/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License.  You may obtain a copy of the License at
*
*   http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied.  See the License for the
* specific language governing permissions and limitations
* under the License.
*/

package org.apache.samza.sql.runner;

import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.stream.Collectors;
import org.apache.calcite.rel.BiRel;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.RelRoot;
import org.apache.calcite.rel.core.TableModify;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Validate;
import org.apache.samza.config.Config;
import org.apache.samza.config.MapConfig;
import org.apache.samza.sql.dsl.SamzaSqlDslConverter;
import org.apache.samza.sql.dsl.SamzaSqlDslConverterFactory;
import org.apache.samza.sql.udf.ReflectionBasedUdfResolver;
import org.apache.samza.sql.interfaces.DslConverter;
import org.apache.samza.sql.interfaces.DslConverterFactory;
import org.apache.samza.sql.interfaces.RelSchemaProvider;
import org.apache.samza.sql.interfaces.RelSchemaProviderFactory;
import org.apache.samza.sql.interfaces.SamzaRelConverter;
import org.apache.samza.sql.interfaces.SamzaRelConverterFactory;
import org.apache.samza.sql.interfaces.SamzaRelTableKeyConverter;
import org.apache.samza.sql.interfaces.SamzaRelTableKeyConverterFactory;
import org.apache.samza.sql.interfaces.SqlIOResolver;
import org.apache.samza.sql.interfaces.SqlIOResolverFactory;
import org.apache.samza.sql.interfaces.SqlIOConfig;
import org.apache.samza.sql.interfaces.UdfMetadata;
import org.apache.samza.sql.interfaces.UdfResolver;
import org.apache.samza.sql.util.JsonUtil;
import org.apache.samza.sql.util.SamzaSqlQueryParser;
import org.apache.samza.util.ReflectionUtil;
import com.fasterxml.jackson.core.type.TypeReference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * Class representing the Samza SQL application config
 */
public class SamzaSqlApplicationConfig {

  private static final Logger LOG = LoggerFactory.getLogger(SamzaSqlApplicationConfig.class);
  public static final String CFG_SQL_STMT = "samza.sql.stmt";
  public static final String CFG_SQL_STMTS_JSON = "samza.sql.stmts.json";
  public static final String CFG_SQL_FILE = "samza.sql.sqlFile";

  public static final String CFG_UDF_CONFIG_DOMAIN = "samza.sql.udf";

  public static final String CFG_FACTORY = "factory";

  public static final String CFG_FMT_REL_SCHEMA_PROVIDER_DOMAIN = "samza.sql.relSchemaProvider.%s.";
  public static final String CFG_FMT_SAMZA_REL_CONVERTER_DOMAIN = "samza.sql.relConverter.%s.";
  public static final String CFG_FMT_SAMZA_REL_TABLE_KEY_CONVERTER_DOMAIN = "samza.sql.relTableKeyConverter.%s.";

  public static final String CFG_IO_RESOLVER = "samza.sql.ioResolver";
  public static final String CFG_FMT_SOURCE_RESOLVER_DOMAIN = "samza.sql.ioResolver.%s.";

  public static final String CFG_UDF_RESOLVER = "samza.sql.udfResolver";
  public static final String CFG_FMT_UDF_RESOLVER_DOMAIN = "samza.sql.udfResolver.%s.";

  public static final String CFG_METADATA_TOPIC_PREFIX = "samza.sql.metadataTopicPrefix";
  public static final String CFG_GROUPBY_WINDOW_DURATION_MS = "samza.sql.groupby.window.ms";
  public static final String CFG_SQL_PROCESS_SYSTEM_EVENTS = "samza.sql.processSystemEvents";
  public static final String CFG_SQL_ENABLE_PLAN_OPTIMIZER = "samza.sql.enablePlanOptimizer";

  public static final String SAMZA_SYSTEM_LOG = "log";

  public static final String DEFAULT_METADATA_TOPIC_PREFIX = "";

  private static final long DEFAULT_GROUPBY_WINDOW_DURATION_MS = 300000; // default groupby window duration is 5 mins.

