import PureYAML

public extension PureYAML.JSON {
    /// JSON-representability checks built on PureYAML's own validation framework.
    /// The parser already guarantees the input is well-formed YAML (and so covers
    /// JSON syntax); this layer reports the value-level reasons a tree cannot be
    /// emitted as JSON: a non-string mapping key, a non-finite number, or (for a
    /// deterministic single-meaning document) a duplicate key.
    ///
    /// JSON the format tolerates duplicate object names, but a tree that carries two
    /// pairs with the same key emits an ambiguous document, so the representability
    /// validator rejects duplicates for determinism. Drop ``unique`` from the rule
    /// set if you want the permissive reading.
    enum Validator {
        /// The full JSON-representability rule set: unique keys, string keys, finite
        /// numbers. Suitable to pass straight to `PureYAML.JSON.Convert`.
        public static var representability: PureYAML.Validation.Validator {
            PureYAML.Validation.Validator(rules: [
                .mappingKeysAreUnique,
                .mappingKeysAreStrings,
                .numbersAreFinite,
            ])
        }

        /// Every reason the value cannot be emitted as strict JSON, in document order.
        public static func issues(for value: PureYAML.Model.Value) -> [PureYAML.Validation.Issue] {
            representability.collect(value).issues
        }

        /// Whether the value can be emitted as strict JSON.
        public static func isRepresentable(_ value: PureYAML.Model.Value) -> Bool {
            issues(for: value).isEmpty
        }
    }
}