//! Ready-made [`Payload`](ktstr::Payload) fixtures for the
//! benchmark binaries that dominate scheduler-regression testing:
//! `fio` (disk IO throughput, emits JSON), `stress-ng`
//! (synthetic CPU/memory stressors, exit-code only), and
//! `schbench` (latency percentiles, routed through LlmExtract).
//!
//! Each fixture is declared via
//! [`#[derive(Payload)]`](ktstr::Payload), the same path downstream
//! test authors use — so this module doubles as an end-to-end
//! exercise of the derive macro. The emitted `const` follows the
//! derive's naming convention: `struct FooPayload` produces
//! `const FOO: Payload`.
//!
//! These fixtures live under `tests/common/` rather than inside the
//! library's `src/` tree because they are TEST SCAFFOLDING, not
//! shipped API. A downstream scheduler author who wants the same
//! `fio` / `stress-ng` / `schbench` shapes should either copy the
//! declarations below into their own crate or write their own via
//! `#[derive(Payload)]`. The library does not ship fio, stress-ng,
//! or schbench binaries — the `kind = PayloadKind::Binary(name)`
//! just declares the name; host-side include-files resolution picks
//! the path up at test time.
//!
//! The fixtures cover all three
//! [`OutputFormat`](ktstr::test_support::OutputFormat) variants
//! — plus the hinted subvariant of `LlmExtract`:
//!
//! - [`FIO`] and [`FIO_JSON`] declare `OutputFormat::Json` with a
//!   set of [`MetricHint`](ktstr::test_support::MetricHint)s
//!   describing the canonical read/write throughput + latency paths.
//!   Extracted metrics land with correct polarity/unit automatically.
//! - [`STRESS_NG`] uses `OutputFormat::ExitCode` with a single
//!   `exit_code_eq(0)` default — stress-ng reports via exit code
//!   (bogo_ops land in stderr and are not machine-extractable
//!   without `--metrics-brief --yaml`).
//! - [`SCHBENCH`] uses `OutputFormat::LlmExtract(None)` — schbench
//!   emits human-readable percentile tables, so extraction is
//!   routed through the local LLM pipeline rather than the JSON
//!   walker.
//! - [`SCHBENCH_HINTED`] declares
//!   `OutputFormat::LlmExtract(Some("wakeup latency percentiles"))`
//!   — identical to [`SCHBENCH`] in every other field, exercising
//!   the derive's `LlmExtract("hint")` call form and the
//!   hint-threading path through
//!   [`extract_via_llm`](ktstr::test_support::model::extract_via_llm).
//!
//! All fixtures use short, stable `name` fields matching their
//! binary names — except FIO_JSON (`"fio_json"`) and
//! SCHBENCH_HINTED (`"schbench_hinted"`), which use distinct
//! names so they can coexist with FIO and SCHBENCH respectively
//! under the pairwise-dedup rule on `#[ktstr_test(workloads =
//! [...])]`. The binary names themselves (`"fio"`, `"stress-ng"`,
//! `"schbench"`) are what ktstr's include-files infrastructure
//! resolves inside the guest.
//!
//! # Polarity::Unknown downstream
//!
//! Metrics extracted from a hinted payload are matched against the
//! payload's `metrics` table by name in
//! [`PayloadRun`](ktstr::scenario::payload_run::PayloadRun)'s post-exit pipeline;
//! names with no matching hint land with
//! [`Polarity::Unknown`](ktstr::test_support::Polarity::Unknown) and
//! an empty unit. Unknown propagates as follows:
//!
//! - **`MetricCheck` assertion pass** — [`MetricCheck`](ktstr::test_support::MetricCheck)
//!   variants (`Min`, `Max`, `Range`, `Exists`, `ExitCodeEq`) compare
//!   values to thresholds without consulting polarity. An Unknown
//!   metric fails checks the same way a hinted metric does; polarity
//!   plays no role at assert time.
//! - **`AssertResult::merge` per-key worst-case** — when multiple
//!   cgroups contribute the same ext_metric, the merge consults the
//!   crate-internal `MetricDef` from the `METRICS` registry. Names
//!   absent from the registry (the case for any Unknown metric not
//!   also registered at crate scope) default to `higher_is_worse=true`
//!   and merge by taking the max — conservative for regressions, but
//!   NOT a declared polarity for the metric.