  private final Map<String, RelSchemaProvider> relSchemaProvidersBySource;
  private final Map<String, SamzaRelConverter> samzaRelConvertersBySource;
  private final Map<String, SamzaRelTableKeyConverter> samzaRelTableKeyConvertersBySource;

  private SqlIOResolver ioResolver;
  private UdfResolver udfResolver;

  private final Collection<UdfMetadata> udfMetadata;

  private final Map<String, SqlIOConfig> inputSystemStreamConfigBySource;
  private final Map<String, SqlIOConfig> outputSystemStreamConfigsBySource;

  // There could only be one output system stream per samza sql statement. The below list datastructure stores the
  // output system streams in the order of SQL query statements. Please note that there could be duplicate entries
  // in it during a fan-in scenario (e.g. two sql statements with two different input streams but same output stream).
  private final List<String> outputSystemStreams;

  private final String metadataTopicPrefix;
  private final long windowDurationMs;
  private final boolean processSystemEvents;
  private final boolean enableQueryPlanOptimizer;

  public SamzaSqlApplicationConfig(Config staticConfig, List<String> inputSystemStreams,
      List<String> outputSystemStreams) {

    ioResolver = createIOResolver(staticConfig);

    this.outputSystemStreams = new LinkedList<>(outputSystemStreams);

    // There could be duplicate streams across different queries. Let's dedupe them.
    Set<String> inputSystemStreamSet = new HashSet<>(inputSystemStreams);
    Set<String> outputSystemStreamSet = new HashSet<>(outputSystemStreams);

    // Let's get the output system stream configs before input system stream configs. This is to account for
    // table descriptor that could be both input and output. Please note that there could be only one
    // instance of table descriptor and writable table is a readable table but vice versa is not true.
    outputSystemStreamConfigsBySource = outputSystemStreamSet.stream()
         .collect(Collectors.toMap(Function.identity(), x -> ioResolver.fetchSinkInfo(x)));

    inputSystemStreamConfigBySource = inputSystemStreamSet.stream()
        .collect(Collectors.toMap(Function.identity(), src -> ioResolver.fetchSourceInfo(src)));

    Map<String, SqlIOConfig> systemStreamConfigsBySource = new HashMap<>(inputSystemStreamConfigBySource);
    systemStreamConfigsBySource.putAll(outputSystemStreamConfigsBySource);

    Set<SqlIOConfig> systemStreamConfigs = new HashSet<>(systemStreamConfigsBySource.values());

    relSchemaProvidersBySource = systemStreamConfigs.stream()
        .collect(Collectors.toMap(SqlIOConfig::getSource,
          x -> initializePlugin("RelSchemaProvider", x.getRelSchemaProviderName(), staticConfig,
            CFG_FMT_REL_SCHEMA_PROVIDER_DOMAIN,
            (o, c) -> ((RelSchemaProviderFactory) o).create(x.getSystemStream(), c))));

    samzaRelConvertersBySource = systemStreamConfigs.stream()
        .collect(Collectors.toMap(SqlIOConfig::getSource,
          x -> initializePlugin("SamzaRelConverter", x.getSamzaRelConverterName(), staticConfig,
            CFG_FMT_SAMZA_REL_CONVERTER_DOMAIN, (o, c) -> ((SamzaRelConverterFactory) o).create(x.getSystemStream(),
              relSchemaProvidersBySource.get(x.getSource()), c))));

    samzaRelTableKeyConvertersBySource = systemStreamConfigs.stream()
        .filter(SqlIOConfig::isRemoteTable)
        .collect(Collectors.toMap(SqlIOConfig::getSource,
          x -> initializePlugin("SamzaRelTableKeyConverter", x.getSamzaRelTableKeyConverterName(),
            staticConfig, CFG_FMT_SAMZA_REL_TABLE_KEY_CONVERTER_DOMAIN,
            (o, c) -> ((SamzaRelTableKeyConverterFactory) o).create(x.getSystemStream(), c))));

    udfResolver = createUdfResolver(staticConfig);
    udfMetadata = udfResolver.getUdfs();

    metadataTopicPrefix =
        staticConfig.get(CFG_METADATA_TOPIC_PREFIX, DEFAULT_METADATA_TOPIC_PREFIX);

