helm-schema-core 0.0.3

use std::collections::{BTreeMap, BTreeSet};

use crate::{GuardValue, ProviderSchemaUse};

/// Values-decidable guard expression that can be lowered into JSON Schema
/// conditionals.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum ConditionalGuard {
    /// The value at `path` is Helm-truthy.
    Truthy {
        /// Values path tested for truthiness.
        path: String,
    },
    /// A `with` action selected the non-empty value at `path`.
    With {
        /// Values path selected by the action.
        path: String,
    },
    /// The value at `path` equals a literal.
    Eq {
        /// Values path compared with the literal.
        path: String,
        /// Literal required at the path.
        value: GuardValue,
    },
    /// The value at `path` differs from a literal.
    NotEq {
        /// Values path compared with the literal.
        path: String,
        /// Literal excluded at the path.
        value: GuardValue,
    },
    /// The value at `path` is absent.
    Absent {
        /// Values path whose absence selects the branch.
        path: String,
    },
    /// The value at `path` has a specific JSON Schema type.
    TypeIs {
        /// Values path subjected to the type test.
        path: String,
        /// JSON Schema type name accepted by the branch.
        schema_type: String,
    },
    /// The string at `path` matches a regular expression.
    MatchesPattern {
        /// Values path subjected to the pattern test.
        path: String,
        /// ECMA-compatible regular expression required by the branch.
        pattern: String,
    },
    /// The path's RAW value is a JSON integer strictly greater than `bound`
    /// — a sound SUBSET of the Sprig coercion (`gt (int64 x) bound`) it
    /// stands in for, valid only where firing less often is safe.
    IntGt {
        /// Values path subjected to the integer comparison.
        path: String,
        /// Exclusive lower bound.
        bound: i64,
    },
    /// The mirror of [`ConditionalGuard::IntGt`]: the path's RAW value is a
    /// JSON integer strictly less than `bound`, under the same sound-subset
    /// contract.
    IntLt {
        /// Values path subjected to the integer comparison.
        path: String,
        /// Exclusive upper bound.
        bound: i64,
    },
    /// The mapping at `path` contains the literal member `key`. The key is
    /// an OPAQUE property name (it may contain dots), so it rides beside
    /// the segmented path instead of being appended to it.
    HasKey {
        /// Values path expected to hold a mapping.
        path: String,
        /// Literal mapping key whose presence selects the branch.
        key: String,
    },
    /// SOME iterated item of the collection at `path` has `member` equal to
    /// `value` — the document-level meaning of a range-sentinel flag
    /// (`Range(path) ∧ Eq(path.*.member, value)`). Lowers to `contains`
    /// over the array lane and the double-negated member quantifier over
    /// the object lane.
    ContainsMemberEquals {
        /// Values path expected to hold the iterated collection.
        path: String,
        /// Member name compared within each collection item.
        member: String,
        /// Literal that at least one member must equal.
        value: GuardValue,
    },
    /// SOME item of the list at `path` deep-equals the scalar literal —
    /// Sprig `has LITERAL .Values.list`. `has` returns false on a nil
    /// haystack and aborts on non-lists, so the guard holds exactly for
    /// arrays carrying the literal; lowers to `contains` with a `const`
    /// item.
    ContainsEquals {
        /// Values path expected to hold the list.
        path: String,
        /// Literal that at least one list item must equal.
        value: GuardValue,
    },
    /// The collection at `path` has at most one entry — the document-level
    /// form of "every iteration of this range is the first" (an
    /// empty-initialized dedup accumulator cannot have shadowed anything).
    /// A sound subset: it may only scope positive-polarity evidence.
    AtMostOneMember {
        /// Values path expected to hold the bounded collection.
        path: String,
    },
    /// The value at `path` is a mapping with at least `bound` members
    /// (`gt (keys X | len) N`). Exact: both polarities encode.
    MinMembers {
        /// Values path expected to hold the mapping.
        path: String,
        /// Inclusive minimum number of members.
        bound: i64,
    },
    /// Logical negation of a guard.
    Not(Box<ConditionalGuard>),
    /// Conjunction of every enclosed guard.
    AllOf(Vec<ConditionalGuard>),
    /// Disjunction of the enclosed guards.
    AnyOf(Vec<ConditionalGuard>),
}

impl ConditionalGuard {
    /// Returns every values path referenced by this guard tree.
    #[must_use]
    pub fn value_paths(&self) -> BTreeSet<String> {
        let mut paths = BTreeSet::new();
        self.collect_value_paths(&mut paths);
        paths
    }

