/*
 * Copyright (c) 2021 AtLarge Research
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package org.opendc.trace.util.parquet

import mu.KotlinLogging
import org.apache.parquet.column.ParquetProperties
import org.apache.parquet.hadoop.ParquetFileWriter
import org.apache.parquet.hadoop.ParquetWriter
import org.apache.parquet.hadoop.api.WriteSupport
import org.apache.parquet.hadoop.metadata.CompressionCodecName
import java.io.File
import java.util.concurrent.ArrayBlockingQueue
import java.util.concurrent.BlockingQueue
import kotlin.concurrent.thread

/**
 * A writer that writes data in Parquet format.
 *
 * @param path The path to the file to write the data to.
 * @param writeSupport The [WriteSupport] implementation for converting the records to Parquet format.
 */
public abstract class ParquetDataWriter<in T>(
    path: File,
    private val writeSupport: WriteSupport<T>,
    bufferSize: Int = 4096,
) : AutoCloseable {
    /**
     * The logging instance to use.
     */
    private val logger = KotlinLogging.logger {}

    /**
     * The queue of records to process.
     */
    private val queue: BlockingQueue<T> = ArrayBlockingQueue(bufferSize)

    /**
     * An exception to be propagated to the actual writer.
     */
    private var exception: Throwable? = null

    /**
     * The thread that is responsible for writing the Parquet records.
     */
    private val writerThread =
        thread(start = false, name = this.toString()) {
            val writer =
                let {
                    val builder =
                        LocalParquetWriter.builder(path.toPath(), writeSupport)
                            .withWriterVersion(ParquetProperties.WriterVersion.PARQUET_2_0)
                            .withCompressionCodec(CompressionCodecName.ZSTD)
                            .withWriteMode(ParquetFileWriter.Mode.OVERWRITE)
                    buildWriter(builder)
                }

            val queue = queue
            val buf = mutableListOf<T>()
            var shouldStop = false

            try {
                while (!shouldStop) {
                    try {
                        writer.write(queue.take())
                    } catch (e: InterruptedException) {
                        shouldStop = true
                    }

                    if (queue.drainTo(buf) > 0) {
                        for (data in buf) {
                            writer.write(data)
                        }
                        buf.clear()
                    }
                }
            } catch (e: Throwable) {
                logger.error(e) { "Failure in Parquet data writer" }
                exception = e
            } finally {
                writer.close()
            }
        }

    /**
     * Build the [ParquetWriter] used to write the Parquet files.
     */
    protected open fun buildWriter(builder: LocalParquetWriter.Builder<@UnsafeVariance T>): ParquetWriter<@UnsafeVariance T> {
        return builder.build()
    }

    /**
     * Write the specified metrics to the database.
     */
    public fun write(data: T) {
        val exception = exception
        if (exception != null) {
            throw IllegalStateException("Writer thread failed", exception)
        }

        queue.put(data)
    }

    /**
     * Signal the writer to stop.
     */
    override fun close() {
        writerThread.interrupt()
        writerThread.join()
    }

    init {
        writerThread.start()
    }
}