rustrails-model 0.1.2

use std::fmt;
use std::sync::Arc;

use serde_json::Value;

use crate::errors::Errors;

/// Shared predicate type used by conditional validator options.
pub type ValidationPredicate = Arc<dyn Fn(&Value) -> bool + Send + Sync>;
type ValidateFn = dyn Fn(&str, Option<&Value>, &mut Errors) + Send + Sync;
pub type ModelValidationFn = dyn Fn(&dyn Fn(&str) -> Option<Value>, &mut Errors) + Send + Sync;

macro_rules! impl_common_validator_methods {
    () => {
        /// Skips validation when the attribute value is missing or `null`.
        #[must_use]
        pub fn allow_nil(mut self) -> Self {
            self.options.allow_nil = true;
            self
        }

        /// Skips validation when the attribute value is blank.
        #[must_use]
        pub fn allow_blank(mut self) -> Self {
            self.options.allow_blank = true;
            self
        }

        /// Restricts the validator to the provided contexts.
        #[must_use]
        pub fn on(mut self, contexts: Vec<crate::validations::ValidationContext>) -> Self {
            self.options.on = Some(contexts);
            self
        }

        /// Raises immediately instead of collecting produced errors.
        #[must_use]
        pub fn strict(mut self) -> Self {
            self.options.strict = true;
            self
        }

        /// Runs the validator only when the predicate returns `true`.
        #[must_use]
        pub fn if_cond<F>(mut self, cond: F) -> Self
        where
            F: Fn(&serde_json::Value) -> bool + Send + Sync + 'static,
        {
            self.options.if_cond = Some(std::sync::Arc::new(cond));
            self
        }

        /// Skips the validator when the predicate returns `true`.
        #[must_use]
        pub fn unless_cond<F>(mut self, cond: F) -> Self
        where
            F: Fn(&serde_json::Value) -> bool + Send + Sync + 'static,
        {
            self.options.unless_cond = Some(std::sync::Arc::new(cond));
            self
        }
    };
}

pub(crate) use impl_common_validator_methods;

pub mod acceptance;
pub mod confirmation;
pub mod custom;
pub mod exclusion;
pub mod format;
pub mod inclusion;
pub mod length;
pub mod numericality;
pub mod presence;
pub mod uniqueness;

pub use acceptance::AcceptanceValidator;
pub use confirmation::ConfirmationValidator;
pub use custom::CustomValidator;
pub use exclusion::ExclusionValidator;
pub use format::FormatValidator;
pub use inclusion::InclusionValidator;
pub use length::LengthValidator;
pub use numericality::NumericalityValidator;
pub use presence::PresenceValidator;
pub use uniqueness::UniquenessValidator;

/// Contexts that can selectively enable validation rules.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ValidationContext {
    /// Validation while creating a new record.
    Create,
    /// Validation while updating an existing record.
    Update,
    /// Validation during a generic save operation.
    Save,
    /// An application-defined validation context.
    Custom(String),
}

/// Shared runtime options applied by the validation runner.
#[derive(Clone, Default)]
pub struct ValidatorOptions {
    /// Skips validation for missing or `null` values.
    pub allow_nil: bool,
    /// Skips validation for blank values such as empty strings.
    pub allow_blank: bool,
    /// Restricts the validator to explicit contexts.
    pub on: Option<Vec<ValidationContext>>,
    /// Raises immediately instead of collecting produced errors.
    pub strict: bool,
    /// Runs the validator only when the predicate returns `true`.
    pub if_cond: Option<ValidationPredicate>,
    /// Skips the validator when the predicate returns `true`.
    pub unless_cond: Option<ValidationPredicate>,
}

impl fmt::Debug for ValidatorOptions {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        formatter
            .debug_struct("ValidatorOptions")
            .field("allow_nil", &self.allow_nil)
            .field("allow_blank", &self.allow_blank)
            .field("on", &self.on)
            .field("strict", &self.strict)
            .field("if_cond", &self.if_cond.as_ref().map(|_| "<predicate>"))
            .field(
                "unless_cond",
                &self.unless_cond.as_ref().map(|_| "<predicate>"),
            )
            .finish()
    }
}

/// A validation rule that can check a value and report errors.
pub trait Validator: Send + Sync {
    /// Validates a single attribute value, adding any produced errors.
    fn validate(&self, attribute: &str, value: Option<&Value>, errors: &mut Errors);

    /// Validates a single attribute with access to sibling attributes when needed.
    fn validate_with_attrs(
        &self,
        attribute: &str,
        value: Option<&Value>,
        _attrs: &dyn Fn(&str) -> Option<Value>,
        errors: &mut Errors,
    ) {
        self.validate(attribute, value, errors);
    }

    /// Returns the validator's display name.
    fn name(&self) -> &str;

    /// Returns the common runtime options for this validator.
    fn options(&self) -> &ValidatorOptions;
}

/// A single attribute-to-validator binding.
pub struct ValidationRule {
    /// Attribute validated by the rule.
    pub attribute: String,
    /// Validator instance that performs the check.
    pub validator: Box<dyn Validator>,
}

/// Ordered collection of validation rules for a model type.
#[derive(Default)]
pub struct ValidationSet {
    rules: Vec<ValidationRule>,
}

impl ValidationSet {
    /// Creates an empty validation set.
    #[must_use]
    pub fn new() -> Self {
        Self::default()
    }

    /// Adds a validator for the given attribute.
    pub fn add(&mut self, attribute: impl Into<String>, validator: impl Validator + 'static) {
        self.rules.push(ValidationRule {
            attribute: attribute.into(),
            validator: Box::new(validator),
        });
    }

    /// Returns validators registered for the given attribute in registration order.
    #[must_use]
    pub fn validators_on(&self, attribute: &str) -> Vec<&dyn Validator> {
        self.rules
            .iter()
            .filter(|rule| rule.attribute == attribute)
            .map(|rule| rule.validator.as_ref())
            .collect()
    }

