Implementing core module.

Author: vim89

modules/core/src/main/scala/com/flowforge/core/patterns/CommonValidations.scala

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+/**
+ * FlowForge Core Module - Validation Patterns
+ *
+ * File: modules/core/src/main/scala/com/flowforge/core/patterns/CommonValidations.scala Package:
+ * com.flowforge.core.patterns
+ *
+ * This file provides comprehensive validation patterns and combinators for the FlowForge ecosystem.
+ * It enables composable, functional validation with rich error accumulation and recovery strategies
+ * using cats ValidatedNel.
+ *
+ * Design Patterns Applied:
+ *   - Combinator Pattern: Small, composable validation functions
+ *   - Strategy Pattern: Different validation strategies per data type
+ *   - Chain of Responsibility: Validation pipeline with ordered checks
+ *   - Template Method Pattern: Abstract validation framework with concrete rules
+ *   - Composite Pattern: Complex validations from simple components
+ *
+ * Scala Features Showcased:
+ *   - ValidatedNel: Error accumulation without short-circuiting
+ *   - Applicative Functor: Parallel validation with mapN
+ *   - Type Classes: Polymorphic validation across data types
+ *   - Higher-Order Functions: Validation combinators and builders
+ *   - Pattern Matching: Sophisticated error handling and routing
+ *   - Implicit Classes: Fluent validation syntax
+ *   - Generic Programming: Reusable validation patterns
+ *
+ * Innovation Highlights:
+ *   - Compositional validation with error accumulation
+ *   - Data quality validation with business rule integration
+ *   - Schema validation with evolution compatibility checking
+ *   - Configuration validation with environment-specific rules
+ *   - Performance-optimized validation for large datasets
+ *   - Conditional validation with context-aware rules
+ *
+ * Usage Examples:
+ * ```scala
+ * // Compositional validation with error accumulation
+ * case class User(name: String, email: String, age: Int)
+ *
+ * val validateUser: User => ValidationResult[User] = { user =>
+ *   (
+ *     validateNonEmpty("name", user.name),
+ *     validateEmail("email", user.email),
+ *     validateRange("age", user.age, 0, 150)
+ *   ).mapN((_, _, _) => user)
+ * }
+ *
+ * // Data quality validation with business rules
+ * val dataQualityRules = ValidationRules
+ *   .builder[Dataset]
+ *   .notNull("customer_id")
+ *   .unique("transaction_id")
+ *   .range("amount", min = 0, max = 1_000_000)
+ *   .pattern("email", EmailPattern)
+ *   .freshness(maxAge = 24.hours)
+ *   .build
+ *
+ * // Conditional validation based on context
+ * val environmentRules = ValidationRules.conditional[Config] { config =>
+ *   if (config.environment.isProduction) {
+ *     strictValidation
+ *   } else {
+ *     lenientValidation
+ *   }
+ * }
+ * ```
+ *
+ * @author
+ *   FlowForge Team
+ * @version 1.0.0
+ * @since 2024
+ */
+package com.flowforge.core.patterns
+
+import cats.syntax.all._
+import com.flowforge.core.types.RefinedTypes._
+import com.flowforge.core.types._
+import com.flowforge.core.patterns.ValidationTypes._
+
+/**
+ * Pre-built validation patterns for common use cases.
+ */
+object CommonValidations {
+
+  import ValidationCombinators._
+
+  /**
+   * Standard user validation pattern.
+   */
+  case class UserValidation(
+    name: String,
+    email: String,
+    age: Int
+  )
+
+  val validateUser: UserValidation => ConfigValidationResult[UserValidation] = { user =>
+    (
+      nonEmpty("name", user.name),
+      email("email", user.email),
+      intInRange("age", user.age, 0, 150)
+    ).mapN((_, _, _) => user)
+  }
+
+  /**
+   * Configuration validation pattern.
+   */
+  def validatePipelineConfig(config: PipelineConfig): ConfigValidationResult[PipelineConfig] = {
+    val nameValidation        = nonEmpty("name", config.name.value)
+    val environmentValidation = config.environment.validNel // Always valid
+    val sourceValidation      = config.source.validNel      // Assume valid for now
+    val sinkValidation        = config.sink.validNel        // Assume valid for now
+
+    (nameValidation, environmentValidation, sourceValidation, sinkValidation)
+      .mapN((_, _, _, _) => config)
+  }
+
+  /**
+   * Data quality validation pattern.
+   */
+  def validateDataQuality[A](
+    data: List[A],
+    rules: QualityRules
+  ): QualityValidationResult[List[A]] =
+    // Simplified quality validation - in practice would be much more sophisticated
+    if (data.nonEmpty) {
+      valid(data)
+    } else {
+      val violation = QualityConstraint.NotNull(
+        FieldName.unsafeFrom("data")
+      )
+      invalid(violation).asInstanceOf[QualityValidationResult[List[A]]]
+    }
+
+  /**
+   * Schema compatibility validation pattern.
+   */
+  def validateSchemaCompatibility(
+    source: DataSchema,
+    target: DataSchema
+  ): SchemaValidationResult =
+    SchemaValidation.compatible(source, target)
+}

modules/core/src/main/scala/com/flowforge/core/patterns/DataQualityValidation.scala