    processSystemEvents = staticConfig.getBoolean(CFG_SQL_PROCESS_SYSTEM_EVENTS, true);
    windowDurationMs = staticConfig.getLong(CFG_GROUPBY_WINDOW_DURATION_MS, DEFAULT_GROUPBY_WINDOW_DURATION_MS);
    enableQueryPlanOptimizer = staticConfig.getBoolean(CFG_SQL_ENABLE_PLAN_OPTIMIZER, true);
  }

  public static <T> T initializePlugin(String pluginName, String plugin, Config staticConfig,
      String pluginDomainFormat, BiFunction<Object, Config, T> factoryInvoker) {
    String pluginDomain = String.format(pluginDomainFormat, plugin);
    Config pluginConfig = staticConfig.subset(pluginDomain);
    String factoryName = pluginConfig.getOrDefault(CFG_FACTORY, "");
    Validate.notEmpty(factoryName, String.format("Factory is not set for %s", plugin));
    Object factory = ReflectionUtil.getObj(factoryName, Object.class);
    LOG.info("Instantiating {} using factory {} with props {}", pluginName, factoryName, pluginConfig);
    return factoryInvoker.apply(factory, pluginConfig);
  }

  public static List<String> deserializeSqlStmts(String value) {
    Validate.notEmpty(value, "json Value is not set or empty");
    return JsonUtil.fromJson(value, new TypeReference<List<String>>() {
    });
  }

  public static String serializeSqlStmts(List<String> sqlStmts) {
    Validate.notEmpty(sqlStmts, "json Value is not set or empty");
    return JsonUtil.toJson(sqlStmts);
  }

  public static SqlIOResolver createIOResolver(Config config) {
    String sourceResolveValue = config.get(CFG_IO_RESOLVER);
    Map<String, String> metadataPrefixProperties = new HashMap<>();
    metadataPrefixProperties.put(
        String.format(CFG_FMT_SOURCE_RESOLVER_DOMAIN, sourceResolveValue) + CFG_METADATA_TOPIC_PREFIX,
        config.get(CFG_METADATA_TOPIC_PREFIX, DEFAULT_METADATA_TOPIC_PREFIX));
    Config newConfig = new MapConfig(Arrays.asList(config, metadataPrefixProperties));
    Validate.notEmpty(sourceResolveValue, "ioResolver config is not set or empty");
    return initializePlugin("SqlIOResolver", sourceResolveValue, newConfig, CFG_FMT_SOURCE_RESOLVER_DOMAIN,
      (o, c) -> ((SqlIOResolverFactory) o).create(c, newConfig));
  }

  private UdfResolver createUdfResolver(Map<String, String> config) {
    String udfResolveValue = config.get(CFG_UDF_RESOLVER);
    Validate.notEmpty(udfResolveValue, "udfResolver config is not set or empty");
    HashMap<String, String> domainConfig =
        getDomainProperties(config, String.format(CFG_FMT_UDF_RESOLVER_DOMAIN, udfResolveValue), false);
    Properties props = new Properties();
    props.putAll(domainConfig);
    HashMap<String, String> udfConfig = getDomainProperties(config, CFG_UDF_CONFIG_DOMAIN, false);
    // TODO: SAMZA-2355: Make the UDFResolver pluggable.
    return new ReflectionBasedUdfResolver(new MapConfig(udfConfig));
  }

  private static HashMap<String, String> getDomainProperties(Map<String, String> props, String prefix,
      boolean preserveFullKey) {
    String fullPrefix;
    if (StringUtils.isBlank(prefix)) {
      fullPrefix = ""; // this will effectively retrieve all properties
    } else {
      fullPrefix = prefix.endsWith(".") ? prefix : prefix + ".";
    }
    HashMap<String, String> ret = new HashMap<>();
    props.keySet().forEach(keyStr -> {
      if (keyStr.startsWith(fullPrefix) && !keyStr.equals(fullPrefix)) {
        if (preserveFullKey) {
          ret.put(keyStr, props.get(keyStr));
        } else {
          ret.put(keyStr.substring(fullPrefix.length()), props.get(keyStr));
        }
      }
    });
    return ret;
  }

  public static Collection<RelRoot> populateSystemStreamsAndGetRelRoots(List<String> dslStmts, Config config,
      List<String> inputSystemStreams, List<String> outputSystemStreams) {
    // TODO: Get the converter factory based on the file type. Create abstraction around this.
    DslConverterFactory dslConverterFactory = new SamzaSqlDslConverterFactory();
    DslConverter dslConverter = dslConverterFactory.create(config);