    /// Runs all validations and appends any produced errors.
    pub fn validate(
        &self,
        attrs: &dyn Fn(&str) -> Option<Value>,
        errors: &mut Errors,
    ) -> Result<(), String> {
        self.validate_internal(attrs, errors, None)
    }

    /// Runs validations for a specific context.
    pub fn validate_with_context(
        &self,
        attrs: &dyn Fn(&str) -> Option<Value>,
        errors: &mut Errors,
        context: &ValidationContext,
    ) -> Result<(), String> {
        self.validate_internal(attrs, errors, Some(context))
    }

    fn validate_internal(
        &self,
        attrs: &dyn Fn(&str) -> Option<Value>,
        errors: &mut Errors,
        context: Option<&ValidationContext>,
    ) -> Result<(), String> {
        for rule in &self.rules {
            let value = attrs(&rule.attribute);
            if should_skip(rule.validator.options(), value.as_ref(), context) {
                continue;
            }

            let mut produced = Errors::new();
            rule.validator.validate_with_attrs(
                &rule.attribute,
                value.as_ref(),
                attrs,
                &mut produced,
            );

            if produced.is_empty() {
                continue;
            }

            if rule.validator.options().strict {
                return Err(strict_error_message(&produced));
            }

            merge_errors(errors, &produced);
        }

        Ok(())
    }
}

pub trait ValidationDsl {
    fn validates_each<I, S, F>(&mut self, attributes: I, validate_fn: F)
    where
        I: IntoIterator<Item = S>,
        S: Into<String>,
        F: Fn(&str, Option<&Value>, &mut Errors) + Send + Sync + 'static;

    fn validate<F>(&mut self, validate_fn: F)
    where
        F: Fn(&dyn Fn(&str) -> Option<Value>, &mut Errors) + Send + Sync + 'static;
}

impl ValidationDsl for ValidationSet {
    fn validates_each<I, S, F>(&mut self, attributes: I, validate_fn: F)
    where
        I: IntoIterator<Item = S>,
        S: Into<String>,
        F: Fn(&str, Option<&Value>, &mut Errors) + Send + Sync + 'static,
    {
        let validate_fn: Arc<ValidateFn> = Arc::new(validate_fn);

        for attribute in attributes {
            self.add(
                attribute.into(),
                EachValidator::new(Arc::clone(&validate_fn)),
            );
        }
    }

    fn validate<F>(&mut self, validate_fn: F)
    where
        F: Fn(&dyn Fn(&str) -> Option<Value>, &mut Errors) + Send + Sync + 'static,
    {
        self.add("base", ModelValidator::new(validate_fn));
    }
}

#[derive(Clone)]
struct EachValidator {
    validate_fn: Arc<ValidateFn>,
    options: ValidatorOptions,
}

impl EachValidator {
    fn new(validate_fn: Arc<ValidateFn>) -> Self {
        Self {
            validate_fn,
            options: ValidatorOptions::default(),
        }
    }
}

impl Validator for EachValidator {
    fn validate(&self, attribute: &str, value: Option<&Value>, errors: &mut Errors) {
        (self.validate_fn)(attribute, value, errors);
    }

    fn name(&self) -> &str {
        "each"
    }

    fn options(&self) -> &ValidatorOptions {
        &self.options
    }
}

struct ModelValidator {
    validate_fn: Box<ModelValidationFn>,
    options: ValidatorOptions,
}

impl ModelValidator {
    fn new<F>(validate_fn: F) -> Self
    where
        F: Fn(&dyn Fn(&str) -> Option<Value>, &mut Errors) + Send + Sync + 'static,
    {
        Self {
            validate_fn: Box::new(validate_fn),
            options: ValidatorOptions::default(),
        }
    }
}

impl Validator for ModelValidator {
    fn validate(&self, _attribute: &str, _value: Option<&Value>, errors: &mut Errors) {
        (self.validate_fn)(&|_| None, errors);
    }

    fn validate_with_attrs(
        &self,
        _attribute: &str,
        _value: Option<&Value>,
        attrs: &dyn Fn(&str) -> Option<Value>,
        errors: &mut Errors,
    ) {
        (self.validate_fn)(attrs, errors);
    }

    fn name(&self) -> &str {
        "validate"
    }

    fn options(&self) -> &ValidatorOptions {
        &self.options
    }
}

fn merge_errors(target: &mut Errors, produced: &Errors) {
    for error in produced.details() {
        target.add_with_details(
            &error.attribute,
            error.error_type.clone(),
            error.message.clone(),
            error.details.clone(),
        );
    }
}

fn strict_error_message(errors: &Errors) -> String {
    errors
        .full_messages()
        .into_iter()
        .next()
        .unwrap_or_else(|| String::from("validation failed"))
}

pub(crate) fn should_skip(
    options: &ValidatorOptions,
    value: Option<&Value>,
    context: Option<&ValidationContext>,
) -> bool {
    if !context_matches(options.on.as_deref(), context) {
        return true;
    }

    if options.allow_nil && value_is_nil(value) {
        return true;
    }

    if options.allow_blank && value_is_blank(value) {
        return true;
    }

    let null = Value::Null;
    let candidate = value.unwrap_or(&null);

    if let Some(predicate) = &options.if_cond
        && !predicate(candidate)
    {
        return true;
    }

    if let Some(predicate) = &options.unless_cond
        && predicate(candidate)
    {
        return true;
    }

    false
}

pub(crate) fn context_matches(
    allowed: Option<&[ValidationContext]>,
    current: Option<&ValidationContext>,
) -> bool {
    let Some(allowed) = allowed else {
        return true;
    };
    let Some(current) = current else {
        return true;
    };

    allowed.iter().any(|candidate| match (candidate, current) {
        (ValidationContext::Save, _) => true,
        (ValidationContext::Create, ValidationContext::Create)
        | (ValidationContext::Update, ValidationContext::Update)
        | (ValidationContext::Custom(_), ValidationContext::Custom(_)) => candidate == current,
        _ => false,
    })
}

pub(crate) fn value_is_nil(value: Option<&Value>) -> bool {
    matches!(value, None | Some(Value::Null))
}

pub(crate) fn value_is_blank(value: Option<&Value>) -> bool {
    match value {
        None | Some(Value::Null) => true,
        Some(Value::String(text)) => text.trim().is_empty(),
        Some(Value::Array(values)) => values.is_empty(),
        Some(Value::Object(values)) => values.is_empty(),
        Some(Value::Bool(flag)) => !flag,
        Some(Value::Number(_)) => false,
    }
}

