babbel_yaml 0.1.0

//! Built-in Validators for YAML Validation
//!
//! This module provides reusable built-in validators for common validation patterns in YAML documents.
//! It includes type checking, range validation, pattern matching, and support for custom validation logic.
//!
//! # Features
//! - Type checking validators
//! - Range and length validation
//! - Pattern matching (regex)
//! - Support for custom validation logic
//!
//! # Usage
//! Use these validators to enforce schema rules and constraints on YAML data.

use alloc::boxed::Box;
use alloc::string::{String, ToString};
use alloc::vec::Vec;
use regex::Regex;

use crate::nodes::node::{Node, Numeric};
use crate::validation::error::ValidationError;
use crate::validation::messages;
use crate::validation::schema::SchemaType;

/// Result of a validation operation
pub type ValidationResult = Result<(), ValidationError>;

/// Trait for validators that can check nodes against rules
pub trait Validator {
    /// Validate a node and return Ok(()) or an error message
    fn validate(&self, node: &Node) -> ValidationResult;

    /// Get a description of what this validator checks
    fn description(&self) -> String;
}

/// Validates node type matches expected type
#[derive(Debug, Clone)]
pub struct TypeValidator {
    expected_type: SchemaType,
}

impl TypeValidator {
    pub fn new(expected_type: SchemaType) -> Self {
        Self { expected_type }
    }
}

impl Validator for TypeValidator {
    fn validate(&self, node: &Node) -> ValidationResult {
        let matches = match (&self.expected_type, node) {
            (SchemaType::String, Node::Str(_, _, _)) => true,
            (SchemaType::Number, Node::Number(_)) => true,
            (SchemaType::Integer, Node::Number(Numeric::Integer(_))) => true,
            (SchemaType::Integer, Node::Number(Numeric::Int32(_))) => true,
            (SchemaType::Integer, Node::Number(Numeric::Int16(_))) => true,
            (SchemaType::Integer, Node::Number(Numeric::Int8(_))) => true,
            (SchemaType::Float, Node::Number(Numeric::Float(_))) => true,
            (SchemaType::Boolean, Node::Boolean(_)) => true,
            (SchemaType::Null, Node::None) => true,
            (SchemaType::Array, Node::Array(_)) => true,
            (SchemaType::Array, Node::Set(_)) => true,
            (SchemaType::Object, Node::Mapping(_)) => true,
            (SchemaType::Any, _) => true,
            _ => false,
        };
        if matches {
            Ok(())
        } else {
            Err(
                crate::validation::engine::ValidationContextCore::fail_type_mismatch(
                    &self.expected_type,
                    node,
                ),
            )
        }
    }

    fn description(&self) -> String {
        messages::type_must_be(&self.expected_type)
    }
}

/// Validates numeric values are within a range
#[derive(Debug, Clone)]
pub struct RangeValidator {
    min: Option<f64>,
    max: Option<f64>,
}

impl RangeValidator {
    pub fn new(min: Option<f64>, max: Option<f64>) -> Self {
        Self { min, max }
    }
}

impl Validator for RangeValidator {
    fn validate(&self, node: &Node) -> ValidationResult {
        let value = match node {
            Node::Number(Numeric::Integer(i)) => *i as f64,
            Node::Number(Numeric::Float(f)) => *f,
            Node::Number(Numeric::UInteger(u)) => *u as f64,
            Node::Number(Numeric::Int32(i)) => *i as f64,
            Node::Number(Numeric::UInt32(u)) => *u as f64,
            Node::Number(Numeric::Int16(i)) => *i as f64,
            Node::Number(Numeric::UInt16(u)) => *u as f64,
            Node::Number(Numeric::Int8(i)) => *i as f64,
            Node::Number(Numeric::Byte(b)) => *b as f64,
            _ => {
                return Err(ValidationError::InvalidNodeType {
                    validator: "RangeValidator".to_string(),
                    found: node_type_name(node).to_string(),
                });
            }
        };

        if let Some(min) = self.min {
            if value < min {
                return Err(
                    crate::validation::engine::ValidationContextCore::fail_range(
                        value, self.min, self.max,
                    ),
                );
            }
        }

        if let Some(max) = self.max {
            if value > max {
                return Err(
                    crate::validation::engine::ValidationContextCore::fail_range(
                        value, self.min, self.max,
                    ),
                );
            }
        }

