/*
 * Table Data Import Service
 * Copyright (C) 2020 Memoriav
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package org.memobase

import com.beust.klaxon.JsonObject
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.kotlin.registerKotlinModule
import java.io.StringWriter
import org.apache.kafka.streams.KeyValue
import org.apache.kafka.streams.StreamsBuilder
import org.apache.kafka.streams.Topology
import org.apache.logging.log4j.LogManager
import org.memobase.helpers.JSON
import org.memobase.model.Report
import org.memobase.model.SearchDoc
import org.memobase.settings.SettingsLoader

class KafkaTopology(private val settings: SettingsLoader) {
    private val log = LogManager.getLogger("SearchDocService")

    private val reportTopic = settings.processReportTopic

    private val searchDocTransform = SearchDocTransform(settings.appSettings.getProperty(KEYS.mediaUrlPropName))
    fun build(): Topology {
        val builder = StreamsBuilder()
        val stream = builder.stream<String, String>(settings.inputTopic)
        val transformedStream = stream
            .flatMapValues { value -> JSON.parse(value) }
            .mapValues { value -> JSON.unpack(value) }
            .mapValues { readOnlyKey, value ->
                try {
                    Pair(transformJson(value), Report(readOnlyKey, "SUCCESS", "Transformed message into search doc."))
                } catch (ex: InvalidInputException) {
                    Pair(null, Report(readOnlyKey, "FAILURE", ex.localizedMessage))
                }
            }

        transformedStream
            .map { _, value -> KeyValue(value.second.id, value.second.toJson()) }
            .to(reportTopic)

        transformedStream
            .filterNot { _, value -> value.second.status == "FAILURE" }
            .map { _, value -> KeyValue(value.first?.id, value.first) }
            .mapValues { value ->
                val writer = StringWriter()
                ObjectMapper().registerKotlinModule().writeValue(writer, value)
                writer.toString()
            }
            .to(settings.outputTopic)

        return builder.build()
    }

    private fun transformJson(input: Map<String, JsonObject>): SearchDoc {
        return searchDocTransform.transform(input)
    }
}