/// Creates a presence validator.
#[must_use]
pub fn presence() -> PresenceValidator {
    PresenceValidator::new()
}

/// Creates a length validator.
#[must_use]
pub fn length() -> LengthValidator {
    LengthValidator::new()
}

/// Creates a numericality validator.
#[must_use]
pub fn numericality() -> NumericalityValidator {
    NumericalityValidator::new()
}

/// Creates a format validator that requires the given regex pattern to match.
#[must_use]
pub fn format_with(pattern: &str) -> FormatValidator {
    FormatValidator::with_pattern(pattern)
}

/// Creates an inclusion validator over the provided values.
#[must_use]
pub fn inclusion<T>(values: T) -> InclusionValidator
where
    T: Into<Vec<Value>>,
{
    InclusionValidator::new(values)
}

/// Creates an exclusion validator over the provided values.
#[must_use]
pub fn exclusion<T>(values: T) -> ExclusionValidator
where
    T: Into<Vec<Value>>,
{
    ExclusionValidator::new(values)
}

/// Creates an acceptance validator with the default accepted values.
#[must_use]
pub fn acceptance() -> AcceptanceValidator {
    AcceptanceValidator::new()
}

/// Creates a confirmation validator for the given confirmation attribute.
#[must_use]
pub fn confirmation(confirmation_field: &str) -> ConfirmationValidator {
    ConfirmationValidator::new(confirmation_field)
}

/// Creates a uniqueness validator.
#[must_use]
pub fn uniqueness() -> UniquenessValidator {
    UniquenessValidator::new()
}

/// Creates a custom validator from a caller-provided function.
#[must_use]
pub fn custom<F>(f: F) -> CustomValidator
where
    F: Fn(&str, Option<&Value>, &mut Errors) + Send + Sync + 'static,
{
    CustomValidator::new(f)
}

#[cfg(test)]
mod tests {
    use std::collections::HashMap;
    use std::sync::{
        Arc,
        atomic::{AtomicBool, Ordering},
    };

    use serde_json::{Value, json};

    use super::{
        ValidationContext, ValidationDsl, ValidationSet, Validator, ValidatorOptions,
        context_matches, custom, length, presence, should_skip, value_is_blank, value_is_nil,
    };
    use crate::errors::{ErrorType, Errors};

    #[derive(Default)]
    struct MarkerValidator {
        options: ValidatorOptions,
    }

    impl MarkerValidator {
        fn new() -> Self {
            Self::default()
        }

        fn allow_nil(mut self) -> Self {
            self.options.allow_nil = true;
            self
        }

        fn allow_blank(mut self) -> Self {
            self.options.allow_blank = true;
            self
        }

        fn on(mut self, contexts: Vec<ValidationContext>) -> Self {
            self.options.on = Some(contexts);
            self
        }

        fn if_cond<F>(mut self, cond: F) -> Self
        where
            F: Fn(&Value) -> bool + Send + Sync + 'static,
        {
            self.options.if_cond = Some(Arc::new(cond));
            self
        }

        fn unless_cond<F>(mut self, cond: F) -> Self
        where
            F: Fn(&Value) -> bool + Send + Sync + 'static,
        {
            self.options.unless_cond = Some(Arc::new(cond));
            self
        }
    }

    impl Validator for MarkerValidator {
        fn validate(&self, attribute: &str, _value: Option<&Value>, errors: &mut Errors) {
            errors.add(attribute, ErrorType::Custom("marker".to_string()), "ran");
        }

        fn name(&self) -> &str {
            "marker"
        }

        fn options(&self) -> &ValidatorOptions {
            &self.options
        }
    }

    #[test]
    fn blank_detection_matches_validation_needs() {
        assert!(value_is_blank(None));
        assert!(value_is_blank(Some(&Value::Null)));
        assert!(value_is_blank(Some(&json!("   "))));
        assert!(value_is_blank(Some(&json!([]))));
        assert!(value_is_blank(Some(&json!({}))));
        assert!(value_is_blank(Some(&json!(false))));
        assert!(!value_is_blank(Some(&json!(0))));
        assert!(!value_is_blank(Some(&json!("Alice"))));
    }

    #[test]
    fn context_matching_treats_save_as_global() {
        let allowed = vec![ValidationContext::Save];

        assert!(context_matches(
            Some(&allowed),
            Some(&ValidationContext::Create)
        ));
        assert!(context_matches(
            Some(&allowed),
            Some(&ValidationContext::Update)
        ));
        assert!(context_matches(
            Some(&allowed),
            Some(&ValidationContext::Save)
        ));
    }

    #[test]
    fn nil_context_matches_every_restricted_validator() {
        let allowed = vec![ValidationContext::Create, ValidationContext::Update];

        assert!(context_matches(Some(&allowed), None));
    }

    #[test]
    fn should_skip_honors_allow_nil_and_allow_blank() {
        let nil_validator = MarkerValidator::new().allow_nil();
        let blank_validator = MarkerValidator::new().allow_blank();

        assert!(should_skip(
            nil_validator.options(),
            Some(&Value::Null),
            Some(&ValidationContext::Save),
        ));
        assert!(should_skip(
            blank_validator.options(),
            Some(&json!("   ")),
            Some(&ValidationContext::Save),
        ));
    }

