aprender-contracts 0.63.0

use std::collections::HashSet;

use crate::error::{Severity, Violation};
use crate::schema::types::{Contract, ContractKind};

/// Validate a parsed contract for completeness and consistency.
///
/// Returns a list of violations. If any violation has
/// [`Severity::Error`], the contract is considered invalid.
///
/// Validation is kind-aware: non-kernel contracts (registries, model-family
/// schemas, reference documents) are validated only for metadata consistency;
/// the provability invariant, equations, and proof/kani/falsification checks
/// only apply to `ContractKind::Kernel`.
pub fn validate_contract(contract: &Contract) -> Vec<Violation> {
    let mut violations = Vec::new();

    validate_metadata(contract, &mut violations);

    // Kernel-only checks: these enforce the provability invariant and
    // require equations + proof obligations + tests + Kani harnesses.
    if contract.kind() == ContractKind::Kernel && !contract.is_registry() {
        validate_equations(contract, &mut violations);
        validate_provability_invariant(contract, &mut violations);
        validate_proof_obligations(contract, &mut violations);
        validate_falsification_tests(contract, &mut violations);
        validate_kani_harnesses(contract, &mut violations);
        validate_qa_gate(contract, &mut violations);
    } else {
        // Non-kernel kinds (registry, model-family, schema): still validate
        // any proof obligations/falsification/kani data that IS present, so
        // mistakes are caught even on exempt contracts.
        validate_proof_obligations(contract, &mut violations);
        validate_falsification_tests(contract, &mut violations);
        validate_kani_harnesses(contract, &mut violations);
    }

    // BeatBenchmark-only checks (PMAT-741): the `beat:` block must pin a
    // falsifiable, four-pillar incumbent baseline. Independent of the
    // kernel/non-kernel split above.
    if contract.kind() == ContractKind::BeatBenchmark {
        validate_beat_benchmark(contract, &mut violations);
    }

    violations
}

/// The four incumbents a BEAT may target (case-insensitive substring match, so
/// `ollama` and `llama.cpp` both satisfy Pillar 4).
const BEAT_INCUMBENTS: [&str; 5] = ["scikit-learn", "pytorch", "unsloth", "ollama", "llama.cpp"];

/// Enforce the BeatBenchmark shape (PMAT-741): a `beat-benchmark` contract MUST
/// carry a well-formed `beat:` block so the claim is a falsifiable CI gate, not
/// prose. Rules BEAT-001..007.
fn validate_beat_benchmark(contract: &Contract, violations: &mut Vec<Violation>) {
    let push = |violations: &mut Vec<Violation>, rule: &str, message: String, field: &str| {
        violations.push(Violation {
            severity: Severity::Error,
            rule: rule.to_string(),
            message,
            location: Some(format!("beat.{field}")),
        });
    };

    let Some(beat) = contract.beat.as_ref() else {
        violations.push(Violation {
            severity: Severity::Error,
            rule: "BEAT-001".to_string(),
            message: "beat-benchmark contract must define a `beat:` block \
                      (incumbent, metric, direction, beat_threshold, ci_gate_name)"
                .to_string(),
            location: Some("beat".to_string()),
        });
        return;
    };

    // BEAT-002: incumbent must name one of the four pillars.
    let incumbent = beat.incumbent.trim().to_lowercase();
    if incumbent.is_empty() {
        push(
            violations,
            "BEAT-002",
            "beat.incumbent must not be empty".to_string(),
            "incumbent",
        );
    } else if !BEAT_INCUMBENTS.iter().any(|p| incumbent.contains(p)) {
        push(
            violations,
            "BEAT-002",
            format!(
                "beat.incumbent {:?} must name one of the four pillars ({})",
                beat.incumbent,
                BEAT_INCUMBENTS.join(", ")
            ),
            "incumbent",
        );
    }

    // BEAT-003: a measured metric is required.
    if beat.metric.trim().is_empty() {
        push(
            violations,
            "BEAT-003",
            "beat.metric must name the measured quantity (e.g. accuracy, wall_clock_ms, \
             tokens_per_sec)"
                .to_string(),
            "metric",
        );
    }

    // BEAT-004: direction fixes which way is a regression.
    match beat.direction.trim() {
        "higher_is_better" | "lower_is_better" => {}
        other => push(
            violations,
            "BEAT-004",
            format!(
                "beat.direction must be `higher_is_better` or `lower_is_better`, got {other:?}"
            ),
            "direction",
        ),
    }