//! - **`cargo ktstr test-stats` cross-run comparison** — the
//!   crate-internal `compare_runs` iterates the `METRICS` registry
//!   only, so Unknown metrics extracted purely via `MetricHint`
//!   absence are NOT classified as regression or improvement. They
//!   are recorded to the sidecar for later manual inspection; to
//!   surface them in a comparison verdict, register a `MetricDef` in
//!   `src/stats.rs` or add a `MetricHint` on the payload with an
//!   explicit polarity.

use ktstr::Payload;

/// `fio` — flexible IO tester. Canonical workload for disk/IO
/// scheduler regressions.
///
/// Output format: JSON. Supply `--output-format=json` at the call
/// site (via `.arg(...)` on the
/// [`PayloadRun`](ktstr::scenario::payload_run::PayloadRun) builder returned by
/// `ctx.payload(&FIO)`, or via a scheduler default_args entry) or
/// use [`FIO_JSON`] which bakes it into `default_args` for the
/// common "just give me metrics" path.
///
/// **Caveat:** `FIO` leaves `default_args` empty, so invoking it
/// without `--output-format=json` causes `fio` to emit its
/// human-readable output, `extract_metrics` finds no JSON region,
/// and the check pass records every referenced metric as missing
/// without otherwise failing. Prefer [`FIO_JSON`] unless the test
/// author intentionally overrides the output mode.
///
/// Metric hints cover the first-job read/write leaf names. Fio's
/// JSON output is deeply nested (`jobs[N].read.iops`,
/// `.write.iops`, `.read.lat_ns.mean`, etc.); the hints pin the
/// four most-commonly-asserted paths. Unhinted paths land as
/// [`Polarity::Unknown`](ktstr::test_support::Polarity::Unknown)
/// and are still extracted for sidecar regression tracking.
#[derive(Payload)]
#[payload(binary = "fio", output = Json)]
#[default_check(exit_code_eq(0))]
#[metric(name = "jobs.0.read.iops", polarity = HigherBetter, unit = "iops")]
#[metric(name = "jobs.0.write.iops", polarity = HigherBetter, unit = "iops")]
#[metric(name = "jobs.0.read.lat_ns.mean", polarity = LowerBetter, unit = "ns")]
#[metric(name = "jobs.0.write.lat_ns.mean", polarity = LowerBetter, unit = "ns")]
#[allow(dead_code)]
pub struct FioPayload;

/// `fio` with `--output-format=json` pre-baked into `default_args`.
///
/// Compared to [`FIO`], this fixture differs in exactly two
/// fields:
///
/// 1. **`name`** — `"fio_json"` instead of `"fio"`. Uses a
///    distinct name so sidecar files and log output can
///    disambiguate the two fixtures. The `binary` field (the name
///    resolved by the include-files infrastructure) is still
///    `"fio"` in both.
/// 2. **`default_args`** — `&["--output-format=json"]` instead of
///    `&[]`. Everything else — `kind`, `output`, `default_checks`,
///    `metrics` — is character-for-character identical to [`FIO`].
///
/// **Caveat: simultaneous FIO + FIO_JSON.** Both fixtures have
/// `kind = PayloadKind::Binary("fio")`, so a scenario that lists
/// `#[ktstr_test(workloads = [FIO, FIO_JSON])]` spawns the `fio`
/// binary TWICE — each with its own argv set, inside whatever
/// cgroup the framework places each fixture in. The pairwise-dedup
/// on the `workloads` attribute only rejects identical Payload
/// paths; two distinct Payload constants that happen to share a
/// binary are NOT deduped. Test authors who want the same fio
/// binary once should pick ONE of the two fixtures, and extend it
/// via `ctx.payload(&FIO).arg("--output-format=json")` if the
/// `FIO_JSON` preset's args don't match their scenario.
#[derive(Payload)]
#[payload(binary = "fio", name = "fio_json", output = Json)]
#[default_args("--output-format=json")]
#[default_check(exit_code_eq(0))]
#[metric(name = "jobs.0.read.iops", polarity = HigherBetter, unit = "iops")]
#[metric(name = "jobs.0.write.iops", polarity = HigherBetter, unit = "iops")]
#[metric(name = "jobs.0.read.lat_ns.mean", polarity = LowerBetter, unit = "ns")]
#[metric(name = "jobs.0.write.lat_ns.mean", polarity = LowerBetter, unit = "ns")]
#[allow(dead_code)]
pub struct FioJsonPayload;

/// `stress-ng` — synthetic load generator (CPU, memory, IO, VM,
/// etc.). Canonical workload for exercising scheduler decisions
/// under configurable contention.