        Ok(())
    }

    fn description(&self) -> String {
        match (self.min, self.max) {
            (Some(min), Some(max)) => messages::value_must_be_between(min, max),
            (Some(min), None) => messages::value_must_be_at_least(min),
            (None, Some(max)) => messages::value_must_be_at_most(max),
            (None, None) => messages::no_range_restriction(),
        }
    }
}

/// Validates string/array length
#[derive(Debug, Clone)]
pub struct LengthValidator {
    min: Option<usize>,
    max: Option<usize>,
}

impl LengthValidator {
    pub fn new(min: Option<usize>, max: Option<usize>) -> Self {
        Self { min, max }
    }
}

impl Validator for LengthValidator {
    fn validate(&self, node: &Node) -> ValidationResult {
        let length = match node {
            n if n.as_str().is_some() => n.as_str().unwrap().len(),
            Node::Array(arr) => arr.len(),
            Node::Set(set) => set.len(),
            _ => {
                return Err(ValidationError::InvalidNodeType {
                    validator: "LengthValidator".to_string(),
                    found: node_type_name(node).to_string(),
                });
            }
        };

        if let Some(min) = self.min {
            if length < min {
                return Err(ValidationError::LengthError {
                    length,
                    min: self.min,
                    max: self.max,
                });
            }
        }

        if let Some(max) = self.max {
            if length > max {
                return Err(ValidationError::LengthError {
                    length,
                    min: self.min,
                    max: self.max,
                });
            }
        }

        Ok(())
    }

    fn description(&self) -> String {
        match (self.min, self.max) {
            (Some(min), Some(max)) => messages::length_must_be_between(min, max),
            (Some(min), None) => messages::length_must_be_at_least(min),
            (None, Some(max)) => messages::length_must_be_at_most(max),
            (None, None) => messages::no_length_restriction(),
        }
    }
}

/// Validates string matches a pattern

#[derive(Debug, Clone)]
pub struct PatternValidator {
    regex: Regex,
    pattern: String,
}

impl PatternValidator {
    pub fn new(pattern: impl Into<String>) -> Self {
        let pattern_str = pattern.into();
        let regex = Regex::new(&pattern_str).expect("Invalid regex pattern");
        Self {
            regex,
            pattern: pattern_str,
        }
    }

    /// Check if string matches regex pattern
    fn matches(&self, s: &str) -> bool {
        self.regex.is_match(s)
    }
}

impl Validator for PatternValidator {
    fn validate(&self, node: &Node) -> ValidationResult {
        if let Some(s) = node.as_str() {
            if self.matches(s) {
                Ok(())
            } else {
                Err(ValidationError::PatternMismatch {
                    pattern: self.pattern.clone(),
                    value: s.to_string(),
                })
            }
        } else {
            Err(ValidationError::InvalidNodeType {
                validator: "PatternValidator".to_string(),
                found: node_type_name(node).to_string(),
            })
        }
    }

    fn description(&self) -> String {
        format!("Must match regex pattern: {}", self.pattern)
    }
}

/// Validates value is one of allowed enum values

#[derive(Debug, Clone)]
pub struct EnumValidator {
    allowed: Vec<String>,
}

impl EnumValidator {
    pub fn new(allowed: Vec<String>) -> Self {
        Self { allowed }
    }