    /// Rewrite the values paths carried by this guard (and every nested
    /// guard).
    #[must_use]
    pub fn map_value_paths<F>(self, map: &mut F) -> Self
    where
        F: FnMut(&str) -> String,
    {
        match self {
            Self::Truthy { path } => Self::Truthy { path: map(&path) },
            Self::With { path } => Self::With { path: map(&path) },
            Self::Eq { path, value } => Self::Eq {
                path: map(&path),
                value,
            },
            Self::NotEq { path, value } => Self::NotEq {
                path: map(&path),
                value,
            },
            Self::Absent { path } => Self::Absent { path: map(&path) },
            Self::TypeIs { path, schema_type } => Self::TypeIs {
                path: map(&path),
                schema_type,
            },
            Self::MatchesPattern { path, pattern } => Self::MatchesPattern {
                path: map(&path),
                pattern,
            },
            Self::IntGt { path, bound } => Self::IntGt {
                path: map(&path),
                bound,
            },
            Self::IntLt { path, bound } => Self::IntLt {
                path: map(&path),
                bound,
            },
            Self::HasKey { path, key } => Self::HasKey {
                path: map(&path),
                key,
            },
            Self::ContainsMemberEquals {
                path,
                member,
                value,
            } => Self::ContainsMemberEquals {
                path: map(&path),
                member,
                value,
            },
            Self::ContainsEquals { path, value } => Self::ContainsEquals {
                path: map(&path),
                value,
            },
            Self::AtMostOneMember { path } => Self::AtMostOneMember { path: map(&path) },
            Self::MinMembers { path, bound } => Self::MinMembers {
                path: map(&path),
                bound,
            },
            Self::Not(inner) => Self::Not(Box::new(inner.map_value_paths(map))),
            Self::AllOf(guards) => Self::AllOf(
                guards
                    .into_iter()
                    .map(|guard| guard.map_value_paths(map))
                    .collect(),
            ),
            Self::AnyOf(guards) => Self::AnyOf(
                guards
                    .into_iter()
                    .map(|guard| guard.map_value_paths(map))
                    .collect(),
            ),
        }
    }

    fn collect_value_paths(&self, paths: &mut BTreeSet<String>) {
        match self {
            Self::Truthy { path }
            | Self::With { path }
            | Self::Eq { path, .. }
            | Self::NotEq { path, .. }
            | Self::Absent { path }
            | Self::TypeIs { path, .. }
            | Self::MatchesPattern { path, .. }
            | Self::IntGt { path, .. }
            | Self::IntLt { path, .. }
            | Self::HasKey { path, .. }
            | Self::ContainsMemberEquals { path, .. }
            | Self::ContainsEquals { path, .. }
            | Self::AtMostOneMember { path }
            | Self::MinMembers { path, .. } => {
                paths.insert(path.clone());
            }
            Self::Not(inner) => inner.collect_value_paths(paths),
            Self::AllOf(guards) | Self::AnyOf(guards) => {
                for guard in guards {
                    guard.collect_value_paths(paths);
                }
            }
        }
    }
}

/// Conditionally-scoped values path whose schema can be lowered under a
/// values-decidable guard set.
///
/// Multiple entries in `guards` mean conjunction: all guards in the set must
/// hold for the overlay to apply.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ConditionalPathOverlay {
    /// Conjoined conditions that select this overlay.
    pub guards: Vec<ConditionalGuard>,
    /// Schema evidence that applies while the guards hold.
    pub evidence: ConditionalOverlayEvidence,
    /// Keep the unconditional/base schema for this path alongside the guarded
    /// overlay because the contract also observed an unguarded use.
    pub preserve_base_schema: bool,
}

/// Branch-local evidence for one conditional schema overlay.
///
/// The target path is implicit from the enclosing [`ContractPathSchemaEvidence`]
/// entry that owns the overlay.
#[derive(Debug, Clone, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ConditionalOverlayEvidence {
    /// Behavioral facts observed in the selected branch.
    pub facts: ContractValuePathFacts,
    /// Kubernetes metadata field roles reached in the branch.
    pub metadata_field_kinds: BTreeSet<MetadataFieldKind>,
    /// JSON Schema type names implied by branch-local consumers.
    pub type_hints: BTreeSet<String>,
    /// Resource-schema sinks reached in the selected branch.
    pub provider_schema_uses: Vec<ProviderSchemaUse>,
}

impl ConditionalOverlayEvidence {
    /// Materializes this branch-local evidence as evidence for `value_path`.
    #[must_use]
    pub fn as_path_evidence(&self, value_path: &str) -> ContractPathSchemaEvidence {
        ContractPathSchemaEvidence {
            value_path: value_path.to_string(),
            is_referenced_value_path: true,
            facts: self.facts,
            guard_predicates: Vec::new(),
            metadata_field_kinds: self.metadata_field_kinds.clone(),
            type_hints: self.type_hints.clone(),
            guarded_type_hints: BTreeSet::new(),
            fallback_type_hints: BTreeSet::new(),
            provider_schema_uses: self.provider_schema_uses.clone(),
            requiredness: ContractRequirednessEvidence::default(),
            conditional_overlays: Vec::new(),
            fail_implications: Vec::new(),
        }
    }
}

