Type System

trait HiveInspectors {
  def toInspector(dataType: DataType): ObjectInspector
  def unwrap(data: Any, oi: ObjectInspector): Any
  def wrap(a: Any, oi: ObjectInspector): AnyRef
}

// Catalyst to Hive ObjectInspector mappings
val primitiveInspectorMap: Map[DataType, PrimitiveObjectInspector] = Map(
  StringType -> PrimitiveObjectInspectorFactory.javaStringObjectInspector,
  IntegerType -> PrimitiveObjectInspectorFactory.javaIntObjectInspector,
  LongType -> PrimitiveObjectInspectorFactory.javaLongObjectInspector,
  DoubleType -> PrimitiveObjectInspectorFactory.javaDoubleObjectInspector,
  FloatType -> PrimitiveObjectInspectorFactory.javaFloatObjectInspector,
  BooleanType -> PrimitiveObjectInspectorFactory.javaBooleanObjectInspector,
  ByteType -> PrimitiveObjectInspectorFactory.javaByteObjectInspector,
  ShortType -> PrimitiveObjectInspectorFactory.javaShortObjectInspector,
  DateType -> PrimitiveObjectInspectorFactory.javaDateObjectInspector,
  TimestampType -> PrimitiveObjectInspectorFactory.javaTimestampObjectInspector,
  BinaryType -> PrimitiveObjectInspectorFactory.javaByteArrayObjectInspector
)

import org.apache.spark.sql.hive.HiveInspectors

val inspectors = new HiveInspectors {}

// Convert Catalyst types to Hive ObjectInspectors
val stringInspector = inspectors.toInspector(StringType)
val intInspector = inspectors.toInspector(IntegerType)
val timestampInspector = inspectors.toInspector(TimestampType)

// Convert data from Hive to Catalyst format
val catalystString = inspectors.unwrap("hello", stringInspector)
val catalystInt = inspectors.unwrap(java.lang.Integer.valueOf(42), intInspector)

// Convert data from Catalyst to Hive format
val hiveString = inspectors.wrap("world", stringInspector)
val hiveInt = inspectors.wrap(123, intInspector)

case class DecimalTypeInspector(precision: Int, scale: Int) extends PrimitiveObjectInspector

// Handle Hive decimal types with precision and scale
val decimalType = DecimalType(10, 2)  // DECIMAL(10,2)
val decimalInspector = inspectors.toInspector(decimalType)

// Convert Hive BigDecimal to Catalyst Decimal
val hiveDecimal = new java.math.BigDecimal("123.45")
val catalystDecimal = inspectors.unwrap(hiveDecimal, decimalInspector)

// Convert Catalyst Decimal to Hive BigDecimal
val catalystDecimalValue = Decimal(123.45, 10, 2)
val hiveDecimalValue = inspectors.wrap(catalystDecimalValue, decimalInspector)

case class ArrayTypeInspector(elementInspector: ObjectInspector) extends ListObjectInspector

// Array of strings: ARRAY<STRING>
val arrayType = ArrayType(StringType)
val arrayInspector = inspectors.toInspector(arrayType)

// Convert Hive array to Catalyst array
val hiveArray = java.util.Arrays.asList("a", "b", "c")
val catalystArray = inspectors.unwrap(hiveArray, arrayInspector)

// Convert Catalyst array to Hive array
val catalystArrayValue = Array("x", "y", "z")
val hiveArrayValue = inspectors.wrap(catalystArrayValue, arrayInspector)

// Complex nested arrays: ARRAY<ARRAY<INT>>
val nestedArrayType = ArrayType(ArrayType(IntegerType))
val nestedArrayInspector = inspectors.toInspector(nestedArrayType)

case class MapTypeInspector(
  keyInspector: ObjectInspector,
  valueInspector: ObjectInspector
) extends MapObjectInspector

// Map type: MAP<STRING, INT>
val mapType = MapType(StringType, IntegerType)
val mapInspector = inspectors.toInspector(mapType)

// Convert Hive map to Catalyst map
val hiveMap = new java.util.HashMap[String, Integer]()
hiveMap.put("key1", 100)
hiveMap.put("key2", 200)
val catalystMap = inspectors.unwrap(hiveMap, mapInspector)

// Convert Catalyst map to Hive map
val catalystMapValue = Map("a" -> 1, "b" -> 2)
val hiveMapValue = inspectors.wrap(catalystMapValue, mapInspector)

// Complex map: MAP<STRING, ARRAY<INT>>
val complexMapType = MapType(StringType, ArrayType(IntegerType))
val complexMapInspector = inspectors.toInspector(complexMapType)

case class StructTypeInspector(
  fields: Seq[StructField],
  fieldInspectors: Seq[ObjectInspector]
) extends StructObjectInspector

// Struct type: STRUCT<name:STRING, age:INT, active:BOOLEAN>
val structType = StructType(Seq(
  StructField("name", StringType),
  StructField("age", IntegerType),
  StructField("active", BooleanType)
))
val structInspector = inspectors.toInspector(structType)

// Convert Hive struct to Catalyst row
val hiveStruct = Array("John", java.lang.Integer.valueOf(30), java.lang.Boolean.TRUE)
val catalystRow = inspectors.unwrap(hiveStruct, structInspector)

// Convert Catalyst row to Hive struct
val catalystRowValue = InternalRow.fromSeq(Seq("Jane", 25, false))
val hiveStructValue = inspectors.wrap(catalystRowValue, structInspector)

// Nested struct: STRUCT<person:STRUCT<name:STRING, age:INT>, score:DOUBLE>
val nestedStructType = StructType(Seq(
  StructField("person", StructType(Seq(
    StructField("name", StringType),
    StructField("age", IntegerType)
  ))),
  StructField("score", DoubleType)
))

trait SerDeSupport extends HiveInspectors {
  def deserialize(writable: Writable, serDe: Deserializer): Any
  def serialize(data: Any, serDe: Serializer): Writable
}

