package parallelai.spyglass.hbase

import java.io.IOException
import org.apache.hadoop.hbase.io.ImmutableBytesWritable
import org.apache.hadoop.hbase.util.Bytes
import com.twitter.scalding.AccessMode
import com.twitter.scalding.Hdfs
import com.twitter.scalding.Mode
import com.twitter.scalding.Read
import com.twitter.scalding.Write
import parallelai.spyglass.hbase.HBaseConstants.{SplitType, SourceMode}
import cascading.scheme.{NullScheme, Scheme}
import cascading.tap.SinkMode
import cascading.tap.Tap
import cascading.tuple.Fields
import org.apache.hadoop.mapred.RecordReader
import org.apache.hadoop.mapred.OutputCollector
import org.apache.hadoop.mapred.JobConf
import parallelai.spyglass.hbase.HBaseConstants.SourceMode
import com.twitter.scalding.Source

object Conversions {
  implicit def bytesToString(bytes: Array[Byte]): String = Bytes.toString(bytes)
  implicit def bytesToLong(bytes: Array[Byte]): Long = augmentString(bytesToString(bytes)).toLong
  implicit def ibwToString(ibw: ImmutableBytesWritable): String = bytesToString(ibw.get())
  implicit def stringToibw(s: String):ImmutableBytesWritable = new ImmutableBytesWritable(Bytes.toBytes(s))
}

case class HBaseSource(
    tableName: String = null,
    quorumNames: String = "localhost",
    keyFields: Fields = null,
    familyNames: List[String] = null,
    valueFields: List[Fields] = null,
    timestamp: Long = 0L,
    sourceMode: SourceMode = SourceMode.SCAN_ALL,
    startKey: String = null,
    stopKey: String = null,
    keyList: List[String] = null,
    versions: Int = 1,
    useSalt: Boolean = false,
    prefixList: String = null,
    sinkMode: SinkMode = SinkMode.UPDATE,
    inputSplitType: SplitType = SplitType.GRANULAR
  ) extends Source {

  val internalScheme = new HBaseScheme(keyFields, timestamp, familyNames.toArray, valueFields.toArray)
  internalScheme.setInputSplitTye(inputSplitType)

  val hdfsScheme = internalScheme.asInstanceOf[Scheme[JobConf, RecordReader[_, _], OutputCollector[_, _], _, _]]

  // To enable local mode testing
  val allFields = keyFields.append(valueFields.toArray)
  def localScheme = new NullScheme(allFields, allFields)

  override def createTap(readOrWrite: AccessMode)(implicit mode: Mode): Tap[_, _, _] = {
    val hBaseScheme = hdfsScheme match {
      case hbase: HBaseScheme => hbase
      case _ => throw new ClassCastException("Failed casting from Scheme to HBaseScheme")
    } 
    mode match { 
      case hdfsMode @ Hdfs(_, _) => readOrWrite match {
        case Read => { 
          val hbt = new HBaseTap(quorumNames, tableName, hBaseScheme, SinkMode.KEEP)
           
          sourceMode match {
            case SourceMode.SCAN_RANGE => {
              
              hbt.setHBaseRangeParms(startKey, stopKey, useSalt, prefixList)
            }
            case SourceMode.SCAN_ALL => {
              hbt.setHBaseScanAllParms(useSalt, prefixList)
            }
            case SourceMode.GET_LIST => {
              if( keyList == null )  
                throw new IOException("Key list cannot be null when Source Mode is " + sourceMode)
              
              hbt.setHBaseListParms(keyList.toArray[String], versions, useSalt, prefixList)
            }
            case _ => throw new IOException("Unknown Source Mode (%)".format(sourceMode))
          }

          hbt.setInputSplitType(inputSplitType)
          
          hbt.asInstanceOf[Tap[_,_,_]]
        }
        case Write => {
          val hbt = new HBaseTap(quorumNames, tableName, hBaseScheme, sinkMode)
          
          hbt.setUseSaltInSink(useSalt)
          
          hbt.asInstanceOf[Tap[_,_,_]]
        }
      }
      case _ => createEmptyTap(readOrWrite)(mode)
    }
  }
  
  
  
  def createEmptyTap(readOrWrite : AccessMode)(mode : Mode) : Tap[_,_,_] = {
    mode match {
      case _ => {
        throw new RuntimeException("Source: (" + toString + ") doesn't support mode: " + mode.toString)
      }
    }
  }  
}