// file: crates/ksp-onchain-transport-lib/unit_tests/pool.rs
// version: 4

fn role(name: &str, priority: u32, request_kinds: std::vec::Vec<crate::HttpRequestKind>) -> crate::HttpEndpointRoleSettings {
    return crate::HttpEndpointRoleSettings::new(
        crate::HttpRoleName::new(name),
        true,
        request_kinds,
        priority,
        crate::HttpRoleLimits::new(std::option::Option::None, std::option::Option::None, std::option::Option::None, std::option::Option::None),
    );
}

fn endpoint(name: &str, enabled: bool, priority: u32, request_kinds: std::vec::Vec<crate::HttpRequestKind>) -> crate::HttpEndpointSettings {
    return crate::HttpEndpointSettings::new(
        name,
        enabled,
        crate::HttpProviderName::new("provider"),
        crate::HttpClusterName::new("devnet"),
        crate::HttpEndpointUrl::parse(format!("https://{name}.invalid/rpc?token=SECRET-CANARY")).expect("test URL must parse"),
        std::time::Duration::from_secs(1),
        std::time::Duration::from_secs(2),
        std::option::Option::Some(4),
        std::vec![role("default", priority, request_kinds)],
    );
}

fn non_zero(value: u32) -> std::num::NonZeroU32 {
    return std::num::NonZeroU32::new(value).expect("test limit must be non-zero");
}

fn limited_endpoint(
    name: &str,
    priority: u32,
    requests_per_second: std::option::Option<u32>,
    burst_capacity: std::option::Option<u32>,
    max_concurrent_requests: std::option::Option<u32>,
    cooldown: std::option::Option<std::time::Duration>,
) -> crate::HttpEndpointSettings {
    let limits = crate::HttpRoleLimits::new(
        requests_per_second.map(|value| return non_zero(value)),
        burst_capacity.map(|value| return non_zero(value)),
        max_concurrent_requests.map(|value| return non_zero(value)),
        cooldown,
    );
    let role = crate::HttpEndpointRoleSettings::new(crate::HttpRoleName::new("default"), true, std::vec![crate::HttpRequestKind::wildcard()], priority, limits);
    return crate::HttpEndpointSettings::new(
        name,
        true,
        crate::HttpProviderName::new("provider"),
        crate::HttpClusterName::new("devnet"),
        crate::HttpEndpointUrl::parse(format!("https://{name}.invalid/rpc?token=SECRET-CANARY")).expect("test URL must parse"),
        std::time::Duration::from_secs(1),
        std::time::Duration::from_secs(2),
        std::option::Option::Some(4),
        std::vec![role],
    );
}

fn settings(endpoints: std::vec::Vec<crate::HttpEndpointSettings>) -> crate::HttpTransportSettings {
    return crate::HttpTransportSettings::new(
        endpoints,
        crate::HttpRetrySettings::new(2, std::time::Duration::from_millis(10), std::time::Duration::from_millis(50)),
    );
}

#[test]
fn pool_prefers_lowest_priority_tier() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![
        endpoint("secondary", true, 20, std::vec![crate::HttpRequestKind::wildcard()]),
        endpoint("primary", true, 10, std::vec![crate::HttpRequestKind::wildcard()]),
    ]))
    .expect("pool must build");
    let selection = pool
        .select_for_request_kind(&crate::HttpRoleName::new("default"), &crate::HttpRequestKind::new("get_balance"))
        .expect("selection must succeed");
    assert_eq!(selection.endpoint_name(), "primary");
    assert_eq!(selection.priority(), 10);
}