    // BEAT-005: a finite, machine-pinned threshold is required (the gate value).
    match beat.beat_threshold {
        None => push(
            violations,
            "BEAT-005",
            "beat.beat_threshold is required — the pinned value CI fails below".to_string(),
            "beat_threshold",
        ),
        Some(t) if !t.is_finite() => push(
            violations,
            "BEAT-005",
            format!("beat.beat_threshold must be finite, got {t}"),
            "beat_threshold",
        ),
        Some(_) => {}
    }

    // BEAT-006: the enforcing CI gate must be named.
    if beat.ci_gate_name.trim().is_empty() {
        push(
            violations,
            "BEAT-006",
            "beat.ci_gate_name must name the CI test that enforces this gate".to_string(),
            "ci_gate_name",
        );
    }

    // BEAT-007: approved_compute is required and must be CPU or GPU (the
    // autonomous-vs-operator track distinction depends on it).
    match beat
        .approved_compute
        .as_deref()
        .map(|c| c.trim().to_uppercase())
    {
        None => push(
            violations,
            "BEAT-007",
            "beat.approved_compute is required — must be `CPU` or `GPU`".to_string(),
            "approved_compute",
        ),
        Some(ref c) if c != "CPU" && c != "GPU" => push(
            violations,
            "BEAT-007",
            format!(
                "beat.approved_compute must be `CPU` or `GPU`, got {:?}",
                beat.approved_compute
            ),
            "approved_compute",
        ),
        Some(_) => {}
    }
}

/// Enforce the provability invariant: kernel contracts (non-registry) MUST have
/// `proof_obligations`, `falsification_tests`, and `kani_harnesses`.
fn validate_provability_invariant(contract: &Contract, violations: &mut Vec<Violation>) {
    for v in contract.provability_violations() {
        violations.push(Violation {
            severity: Severity::Error,
            rule: "PROVABILITY-001".to_string(),
            message: v,
            location: None,
        });
    }
}

fn validate_metadata(contract: &Contract, violations: &mut Vec<Violation>) {
    if contract.metadata.references.is_empty() {
        violations.push(Violation {
            severity: Severity::Error,
            rule: "SCHEMA-001".to_string(),
            message: "metadata.references must not be empty — \
                      every contract must cite its source paper(s)"
                .to_string(),
            location: Some("metadata.references".to_string()),
        });
    }

    if contract.metadata.version.is_empty() {
        violations.push(Violation {
            severity: Severity::Error,
            rule: "SCHEMA-002".to_string(),
            message: "metadata.version must not be empty".to_string(),
            location: Some("metadata.version".to_string()),
        });
    }
}

fn validate_equations(contract: &Contract, violations: &mut Vec<Violation>) {
    if contract.equations.is_empty() {
        violations.push(Violation {
            severity: Severity::Error,
            rule: "SCHEMA-003".to_string(),
            message: "equations must contain at least one equation".to_string(),
            location: Some("equations".to_string()),
        });
    }

    for (name, eq) in &contract.equations {
        if eq.formula.is_empty() {
            violations.push(Violation {
                severity: Severity::Error,
                rule: "SCHEMA-004".to_string(),
                message: format!("equations.{name}.formula must not be empty"),
                location: Some(format!("equations.{name}.formula")),
            });
        }
    }
}

fn validate_proof_obligations(contract: &Contract, violations: &mut Vec<Violation>) {
    use crate::schema::types::ObligationType;

    let mut seen_ids = HashSet::new();
    for (i, ob) in contract.proof_obligations.iter().enumerate() {
        if ob.property.is_empty() {
            violations.push(Violation {
                severity: Severity::Error,
                rule: "SCHEMA-005".to_string(),
                message: format!("proof_obligations[{i}].property must not be empty"),
                location: Some(format!("proof_obligations[{i}].property")),
            });
        }
        if let Some(ref formal) = ob.formal {
            if !seen_ids.insert(formal.clone()) {
                violations.push(Violation {
                    severity: Severity::Warning,
                    rule: "SCHEMA-006".to_string(),
                    message: format!("Duplicate formal predicate: {formal}"),
                    location: Some(format!("proof_obligations[{i}].formal")),
                });
            }
        }