/// Kubernetes `metadata.*` field shape referenced by a values path.
///
/// The contract layer records the field category structurally from the
/// rendered document path. JSON Schema lowering remains a generator policy.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum MetadataFieldKind {
    /// `metadata.labels` and `metadata.annotations`.
    StringMap,
    /// `metadata.name`.
    Name,
    /// `metadata.namespace`.
    Namespace,
}

/// All schema-lowering evidence for one values path.
///
/// The contract layer owns this view so downstream generation can consume one
/// path-local static-analysis fact instead of reassembling meaning from
/// several parallel maps.
#[derive(Debug, Clone, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ContractPathSchemaEvidence {
    /// Canonical dot-separated values path described by this evidence.
    pub value_path: String,
    /// Whether template analysis directly referenced this path.
    pub is_referenced_value_path: bool,
    /// Aggregate behavioral facts observed for the path.
    pub facts: ContractValuePathFacts,
    /// Unconditional guard facts attached to the path.
    pub guard_predicates: Vec<ConditionalGuard>,
    /// Kubernetes metadata field roles reached from the path.
    pub metadata_field_kinds: BTreeSet<MetadataFieldKind>,
    /// Unconditional JSON Schema type hints.
    pub type_hints: BTreeSet<String>,
    /// Hints observed only under branch predicates. At the path level these
    /// may only WIDEN (add accepted alternatives to an otherwise-typed
    /// base): `allOf` branches can narrow but never re-widen a base, so a
    /// branch-scoped domain alternative must surface here.
    pub guarded_type_hints: BTreeSet<String>,
    /// Hints from literal `default`/`coalesce` fallbacks. The selection call
    /// never consumes the raw value — every Helm-empty input takes the
    /// fallback — so these type only the truthy arm and base lowering must
    /// keep the whole Helm-falsy set open beside them.
    pub fallback_type_hints: BTreeSet<String>,
    /// Resource-schema sinks that consume the path.
    pub provider_schema_uses: Vec<ProviderSchemaUse>,
    /// Facts used by optional required-property inference.
    pub requiredness: ContractRequirednessEvidence,
    /// Branch-local evidence keyed by values-decidable guards.
    pub conditional_overlays: Vec<ConditionalPathOverlay>,
    /// Requirements implied by explicit `fail` branches: the failing test's
    /// negation must hold wherever the outer guards do. Runtime-hard
    /// evidence — rendering genuinely aborts — so lowering must not let
    /// weaker streams suppress it.
    pub fail_implications: Vec<ContractFailImplication>,
}

/// A chart-authored values-program wrapper convention: within `scope_path`
/// (empty for the whole values tree), any node may be a singleton
/// `{key: PROGRAM}` map that the chart's engine replaces with the
/// `tpl`-rendered, YAML-reparsed program result before consumers read it.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ValuesProgramWrapper {
    /// Values subtree the engine rewrites; empty means the whole tree.
    pub scope_path: String,
    /// The wrapper's sentinel member key (`$tplYaml`).
    pub key: String,
    /// Whether the engine SPREADS the program result into the parent
    /// collection instead of replacing the node (`$tplYamlSpread`): the
    /// result's kind must match the parent's kind (a null result is a
    /// no-op removal), and the values root itself rejects the wrapper.
    pub spread: bool,
}

/// A chart-wide default subtree merged into an effective `.Values` subtree.
///
/// The target remains user-overridable; the source supplies only keys absent
/// from the target, matching `mustMergeOverwrite SOURCE TARGET` before the
/// result replaces a root or nested `Values` object.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ValuesDefaultSource {
    /// Effective values subtree receiving defaults, with an empty path denoting `.Values`.
    pub target_path: String,
    /// Chart values subtree supplying defaults.
    pub source_path: String,
}

/// One `fail`-branch implication on a values path.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ContractFailImplication {
    /// Conditions outside the failing test; empty means the requirement
    /// binds the path unconditionally.
    pub outer_guards: Vec<ConditionalGuard>,
    /// The runtime value affected by the requirement.
    pub target: ContractRequirementTarget,
    /// Conjunction of requirements the affected value must satisfy.
    pub requirements: Vec<FailValueRequirement>,
}