#[test]
fn pool_round_robins_fairly_inside_best_priority_tier() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![
        endpoint("one", true, 10, std::vec![crate::HttpRequestKind::wildcard()]),
        endpoint("two", true, 10, std::vec![crate::HttpRequestKind::wildcard()]),
        endpoint("fallback", true, 20, std::vec![crate::HttpRequestKind::wildcard()]),
    ]))
    .expect("pool must build");
    let role = crate::HttpRoleName::new("default");
    let kind = crate::HttpRequestKind::new("get_balance");
    let first = pool.select_for_request_kind(&role, &kind).expect("first selection must succeed");
    let second = pool.select_for_request_kind(&role, &kind).expect("second selection must succeed");
    let third = pool.select_for_request_kind(&role, &kind).expect("third selection must succeed");
    assert_eq!(first.endpoint_name(), "one");
    assert_eq!(second.endpoint_name(), "two");
    assert_eq!(third.endpoint_name(), "one");
}

#[test]
fn disabled_best_priority_endpoint_falls_back_to_next_tier() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![
        endpoint("disabled-primary", false, 1, std::vec![crate::HttpRequestKind::wildcard()]),
        endpoint("fallback", true, 20, std::vec![crate::HttpRequestKind::wildcard()]),
    ]))
    .expect("pool must build");
    let selection = pool
        .select_for_request_kind(&crate::HttpRoleName::new("default"), &crate::HttpRequestKind::new("get_balance"))
        .expect("fallback must be selected");
    assert_eq!(selection.endpoint_name(), "fallback");
}

#[test]
fn pool_filters_role_and_capability_before_priority() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![
        endpoint("wrong-capability", true, 1, std::vec![crate::HttpRequestKind::new("send_transaction")]),
        endpoint("matching", true, 50, std::vec![crate::HttpRequestKind::new("get_balance")]),
    ]))
    .expect("pool must build");
    let selection = pool
        .select_for_request_kind(&crate::HttpRoleName::new("default"), &crate::HttpRequestKind::new("get_balance"))
        .expect("matching capability must be selected");
    assert_eq!(selection.endpoint_name(), "matching");
}

#[test]
fn pool_returns_structured_error_when_no_endpoint_matches() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![endpoint("read-only", true, 10, std::vec![crate::HttpRequestKind::new("get_balance")],)]))
        .expect("pool must build");
    let error = pool
        .select_for_request_kind(&crate::HttpRoleName::new("default"), &crate::HttpRequestKind::new("send_transaction"))
        .expect_err("unsupported request kind must fail selection");
    assert_eq!(error.code(), crate::ERROR_CODE_ENDPOINT_SELECTION_FAILED);
    assert!(!format!("{error:?}").contains("SECRET-CANARY"));
}

#[test]
fn standard_method_selection_uses_registry_request_kind() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![endpoint("balance", true, 10, std::vec![crate::HttpRequestKind::new("get_balance")],)]))
        .expect("pool must build");
    let method = crate::find_http_rpc_method("getBalance").expect("audited method must exist");
    let selection = pool.select_for_method(&crate::HttpRoleName::new("default"), method).expect("standard method must route");
    assert_eq!(selection.request_kind().as_str(), "get_balance");
}

#[test]
fn pool_snapshot_is_safe_and_preserves_disabled_endpoints() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![
        endpoint("enabled", true, 10, std::vec![crate::HttpRequestKind::wildcard()]),
        endpoint("disabled", false, 10, std::vec![crate::HttpRequestKind::wildcard()]),
    ]))
    .expect("pool must build");
    let snapshot = pool.snapshot();
    let rendered = format!("{snapshot:?} {pool:?}");
    assert_eq!(snapshot.endpoint_count(), 2);
    assert_eq!(snapshot.available_endpoint_count(), 1);
    assert!(!rendered.contains("SECRET-CANARY"));
    assert!(!rendered.contains(".invalid/rpc"));
}