    /// Extracts a scalar value from a node as a string for comparison
    fn node_scalar_value(node: &Node) -> Option<String> {
        match node {
            Node::Str(s, _, _) => Some(s.clone()),
            Node::Number(n) => Some(match n {
                Numeric::Integer(i) => i.to_string(),
                Numeric::Float(f) => f.to_string(),
                Numeric::UInteger(u) => u.to_string(),
                Numeric::Byte(b) => b.to_string(),
                Numeric::Int32(i) => i.to_string(),
                Numeric::UInt32(u) => u.to_string(),
                Numeric::Int16(i) => i.to_string(),
                Numeric::UInt16(u) => u.to_string(),
                Numeric::Int8(i) => i.to_string(),
                Numeric::UInt8(u) => u.to_string(),
            }),
            Node::Boolean(b) => Some(b.to_string()),
            Node::None => Some("null".to_string()),
            _ => None,
        }
    }
}

impl Validator for EnumValidator {
    fn validate(&self, node: &Node) -> ValidationResult {
        match Self::node_scalar_value(node) {
            Some(value) => {
                if self.allowed.contains(&value) {
                    Ok(())
                } else {
                    Err(ValidationError::EnumMismatch {
                        allowed: self.allowed.clone(),
                        value,
                    })
                }
            }
            None => Err(ValidationError::InvalidNodeType {
                validator: "EnumValidator".to_string(),
                found: node_type_name(node).to_string(),
            }),
        }
    }

    fn description(&self) -> String {
        messages::must_be_one_of(&self.allowed)
    }
}

/// Validates a required field exists
#[derive(Debug, Clone)]
pub struct RequiredValidator {
    field_name: String,
}

impl RequiredValidator {
    pub fn new(field_name: impl Into<String>) -> Self {
        Self {
            field_name: field_name.into(),
        }
    }
}

impl Validator for RequiredValidator {
    fn validate(&self, node: &Node) -> ValidationResult {
        match node {
            Node::Mapping(pairs) => {
                let found = pairs.iter().any(|(k, _)| match k {
                    Node::Str(s, _, _) => s == &self.field_name,
                    Node::Number(n) => {
                        let key_str = match n {
                            Numeric::Integer(i) => i.to_string(),
                            Numeric::Float(f) => f.to_string(),
                            Numeric::UInteger(u) => u.to_string(),
                            Numeric::Byte(b) => b.to_string(),
                            Numeric::Int32(i) => i.to_string(),
                            Numeric::UInt32(u) => u.to_string(),
                            Numeric::Int16(i) => i.to_string(),
                            Numeric::UInt16(u) => u.to_string(),
                            Numeric::Int8(i) => i.to_string(),
                            Numeric::UInt8(u) => u.to_string(),
                        };
                        key_str == self.field_name
                    }
                    Node::Boolean(b) => b.to_string() == self.field_name,
                    Node::None => self.field_name == "null",
                    _ => false,
                });

                if found {
                    Ok(())
                } else {
                    Err(
                        crate::validation::engine::ValidationContextCore::fail_required(
                            &self.field_name,
                        ),
                    )
                }
            }
            _ => Err(ValidationError::InvalidNodeType {
                validator: "RequiredValidator".to_string(),
                found: node_type_name(node).to_string(),
            }),
        }
    }

    fn description(&self) -> String {
        format!("Field '{}' is required", self.field_name)
    }
}

/// Custom validator using a closure
pub struct CustomValidator {
    validate_fn: Box<dyn Fn(&Node) -> ValidationResult>,
    description: String,
}

impl CustomValidator {
    pub fn new<F>(description: impl Into<String>, validate_fn: F) -> Self
    where
        F: Fn(&Node) -> ValidationResult + 'static,
    {
        Self {
            validate_fn: Box::new(validate_fn),
            description: description.into(),
        }
    }
}

impl Validator for CustomValidator {
    fn validate(&self, node: &Node) -> ValidationResult {
        (self.validate_fn)(node)
    }

    fn description(&self) -> String {
        self.description.clone()
    }
}

/// Get human-readable name for node type
pub fn node_type_name(node: &Node) -> &'static str {
    match node {
        Node::Boolean(_) => "Boolean",
        Node::Number(_) => "Number",
        Node::Str(_, _, _) => "String",
        Node::Array(_) => "Array",
        Node::Set(_) => "Set",
        Node::Mapping(_) => "Mapping",
        Node::Comment(_) => "Comment",
        Node::Document(_) => "Document",
        Node::Anchored(_, _) => "Anchored",
        Node::Tagged(_, _) => "Tagged",
        Node::Alias(_) => "Alias",
        Node::Documents(_) => "Documents",
        Node::None => "Null",
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_type_validator() {
        let validator = TypeValidator::new(SchemaType::String);

        assert!(validator.validate(&Node::from("hello")).is_ok());
        assert!(validator.validate(&Node::from(42)).is_err());
    }