///
/// Output format: `ExitCode`. stress-ng emits human-readable
/// progress lines to stderr; its machine-readable-metrics flags
/// write structured output to a caller-named file, not to stdout
/// or stderr. Since the extraction pipeline only consumes stdout,
/// no default stress-ng invocation feeds `extract_metrics`; the
/// fixture stays in exit-code mode and the happy path is a zero
/// exit.
///
/// **Caveat:** `default_args` is empty, so invoking `STRESS_NG`
/// without at least one stressor flag (e.g. `--cpu 1`, `--vm 1`)
/// causes stress-ng to print usage and exit nonzero on some
/// versions. Always append a stressor via `.arg(...)` on the
/// [`PayloadRun`](ktstr::scenario::payload_run::PayloadRun) builder returned
/// by `ctx.payload(&STRESS_NG)`.
///
/// Tests that want bogo_ops/sec metrics should declare their own
/// custom `Payload` via [`#[derive(Payload)]`](ktstr::Payload) and
/// pair it with a post-hoc stderr-to-stdout bridge, or declare
/// `output = LlmExtract("bogo ops")`. stress-ng emits bogo_ops on
/// stderr by default and its machine-readable-metrics flags write
/// to a caller-named file, not stdout, so a wrapper that captures
/// or redirects structured output onto stdout is still required
/// to give the LLM a non-empty body.
#[derive(Payload)]
#[payload(binary = "stress-ng")]
#[default_check(exit_code_eq(0))]
#[allow(dead_code)]
pub struct StressNgPayload;

/// Latency-focused scheduler benchmark. Uses `LlmExtract` to
/// exercise the LLM extraction pipeline (schbench supports `--json`
/// but this fixture intentionally uses the third acquisition path).
///
/// **Contract — no polarity-classified metrics by design.** A bare
/// `ctx.payload(&SCHBENCH)` run is expected to reach the
/// `default_check(exit_code_eq(0))` gate cleanly and produce **no
/// polarity-tagged metrics**. Not a bug, not a pipeline failure:
/// the fixture declares `metrics = []`, so no hint ever binds an
/// extracted metric name to a polarity / unit pair, and whatever
/// the LLM pulls out of schbench's output stays at
/// [`Polarity::Unknown`](ktstr::test_support::Polarity::Unknown).
/// The happy-path assertion is the exit-code gate; anything else
/// is the caller's responsibility. Two orthogonal reasons drive
/// this, each expanded below:
///
/// 1. schbench writes latency tables and summary lines to **stderr**
///    by default — stdout is empty unless `--json -` is passed.
///    [`OutputFormat::LlmExtract`](ktstr::test_support::OutputFormat::LlmExtract)
///    runs stdout-primary with a stderr fallback: the LLM extracts
///    first against (empty) stdout, observes zero metrics, then
///    retries against stderr's latency text. See the stderr-fallback
///    section below for the details.
/// 2. LLM-extracted metric names are non-deterministic, so any hint
///    declared on this fixture would silently fail to match. The
///    fixture ships with `metrics = []` so the absence of polarity
///    classification is visible by construction rather than implied.
///
/// Tests that want actual schbench metrics should use
/// [`SCHBENCH_JSON`] (pre-baked `--json -`, stable dotted-path
/// schema, no LLM in the loop) or append `--json -` to this
/// fixture's builder.
///
/// **No metric hints.** schbench emits canonical latency stats
/// (`Wakeup Latencies`, `Request Latencies`, `RPS`) with standard
/// percentiles that would otherwise be obvious
/// [`Polarity::LowerBetter`](ktstr::test_support::Polarity::LowerBetter)
/// candidates — yet `metrics` is deliberately empty. The reason is
/// upstream: hints in [`Payload`](ktstr::Payload)'s `metrics`
/// field bind a fixed dotted-path name to a polarity/unit pair,
/// and the post-extraction resolver inside
/// [`PayloadRun`](ktstr::scenario::payload_run::PayloadRun) looks
/// each extracted metric up by exact name. The
/// [`OutputFormat::LlmExtract`](ktstr::test_support::OutputFormat::LlmExtract)
/// path produces metric names from whatever JSON the local model
/// emits — not from a stable schema. The model's dotted paths vary
/// with weights, prompt, and the hinted-focus string (even under
/// ArgMax, a different base model produces different keys). A hint
/// declared against e.g. `"wakeup_latency_pct99"` would miss when
/// the model emits `"wakeup.latency.p99"` or
/// `"wakeup_latency.99th_percentile"`. Rather than ship hints that
/// silently fail to apply and leave every metric at
/// [`Polarity::Unknown`](ktstr::test_support::Polarity::Unknown)
/// anyway, the fixture leaves `metrics` empty so the absence of
/// polarity classification is visible by construction. Tests that
/// need strict regression direction for schbench should pipe
/// `--json -` instead and declare an `OutputFormat::Json` fixture
/// with concrete hint paths that match the fixed schbench schema
/// (e.g. `"int.wakeup_latency_pct99.0"` from `write_json_stats`
/// in schbench.c).