    Collection<RelRoot> relRoots = dslConverter.convertDsl(String.join("\n", dslStmts));

    // RelRoot does not have sink node for Samza SQL dsl, so we can not traverse the relRoot tree to get
    // "outputSystemStreams"
    // FIXME: the snippet below does not work for Samza SQL dsl but is required for other dsls. Future fix could be
    // for samza sql to build TableModify for sink and stick it to the relRoot, so we could get output stream out of it.

    // for (RelRoot relRoot : relRoots) {
    //   SamzaSqlApplicationConfig.populateSystemStreams(relRoot.project(), inputSystemStreams, outputSystemStreams);
    // }

    // The below code is specific to Samza SQL dsl and should be removed once Samza SQL includes sink as part of
    // relRoot and the above code in uncommented.
    List<String> sqlStmts = SamzaSqlDslConverter.fetchSqlFromConfig(config);
    List<SamzaSqlQueryParser.QueryInfo> queryInfo = SamzaSqlDslConverter.fetchQueryInfo(sqlStmts);
    inputSystemStreams.addAll(queryInfo.stream().map(SamzaSqlQueryParser.QueryInfo::getSources).flatMap(Collection::stream)
          .collect(Collectors.toList()));
    outputSystemStreams.addAll(queryInfo.stream().map(SamzaSqlQueryParser.QueryInfo::getSink).collect(Collectors.toList()));

    return relRoots;
  }

  private static void populateSystemStreams(RelNode relNode, List<String> inputSystemStreams,
      List<String> outputSystemStreams) {
    if (relNode instanceof TableModify) {
      outputSystemStreams.add(getSystemStreamName(relNode));
    } else {
      if (relNode instanceof BiRel) {
        BiRel biRelNode = (BiRel) relNode;
        populateSystemStreams(biRelNode.getLeft(), inputSystemStreams, outputSystemStreams);
        populateSystemStreams(biRelNode.getRight(), inputSystemStreams, outputSystemStreams);
      } else {
        if (relNode.getTable() != null) {
          inputSystemStreams.add(getSystemStreamName(relNode));
        }
      }
    }
    List<RelNode> relNodes = relNode.getInputs();
    if (relNodes == null || relNodes.isEmpty()) {
      return;
    }
    relNodes.forEach(node -> populateSystemStreams(node, inputSystemStreams, outputSystemStreams));
  }

  private static String getSystemStreamName(RelNode relNode) {
    return relNode.getTable().getQualifiedName().stream().map(Object::toString).collect(Collectors.joining("."));
  }

  public Collection<UdfMetadata> getUdfMetadata() {
    return udfMetadata;
  }

  public List<String> getOutputSystemStreams() {
    return outputSystemStreams;
  }

  public Map<String, SqlIOConfig> getInputSystemStreamConfigBySource() {
    return inputSystemStreamConfigBySource;
  }

  public Map<String, SqlIOConfig> getOutputSystemStreamConfigsBySource() {
    return outputSystemStreamConfigsBySource;
  }

  public SqlIOConfig getOutputSqlIOConfig(String source) {
    return outputSystemStreamConfigsBySource.get(source);
  }

  public Map<String, SamzaRelConverter> getSamzaRelConverters() {
    return samzaRelConvertersBySource;
  }

  public Map<String, SamzaRelTableKeyConverter> getSamzaRelTableKeyConverters() {
    return samzaRelTableKeyConvertersBySource;
  }

  public Map<String, RelSchemaProvider> getRelSchemaProviders() {
    return relSchemaProvidersBySource;
  }

  public String getMetadataTopicPrefix() {
    return metadataTopicPrefix;
  }

  public long getWindowDurationMs() {
    return windowDurationMs;
  }

  public boolean isProcessSystemEvents() {
    return processSystemEvents;
  }

  public boolean isQueryPlanOptimizerEnabled() {
    return enableQueryPlanOptimizer;
  }
}