// JSON SerDe integration
val jsonSerDe = new org.apache.hive.hcatalog.data.JsonSerDe()
val jsonInspector = jsonSerDe.getObjectInspector()

// Deserialize JSON data
val jsonWritable = new Text("""{"name": "John", "age": 30}""")
val catalystData = inspectors.deserialize(jsonWritable, jsonSerDe)

// RegEx SerDe integration
val regexSerDe = new org.apache.hadoop.hive.serde2.RegexSerDe()
regexSerDe.initialize(conf, properties)
val regexInspector = regexSerDe.getObjectInspector()

class LazySimpleSerDeInspector(
  fieldSeparator: String,
  fieldInspectors: Seq[ObjectInspector]
) extends StructObjectInspector

// Default Hive text format with tab separation
val lazySerDe = new org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe()
val properties = new Properties()
properties.setProperty("field.delim", "\t")
properties.setProperty("columns", "id,name,amount")
properties.setProperty("columns.types", "bigint:string:double")

lazySerDe.initialize(conf, properties)
val lazyInspector = lazySerDe.getObjectInspector()

// Parse delimited text data
val textData = new Text("123\tJohn Doe\t45.67")
val parsedData = inspectors.unwrap(
  lazySerDe.deserialize(textData), 
  lazyInspector
)

trait UDFTypeSupport extends HiveInspectors {
  def invokeUDF(udf: GenericUDF, args: Seq[Any]): Any
  def convertUDFResult(result: Any, outputInspector: ObjectInspector): Any
}

// Custom UDF with type conversion
class StringLengthUDF extends GenericUDF {
  override def initialize(arguments: Array[ObjectInspector]): ObjectInspector = {
    // Return integer inspector for string length
    PrimitiveObjectInspectorFactory.javaIntObjectInspector
  }
  
  override def evaluate(arguments: DeferredObject[]): AnyRef = {
    val stringArg = arguments(0).get().asInstanceOf[String]
    java.lang.Integer.valueOf(stringArg.length)
  }
}

// Register and use UDF
val lengthUDF = new StringLengthUDF()
val inputInspectors = Array(
  PrimitiveObjectInspectorFactory.javaStringObjectInspector
)
val outputInspector = lengthUDF.initialize(inputInspectors)

// Convert arguments and invoke UDF
val catalystString = "Hello World"
val hiveString = inspectors.wrap(catalystString, inputInspectors(0))
val result = lengthUDF.evaluate(Array(new DeferredObjectAdapter(hiveString)))
val catalystResult = inspectors.unwrap(result, outputInspector)

case class UnionTypeInspector(
  typeInspectors: Seq[ObjectInspector]
) extends UnionObjectInspector

// Union type: UNIONTYPE<STRING, INT, DOUBLE>
val unionInspectors = Seq(
  PrimitiveObjectInspectorFactory.javaStringObjectInspector,
  PrimitiveObjectInspectorFactory.javaIntObjectInspector,
  PrimitiveObjectInspectorFactory.javaDoubleObjectInspector
)
val unionInspector = new UnionTypeInspector(unionInspectors)

// Handle union data (tag + value format)
val unionData = Array(0.toByte, "string_value")  // Tag 0 = string
val catalystUnion = inspectors.unwrap(unionData, unionInspector)

val voidInspector: VoidObjectInspector = 
  PrimitiveObjectInspectorFactory.javaVoidObjectInspector

def isCompatible(catalystType: DataType, hiveInspector: ObjectInspector): Boolean
def canConvert(fromType: DataType, toType: DataType): Boolean

// Check type compatibility
val catalystType = StructType(Seq(
  StructField("name", StringType),
  StructField("age", IntegerType)
))

val hiveInspector = // ... from Hive table metadata
val compatible = inspectors.isCompatible(catalystType, hiveInspector)

if (compatible) {
  // Proceed with data conversion
} else {
  // Handle schema mismatch
  println("Schema incompatible - check field types and names")
}

def coerceType(value: Any, fromType: DataType, toType: DataType): Any

// Automatic type coercion for compatible types
val stringValue = "123"
val intValue = inspectors.coerceType(stringValue, StringType, IntegerType)
// Result: 123 as Integer

val longValue = 123L
val doubleValue = inspectors.coerceType(longValue, LongType, DoubleType)
// Result: 123.0 as Double

class CachedObjectInspectorFactory {
  private val cache = new ConcurrentHashMap[DataType, ObjectInspector]()
  
  def getInspector(dataType: DataType): ObjectInspector = {
    cache.computeIfAbsent(dataType, _ => createInspector(dataType))
  }
}

def convertBatch(
  data: Seq[Any], 
  fromInspector: ObjectInspector,
  toInspector: ObjectInspector
): Seq[Any]

// Efficient batch conversion for large datasets
val hiveData = Seq(/* large collection of Hive objects */)
val catalystData = inspectors.convertBatch(
  hiveData,
  hiveInspector,
  catalystInspector
)

try {
  val result = inspectors.unwrap(hiveData, inspector)
} catch {
  case e: ClassCastException =>
    println("Type conversion failed - data type mismatch")
  case e: NumberFormatException =>
    println("Numeric conversion failed - invalid format")
  case e: UnsupportedOperationException =>
    println("Unsupported type conversion")
}

try {
  val inspector = inspectors.toInspector(complexType)
} catch {
  case e: IllegalArgumentException =>
    println("Invalid type definition")
  case e: UnsupportedTypeException =>
    println("Type not supported in Hive")
}