/// Runtime value within a values-path contract that must satisfy a requirement.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum ContractRequirementTarget {
    /// The values path itself.
    Value,
    /// Every value produced by ranging the path.
    ///
    /// `allow_integer` describes the range header's own integer lane. It is
    /// false for a two-variable range, even when the member requirement would
    /// otherwise accept integer values.
    Members {
        /// Whether Helm's integer-count range form remains accepted.
        allow_integer: bool,
    },
    /// Values of object entries whose keys start with the literal prefix.
    /// Empty arrays and null remain valid because they execute no range body.
    MembersMatchingPrefix {
        /// Literal key prefix selecting affected object entries.
        prefix: String,
    },
    /// Each ranged member whose literal sibling equals `value` must satisfy
    /// the requirements at `target_path`, both relative to that member.
    MembersWhereEquals {
        /// Relative member path used as the selector.
        guard_path: Vec<String>,
        /// Literal required at the selector path.
        value: GuardValue,
        /// Relative member path constrained by the requirement.
        target_path: Vec<String>,
    },
    /// Every ranged member must CONTAIN `target_path` and its value there
    /// must satisfy the requirements — an unconditional per-member field
    /// read by a strict consumer (`tpl $member.url` fails on a missing or
    /// non-string field). `allow_integer` mirrors [`Self::Members`].
    MembersAt {
        /// Relative member path that must exist.
        target_path: Vec<String>,
        /// Whether Helm's integer-count range form remains accepted.
        allow_integer: bool,
    },
    /// Every key produced by ranging the path.
    Keys,
}

/// The quoting style of a manually quoted YAML scalar hosting a raw splice.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum QuotedScalarStyle {
    /// `"…"` — every `\` must begin a YAML escape and every `"` be escaped.
    Double,
    /// `'…'` — `''` is the only escape, so every apostrophe must be doubled.
    Single,
}

impl QuotedScalarStyle {
    /// Valid CONTENT of a scalar quoted in this style; raw text outside the
    /// grammar corrupts the manually quoted token.
    #[must_use]
    pub fn safe_content_pattern(self) -> &'static str {
        match self {
            Self::Double => {
                r#"^([^"\\]|\\["\\/0abtnvfre N_LP]|\\x[0-9A-Fa-f]{2}|\\u[0-9A-Fa-f]{4}|\\U[0-9A-Fa-f]{8})*$"#
            }
            Self::Single => r"^([^']|'')*$",
        }
    }
}

