//! Example binding — JouleClaw's **L3 (Model)** tier as a Joule Code cascade stage.
//!
//! This shows how a consumer plugs the JouleClaw agent schema's local-model
//! layer ([`jouleclaw_llm::LlmBackend`]) into the Joule Code cascade
//! ([`joule_code_cascade::Stage`]) at tier L3. A coding request that misses the
//! cheaper tiers (L0 cache, L1 lawful, L2 embed) is generated by a local model
//! here, producing a content-addressed [`CodingOp`] and a joules-class L3
//! [`Receipt`].
//!
//! It is verified **model-free** with [`EchoBackend`] (a deterministic backend
//! JouleClaw ships for exactly this). Real backends implement the same
//! `LlmBackend` trait and drop into the same slot:
//!
//! - [`llama_backend::LlamaCompletionBackend`] — shells out to `llama.cpp`.
//! - [`runtime_backend::JouleclawRuntimeBackend`] — runs the model **in-process
//!   on JouleClaw's own from-scratch GGUF tensor runtime** (`jouleclaw-runtime`),
//!   no external binary and no FFI.
//! - [`hybrid_backend::HybridBackend`] — runs the Mamba2/attention **hybrid**
//!   safetensors families (NemotronH, Granite-4.0-H, Falcon-H1) in-process via
//!   `jouleclaw_loader_gguf::hybrid_lm`, family auto-detected from
//!   `config.json`.
//!
//! In production the cheapest capable backend is chosen by
//! `jouleclaw_dispatch::ModelBank`'s cost table.

pub mod hybrid_backend;
pub mod llama_backend;
pub mod runtime_backend;

use joule_code_cargo::{Anchor, CodingOp, Edit};
use joule_code_cascade::{FnStage, Request, Resolution, Stage};
use joule_code_receipt::{Energy, Provenance, Receipt};
use joule_code_schema::{ContentId, Tier, ALG_ED25519};
use jouleclaw_fabric::EnergyProvenance;
use jouleclaw_llm::{EchoBackend, LlmBackend, LlmRequest};
use jouleclaw_loader_gguf::fabric_dispatch::{ledger_reset, ledger_snapshot, LedgerEntry};

/// The grade of a per-call energy figure projected from the fabric attribution
/// ledger (`window`: the ledger's entries for that call), by its **weakest
/// input**.
///
/// A projection is GFLOPs × each member's µJ/GFLOP; it is never a reading, so
/// at best it is a calibrated per-operation model, `ModelBased` (joule-code
/// SPEC §6). It is that only when every member that ran was priced by a
/// calibrated figure: `Measured` (a calibration row a live meter read) or
/// `Benchmarked` (a recorded run on that member class). One input priced by an
/// `Estimated` figure — a coarse model, such as the fabric's seeded GPU figures —
/// makes the whole projection an estimate, `Estimator`; so does a member that
/// ran unpriced (its work is missing from the sum), and an empty window (a
/// figure that cannot be traced to any priced input).
pub fn projection_grade(window: &[LedgerEntry]) -> Provenance {
    if window.is_empty() {
        return Provenance::Estimator;
    }
    let mut grade = Provenance::ModelBased;
    for entry in window {
        match entry.projected_grade {
            Some(EnergyProvenance::Measured | EnergyProvenance::Benchmarked) => {}
            Some(EnergyProvenance::Estimated) | None => grade = Provenance::Estimator,
        }
    }
    grade
}

/// Build an L3 cascade [`Stage`] backed by any JouleClaw [`LlmBackend`]. The
/// stage generates a coding operation from the request intent and reports the
/// backend's joule cost as the receipt energy (tier L3, joules class).
///
/// The stage opens the fabric attribution window around the call (it resets
/// the process-wide ledger first), so the figure a backend reports is graded by
/// the inputs this call was priced from ([`projection_grade`]) and by nothing an
/// earlier call left in the ledger. The ledger is process-wide: work another
/// thread dispatches during the call lands in the same window.
pub fn jouleclaw_l3_stage(backend: Box<dyn LlmBackend>) -> impl Stage {
    FnStage::new(Tier::L3, move |req: &Request| {
        ledger_reset();
        let response = backend
            .complete(&LlmRequest::from_prompt(req.intent.clone(), 256))
            .ok()?;
        let window = ledger_snapshot();

        // Reference materialization: the model's output becomes one edit. A
        // production binding would parse structured edits from the model.
        let edit = Edit {
            path: "OUTPUT.md".into(),
            anchor: Anchor::ByteRange { start: 0, end: 0 },
            replacement: response.text.clone().into_bytes(),
        };
        let op = CodingOp {
            alg: ALG_ED25519,
            prior: ContentId::of_bytes(req.prior.as_bytes()),
            edits: vec![edit],
            author: [0u8; 32],
            intent: req.intent.clone(),
            tier: Tier::L3,
        };
        let op_id = op.op_id().ok()?;

        // L3 energy. When the backend reports a per-call figure
        // (the hybrid backend's fabric projection — GFLOPs
        // attributed per member, priced by each member's loaded
        // matmul figure), it is graded by its weakest input:
        // ModelBased only if every member was priced by a
        // Measured or Benchmarked figure, Estimator otherwise.
        // Without a figure, the catalog constant, Estimator.
        let (estimated_uj, provenance) = match response.energy_joules {
            Some(j) => ((j * 1_000_000.0) as u64, projection_grade(&window)),
            None => (
                (backend.typical_joules_per_call() * 1_000_000.0) as u64,
                Provenance::Estimator,
            ),
        };

        Some(Resolution {
            op: Some(op),
            answer: Some(response.text),
            receipt: Receipt {
                op_id,
                tier: Tier::L3,
                energy: Energy {
                    measured_uj: None,
                    estimated_uj,
                    provenance,
                },
                sequence: 0,
                nonce: [0u8; 8],
            },
        })
    })
}