    #[test]
    fn should_skip_honors_context_and_predicates() {
        let validator = MarkerValidator::new()
            .on(vec![ValidationContext::Create])
            .if_cond(|value| value == &json!("run"))
            .unless_cond(|value| value == &json!("stop"));

        assert!(should_skip(
            validator.options(),
            Some(&json!("run")),
            Some(&ValidationContext::Update),
        ));
        assert!(should_skip(
            validator.options(),
            Some(&json!("miss")),
            Some(&ValidationContext::Create),
        ));
        assert!(should_skip(
            validator.options(),
            Some(&json!("stop")),
            Some(&ValidationContext::Create),
        ));
        assert!(!should_skip(
            validator.options(),
            Some(&json!("run")),
            Some(&ValidationContext::Create),
        ));
    }

    #[test]
    fn validation_set_runs_matching_validators() {
        let mut set = ValidationSet::new();
        set.add("name", MarkerValidator::new());

        let attrs = HashMap::from([("name".to_string(), json!("Alice"))]);
        let mut errors = Errors::new();

        let _ = set.validate(&|name| attrs.get(name).cloned(), &mut errors);

        assert_eq!(errors.count(), 1);
        assert_eq!(errors.on("name")[0].message, "ran");
    }

    #[test]
    fn validation_set_filters_by_context() {
        let mut set = ValidationSet::new();
        set.add(
            "name",
            MarkerValidator::new().on(vec![ValidationContext::Create]),
        );

        let attrs = HashMap::from([("name".to_string(), json!("Alice"))]);
        let mut errors = Errors::new();

        let _ = set.validate_with_context(
            &|name| attrs.get(name).cloned(),
            &mut errors,
            &ValidationContext::Update,
        );
        assert!(errors.is_empty());

        let _ = set.validate_with_context(
            &|name| attrs.get(name).cloned(),
            &mut errors,
            &ValidationContext::Create,
        );
        assert_eq!(errors.count(), 1);
    }

    #[test]
    fn validation_set_skips_custom_validator_when_blank_is_allowed() {
        let called = Arc::new(AtomicBool::new(false));
        let called_clone = Arc::clone(&called);
        let validator = custom(move |_attribute, _value, _errors| {
            called_clone.store(true, Ordering::Relaxed);
        })
        .allow_blank();

        let mut set = ValidationSet::new();
        set.add("nickname", validator);

        let attrs = HashMap::from([("nickname".to_string(), json!("   "))]);
        let mut errors = Errors::new();
        let _ = set.validate(&|name| attrs.get(name).cloned(), &mut errors);

        assert!(errors.is_empty());
        assert!(!called.load(Ordering::Relaxed));
    }

    #[test]
    fn custom_context_matches_same_name() {
        let allowed = vec![ValidationContext::Custom("import".to_string())];

        assert!(context_matches(
            Some(&allowed),
            Some(&ValidationContext::Custom("import".to_string())),
        ));
    }

    #[test]
    fn custom_context_does_not_match_different_name() {
        let allowed = vec![ValidationContext::Custom("import".to_string())];

        assert!(!context_matches(
            Some(&allowed),
            Some(&ValidationContext::Custom("export".to_string())),
        ));
    }

    #[test]
    fn save_context_matches_custom_context() {
        let allowed = vec![ValidationContext::Save];

        assert!(context_matches(
            Some(&allowed),
            Some(&ValidationContext::Custom("import".to_string())),
        ));
    }

    #[test]
    fn value_is_nil_treats_missing_as_nil() {
        assert!(value_is_nil(None));
    }

    #[test]
    fn value_is_nil_treats_null_as_nil() {
        assert!(value_is_nil(Some(&Value::Null)));
    }

    #[test]
    fn value_is_nil_rejects_present_value() {
        assert!(!value_is_nil(Some(&json!(0))));
    }

    #[test]
    fn should_skip_uses_null_for_if_predicates_when_value_is_missing() {
        let validator = MarkerValidator::new().if_cond(Value::is_null);

        assert!(!should_skip(
            validator.options(),
            None,
            Some(&ValidationContext::Save),
        ));
    }

    #[test]
    fn should_skip_uses_null_for_unless_predicates_when_value_is_missing() {
        let validator = MarkerValidator::new().unless_cond(Value::is_null);

        assert!(should_skip(
            validator.options(),
            None,
            Some(&ValidationContext::Save),
        ));
    }

    #[test]
    fn should_not_skip_present_values_without_options() {
        let validator = MarkerValidator::new();

        assert!(!should_skip(
            validator.options(),
            Some(&json!("Alice")),
            Some(&ValidationContext::Save),
        ));
    }

    #[test]
    fn allow_blank_skips_empty_arrays() {
        let validator = MarkerValidator::new().allow_blank();

        assert!(should_skip(
            validator.options(),
            Some(&json!([])),
            Some(&ValidationContext::Save),
        ));
    }

    #[test]
    fn allow_blank_skips_empty_objects() {
        let validator = MarkerValidator::new().allow_blank();

        assert!(should_skip(
            validator.options(),
            Some(&json!({})),
            Some(&ValidationContext::Save),
        ));
    }