    #[test]
    fn test_range_validator() {
        let validator = RangeValidator::new(Some(0.0), Some(100.0));

        assert!(
            validator
                .validate(&Node::Number(Numeric::Integer(50)))
                .is_ok()
        );
        assert!(
            validator
                .validate(&Node::Number(Numeric::Integer(150)))
                .is_err()
        );
        assert!(
            validator
                .validate(&Node::Number(Numeric::Integer(-10)))
                .is_err()
        );
    }

    #[test]
    fn test_length_validator() {
        let validator = LengthValidator::new(Some(3), Some(10));

        assert!(validator.validate(&Node::from("hello")).is_ok());
        assert!(validator.validate(&Node::from("hi")).is_err());
        assert!(validator.validate(&Node::from("verylongstring")).is_err());
    }

    #[test]
    fn test_pattern_validator() {
        // Simple substring pattern
        let validator = PatternValidator::new("@");
        assert!(validator.validate(&Node::from("user@example.com")).is_ok());
        assert!(validator.validate(&Node::from("invalid")).is_err());

        // Regex pattern: email
        let validator = PatternValidator::new(r"^[\w.-]+@[\w.-]+\.[a-zA-Z]{2,}$");
        assert!(validator.validate(&Node::from("user@example.com")).is_ok());
        assert!(validator.validate(&Node::from("user@domain")).is_err());
        assert!(validator.validate(&Node::from("@domain.com")).is_err());

        // Non-string node
        assert!(
            validator
                .validate(&Node::Number(Numeric::Integer(42)))
                .is_err()
        );
    }

    #[test]
    fn test_enum_validator() {
        // String values
        let validator = EnumValidator::new(vec![
            "red".to_string(),
            "green".to_string(),
            "blue".to_string(),
        ]);
        assert!(validator.validate(&Node::from("red")).is_ok());
        assert!(validator.validate(&Node::from("yellow")).is_err());

        // Integer values
        let validator = EnumValidator::new(vec!["1".to_string(), "2".to_string()]);
        assert!(
            validator
                .validate(&Node::Number(Numeric::Integer(1)))
                .is_ok()
        );
        assert!(
            validator
                .validate(&Node::Number(Numeric::Integer(3)))
                .is_err()
        );

        // Boolean values
        let validator = EnumValidator::new(vec!["true".to_string(), "false".to_string()]);
        assert!(validator.validate(&Node::Boolean(true)).is_ok());
        assert!(validator.validate(&Node::Boolean(false)).is_ok());
        assert!(validator.validate(&Node::from("true")).is_ok());
        assert!(validator.validate(&Node::from("maybe")).is_err());

        // Null value
        let validator = EnumValidator::new(vec!["null".to_string()]);
        assert!(validator.validate(&Node::None).is_ok());
        assert!(validator.validate(&Node::from("null")).is_ok());
        assert!(validator.validate(&Node::from("notnull")).is_err());

        // Non-scalar node
        assert!(validator.validate(&Node::Array(vec![])).is_err());
    }

    #[test]
    fn test_required_validator() {
        // String key
        let validator = RequiredValidator::new("name");
        let mapping = Node::Mapping(vec![
            (Node::from("name"), Node::from("Alice")),
            (Node::from("age"), Node::from(30)),
        ]);
        assert!(validator.validate(&mapping).is_ok());
        let mapping2 = Node::Mapping(vec![(Node::from("age"), Node::from(30))]);
        assert!(validator.validate(&mapping2).is_err());