/// One requirement a `fail` branch imposes on an affected value.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum FailValueRequirement {
    /// The value must be of this JSON Schema type.
    SchemaType(String),
    /// The value must be of this JSON Schema type EVEN WHEN NULL: the
    /// consumer type-asserts before any nil check (Sprig `dig` subjects),
    /// so an explicit null aborts while structural absence stays open
    /// through the arm's properties anchoring.
    SchemaTypeEvenNull(String),
    /// The value must be of this JSON Schema type only when Helm-truthy:
    /// every falsy spelling escapes through the consumer's own truthiness
    /// selection (a ranged ACL member's `default ""` password reaching
    /// `sha256sum` behind `if $password`).
    TruthyImpliesSchemaType(String),
    /// The value must be Helm-truthy (sealed-secrets aborts on any falsy
    /// `privateKeyAnnotations` member, including the empty string).
    HelmTruthy,
    /// The value must be Helm-FALSY — the negation of a member's own
    /// truthiness test inside a compound ranged terminal: the fail fires
    /// only for truthy members, so falsiness is one escape alternative
    /// (traefik's `if $config` gate around the http3-without-tls abort).
    HelmFalsy,
    /// The value's field at `path`, when present, must be Helm-FALSY: the
    /// failing test fired on the field's truthiness (oauth2-proxy aborts
    /// when a legacy `extraPaths[].backend.serviceName` is set under the
    /// `networking.k8s.io/v1` Ingress api).
    FieldHelmFalsy {
        /// Relative field path constrained to Helm-falsy values.
        path: Vec<String>,
    },
    /// The value must be an object whose field at `path` is present and
    /// equals the literal: the failing test's negation held an equality on
    /// the field (traefik's `eq $plugin.type "hostPath"` dispatch arm; Go's
    /// `eq` aborts on a nil operand, so presence rides along).
    FieldEquals {
        /// Relative field path compared with the literal.
        path: Vec<String>,
        /// Literal required at the field path.
        value: GuardValue,
    },
    /// The value must be an object whose field at `path` is present and
    /// non-null: a ranged member's leaf renders into a provider-REQUIRED
    /// resource field, where a missing or null source emits an explicit
    /// null the provider rejects (promtail's extra Service `port`).
    FieldPresentNotNull {
        /// Relative field path that must contain a non-null value.
        path: Vec<String>,
    },
    /// The value must be an object whose field at `path` is present and
    /// Helm-truthy — the positive mirror of [`Self::FieldHelmFalsy`], used
    /// as the ESCAPE alternative when a member-scoped branch guard selects
    /// another render for truthy fields (promtail's `service` arm renders
    /// its own port instead of `containerPort`).
    FieldHelmTruthy {
        /// Relative field path constrained to Helm-truthy values.
        path: Vec<String>,
    },
    /// At least one alternative (each a conjunction of requirements) must
    /// hold. A `fail` whose test conjoins several member conditions negates
    /// to the DISJUNCTION of their negations — traefik's local plugins
    /// render with a truthy `type` OR a legacy truthy `hostPath`, and
    /// conjoining those requirements rejected both documented shapes.
    AnyOf(Vec<Vec<FailValueRequirement>>),
    /// The value must not equal this literal (cilium forbids ranged
    /// `extraEnv` names colliding with its own backoff variables).
    NotEquals(GuardValue),
    /// The value's field at `path`, when present, must differ from the
    /// literal — the negation of a member-field equality test. Absent and
    /// null fields differ from every literal (Helm's `eq` compares `nil`
    /// without aborting), so no presence requirement rides along
    /// (traefik's HTTPS-protocol listeners must carry `certificateRefs`;
    /// non-HTTPS listeners escape through this arm).
    FieldNotEquals {
        /// Relative field path compared with the literal.
        path: Vec<String>,
        /// Literal excluded at the field path.
        value: GuardValue,
    },
    /// The value must be of this JSON Schema type IF present and non-null:
    /// Go's `eq`/`ne` compare `nil` against anything, so a missing or null
    /// comparison operand renders while a present value of a different
    /// basic kind aborts.
    ComparableKind(String),
    /// The value must NOT be of this JSON Schema type.
    NotSchemaType(String),
    /// The value must be an object containing this member.
    HasMember(String),
    /// The value must be an object containing this member EVEN when the
    /// chart's own defaults supply it: the consumer aborts on an absent
    /// subject (a nil `dig` dict), and under coalesced-document semantics
    /// the member is absent exactly when a user null-deletes it — the
    /// state the requirement must reject. Exempt from the
    /// default-supplied `required` relaxation that render-grade presence
    /// claims get.
    HasMemberEvenDefaulted(String),
    /// The value must be a string matching this regular expression
    /// (`regexMatch` type-asserts a string subject, so string-ness rides
    /// along).
    MatchesPattern {
        /// Regular expression the string must match.
        pattern: String,
        /// Whether the pattern originated from a templated expression.
        templated: bool,
    },
    /// The value must be a string NOT matching this regular expression —
    /// the failing test fired on matches, and its `regexMatch` still
    /// type-asserts a string subject (traefik's uppercase key gate).
    NotMatchesPattern {
        /// Regular expression the string must not match.
        pattern: String,
    },
    /// The value must be a string whose length lies inside the window — a
    /// provider key slot's `minLength`/`maxLength` projected onto a ranged
    /// collection's keys (traefik's Gateway listener names).
    StringLengthBounds {
        /// Inclusive minimum length, when one is known.
        min: Option<u64>,
        /// Inclusive maximum length, when one is known.
        max: Option<u64>,
    },
    /// The value HOSTS literal member reads: it must be an object — or one
    /// of the kinds the chart's own type dispatch provably handles before
    /// the reads run (nack converts the string image form with `set`).
    MemberHost {
        /// Non-object JSON kinds explicitly handled by chart dispatch.
        handled_kinds: Vec<String>,
    },
    /// The value is iterated by `range`: collections and nil render, and
    /// integer counts iterate when the loop body has no member structure.
    Iterable {
        /// Whether Helm's integer-count range form remains accepted.
        allow_integer: bool,
    },
    /// A zero-based position must exist before `index` can project it.
    /// Arrays lower exactly; strings remain conservative because Go indexes
    /// bytes while JSON Schema `minLength` counts Unicode code points.
    IndexableAt(usize),
    /// Splitting the textual form must produce at least `segments` entries.
    /// When the input was first passed through a total text conversion,
    /// non-string inputs remain conservatively accepted.
    SplitSegmentsAtLeast {
        /// Literal delimiter used by the split operation.
        separator: String,
        /// Minimum number of produced segments.
        segments: usize,
        /// Whether a preceding total conversion admits non-string inputs.
        allow_non_string: bool,
    },
    /// The value renders inside a manually quoted YAML scalar: every string
    /// it contributes to the token — the value itself, or any nested string
    /// or mapping key when Go's fmt serializes a collection
    /// (`map[k:v]` / `[a b]`) with its strings embedded raw — must be valid
    /// content for the quoting style. Non-string scalars format as plain
    /// digits/words and are always safe.
    QuotedSerializationSafe {
        /// YAML quoting grammar that serialized content must satisfy.
        style: QuotedScalarStyle,
    },
}

impl ContractPathSchemaEvidence {
    /// Reports whether positive, unconditional evidence can make the path required.
    #[must_use]
    pub fn is_required_inference_candidate(&self) -> bool {
        self.requiredness.is_positive_header
            && !self.requiredness.has_default_fallback
            && !self.requiredness.is_conditionally_optional
            && self.facts.has_non_self_guarded_render_use()
    }
}