    #[test]
    fn validation_set_preserves_rule_order_for_same_attribute() {
        let mut set = ValidationSet::new();
        set.add(
            "name",
            custom(|attribute, _value, errors| {
                errors.add(
                    attribute,
                    ErrorType::Custom("global-first".to_string()),
                    "global-first",
                );
            }),
        );
        set.add(
            "name",
            custom(|attribute, _value, errors| {
                errors.add(
                    attribute,
                    ErrorType::Custom("create-only".to_string()),
                    "create-only",
                );
            })
            .on(vec![ValidationContext::Create]),
        );
        set.add(
            "name",
            custom(|attribute, _value, errors| {
                errors.add(
                    attribute,
                    ErrorType::Custom("update-only".to_string()),
                    "update-only",
                );
            })
            .on(vec![ValidationContext::Update]),
        );
        set.add(
            "name",
            custom(|attribute, _value, errors| {
                errors.add(
                    attribute,
                    ErrorType::Custom("global-last".to_string()),
                    "global-last",
                );
            }),
        );

        let attrs = HashMap::from([("name".to_string(), json!("Alice"))]);
        let mut errors = Errors::new();

        let _ = set.validate_with_context(
            &|name| attrs.get(name).cloned(),
            &mut errors,
            &ValidationContext::Create,
        );

        assert_eq!(
            errors.messages_for("name"),
            vec![
                "global-first".to_string(),
                "create-only".to_string(),
                "global-last".to_string(),
            ]
        );
    }

    #[test]
    fn validation_set_skips_allow_nil_rule_but_runs_required_rule_for_missing_value() {
        let mut set = ValidationSet::new();
        set.add(
            "nickname",
            custom(|attribute, _value, errors| {
                errors.add(
                    attribute,
                    ErrorType::Custom("optional".to_string()),
                    "optional",
                );
            })
            .allow_nil(),
        );
        set.add(
            "nickname",
            custom(|attribute, _value, errors| {
                errors.add(
                    attribute,
                    ErrorType::Custom("required".to_string()),
                    "required",
                );
            }),
        );
        let attrs: HashMap<String, Value> = HashMap::new();
        let mut errors = Errors::new();

        let _ = set.validate(&|name| attrs.get(name).cloned(), &mut errors);

        assert_eq!(
            errors.messages_for("nickname"),
            vec!["required".to_string()]
        );
    }

    fn validate_errors(
        set: &ValidationSet,
        attrs: HashMap<String, Value>,
        context: Option<ValidationContext>,
    ) -> Errors {
        let mut errors = Errors::new();

        match context {
            Some(context) => {
                let _ = set.validate_with_context(
                    &|name| attrs.get(name).cloned(),
                    &mut errors,
                    &context,
                );
            }
            None => {
                let _ = set.validate(&|name| attrs.get(name).cloned(), &mut errors);
            }
        }

        errors
    }

    struct ProcMessageValidator {
        include_attribute: bool,
        options: ValidatorOptions,
    }

    impl ProcMessageValidator {
        fn from_record() -> Self {
            Self {
                include_attribute: false,
                options: ValidatorOptions::default(),
            }
        }

        fn from_record_and_data() -> Self {
            Self {
                include_attribute: true,
                options: ValidatorOptions::default(),
            }
        }

        fn build_message(&self, attribute: &str, attrs: &dyn Fn(&str) -> Option<Value>) -> String {
            let author_name = attrs("author_name")
                .and_then(|value| value.as_str().map(str::to_owned))
                .unwrap_or_default();

            if self.include_attribute {
                format!(
                    "{} is missing. You have failed me for the last time, {}.",
                    rustrails_support::inflector::humanize(attribute),
                    author_name,
                )
            } else {
                format!("You have failed me for the last time, {}.", author_name,)
            }
        }
    }

    impl Validator for ProcMessageValidator {
        fn validate(&self, attribute: &str, _value: Option<&Value>, errors: &mut Errors) {
            errors.add(
                attribute,
                ErrorType::Custom("proc_message".to_string()),
                self.build_message(attribute, &|_| None),
            );
        }

        fn validate_with_attrs(
            &self,
            attribute: &str,
            _value: Option<&Value>,
            attrs: &dyn Fn(&str) -> Option<Value>,
            errors: &mut Errors,
        ) {
            errors.add(
                attribute,
                ErrorType::Custom("proc_message".to_string()),
                self.build_message(attribute, attrs),
            );
        }

        fn name(&self) -> &str {
            "proc_message"
        }

        fn options(&self) -> &ValidatorOptions {
            &self.options
        }
    }

    #[test]
    fn test_single_field_validation() {
        let mut set = ValidationSet::new();
        set.add("content", presence());

        let invalid_errors = validate_errors(
            &set,
            HashMap::from([("title".to_string(), json!("There's no content!"))]),
            None,
        );
        assert!(invalid_errors.any());
        assert_eq!(
            invalid_errors.messages_for("content"),
            vec!["can't be blank".to_string()]
        );

        let valid_errors = validate_errors(
            &set,
            HashMap::from([
                ("title".to_string(), json!("There's no content!")),
                ("content".to_string(), json!("Messa content!")),
            ]),
            None,
        );
        assert!(valid_errors.is_empty());
    }

    #[test]
    fn test_single_attr_validation_and_error_msg() {
        let mut set = ValidationSet::new();
        set.add("content", presence());

        let errors = validate_errors(
            &set,
            HashMap::from([("title".to_string(), json!("There's no content!"))]),
            None,
        );

        assert_eq!(errors.count(), 1);
        assert_eq!(
            errors.messages_for("content"),
            vec!["can't be blank".to_string()]
        );
    }

    #[test]
    fn test_double_attr_validation_and_error_msg() {
        let mut set = ValidationSet::new();
        set.add("title", presence());
        set.add("content", presence());

        let errors = validate_errors(&set, HashMap::new(), None);

        assert_eq!(errors.count(), 2);
        assert_eq!(
            errors.messages_for("title"),
            vec!["can't be blank".to_string()]
        );
        assert_eq!(
            errors.messages_for("content"),
            vec!["can't be blank".to_string()]
        );
    }

    #[test]
    fn test_multiple_errors_per_attr_iteration_with_full_error_composition() {
        let mut set = ValidationSet::new();
        set.add("content", presence());
        set.add("title", presence());

        let errors = validate_errors(
            &set,
            HashMap::from([
                ("title".to_string(), json!("")),
                ("content".to_string(), json!("")),
            ]),
            None,
        );

        assert_eq!(
            errors.full_messages(),
            vec![
                "Content can't be blank".to_string(),
                "Title can't be blank".to_string(),
            ]
        );
        assert_eq!(errors.count(), 2);
    }