/// Convenience: an L3 stage backed by the model-free [`EchoBackend`] (for tests
/// and smoke runs without a real model).
pub fn echo_l3_stage() -> impl Stage {
    jouleclaw_l3_stage(Box::new(EchoBackend::new()))
}

#[cfg(test)]
mod tests {
    use super::*;
    use joule_code_cascade::{Cascade, L0Cache};

    #[test]
    fn l3_stage_generates_op_and_joules_receipt() {
        let stage = echo_l3_stage();
        let res = stage
            .try_resolve(&Request {
                prior: "b3:AAAA".into(),
                intent: "write a hello function".into(),
            })
            .expect("L3 resolved");
        assert_eq!(res.receipt.tier, Tier::L3);
        assert!(res.op.is_some());
        // EchoBackend prefixes the prompt; the model output flowed through.
        assert!(res.answer.unwrap().contains("hello"));
        // Joules-class energy, honestly tagged as an estimate.
        assert!(res.receipt.energy.estimated_uj > 0);
        assert_eq!(res.receipt.energy.provenance, Provenance::Estimator);
    }

    /// A ledger entry for `member`, priced at `grade` (`None`: unpriced).
    fn entry(member: &str, grade: Option<EnergyProvenance>) -> LedgerEntry {
        LedgerEntry {
            member_id: member.into(),
            ops: 3,
            gflops: 1.5,
            projected_uj: grade.map(|_| 1.5 * 7_000.0),
            projected_grade: grade,
        }
    }

    /// The weakest input decides: calibrated figures (Measured, Benchmarked)
    /// make a ModelBased projection; one Estimated or unpriced input, or no input
    /// at all, makes it an Estimator figure.
    #[test]
    fn a_projection_is_graded_by_its_weakest_input() {
        use EnergyProvenance::*;
        let cases: [(&[Option<EnergyProvenance>], Provenance); 8] = [
            (&[Some(Measured)], Provenance::ModelBased),
            (&[Some(Benchmarked)], Provenance::ModelBased),
            (&[Some(Measured), Some(Benchmarked)], Provenance::ModelBased),
            (&[Some(Estimated)], Provenance::Estimator),
            (&[Some(Benchmarked), Some(Estimated)], Provenance::Estimator),
            (&[Some(Estimated), Some(Measured)], Provenance::Estimator),
            (&[Some(Measured), None], Provenance::Estimator),
            (&[], Provenance::Estimator),
        ];
        for (grades, want) in cases {
            let window: Vec<LedgerEntry> =
                grades.iter().enumerate().map(|(i, g)| entry(&format!("local/m{i}"), *g)).collect();
            assert_eq!(projection_grade(&window), want, "{grades:?}");
        }
    }

    /// A backend that runs one real matmul through the fabric dispatcher (the
    /// path the hybrid models take) and reports a per-call figure, as the hybrid
    /// backend does from the ledger.
    struct DispatchingBackend {
        /// Run the matmul (and so leave a ledger entry), or not.
        dispatch: bool,
    }

    impl LlmBackend for DispatchingBackend {
        fn model_name(&self) -> &str {
            "dispatching"
        }
        fn complete(&self, request: &LlmRequest) -> Result<jouleclaw_llm::LlmResponse, jouleclaw_llm::LlmError> {
            if self.dispatch {
                let (m, n, k) = (1usize, 32usize, 64usize);
                let a = vec![0.5f32; m * k];
                let w = vec![0u8; 2 * n * k];
                let mut out = vec![0f32; m * n];
                jouleclaw_loader_gguf::fabric_dispatch::matmul_bf16_auto(&a, &w, &[], m, n, k, &mut out);
            }
            Ok(jouleclaw_llm::LlmResponse {
                text: format!("fn answer() {{}} // {}", request.prompt),
                finish_reason: jouleclaw_llm::FinishReason::Stop,
                input_tokens: 4,
                output_tokens: 4,
                energy_joules: Some(0.25),
            })
        }
        fn typical_joules_per_call(&self) -> f64 {
            1.0
        }
    }

    fn resolve(backend: DispatchingBackend) -> Energy {
        let stage = jouleclaw_l3_stage(Box::new(backend));
        let res = stage
            .try_resolve(&Request { prior: "b3:AAAA".into(), intent: "write a hello function".into() })
            .expect("L3 resolved");
        res.receipt.energy
    }

    /// A per-call figure is no longer ModelBased by default. Here the fabric is
    /// off (no `JOULECLAW_FABRIC=1`), so the member that ran was priced by
    /// nothing: the figure is reported, as an estimate. A figure with no ledger
    /// input at all is an estimate too.
    #[test]
    fn a_figure_the_ledger_did_not_price_is_an_estimate() {
        for dispatch in [true, false] {
            let e = resolve(DispatchingBackend { dispatch });
            assert_eq!(
                (e.measured_uj, e.estimated_uj, e.provenance),
                (None, 250_000, Provenance::Estimator),
                "dispatch={dispatch}"
            );
            assert!(e.check_provenance().is_ok());
        }
    }

    #[test]
    fn cascade_falls_through_l0_to_l3() {
        // Empty L0 cache in front of the L3 model stage: L0 misses, L3 closes.
        let cascade = Cascade::new([
            Box::new(L0Cache::new()) as Box<dyn Stage>,
            Box::new(echo_l3_stage()) as Box<dyn Stage>,
        ]);
        let res = cascade
            .resolve(&Request {
                prior: "b3:AAAA".into(),
                intent: "refactor this".into(),
            })
            .expect("resolved");
        assert_eq!(res.receipt.tier, Tier::L3);
    }
}