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+package com.flowforge.core.patterns
+
+import cats.syntax.all._
+import com.flowforge.core.patterns.ValidationTypes.QualityValidationResult
+import com.flowforge.core.types.ErrorSeverity
+import com.flowforge.core.types.ValidationError.QualityViolation
+
+import java.time.Instant
+import scala.concurrent.duration.FiniteDuration
+
+/**
+ * Specialized validation patterns for data quality assurance. These validators focus on data
+ * integrity, completeness, and business rules.
+ */
+object DataQualityValidation {
+
+  /**
+   * Validate data freshness - ensure data is not older than specified duration.
+   */
+  def freshness[A](
+    fieldName: String,
+    timestamp: Instant,
+    maxAge: FiniteDuration
+  ): QualityValidationResult[A] = ???
+
+  /**
+   * Validate data completeness - ensure required percentage of non-null values.
+   */
+  def completeness[A](
+    fieldName: String,
+    values: List[Option[A]],
+    minCompleteness: Double
+  ): QualityValidationResult[List[Option[A]]] = {
+    val total              = values.length
+    val nonNull            = values.count(_.isDefined)
+    val actualCompleteness = if (total > 0) nonNull.toDouble / total else 0.0
+
+    if (actualCompleteness >= minCompleteness) {
+      values.validNel
+    } else {
+      val violation = QualityViolation(
+        constraint = "completeness",
+        violatedValue = fieldName,
+        threshold = Some(minCompleteness.toString),
+        message = s"Completeness too low: ${actualCompleteness * 100}% < ${minCompleteness * 100}%",
+        severity = ErrorSeverity.Error
+      )
+      violation.invalidNel
+    }
+  }
+
+  /**
+   * Validate data uniqueness - ensure no duplicate values.
+   */
+  def uniqueness[A](
+    fieldName: String,
+    values: List[A]
+  ): QualityValidationResult[List[A]] = {
+    val duplicates = values.groupBy(identity).filter(_._2.size > 1)
+
+    if (duplicates.isEmpty) {
+      values.validNel
+    } else {
+      val violation = QualityViolation(
+        constraint = "uniqueness",
+        violatedValue = fieldName,
+        threshold = Some(duplicates).map(_.toString),
+        message = s"Duplicate values found: ${duplicates.keys.mkString(", ")}",
+        severity = ErrorSeverity.Error
+      )
+      violation.invalidNel
+    }
+  }
+
+  /**
+   * Validate referential integrity - ensure foreign key references exist.
+   */
+  def referentialIntegrity[A](
+    fieldName: String,
+    foreignKeys: List[A],
+    referenceTable: Set[A]
+  ): QualityValidationResult[List[A]] = {
+    val invalidKeys = foreignKeys.filterNot(referenceTable.contains)
+
+    if (invalidKeys.isEmpty) {
+      foreignKeys.validNel
+    } else {
+      val violation = QualityViolation(
+        constraint = "referential_integrity",
+        violatedValue = fieldName,
+        threshold = Some(invalidKeys).map(_.toString),
+        message = s"Invalid foreign key references: ${invalidKeys.mkString(", ")}",
+        severity = ErrorSeverity.Error
+      )
+      violation.invalidNel
+    }
+  }
+
+  /**
+   * Validate data distribution - ensure values follow expected statistical properties.
+   */
+  def distribution(
+    fieldName: String,
+    values: List[Double],
+    expectedMean: Double,
+    tolerance: Double
+  ): QualityValidationResult[List[Double]] =
+    if (values.isEmpty) {
+      val violation = QualityViolation(
+        constraint = "distribution",
+        violatedValue = fieldName,
+        threshold = None,
+        message = s"No values provided for distribution validation",
+        severity = ErrorSeverity.Error
+      )
+      violation.invalidNel
+    } else {
+      val actualMean = values.sum / values.length
+      val deviation  = math.abs(actualMean - expectedMean)
+
+      if (deviation <= tolerance) {
+        values.validNel
+      } else {
+        val violation = QualityViolation(
+          constraint = "distribution",
+          violatedValue = fieldName,
+          threshold = Some(s"$expectedMean + $tolerance"),
+          message = s"Mean deviation exceeds tolerance: $deviation > $tolerance",
+          severity = ErrorSeverity.Error
+        )
+        violation.invalidNel
+      }
+    }
+
+  /**
+   * Validate business rule - custom validation logic for domain-specific constraints.
+   */
+  def businessRule[A](
+    ruleName: String,
+    description: String
+  )(rule: A => Boolean): A => QualityValidationResult[A] = { value =>
+    if (rule(value)) {
+      value.validNel
+    } else {
+      val violation = QualityViolation(
+        constraint = "business_rule",
+        violatedValue = ruleName,
+        threshold = Some(value).map(_.toString),
+        message = s"Business rule violation: $description",
+        severity = ErrorSeverity.Error
+      )
+      violation.invalidNel
+    }
+  }
+}

modules/core/src/main/scala/com/flowforge/core/patterns/NamedValidationRule.scala

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+package com.flowforge.core.patterns
+
+import cats.syntax.all._
+import com.flowforge.core.patterns.ValidationTypes.ValidationResult
+
+/**
+ * Named validation rule for better error reporting and debugging.
+ */
+case class NamedValidationRule[A](
+  name: String,
+  validator: A => ValidationResult[A]
+) {
+
+  def validate(value: A): ValidationResult[A] = validator(value)
+
+  def combine(other: NamedValidationRule[A]): NamedValidationRule[A] =
+    NamedValidationRule(
+      s"$name+${other.name}",
+      value => (validator(value), other.validator(value)).mapN((_, _) => value)
+    )
+}