        // Integer key
        let validator = RequiredValidator::new("42");
        let mapping = Node::Mapping(vec![(
            Node::Number(Numeric::Integer(42)),
            Node::from("answer"),
        )]);
        assert!(validator.validate(&mapping).is_ok());
        let mapping2 = Node::Mapping(vec![(
            Node::Number(Numeric::Integer(43)),
            Node::from("not answer"),
        )]);
        assert!(validator.validate(&mapping2).is_err());

        // Boolean key
        let validator = RequiredValidator::new("true");
        let mapping = Node::Mapping(vec![(Node::Boolean(true), Node::from("yes"))]);
        assert!(validator.validate(&mapping).is_ok());
        let mapping2 = Node::Mapping(vec![(Node::Boolean(false), Node::from("no"))]);
        assert!(validator.validate(&mapping2).is_err());

        // Null key
        let validator = RequiredValidator::new("null");
        let mapping = Node::Mapping(vec![(Node::None, Node::from("missing"))]);
        assert!(validator.validate(&mapping).is_ok());
        let mapping2 = Node::Mapping(vec![(Node::from("notnull"), Node::from("not missing"))]);
        assert!(validator.validate(&mapping2).is_err());

        // Non-mapping node
        assert!(validator.validate(&Node::Array(vec![])).is_err());
    }

    #[test]
    fn test_custom_validator() {
        let validator = CustomValidator::new("Must be positive", |node| match node {
            Node::Number(Numeric::Integer(i)) if *i > 0 => Ok(()),
            Node::Number(Numeric::Integer(_)) => {
                Err(ValidationError::Custom("Number must be positive".to_string()).into())
            }
            _ => Err(ValidationError::Custom("Not a number".to_string()).into()),
        });

        assert!(
            validator
                .validate(&Node::Number(Numeric::Integer(10)))
                .is_ok()
        );
        assert!(
            validator
                .validate(&Node::Number(Numeric::Integer(-5)))
                .is_err()
        );
    }
}

#[cfg(test)]
mod additional_validators_tests {
    use super::*;

    #[test]
    fn test_type_validator_any() {
        let validator = TypeValidator::new(SchemaType::Any);
        assert!(validator.validate(&Node::from("string")).is_ok());
        assert!(validator.validate(&Node::Number(Numeric::Integer(1))).is_ok());
        assert!(validator.validate(&Node::Boolean(true)).is_ok());
    }

    #[test]
    fn test_range_validator_invalid_node() {
        let validator = RangeValidator::new(Some(0.0), Some(10.0));
        let result = validator.validate(&Node::from("not a number"));
        assert!(result.is_err());
        if let Err(ValidationError::InvalidNodeType { validator: v, .. }) = result {
            assert_eq!(v, "RangeValidator");
        } else {
            panic!("Expected InvalidNodeType error");
        }
    }

    #[test]
    fn test_length_validator_string_and_array() {
        let validator = LengthValidator::new(Some(2), Some(4));
        assert!(validator.validate(&Node::from("ab")).is_ok());
        assert!(validator.validate(&Node::from("abcd")).is_ok());
        assert!(validator.validate(&Node::from("a")).is_err());
        assert!(validator.validate(&Node::from("abcde")).is_err());

        let arr = Node::Array(vec![Node::from(1), Node::from(2)]);
        assert!(validator.validate(&arr).is_ok());
        let arr = Node::Array(vec![Node::from(1)]);
        assert!(validator.validate(&arr).is_err());
    }

    #[test]
    fn test_pattern_validator() {
        let validator = PatternValidator::new("^abc[0-9]+$".to_string());
        assert!(validator.validate(&Node::from("abc123")).is_ok());
        assert!(validator.validate(&Node::from("ab123")).is_err());
    }

    #[test]
    fn test_enum_validator() {
        let validator = EnumValidator::new(vec!["A".to_string(), "B".to_string()]);
        assert!(validator.validate(&Node::from("A")).is_ok());
        assert!(validator.validate(&Node::from("C")).is_err());
    }

    #[test]
    fn test_required_validator_non_mapping() {
        let validator = RequiredValidator::new("foo");
        let node = Node::Array(vec![]);
        assert!(validator.validate(&node).is_err());
    }
}