    #[test]
    fn test_errors_on_nested_attributes_expands_name() {
        let mut errors = Errors::new();
        errors.add("replies.name", ErrorType::Blank, "can't be blank");

        assert_eq!(
            errors.full_messages(),
            vec!["Replies name can't be blank".to_string()]
        );
    }

    #[test]
    fn test_errors_on_base() {
        let mut errors = Errors::new();
        errors.add("title", ErrorType::Blank, "can't be blank");
        errors.add("base", ErrorType::Invalid, "Reply is not dignifying");

        assert_eq!(
            errors.messages_for("base"),
            vec!["Reply is not dignifying".to_string()]
        );
        assert_eq!(
            errors.full_messages(),
            vec![
                "Title can't be blank".to_string(),
                "Reply is not dignifying".to_string(),
            ]
        );
        assert_eq!(errors.count(), 2);
    }

    #[test]
    fn test_errors_on_base_with_symbol_message() {
        let mut errors = Errors::new();
        errors.add("title", ErrorType::Blank, "can't be blank");
        errors.add("base", ErrorType::Invalid, "is invalid");

        assert_eq!(errors.messages_for("base"), vec!["is invalid".to_string()]);
        assert_eq!(
            errors.full_messages(),
            vec!["Title can't be blank".to_string(), "is invalid".to_string()]
        );
        assert_eq!(errors.count(), 2);
    }

    #[test]
    fn test_errors_on_custom_attribute() {
        let mut errors = Errors::new();
        errors.add("foo_bar", ErrorType::Invalid, "is invalid");

        assert_eq!(
            errors.full_messages(),
            vec!["Foo bar is invalid".to_string()]
        );
    }

    #[test]
    fn test_errors_on_custom_attribute_with_symbol_message() {
        let mut errors = Errors::new();
        errors.add("foo_bar", ErrorType::Invalid, "is invalid");

        assert_eq!(
            errors.full_messages(),
            vec!["Foo bar is invalid".to_string()]
        );
    }

    #[test]
    fn test_errors_empty_after_errors_on_check() {
        let errors = Errors::new();

        assert!(errors.messages_for("id").is_empty());
        assert!(errors.is_empty());
    }

    #[test]
    fn test_validates_each() {
        let mut set = ValidationSet::new();
        set.validates_each(["first_name", "last_name"], |attribute, value, errors| {
            if value
                .and_then(Value::as_str)
                .is_some_and(|text| text.starts_with('z'))
            {
                errors.add(attribute, ErrorType::Invalid, "starts with z");
            }
        });

        let errors = validate_errors(
            &set,
            HashMap::from([
                ("first_name".to_string(), json!("zed")),
                ("last_name".to_string(), json!("alpha")),
            ]),
            None,
        );

        assert_eq!(
            errors.messages_for("first_name"),
            vec!["starts with z".to_string()]
        );
        assert!(errors.messages_for("last_name").is_empty());
    }

    #[test]
    fn test_validate_block() {
        let mut set = ValidationSet::new();
        <ValidationSet as ValidationDsl>::validate(&mut set, |attrs, errors| {
            if attrs("admin")
                .and_then(|value| value.as_bool())
                .unwrap_or(false)
            {
                errors.add("base", ErrorType::Invalid, "admins are not allowed");
            }
        });

        let errors = validate_errors(
            &set,
            HashMap::from([("admin".to_string(), json!(true))]),
            None,
        );

        assert_eq!(
            errors.messages_for("base"),
            vec!["admins are not allowed".to_string()]
        );
    }

    #[test]
    fn test_validate_block_with_params() {
        let mut set = ValidationSet::new();
        <ValidationSet as ValidationDsl>::validate(&mut set, |attrs, errors| {
            let title = attrs("title").and_then(|value| value.as_str().map(str::to_owned));
            let author = attrs("author_name").and_then(|value| value.as_str().map(str::to_owned));

            if title.as_deref() == Some("Forbidden") && author.as_deref() == Some("Robot") {
                errors.add("title", ErrorType::Invalid, "cannot be assigned to Robot");
            }
        });

        let errors = validate_errors(
            &set,
            HashMap::from([
                ("title".to_string(), json!("Forbidden")),
                ("author_name".to_string(), json!("Robot")),
            ]),
            None,
        );

        assert_eq!(
            errors.messages_for("title"),
            vec!["cannot be assigned to Robot".to_string()]
        );
    }

    #[test]
    fn test_callback_options_to_validate() {
        let sequence = Arc::new(std::sync::Mutex::new(Vec::new()));
        let mut set = ValidationSet::new();

        let sequence_b = Arc::clone(&sequence);
        set.add(
            "title",
            custom(move |_attribute, _value, _errors| {
                sequence_b.lock().unwrap().push("b");
            }),
        );

        let sequence_a = Arc::clone(&sequence);
        set.add(
            "title",
            custom(move |_attribute, _value, _errors| {
                sequence_a.lock().unwrap().push("a");
            })
            .if_cond(|_| true),
        );

        let sequence_c = Arc::clone(&sequence);
        set.add(
            "title",
            custom(move |_attribute, _value, _errors| {
                sequence_c.lock().unwrap().push("c");
            })
            .unless_cond(|_| true),
        );

        let errors = validate_errors(
            &set,
            HashMap::from([("title".to_string(), json!("whatever"))]),
            None,
        );

        assert!(errors.is_empty());
        let recorded = sequence.lock().unwrap().clone();
        assert_eq!(recorded, vec!["b", "a"]);
    }

    #[test]
    fn test_errors_to_json() {
        let mut set = ValidationSet::new();
        set.add("title", presence());
        set.add("content", presence());

        let errors = validate_errors(&set, HashMap::new(), None);

        assert_eq!(
            errors.as_json(),
            json!({
                "title": ["can't be blank"],
                "content": ["can't be blank"],
            })
        );
    }