///
/// **Stderr-fallback extraction.** schbench writes its percentile
/// tables (`show_latencies` → `fprintf(stderr, ...)`) and summary
/// lines (`avg worker transfer`, `average rps`, `sched delay`) to
/// **stderr** by default; stdout only carries output when
/// `--json -` is passed. Under the stdout-primary / stderr-fallback
/// contract on
/// [`OutputFormat`](ktstr::test_support::OutputFormat) (documented
/// on [`PayloadRun::run`](ktstr::scenario::payload_run::PayloadRun::run)),
/// [`extract_via_llm`](ktstr::test_support::model::extract_via_llm)
/// is invoked against stdout first — for this fixture that yields
/// zero metrics because stdout is empty — and then re-invoked
/// against stderr since the stdout pass produced nothing and
/// stderr is non-empty. The LLM therefore receives schbench's
/// latency text on the fallback leg. The extracted metric names
/// are model-dependent (see "No metric hints." above), so with
/// `metrics = []` none of them pick up a polarity / unit, and the
/// happy-path assertion remains the exit-code gate in
/// `default_checks`. For a stable regression-direction schema,
/// append `--json -` via `.arg("--json").arg("-")` on the runtime
/// builder — the JSON block lands on stdout, the stdout-primary
/// pass consumes it, and the stderr fallback never fires.
///
/// **`--runtime 5` tradeoff.** The 5-second `default_args` runtime
/// is sized for fast CI smoke signal, NOT for tail-latency
/// regression hunting — schbench's sample count scales with
/// runtime (`nr_samples` in `show_latencies`), so 5 s collects
/// roughly a sixth of what `--runtime 30` does and leaves p99.9+
/// estimates dominated by variance. Scheduler authors
/// investigating tail regressions should override via
/// `.arg("--runtime").arg("30")` on the
/// [`PayloadRun`](ktstr::scenario::payload_run::PayloadRun)
/// builder returned by `ctx.payload(&SCHBENCH)`. schbench parses
/// argv with `getopt_long` and each `case 'r'` overwrites
/// `runtime = atoi(optarg)`, so the trailing setting wins on
/// duplicates and the appended override takes effect.
#[derive(Payload)]
#[payload(binary = "schbench", output = LlmExtract)]
#[default_args("--runtime", "5", "--message-threads", "2")]
#[default_check(exit_code_eq(0))]
#[allow(dead_code)]
pub struct SchbenchPayload;

/// Hint-carrying sibling of [`SCHBENCH`] — identical in every
/// field except `name` (uses a distinct name so sidecar files and
/// log output can disambiguate the two fixtures) and `output`.
///
/// Declares `output = LlmExtract("wakeup latency percentiles")`.
/// The derive macro translates the call form into
/// [`OutputFormat::LlmExtract(Some(...))`](ktstr::test_support::OutputFormat::LlmExtract),
/// and the stored `&'static str` is inserted between the template
/// and the stdout block as a `Focus:` directive by
/// [`extract_via_llm`](ktstr::test_support::model::extract_via_llm)
/// when the fixture runs — steering the model toward the stat the
/// scheduler regression cares about instead of whatever numeric
/// leaf the model picks first.
///
/// Exists as a fixture (rather than only as an ad-hoc
/// `#[derive(Payload)]` inside the test file) so downstream
/// scheduler-author crates have a copy-ready template for the
/// hint-carrying shape — the bare [`SCHBENCH`] covers the
/// no-hint form, this fixture covers the with-hint form.