/// Contract-derived facts consumed by core values-schema generation.
///
/// This is the typed boundary between static template interpretation and JSON
/// Schema lowering. Optional post-passes can ask for their own projections,
/// but core schema generation should consume this artifact rather than
/// re-reading raw contract claims.
#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct ContractSchemaSignals {
    schema_evidence_by_value_path: BTreeMap<String, ContractPathSchemaEvidence>,
    referenced_value_paths: BTreeSet<String>,
    pruned_parent_value_paths: BTreeSet<String>,
    direct_ranged_value_paths: BTreeSet<String>,
    values_default_sources: BTreeSet<ValuesDefaultSource>,
    values_program_wrappers: BTreeSet<ValuesProgramWrapper>,
    /// Values paths whose nodes must not gain a wrapper alternative: a
    /// strict string consumer reads them before the engine's values-root
    /// rewrite, so a wrapper map there aborts rendering.
    values_program_wrapper_exclusions: BTreeSet<String>,
    /// Terminating validator formulas spanning several paths: rendering
    /// aborts whenever ALL guards of one clause hold, so no valid values
    /// document may satisfy them (`fail`/`required` under fully lowerable
    /// cross-path conditions).
    terminal_clauses: Vec<Vec<ConditionalGuard>>,
}

impl ContractSchemaSignals {
    /// Builds a stable signal set from path evidence and terminal clauses.
    #[must_use]
    pub fn new(
        schema_evidence_by_value_path: BTreeMap<String, ContractPathSchemaEvidence>,
        terminal_clauses: Vec<Vec<ConditionalGuard>>,
    ) -> Self {
        let referenced_value_paths = schema_evidence_by_value_path
            .iter()
            .filter(|(_, evidence)| evidence.is_referenced_value_path)
            .map(|(path, _)| path.clone())
            .collect();
        let pruned_parent_value_paths = schema_evidence_by_value_path
            .iter()
            .filter(|(_, evidence)| {
                evidence.facts.has_referenced_descendants && !evidence.facts.used_as_fragment
            })
            .map(|(path, _)| path.clone())
            .collect();
        let direct_ranged_value_paths = schema_evidence_by_value_path
            .iter()
            .filter(|(_, evidence)| evidence.facts.is_direct_ranged_source)
            .map(|(path, _)| path.clone())
            .collect();
        Self {
            schema_evidence_by_value_path,
            referenced_value_paths,
            pruned_parent_value_paths,
            direct_ranged_value_paths,
            values_default_sources: BTreeSet::new(),
            values_program_wrappers: BTreeSet::new(),
            values_program_wrapper_exclusions: BTreeSet::new(),
            terminal_clauses,
        }
    }

    /// Attaches chart subtrees that supply runtime defaults to effective values paths.
    #[must_use]
    pub fn with_values_default_sources(
        mut self,
        sources: impl IntoIterator<Item = ValuesDefaultSource>,
    ) -> Self {
        self.values_default_sources.extend(sources);
        self
    }

    /// Default subtrees applied to effective values before templates consume them.
    #[must_use]
    pub fn values_default_sources(&self) -> &BTreeSet<ValuesDefaultSource> {
        &self.values_default_sources
    }

    /// Projects fail-grade contracts on effective-root paths onto their
    /// prefixed spellings for every in-place root overlay
    /// (`mustMergeOverwrite $.Values (index $.Values "pilot")`): a member
    /// the user writes under the prefix overwrites its effective-root twin
    /// before any consumer reads it, so the same abort-grade requirements
    /// bind the prefixed path (istiod's `pilot.env: "oops"` aborts exactly
    /// like `env: "oops"`). Guards about the subject path or its
    /// descendants move to the prefixed spelling; foreign guard paths keep
    /// their root spellings — a bounded reading that assumes cross-path
    /// conditions are supplied at the root, not through the same overlay.
    #[must_use]
    pub fn with_root_overlay_fail_implications(
        mut self,
        prefixes: impl IntoIterator<Item = String>,
    ) -> Self {
        for prefix in prefixes {
            if prefix.trim().is_empty() {
                continue;
            }
            let twins: Vec<(String, Vec<ContractFailImplication>)> = self
                .schema_evidence_by_value_path
                .iter()
                .filter(|(path, evidence)| {
                    !evidence.fail_implications.is_empty()
                        && path.as_str() != prefix
                        && !crate::values_path_is_descendant(path, &prefix)
                        && !crate::values_path_is_descendant(&prefix, path)
                })
                .map(|(path, evidence)| {
                    let implications = evidence
                        .fail_implications
                        .iter()
                        .map(|implication| {
                            let mut twin = implication.clone();
                            twin.outer_guards = twin
                                .outer_guards
                                .into_iter()
                                .map(|guard| {
                                    guard.map_value_paths(&mut |guard_path: &str| {
                                        if guard_path == path
                                            || crate::values_path_is_descendant(guard_path, path)
                                        {
                                            format!("{prefix}.{guard_path}")
                                        } else {
                                            guard_path.to_string()
                                        }
                                    })
                                })
                                .collect();
                            twin
                        })
                        .collect();
                    (format!("{prefix}.{path}"), implications)
                })
                .collect();
            for (twin_path, implications) in twins {
                let entry = self
                    .schema_evidence_by_value_path
                    .entry(twin_path.clone())
                    .or_insert_with(|| ContractPathSchemaEvidence {
                        value_path: twin_path,
                        ..ContractPathSchemaEvidence::default()
                    });
                for implication in implications {
                    if !entry.fail_implications.contains(&implication) {
                        entry.fail_implications.push(implication);
                    }
                }
            }
        }
        self
    }