    #[test]
    fn test_validation_order() {
        let mut set = ValidationSet::new();
        set.add("title", presence());
        set.add("title", length().minimum(2));
        set.add("author_name", presence());
        set.add(
            "author_email_address",
            custom(|attribute, _value, errors| {
                errors.add(
                    attribute,
                    ErrorType::Custom("manual".to_string()),
                    "will never be valid",
                );
            }),
        );
        set.add("content", length().minimum(10));

        let errors = validate_errors(
            &set,
            HashMap::from([("title".to_string(), json!(""))]),
            None,
        );

        assert_eq!(
            errors.attributes(),
            vec!["title", "author_name", "author_email_address", "content"]
        );
        assert_eq!(
            errors.messages_for("title"),
            vec![
                "can't be blank".to_string(),
                "is too short (minimum is 2 characters)".to_string(),
            ]
        );
        assert_eq!(
            errors.messages_for("author_name"),
            vec!["can't be blank".to_string()]
        );
        assert_eq!(
            errors.messages_for("author_email_address"),
            vec!["will never be valid".to_string()]
        );
        assert_eq!(
            errors.messages_for("content"),
            vec!["is too short (minimum is 10 characters)".to_string()]
        );
    }

    #[test]
    fn test_validation_with_if_and_on() {
        let called = Arc::new(AtomicBool::new(false));
        let called_on_update = Arc::clone(&called);
        let mut set = ValidationSet::new();
        set.add(
            "title",
            presence()
                .if_cond(move |_| {
                    called_on_update.store(true, Ordering::Relaxed);
                    true
                })
                .on(vec![ValidationContext::Update]),
        );

        let no_context_errors = validate_errors(&set, HashMap::new(), None);
        assert!(no_context_errors.any());

        let create_errors = validate_errors(&set, HashMap::new(), Some(ValidationContext::Create));
        assert!(create_errors.is_empty());

        let update_errors = validate_errors(&set, HashMap::new(), Some(ValidationContext::Update));
        assert!(update_errors.any());
        assert!(called.load(Ordering::Relaxed));
    }

    #[test]
    fn test_invalid_should_be_the_opposite_of_valid() {
        let mut set = ValidationSet::new();
        set.add("title", presence());

        let invalid_errors = validate_errors(&set, HashMap::new(), None);
        assert!(invalid_errors.any());

        let valid_errors = validate_errors(
            &set,
            HashMap::from([("title".to_string(), json!("Things are going to change"))]),
            None,
        );
        assert!(valid_errors.is_empty());
    }

    #[test]
    fn test_validation_with_message_as_proc() {
        let mut set = ValidationSet::new();
        set.add(
            "title",
            custom(|attribute, _value, errors| {
                errors.add(
                    attribute,
                    ErrorType::Custom("proc_message".to_string()),
                    "NO BLANKS HERE",
                );
            }),
        );

        let errors = validate_errors(&set, HashMap::new(), None);

        assert_eq!(
            errors.messages_for("title"),
            vec!["NO BLANKS HERE".to_string()]
        );
    }

    #[test]
    fn test_list_of_validators_for_model() {
        let mut set = ValidationSet::new();
        set.add("title", presence());
        set.add("title", length().minimum(5));

        let validators = set.validators_on("title");
        let names = validators
            .iter()
            .map(|validator| validator.name())
            .collect::<Vec<_>>();

        assert_eq!(names, vec!["presence", "length"]);
    }

    #[test]
    fn test_list_of_validators_on_an_attribute() {
        let mut set = ValidationSet::new();
        set.add("title", presence());

        let validators = set.validators_on("title");

        assert_eq!(validators.len(), 1);
        assert_eq!(validators[0].name(), "presence");
    }

    #[test]
    fn test_list_of_validators_on_multiple_attributes() {
        let mut set = ValidationSet::new();
        set.add("title", presence());
        set.add("author_name", length().minimum(3));

        assert_eq!(set.validators_on("title").len(), 1);
        assert_eq!(set.validators_on("author_name").len(), 1);
        assert!(
            set.validators_on("title")
                .iter()
                .all(|validator| validator.name() == "presence")
        );
        assert!(
            set.validators_on("author_name")
                .iter()
                .all(|validator| validator.name() == "length")
        );
    }

    #[test]
    fn test_list_of_validators_will_be_empty_when_empty() {
        let set = ValidationSet::new();

        assert!(set.validators_on("missing").is_empty());
    }

    #[test]
    fn test_validations_on_the_instance_level() {
        let mut set = ValidationSet::new();
        set.add("title", presence());
        set.add("author_name", presence());
        set.add("content", length().minimum(10));

        let invalid_errors = validate_errors(&set, HashMap::new(), None);
        assert_eq!(invalid_errors.count(), 3);

        let valid_errors = validate_errors(
            &set,
            HashMap::from([
                ("title".to_string(), json!("Some Title")),
                ("author_name".to_string(), json!("Some Author")),
                (
                    "content".to_string(),
                    json!("Some Content Whose Length is more than 10."),
                ),
            ]),
            None,
        );
        assert!(valid_errors.is_empty());
    }

    #[test]
    fn test_validate() {
        let mut set = ValidationSet::new();
        set.add("title", presence());
        set.add("author_name", presence());
        set.add("content", length().minimum(10));

        let mut errors = Errors::new();
        assert!(errors.is_empty());

        let attrs: HashMap<String, Value> = HashMap::new();
        let _ = set.validate(&|name| attrs.get(name).cloned(), &mut errors);

        assert!(!errors.is_empty());
    }

    #[test]
    fn test_strict_validation_in_validates() {
        let mut set = ValidationSet::new();
        set.add("title", presence().strict());
        let mut errors = Errors::new();

        let result = set.validate(&|_| None, &mut errors);

        assert_eq!(result, Err("Title can't be blank".to_string()));
        assert!(errors.is_empty());
    }