///
/// **Empty-metrics contract inherited from [`SCHBENCH`].** This
/// fixture declares `metrics = []` just like its sibling, so the
/// "no polarity-classified metrics by design" contract described
/// on [`SCHBENCH`] applies here verbatim — the hint steers which
/// numeric leaf the LLM surfaces, but every extracted metric
/// still lands at [`Polarity::Unknown`](ktstr::test_support::Polarity::Unknown).
/// See the SCHBENCH doc's "Contract — no polarity-classified
/// metrics by design" section for the full rationale and the
/// stdout-vs-stderr extraction fallback.
///
/// **`--runtime 5` tradeoff inherited from [`SCHBENCH`].** See the
/// SCHBENCH doc for the fast-CI vs tail-latency tradeoff and the
/// `.arg("--runtime").arg("30")` override path.
#[derive(Payload)]
#[payload(
    binary = "schbench",
    name = "schbench_hinted",
    output = LlmExtract("wakeup latency percentiles"),
)]
#[default_args("--runtime", "5", "--message-threads", "2")]
#[default_check(exit_code_eq(0))]
#[allow(dead_code)]
pub struct SchbenchHintedPayload;

/// `schbench` with `--json -` pre-baked into `default_args`.
///
/// Schbench writes a JSON summary block to stdout when invoked with
/// `--json -` (the third argument hyphen selects stdout over a file
/// path). That block is parseable by the
/// [`OutputFormat::Json`](ktstr::test_support::OutputFormat::Json)
/// extraction pipeline — stable dotted-path metric names pinned at
/// schbench's source-level JSON schema (`write_json_stats` in
/// `schbench.c`), no LLM in the loop.
///
/// Compared to [`SCHBENCH`] and [`SCHBENCH_HINTED`], this fixture
/// differs in:
///
/// 1. **`name`** — `"schbench_json"` instead of `"schbench"`. Uses
///    a distinct name so sidecar files and log output can
///    disambiguate the three fixtures. The `binary` field stays
///    `"schbench"` in all three.
/// 2. **`output`** — `OutputFormat::Json` rather than `LlmExtract`,
///    so extraction goes through `find_and_parse_json` +
///    `walk_json_leaves` and bypasses the 2.44 GiB model load
///    altogether. Tests that only want schbench metrics (no
///    scheduler-regression narrative) save minutes of CPU time by
///    picking this over [`SCHBENCH`].
/// 3. **`default_args`** — includes `--json -` so a bare
///    `ctx.payload(&SCHBENCH_JSON)` call immediately produces the
///    JSON body.
/// 4. **`metrics`** — concrete hints on the schbench JSON schema.
///    Polarity annotations follow schbench convention: latency
///    percentiles are `LowerBetter`, request-per-second is
///    `HigherBetter`.
///
/// **Caveat: simultaneous SCHBENCH + SCHBENCH_JSON.** All three
/// fixtures share `kind = PayloadKind::Binary("schbench")`. A
/// scenario that lists multiple of them as workloads spawns
/// schbench once per fixture — each with its own argv set. The
/// pairwise-dedup on the `workloads` attribute only rejects
/// identical Payload paths; distinct constants that share a binary
/// are NOT deduped. Pick one fixture per scenario.
///
/// Hint paths match the JSON keys emitted by schbench's
/// `write_json_stats` in `schbench.c`. Unhinted paths still land in
/// the extracted metric set with
/// [`Polarity::Unknown`](ktstr::test_support::Polarity::Unknown),
/// so the JSON blob is surfaced in sidecar output for regression
/// tracking even when a specific percentile is not pinned here.
///
/// **`--runtime 5` tradeoff inherited from [`SCHBENCH`].** See the
/// SCHBENCH doc for the fast-CI vs tail-latency tradeoff and the
/// `.arg("--runtime").arg("30")` override path.
#[derive(Payload)]
#[payload(binary = "schbench", name = "schbench_json", output = Json)]
#[default_args("--runtime", "5", "--message-threads", "2", "--json", "-")]
#[default_check(exit_code_eq(0))]
#[metric(name = "rps", polarity = HigherBetter, unit = "rps")]
#[metric(name = "wakeup_latencies_usec.p99", polarity = LowerBetter, unit = "us")]
#[metric(name = "wakeup_latencies_usec.p50", polarity = LowerBetter, unit = "us")]
#[metric(name = "request_latencies_usec.p99", polarity = LowerBetter, unit = "us")]
#[metric(name = "request_latencies_usec.p50", polarity = LowerBetter, unit = "us")]
#[allow(dead_code)]
pub struct SchbenchJsonPayload;