#[test]
fn disabled_role_is_excluded_before_priority_selection() {
    let base = endpoint("disabled-role", true, 1, std::vec![crate::HttpRequestKind::wildcard()]);
    let disabled_role = crate::HttpEndpointRoleSettings::new(
        crate::HttpRoleName::new("default"),
        false,
        std::vec![crate::HttpRequestKind::wildcard()],
        1,
        crate::HttpRoleLimits::new(std::option::Option::None, std::option::Option::None, std::option::Option::None, std::option::Option::None),
    );
    let enabled_non_matching_role = crate::HttpEndpointRoleSettings::new(
        crate::HttpRoleName::new("maintenance"),
        true,
        std::vec![crate::HttpRequestKind::wildcard()],
        1,
        crate::HttpRoleLimits::new(std::option::Option::None, std::option::Option::None, std::option::Option::None, std::option::Option::None),
    );
    let disabled_role_endpoint = crate::HttpEndpointSettings::new(
        base.name(),
        true,
        base.provider().clone(),
        base.cluster().clone(),
        base.url().clone(),
        base.connect_timeout(),
        base.request_timeout(),
        base.max_idle_connections_per_host(),
        std::vec![disabled_role, enabled_non_matching_role],
    );
    let pool = crate::HttpTransportPool::new(settings(std::vec![
        disabled_role_endpoint,
        endpoint("fallback", true, 20, std::vec![crate::HttpRequestKind::wildcard()]),
    ]))
    .expect("pool must build");
    let selection = pool
        .select_for_request_kind(&crate::HttpRoleName::new("default"), &crate::HttpRequestKind::new("get_balance"))
        .expect("enabled fallback role must be selected");
    assert_eq!(selection.endpoint_name(), "fallback");
}

#[test]
fn removed_standard_method_is_rejected_before_endpoint_routing() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![endpoint("wildcard", true, 10, std::vec![crate::HttpRequestKind::wildcard()],)]))
        .expect("pool must build");
    let method = crate::find_http_rpc_method("confirmTransaction").expect("historical method must exist");
    let error = pool.select_for_method(&crate::HttpRoleName::new("default"), method).expect_err("removed standard method must be rejected before routing");
    assert_eq!(error.code(), crate::ERROR_CODE_METHOD_REMOVED);
}

#[tokio::test]
async fn runtime_concurrency_saturation_falls_back_to_lower_priority_tier() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![
        limited_endpoint("primary", 1, std::option::Option::None, std::option::Option::None, std::option::Option::Some(1), std::option::Option::None),
        limited_endpoint("fallback", 20, std::option::Option::None, std::option::Option::None, std::option::Option::Some(1), std::option::Option::None),
    ]))
    .expect("pool must build");
    let role = crate::HttpRoleName::new("default");
    let kind = crate::HttpRequestKind::new("get_balance");
    let first = pool.acquire_for_request_kind(&role, &kind).await.expect("first request must acquire primary");
    assert_eq!(first.selection().endpoint_name(), "primary");
    let second = pool.acquire_for_request_kind(&role, &kind).await.expect("second request must fall back while primary is saturated");
    assert_eq!(second.selection().endpoint_name(), "fallback");
}

#[tokio::test]
async fn runtime_token_bucket_exhaustion_falls_back_without_busy_waiting() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![
        limited_endpoint("primary", 1, std::option::Option::Some(1), std::option::Option::Some(1), std::option::Option::None, std::option::Option::None),
        limited_endpoint("fallback", 20, std::option::Option::None, std::option::Option::None, std::option::Option::None, std::option::Option::None),
    ]))
    .expect("pool must build");
    let role = crate::HttpRoleName::new("default");
    let kind = crate::HttpRequestKind::new("get_balance");
    let first = pool.acquire_for_request_kind(&role, &kind).await.expect("first request must consume primary token");
    assert_eq!(first.selection().endpoint_name(), "primary");
    drop(first);
    let second = pool.acquire_for_request_kind(&role, &kind).await.expect("fallback must be used while primary token bucket refills");
    assert_eq!(second.selection().endpoint_name(), "fallback");
}