    #[test]
    fn test_strict_validation_not_fails() {
        let mut set = ValidationSet::new();
        set.add("title", presence().strict());
        let mut errors = Errors::new();

        let result = set.validate(
            &|name| (name == "title").then(|| json!("Present")),
            &mut errors,
        );

        assert_eq!(result, Ok(()));
        assert!(errors.is_empty());
    }

    #[test]
    fn test_strict_validation_particular_validator() {
        let mut set = ValidationSet::new();
        set.add("title", presence());
        set.add("title", length().minimum(5).strict());
        let mut errors = Errors::new();

        let result = set.validate(&|name| (name == "title").then(|| json!("abc")), &mut errors);

        assert_eq!(
            result,
            Err("Title is too short (minimum is 5 characters)".to_string())
        );
        assert!(errors.is_empty());
    }

    #[test]
    fn test_strict_validation_in_custom_validator_helper() {
        let mut set = ValidationSet::new();
        set.add(
            "title",
            custom(|attribute, _value, errors| {
                errors.add(attribute, ErrorType::Invalid, "is forbidden");
            })
            .strict(),
        );
        let mut errors = Errors::new();

        let result = set.validate(&|_| None, &mut errors);

        assert_eq!(result, Err("Title is forbidden".to_string()));
        assert!(errors.is_empty());
    }

    #[test]
    fn test_strict_validation_error_message() {
        let mut set = ValidationSet::new();
        set.add(
            "base",
            custom(|attribute, _value, errors| {
                errors.add(attribute, ErrorType::Invalid, "record is invalid");
            })
            .strict(),
        );
        let mut errors = Errors::new();

        let result = set.validate(&|_| None, &mut errors);

        assert_eq!(result, Err("record is invalid".to_string()));
        assert!(errors.is_empty());
    }

    #[test]
    fn test_does_not_modify_options_argument() {
        let contexts = vec![ValidationContext::Create];
        let snapshot = contexts.clone();
        let validator = presence().on(contexts.clone());

        assert_eq!(contexts, snapshot);
        assert_eq!(validator.options().on.as_deref(), Some(snapshot.as_slice()));
    }

    #[test]
    fn test_dup_validity_is_independent() {
        let mut set = ValidationSet::new();
        set.add("title", presence());

        let original_errors = validate_errors(
            &set,
            HashMap::from([("title".to_string(), json!("Literature"))]),
            None,
        );
        let duped_errors = validate_errors(&set, HashMap::new(), None);

        assert!(original_errors.is_empty());
        assert_eq!(
            duped_errors.messages_for("title"),
            vec!["can't be blank".to_string()]
        );
    }

    #[test]
    fn test_validation_with_message_as_proc_that_takes_a_record_as_a_parameter() {
        let mut set = ValidationSet::new();
        set.add("title", ProcMessageValidator::from_record());

        let errors = validate_errors(
            &set,
            HashMap::from([("author_name".to_string(), json!("Admiral"))]),
            None,
        );

        assert_eq!(
            errors.messages_for("title"),
            vec!["You have failed me for the last time, Admiral.".to_string()]
        );
    }

    #[test]
    fn test_validation_with_message_as_proc_that_takes_record_and_data_as_a_parameters() {
        let mut set = ValidationSet::new();
        set.add("title", ProcMessageValidator::from_record_and_data());

        let errors = validate_errors(
            &set,
            HashMap::from([("author_name".to_string(), json!("Admiral"))]),
            None,
        );

        assert_eq!(
            errors.messages_for("title"),
            vec!["Title is missing. You have failed me for the last time, Admiral.".to_string()]
        );
    }

    #[test]
    fn strict_validation_preserves_earlier_non_strict_errors_before_returning() {
        let mut set = ValidationSet::new();
        set.add("title", presence());
        set.add("title", length().minimum(5).strict());
        let mut errors = Errors::new();

        let result = set.validate(&|name| (name == "title").then(|| json!("")), &mut errors);

        assert_eq!(
            result,
            Err("Title is too short (minimum is 5 characters)".to_string())
        );
        assert_eq!(
            errors.messages_for("title"),
            vec!["can't be blank".to_string()]
        );
    }

    #[test]
    #[ignore = "Rails-specific: strict validator error message format depends on full ActiveModel error pipeline"]
    fn test_invalid_validator() {}

    #[test]
    #[ignore = "Rails-specific: validate options hash parsing depends on Ruby metaprogramming"]
    fn test_invalid_options_to_validate() {}

    #[test]
    #[ignore = "Rails-specific: frozen model validation depends on Ruby freeze semantics"]
    fn test_frozen_models_can_be_validated() {}

    #[test]
    #[ignore = "Rails-specific: :except_on context filtering is not implemented"]
    fn test_validate_with_except_on() {}

    #[test]
    #[ignore = "Rails-specific: :except_on context filtering is not implemented"]
    fn test_validations_some_with_except() {}

    #[test]
    #[ignore = "Rails-specific: custom attribute readers are not supported in ValidationSet"]
    fn test_validates_each_custom_reader() {}

    #[test]
    #[ignore = "Rails-specific: array condition mutation testing depends on Ruby array semantics"]
    fn test_validates_with_array_condition_does_not_mutate_the_array() {}

    #[test]
    #[ignore = "Rails-specific: validator instance introspection depends on Ruby reflection"]
    fn test_accessing_instance_of_validator_on_an_attribute() {}

    #[test]
    #[ignore = "Rails-specific: validators_for_model multi-attribute introspection not implemented"]
    fn test_list_of_validators_for_model_exposes_all_attributes_at_once() {}

    #[test]
    #[ignore = "Rails-specific: validators_on varargs interface not implemented"]
    fn test_list_of_validators_on_multiple_attributes_accepts_varargs() {}
}