//! End-to-end: a Codex transcript through the real ledger and footer.
//!
//! The unit tests prove the adapter builds the right observations. These prove
//! the observations still obey every decision 0012 rule once they reach
//! `lumbridge-core`, which is the property that actually matters to a user
//! reading the footer.
//!
//! Every transcript below is hand-written from the documented wire shape in
//! openai/codex (Apache-2.0), commit
//! `17e8101699c5062117d0d37f504313e8af53b043`, `codex-rs/app-server/README.md`
//! section "7) Rate limits (`ChatGPT`)". No real account, transcript, or
//! credential is used, and all timestamps are small synthetic integers.

use lumbridge_core::{
    AccountProfileId, FooterUsage, UsageConfidence, UsageLedger, UsageProvenance,
};
use lumbridge_harness::codex::replay_transcript;

const HOUR_MS: u64 = 3_600_000;
/// A synthetic reset five hours after the epoch, in seconds.
const RESETS_AT_SECONDS: u64 = 5 * 3_600;
const RESETS_AT_MS: u64 = 5 * HOUR_MS;

fn initialize_response() -> &'static str {
    r#"{"jsonrpc":"2.0","id":1,"result":{"userAgent":"codex"}}"#
}

fn read_response(id: u64, percent: u64) -> String {
    format!(
        r#"{{"jsonrpc":"2.0","id":{id},"result":{{"rateLimits":{{"primary":{{"usedPercent":{percent},"windowDurationMins":300,"resetsAt":{RESETS_AT_SECONDS}}},"secondary":null,"rateLimitReachedType":null}}}}}}"#
    )
}

fn primary() -> AccountProfileId {
    AccountProfileId::new("codex-app-server-primary").expect("the probe's static ID is valid")
}

fn ledger_from(frames: &[(&str, u64)]) -> UsageLedger {
    let mut ledger = UsageLedger::new();
    for observation in replay_transcript(frames) {
        ledger
            .record(observation)
            .expect("the adapter emits observations in time order");
    }
    ledger
}

#[test]
fn a_two_reading_transcript_produces_a_provider_reported_footer() {
    let first = read_response(2, 20);
    let second = read_response(3, 35);
    let ledger = ledger_from(&[
        (initialize_response(), 0),
        (first.as_str(), HOUR_MS),
        (second.as_str(), 2 * HOUR_MS),
    ]);

    let projection = ledger.project(&primary(), 2 * HOUR_MS);
    assert_eq!(projection.provenance(), UsageProvenance::ProviderReported);
    assert_eq!(projection.confidence(), UsageConfidence::Exact);
    assert_eq!(projection.consumed_permille(), Some(350));
    assert_eq!(projection.resets_in_ms(), Some(3 * HOUR_MS));
    // 200 permille burned over one hour, derived rather than reported.
    assert_eq!(projection.burn_per_hour(), Some(150));
    assert_eq!(projection.burn_provenance(), UsageProvenance::Estimated);
}

#[test]
fn a_single_reading_yields_a_percentage_but_no_rate() {
    let only = read_response(2, 20);
    let ledger = ledger_from(&[(initialize_response(), 0), (only.as_str(), HOUR_MS)]);

    let projection = ledger.project(&primary(), HOUR_MS);
    assert_eq!(projection.consumed_permille(), Some(200));
    assert_eq!(
        projection.burn_per_hour(),
        None,
        "one provider reading is not a rate"
    );
    assert_eq!(projection.exhaustion_in_ms(), None);
}

#[test]
fn an_api_key_account_renders_the_unavailable_path_rather_than_a_zero() {
    // Codex answers -32600 with "chatgpt authentication required to read rate
    // limits" for an account that has no subscription quota.
    let denied = r#"{"jsonrpc":"2.0","id":2,"error":{"code":-32600,"message":"chatgpt authentication required to read rate limits"}}"#;
    let ledger = ledger_from(&[(initialize_response(), 0), (denied, HOUR_MS)]);

    let projection = ledger.project(&primary(), HOUR_MS);
    assert!(!projection.is_available());
    assert_eq!(projection.consumed_permille(), None);

    let profile = lumbridge_core::AccountProfile::new(
        "codex-app-server-primary",
        "Codex",
        "ChatGPT",
        "primary window",
        "subscription",
    )
    .expect("a valid profile");
    let footer = FooterUsage::new(&profile, &projection);
    assert_eq!(footer.window(), "usage unavailable");
    assert_eq!(footer.burn(), "burn rate unavailable");
    assert_eq!(footer.trust(), "no usage source");
    assert!(
        !footer.to_string().contains('%'),
        "an account with no quota must not render a percentage"
    );
}

#[test]
fn a_reading_taken_after_the_reset_never_renders_a_frozen_percentage() {
    let stale = read_response(2, 90);
    let ledger = ledger_from(&[
        (initialize_response(), 0),
        // Observed one millisecond after the window it describes ended.
        (stale.as_str(), RESETS_AT_MS + 1),
    ]);

    let projection = ledger.project(&primary(), RESETS_AT_MS + 1);
    assert!(!projection.is_available());
    assert_eq!(
        projection.consumed_permille(),
        None,
        "an ended window must not keep rendering its last percentage"
    );
}

#[test]
fn a_credential_refresh_request_produces_no_observation_at_all() {
    let refresh = r#"{"jsonrpc":"2.0","id":77,"method":"account/chatgptAuthTokens/refresh"}"#;
    let reading = read_response(2, 20);
    let observations = replay_transcript(&[
        (initialize_response(), 0),
        (refresh, 1_000),
        (reading.as_str(), HOUR_MS),
    ]);
    assert_eq!(
        observations.len(),
        1,
        "the refused credential request must not enter the usage stream"
    );
}

#[test]
fn a_repeated_identical_reading_does_not_flood_the_ledger() {
    let a = read_response(2, 20);
    let b = read_response(3, 20);
    let c = read_response(4, 20);
    let ledger = ledger_from(&[
        (initialize_response(), 0),
        (a.as_str(), HOUR_MS),
        (b.as_str(), HOUR_MS + 60_000),
        (c.as_str(), HOUR_MS + 120_000),
    ]);
    assert_eq!(
        ledger.observation_count(&primary()),
        1,
        "identical readings inside the re-emit floor must not evict history"
    );
}

#[test]
fn a_malformed_transcript_records_nothing_rather_than_guessing() {
    let observations = replay_transcript(&[
        (initialize_response(), 0),
        ("}{ not json", 1_000),
        (
            r#"{"jsonrpc":"2.0","id":2,"result":{"rateLimits":"a string"}}"#,
            2_000,
        ),
    ]);
    assert!(observations.is_empty());
}