#[tokio::test]
async fn provider_cooldown_excludes_rate_limited_role_and_uses_fallback() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![
        limited_endpoint(
            "primary",
            1,
            std::option::Option::None,
            std::option::Option::None,
            std::option::Option::None,
            std::option::Option::Some(std::time::Duration::from_millis(50)),
        ),
        limited_endpoint("fallback", 20, std::option::Option::None, std::option::Option::None, std::option::Option::None, std::option::Option::None),
    ]))
    .expect("pool must build");
    let role = crate::HttpRoleName::new("default");
    let kind = crate::HttpRequestKind::new("get_balance");
    let primary = pool.acquire_for_request_kind(&role, &kind).await.expect("primary must be acquired");
    assert_eq!(primary.selection().endpoint_name(), "primary");
    let pause = primary.record_rate_limited(std::option::Option::None);
    assert_eq!(pause, std::time::Duration::from_millis(50));
    drop(primary);
    let fallback = pool.acquire_for_request_kind(&role, &kind).await.expect("fallback must be selected during primary cooldown");
    assert_eq!(fallback.selection().endpoint_name(), "fallback");
}

#[tokio::test]
async fn admission_waits_for_released_concurrency_without_holding_a_sync_mutex_across_await() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![limited_endpoint(
        "primary",
        1,
        std::option::Option::None,
        std::option::Option::None,
        std::option::Option::Some(1),
        std::option::Option::None,
    )]))
    .expect("pool must build");
    let role = crate::HttpRoleName::new("default");
    let kind = crate::HttpRequestKind::new("get_balance");
    let first = pool.acquire_for_request_kind(&role, &kind).await.expect("first permit must be acquired");
    let release_task = tokio::spawn(async move {
        tokio::time::sleep(std::time::Duration::from_millis(10)).await;
        drop(first);
    });
    let second = pool
        .acquire_for_request_kind_with_timeout(&role, &kind, std::time::Duration::from_millis(100))
        .await
        .expect("second permit must wake after concurrency release");
    assert_eq!(second.selection().endpoint_name(), "primary");
    release_task.await.expect("release task must complete");
}

#[tokio::test]
async fn admission_timeout_is_bounded_when_concurrency_never_becomes_available() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![limited_endpoint(
        "primary",
        1,
        std::option::Option::None,
        std::option::Option::None,
        std::option::Option::Some(1),
        std::option::Option::None,
    )]))
    .expect("pool must build");
    let role = crate::HttpRoleName::new("default");
    let kind = crate::HttpRequestKind::new("get_balance");
    let _held = pool.acquire_for_request_kind(&role, &kind).await.expect("first permit must be acquired");
    let error = pool
        .acquire_for_request_kind_with_timeout(&role, &kind, std::time::Duration::from_millis(20))
        .await
        .expect_err("second permit must time out while concurrency remains saturated");
    assert_eq!(error.code(), crate::ERROR_CODE_TIMEOUT);
}

#[tokio::test]
async fn passive_health_snapshot_moves_from_degraded_back_to_available_after_success() {
    let pool = crate::HttpTransportPool::new(settings(std::vec![limited_endpoint(
        "primary",
        1,
        std::option::Option::None,
        std::option::Option::None,
        std::option::Option::None,
        std::option::Option::None,
    )]))
    .expect("pool must build");
    let role = crate::HttpRoleName::new("default");
    let kind = crate::HttpRequestKind::new("get_balance");
    let first = pool.acquire_for_request_kind(&role, &kind).await.expect("request permit must be acquired");
    first.record_failure();
    drop(first);
    let degraded = pool.snapshot();
    assert_eq!(degraded.endpoints()[0].availability(), crate::HttpEndpointAvailability::Degraded);
    assert_eq!(degraded.endpoints()[0].roles()[0].failure_count(), 1);
    let second = pool.acquire_for_request_kind(&role, &kind).await.expect("degraded endpoint remains eligible for passive recovery");
    second.record_success();
    drop(second);
    let recovered = pool.snapshot();
    assert_eq!(recovered.endpoints()[0].availability(), crate::HttpEndpointAvailability::Available);
    assert_eq!(recovered.endpoints()[0].roles()[0].success_count(), 1);
}