e.reason.map(|r| !r.trim().is_empty()).unwrap_or(false),
                "{:?} route {} has no documented CSRF justification",
                e.posture,
                e.path
            );
        }
    }
}

/// CHRONIC A′ regression test (gap CLOSED 2026-06-15). `/forgot-password` is
/// Auto-posture and always reached logged-out. It used to slip through because
/// `validate_auto` skipped token validation for logged-out callers. That skip
/// is gone, so a pre-auth tokenless POST is now rejected by the per-route token
/// check. This pins the fix: if the `!has_user` skip is ever reintroduced, this
/// flips red.
#[tokio::test]
async fn forgot_password_rejects_preauth_tokenless_post() {
    let mut h = TestHarness::new().await;
    // Anonymous client (no signup) + no CSRF token + a real-looking form body.
    // No Origin/Sec-Fetch-Site headers, so the origin_gate allows it through —
    // the rejection here comes from the per-route token check (the seal for
    // header-less forged clients the origin gate intentionally lets pass).
    let resp = h
        .client
        .request_with_headers(
            "POST",
            "/forgot-password",
            Some("email=nobody@example.com"),
            &[("Content-Type", "application/x-www-form-urlencoded")],
        )
        .await;

    assert_eq!(
        resp.status, 403,
        "CHRONIC A' regressed: /forgot-password accepted a pre-auth tokenless \
         POST (got {}). The validate_auto !has_user skip must stay removed.",
        resp.status
    );
}

/// The posture-independent origin gate rejects a positively cross-site mutating
/// request regardless of posture or auth state, before the handler runs.
#[tokio::test]
async fn origin_gate_rejects_cross_site_mutation() {
    let mut h = TestHarness::new().await;
    let resp = h
        .client
        .request_with_headers(
            "POST",
            "/forgot-password",
            Some("email=nobody@example.com"),
            &[
                ("Content-Type", "application/x-www-form-urlencoded"),
                ("Sec-Fetch-Site", "cross-site"),
            ],
        )
        .await;
    assert_eq!(
        resp.status, 403,
        "origin gate let a Sec-Fetch-Site: cross-site mutation through (got {})",
        resp.status
    );
}

/// A header-less request (no Sec-Fetch-Site, no Origin/Referer) is allowed past
/// the origin gate — this is the server-to-server / CLI path. It is still
/// subject to the per-route token check, so the response is whatever that check
/// returns (here 403 for a tokenless form), NOT a gate rejection. We assert the
/// gate did not block on a same-origin Sec-Fetch-Site signal.
#[tokio::test]
async fn origin_gate_allows_same_origin_signal() {
    let mut h = TestHarness::new().await;
    // same-origin Sec-Fetch-Site must pass the gate; with no token it then hits
    // the token check. Use an authenticated session + a valid token would be a
    // fuller test, but here we only assert the gate itself does not 403 on a
    // same-origin signal by confirming the failure mode is the token layer, not
    // an early gate block. A same-origin GET (safe method) is the cleanest probe.
    let resp = h
        .client
        .request_with_headers(
            "GET",
            "/forgot-password",
            None,
            &[("Sec-Fetch-Site", "same-origin")],
        )
        .await;
    assert!(
        resp.status.is_success(),
        "origin gate or routing blocked a same-origin safe request (got {})",
        resp.status
    );
}