/*
 * Copyright OpenSearch Contributors
 * SPDX-License-Identifier: Apache-2.0
 */

package org.opensearch.indexmanagement.rollup.util

import org.opensearch.Version
import org.opensearch.client.Client
import org.opensearch.cluster.metadata.IndexMetadata
import org.opensearch.cluster.service.ClusterService
import org.opensearch.core.common.io.stream.NamedWriteableRegistry
import org.opensearch.common.regex.Regex
import org.opensearch.common.settings.IndexScopedSettings
import org.opensearch.common.settings.Settings
import org.opensearch.common.settings.SettingsModule
import org.opensearch.common.util.BigArrays
import org.opensearch.core.xcontent.NamedXContentRegistry
import org.opensearch.env.Environment
import org.opensearch.core.index.Index
import org.opensearch.index.IndexSettings
import org.opensearch.index.mapper.MapperService
import org.opensearch.index.query.QueryShardContext
import org.opensearch.index.similarity.SimilarityService
import org.opensearch.indices.IndicesModule
import org.opensearch.indices.analysis.AnalysisModule
import org.opensearch.plugins.MapperPlugin
import org.opensearch.plugins.PluginsService
import org.opensearch.script.ScriptService
import java.time.Instant

/**
 * Creates QueryShardContext object which is used in QueryStringQuery rewrite.
 * We need this because we have to use QueryStringQueryParser class which requires QueryShardContext as parameter
 */
object QueryShardContextFactory {
    lateinit var client: Client
    lateinit var clusterService: ClusterService
    lateinit var scriptService: ScriptService
    lateinit var xContentRegistry: NamedXContentRegistry
    lateinit var namedWriteableRegistry: NamedWriteableRegistry
    lateinit var environment: Environment

    @Suppress("LongParameterList")
    fun init(
        client: Client,
        clusterService: ClusterService,
        scriptService: ScriptService,
        xContentRegistry: NamedXContentRegistry,
        namedWriteableRegistry: NamedWriteableRegistry,
        environment: Environment
    ) {
        this.client = client
        this.clusterService = clusterService
        this.scriptService = scriptService
        this.xContentRegistry = xContentRegistry
        this.namedWriteableRegistry = namedWriteableRegistry
        this.environment = environment
    }

    private fun getIndexSettingsAndMetadata(indexName: String?): Triple<Index?, Settings?, IndexMetadata?> {
        val index: Index?
        val indexSettings: Settings?
        val indexMetadata = clusterService.state().metadata.index(indexName)
            ?: throw IllegalArgumentException("Can't find IndexMetadata for index: [$indexName]")
        index = indexMetadata.index
        indexSettings = indexMetadata.settings
        return Triple(index, indexSettings, indexMetadata)
    }

    fun createShardContext(indexName: String?): QueryShardContext {
        val (index, indexSettings, indexMetadata) = getIndexSettingsAndMetadata(indexName)
        val nodeSettings = Settings.builder()
            .put("node.name", "dummyNodeName")
            .put(Environment.PATH_HOME_SETTING.key, environment.tmpDir())
            .build()
        val pluginsService =
            PluginsService(nodeSettings, null, null, null, listOf())
        val additionalSettings = pluginsService.pluginSettings
        val settingsModule = SettingsModule(
            nodeSettings,
            additionalSettings,
            pluginsService.pluginSettingsFilter, emptySet()
        )
        val indexScopedSettings: IndexScopedSettings = settingsModule.indexScopedSettings
        val idxSettings = newIndexSettings(index, indexSettings, indexScopedSettings)
        val indicesModule = IndicesModule(pluginsService.filterPlugins(MapperPlugin::class.java))
        val mapperRegistry = indicesModule.mapperRegistry
        val analysisModule = AnalysisModule(environment, emptyList())
        val indexAnalyzers = analysisModule.analysisRegistry.build(idxSettings)
        val similarityService = SimilarityService(idxSettings, null, emptyMap())
        val mapperService = MapperService(
            idxSettings,
            indexAnalyzers,
            xContentRegistry,
            similarityService,
            mapperRegistry,
            { createShardContext(null) },
            { false },
            scriptService
        )
        // In order to be able to call toQuery method on QueryBuilder, we need to setup mappings in MapperService
        mapperService.merge("_doc", indexMetadata?.mapping()?.source(), MapperService.MergeReason.MAPPING_UPDATE)

        return QueryShardContext(
            0,
            idxSettings,
            BigArrays.NON_RECYCLING_INSTANCE,
            null,
            null,
            mapperService,
            null,
            scriptService,
            xContentRegistry,
            namedWriteableRegistry,
            null,
            null,
            { Instant.now().toEpochMilli() },
            null,
            { pattern -> Regex.simpleMatch(pattern, index?.name) },
            { true },
            null
        )
    }

    private fun newIndexSettings(index: Index?, settings: Settings?, indexScopedSettings: IndexScopedSettings?): IndexSettings? {
        val build = Settings.builder()
            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
            .put(settings)
            .build()
        val metadata = IndexMetadata.builder(index?.name).settings(build).build()
        return IndexSettings(metadata, Settings.EMPTY, indexScopedSettings)
    }
}