        // DbC field/type constraints
        if ob.requires.is_some() && ob.obligation_type != ObligationType::Postcondition {
            violations.push(Violation {
                severity: Severity::Error,
                rule: "SCHEMA-014".to_string(),
                message: format!(
                    "proof_obligations[{i}].requires is only valid on \
                     postcondition obligations (found on {})",
                    ob.obligation_type
                ),
                location: Some(format!("proof_obligations[{i}].requires")),
            });
        }

        if ob.applies_to_phase.is_some()
            && ob.obligation_type != ObligationType::LoopInvariant
            && ob.obligation_type != ObligationType::LoopVariant
        {
            violations.push(Violation {
                severity: Severity::Error,
                rule: "SCHEMA-015".to_string(),
                message: format!(
                    "proof_obligations[{i}].applies_to_phase is only valid on \
                     loop_invariant or loop_variant obligations (found on {})",
                    ob.obligation_type
                ),
                location: Some(format!("proof_obligations[{i}].applies_to_phase")),
            });
        }

        if ob.parent_contract.is_some() && ob.obligation_type != ObligationType::Subcontract {
            violations.push(Violation {
                severity: Severity::Error,
                rule: "SCHEMA-016".to_string(),
                message: format!(
                    "proof_obligations[{i}].parent_contract is only valid on \
                     subcontract obligations (found on {})",
                    ob.obligation_type
                ),
                location: Some(format!("proof_obligations[{i}].parent_contract")),
            });
        }

        // Subcontract parent_contract must be in depends_on
        if let Some(ref parent) = ob.parent_contract {
            if ob.obligation_type == ObligationType::Subcontract
                && !contract.metadata.depends_on.contains(parent)
            {
                violations.push(Violation {
                    severity: Severity::Error,
                    rule: "SCHEMA-017".to_string(),
                    message: format!(
                        "proof_obligations[{i}].parent_contract \"{parent}\" \
                         must be listed in metadata.depends_on"
                    ),
                    location: Some(format!("proof_obligations[{i}].parent_contract")),
                });
            }
        }
    }
}

fn validate_falsification_tests(contract: &Contract, violations: &mut Vec<Violation>) {
    let mut ids = HashSet::new();
    for test in &contract.falsification_tests {
        if !ids.insert(&test.id) {
            violations.push(Violation {
                severity: Severity::Error,
                rule: "SCHEMA-007".to_string(),
                message: format!("Duplicate falsification test ID: {}", test.id),
                location: Some(format!("falsification_tests.{}", test.id)),
            });
        }
        if test.prediction.is_empty() {
            violations.push(Violation {
                severity: Severity::Error,
                rule: "SCHEMA-008".to_string(),
                message: format!(
                    "falsification_tests.{}.prediction must not be empty — \
                     every test must make a falsifiable prediction",
                    test.id
                ),
                location: Some(format!("falsification_tests.{}.prediction", test.id)),
            });
        }
        if test.if_fails.is_empty() {
            violations.push(Violation {
                severity: Severity::Warning,
                rule: "SCHEMA-009".to_string(),
                message: format!(
                    "falsification_tests.{}.if_fails is empty — \
                     should describe root cause diagnosis",
                    test.id
                ),
                location: Some(format!("falsification_tests.{}.if_fails", test.id)),
            });
        }
    }
}

fn validate_kani_harnesses(contract: &Contract, violations: &mut Vec<Violation>) {
    let mut ids = HashSet::new();
    for harness in &contract.kani_harnesses {
        if !ids.insert(&harness.id) {
            violations.push(Violation {
                severity: Severity::Error,
                rule: "SCHEMA-010".to_string(),
                message: format!("Duplicate Kani harness ID: {}", harness.id),
                location: Some(format!("kani_harnesses.{}", harness.id)),
            });
        }
        if harness.obligation.is_empty() {
            violations.push(Violation {
                severity: Severity::Error,
                rule: "SCHEMA-011".to_string(),
                message: format!(
                    "kani_harnesses.{}.obligation must not be empty — \
                     every harness must reference a proof obligation",
                    harness.id
                ),
                location: Some(format!("kani_harnesses.{}.obligation", harness.id)),
            });
        }
        if harness.bound.is_none() {
            violations.push(Violation {
                severity: Severity::Warning,
                rule: "SCHEMA-012".to_string(),
                message: format!(
                    "kani_harnesses.{}.bound not specified — \
                     Kani requires an unwind bound",
                    harness.id
                ),
                location: Some(format!("kani_harnesses.{}.bound", harness.id)),
            });
        }
    }
}

fn validate_qa_gate(contract: &Contract, violations: &mut Vec<Violation>) {
    if contract.qa_gate.is_none() {
        violations.push(Violation {
            severity: Severity::Warning,
            rule: "SCHEMA-013".to_string(),
            message: "No qa_gate defined — contract should define a \
                      certeza quality gate"
                .to_string(),
            location: Some("qa_gate".to_string()),
        });
    }
}

#[cfg(test)]
mod tests {
    include!("validator_tests.rs");
}