    /// Attaches chart-authored program-wrapper conventions.
    #[must_use]
    pub fn with_values_program_wrappers(
        mut self,
        wrappers: impl IntoIterator<Item = ValuesProgramWrapper>,
    ) -> Self {
        self.values_program_wrappers.extend(wrappers);
        self
    }

    /// Program-wrapper conventions the chart's engine applies to its values.
    #[must_use]
    pub fn values_program_wrappers(&self) -> &BTreeSet<ValuesProgramWrapper> {
        &self.values_program_wrappers
    }

    /// Attaches paths excluded from wrapper alternatives (pre-rewrite
    /// strict consumers).
    #[must_use]
    pub fn with_values_program_wrapper_exclusions(
        mut self,
        paths: impl IntoIterator<Item = String>,
    ) -> Self {
        self.values_program_wrapper_exclusions.extend(paths);
        self
    }

    /// Values paths whose nodes must not gain a wrapper alternative.
    #[must_use]
    pub fn values_program_wrapper_exclusions(&self) -> &BTreeSet<String> {
        &self.values_program_wrapper_exclusions
    }

    /// Paths the chart ranges DIRECTLY: their runtime iterable domain is
    /// wider than any declared shape, so ancestor subtree schemas must not
    /// shadow their own resolutions.
    #[must_use]
    pub fn direct_ranged_value_paths(&self) -> &BTreeSet<String> {
        &self.direct_ranged_value_paths
    }

    /// Terminating validator formulas: no valid values document satisfies
    /// all guards of one clause.
    #[must_use]
    pub fn terminal_clauses(&self) -> &[Vec<ConditionalGuard>] {
        &self.terminal_clauses
    }

    /// Returns schema-lowering evidence indexed by canonical values path.
    #[must_use]
    pub fn schema_evidence_by_value_path(&self) -> &BTreeMap<String, ContractPathSchemaEvidence> {
        &self.schema_evidence_by_value_path
    }

    /// Values paths the contract directly referenced, in stable order.
    #[must_use]
    pub fn referenced_value_paths(&self) -> &BTreeSet<String> {
        &self.referenced_value_paths
    }

    /// Non-fragment parent paths whose referenced descendants own their own
    /// schema evidence, so parent-level defaults must not restate them.
    #[must_use]
    pub fn pruned_parent_value_paths(&self) -> &BTreeSet<String> {
        &self.pruned_parent_value_paths
    }

    /// Returns schema evidence for one canonical values path.
    #[must_use]
    pub fn evidence_for(&self, value_path: &str) -> Option<&ContractPathSchemaEvidence> {
        self.schema_evidence_by_value_path.get(value_path)
    }
}

/// Schema-generation facts for one input values path.
///
/// This bundles the contract-owned path state that schema lowering needs, so
/// generator code does not have to reconstruct semantic facts from multiple
/// lower-level projections.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ContractValuePathFacts {
    /// Whether analysis observed referenced paths below this path.
    pub has_referenced_descendants: bool,
    /// Descendant rows that continue through a `*` item segment. Item rows
    /// describe a ranged collection's element shape; a literal member read
    /// (e.g. a guard probing one key of a user-populated map) does not.
    pub has_item_descendants: bool,
    /// Item descendants that continue INTO element structure (`p.*.field`).
    /// A bare `p.*` value row proves no LIST shape: `range` iterates maps
    /// too, so declared-empty maps with only bare member-value rows stay
    /// user-populated.
    pub has_structured_item_descendants: bool,
    /// Whether the path renders as a structural YAML fragment.
    pub used_as_fragment: bool,
    /// The path renders through a serializing or total-stringification sink
    /// (`tpl (toYaml …)`, `quote`, `toString`, `join`): any input type
    /// renders, so the use exposes provenance but no input shape.
    pub used_as_serialized: bool,
    /// The path is rendered through `toYaml`. The input kind is unrestricted,
    /// while the resulting YAML fragment still obeys structural placement.
    pub used_as_yaml_serialized: bool,
    /// A string-consuming transform (`trunc`, `b64enc`, `fromYaml`, a
    /// dynamic `printf` format) bound a real runtime string contract on the
    /// path: rendering fails for non-string values, so this typing survives
    /// even when another use stringifies the path.
    pub has_string_contract: bool,
    /// Some `path.*` member row carries a runtime string contract (`tpl`
    /// over each ranged member): integer iteration yields int members the
    /// contract rejects, so the integer lane closes.
    pub has_string_contract_items: bool,
    /// Whether fragment rendering lost a precise output location.
    pub used_as_pathless_fragment: bool,
    /// Whether the path may supply the chart's complete values-root fragment.
    pub accepted_values_root_fragment: bool,
    /// Whether the path may supply a dependency values-root fragment.
    pub accepted_dependency_values_root_fragment: bool,
    /// Whether this path or one of its projections supplies a range action.
    pub is_ranged_source: bool,
    /// The chart ranges this path DIRECTLY (`range .Values.x`), so the
    /// runtime iterable domain applies to the path's own value.
    pub is_direct_ranged_source: bool,
    /// Some direct range over this path uses TWO variables
    /// (`range $k, $v := …`): integers iterate single-variable ranges only
    /// ("can't use 2 to iterate over more than one variable").
    pub has_destructured_range_use: bool,
    /// Some direct range sees the path after JSON decoding, where numbers are
    /// `float64` values rather than Helm's integer iteration counts.
    pub has_json_decoded_range_use: bool,
    /// Whether the path contributes only part of a rendered scalar token.
    pub is_partial_scalar_value_path: bool,
    /// Whether any rendering sink consumes the path.
    pub has_render_use: bool,
    /// Whether a rendering sink consumes the path without a branch guard.
    pub has_unconditional_render_use: bool,
    /// Whether any rendering sink is guarded by this path's own truthiness.
    pub has_self_guarded_render_use: bool,
    /// Whether every rendering sink is guarded by this path's own truthiness.
    pub all_render_uses_self_guarded: bool,
    /// A render consumed this path as one layer of an ordered merge: the
    /// generator synthesizes the layer's typing as root arms, and the
    /// layer's synthetic self-truthiness guard must not drive base
    /// classification (a declared `{}` default stays an open map — the
    /// merged sink renders any user-supplied members).
    pub has_merge_layered_use: bool,
    /// Every render use either sits behind the path's own truthy selection or
    /// cannot reject a Helm-falsy value at all: a `merge` operand's strict
    /// map contract rides its fail implication (which keys on the call's live
    /// gate), and a checksum digest row hashes re-rendered text without
    /// consuming the raw value. Unlike `all_render_uses_self_guarded`, this
    /// bit feeds ONLY the base falsy escape — never overlay-branch routing or
    /// declared-default placement.
    pub all_render_uses_falsy_tolerant: bool,
    /// Whether a direct range guard protects a rendering sink for this path.
    pub has_self_range_guard_render_use: bool,
    /// Whether observed semantics explicitly admit null.
    pub is_nullable: bool,
}

impl ContractValuePathFacts {
    /// Incorporates one rendering use into the aggregate path facts.
    pub fn record_render_use(
        &mut self,
        range_guarded: bool,
        self_guarded: Option<bool>,
        falsy_tolerant: Option<bool>,
    ) {
        if !self.has_render_use {
            self.all_render_uses_self_guarded = true;
            self.all_render_uses_falsy_tolerant = true;
        }
        self.has_render_use = true;
        self.has_self_range_guard_render_use |= range_guarded;
        if let Some(self_guarded) = self_guarded {
            self.has_self_guarded_render_use |= self_guarded;
            self.all_render_uses_self_guarded &= self_guarded;
        }
        if let Some(falsy_tolerant) = falsy_tolerant {
            self.all_render_uses_falsy_tolerant &= falsy_tolerant;
        }
    }

    /// Merges rendering facts collected by another analysis branch.
    pub fn merge_render_use_facts(&mut self, other: Self) {
        if !other.has_render_use {
            return;
        }
        if !self.has_render_use {
            self.all_render_uses_self_guarded = true;
            self.all_render_uses_falsy_tolerant = true;
        }
        self.has_render_use = true;
        self.has_unconditional_render_use |= other.has_unconditional_render_use;
        self.has_self_guarded_render_use |= other.has_self_guarded_render_use;
        self.has_merge_layered_use |= other.has_merge_layered_use;
        self.has_self_range_guard_render_use |= other.has_self_range_guard_render_use;
        self.all_render_uses_self_guarded &= other.all_render_uses_self_guarded;
        self.all_render_uses_falsy_tolerant &= other.all_render_uses_falsy_tolerant;
    }

    #[must_use]
    pub(crate) fn has_non_self_guarded_render_use(self) -> bool {
        self.has_render_use
            && !self.has_self_guarded_render_use
            && !self.all_render_uses_self_guarded
    }
}

/// Path-local evidence consumed by the optional `--infer-required` post-pass.
///
/// These are still static-analysis facts, not a decision that the path must be
/// required. The generator combines them with render-use facts and chart
/// defaults before mutating the JSON Schema.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ContractRequirednessEvidence {
    /// Whether the path appears in a positive control-flow header.
    pub is_positive_header: bool,
    /// Whether some branch permits the path to remain absent.
    pub is_conditionally_optional: bool,
    /// Whether a defaulting operation supplies an absent value.
    pub has_default_fallback: bool,
}