/*
 * 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.nifi.avro;

import com.github.benmanes.caffeine.cache.Caffeine;
import com.github.benmanes.caffeine.cache.LoadingCache;
import org.apache.avro.Schema;
import org.apache.nifi.annotation.documentation.CapabilityDescription;
import org.apache.nifi.annotation.documentation.Tags;
import org.apache.nifi.annotation.lifecycle.OnEnabled;
import org.apache.nifi.components.AllowableValue;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.context.PropertyContext;
import org.apache.nifi.controller.ConfigurationContext;
import org.apache.nifi.logging.ComponentLog;
import org.apache.nifi.migration.PropertyConfiguration;
import org.apache.nifi.processor.util.StandardValidators;
import org.apache.nifi.schema.access.SchemaAccessStrategy;
import org.apache.nifi.schema.access.SchemaNotFoundException;
import org.apache.nifi.schemaregistry.services.SchemaRegistry;
import org.apache.nifi.serialization.RecordReader;
import org.apache.nifi.serialization.RecordReaderFactory;
import org.apache.nifi.serialization.SchemaRegistryService;
import org.apache.nifi.serialization.record.RecordSchema;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Optional;

@Tags({"avro", "parse", "record", "row", "reader", "delimited", "comma", "separated", "values"})
@CapabilityDescription("Parses Avro data and returns each Avro record as an separate Record object. The Avro data may contain the schema itself, "
    + "or the schema can be externalized and accessed by one of the methods offered by the 'Schema Access Strategy' property.")
public class AvroReader extends SchemaRegistryService implements RecordReaderFactory {
    private static final AllowableValue EMBEDDED_AVRO_SCHEMA = new AllowableValue("embedded-avro-schema",
        "Use Embedded Avro Schema", "The FlowFile has the Avro Schema embedded within the content, and this schema will be used.");

    static final PropertyDescriptor CACHE_SIZE = new PropertyDescriptor.Builder()
            .name("Cache Size")
            .description("Specifies how many Schemas should be cached")
            .addValidator(StandardValidators.NON_NEGATIVE_INTEGER_VALIDATOR)
            .defaultValue("1000")
            .required(true)
            .build();

    static final PropertyDescriptor FAST_READER_ENABLED = new PropertyDescriptor.Builder()
            .name("Fast Reader Enabled")
            .description("""
                    When enabled, the Avro library uses an optimized reader implementation that improves read performance
                    by creating a detailed execution plan at initialization. However, this optimization can lead to
                    significantly higher memory consumption, especially when using schema inference. If OutOfMemory errors
                    occur during Avro processing, consider disabling this option.""")
            .addValidator(StandardValidators.BOOLEAN_VALIDATOR)
            .allowableValues("true", "false")
            .defaultValue("true")
            .required(true)
            .build();

    private LoadingCache<String, Schema> compiledAvroSchemaCache;
    private boolean fastReaderEnabled;

    @Override
    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
        final List<PropertyDescriptor> properties = new ArrayList<>(super.getSupportedPropertyDescriptors());
        properties.add(CACHE_SIZE);
        properties.add(FAST_READER_ENABLED);
        return properties;
    }

    @OnEnabled
    public void onEnabled(final ConfigurationContext context) {
        final int cacheSize = context.getProperty(CACHE_SIZE).asInteger();
        compiledAvroSchemaCache = Caffeine.newBuilder()
                .maximumSize(cacheSize)
                .build(schemaText -> new Schema.Parser().parse(schemaText));
        fastReaderEnabled = context.getProperty(FAST_READER_ENABLED).asBoolean();
    }

    @Override
    public void migrateProperties(PropertyConfiguration config) {
        super.migrateProperties(config);
        config.renameProperty("cache-size", CACHE_SIZE.getName());
    }

    @Override
    protected List<AllowableValue> getSchemaAccessStrategyValues() {
        final List<AllowableValue> allowableValues = new ArrayList<>(super.getSchemaAccessStrategyValues());
        allowableValues.add(EMBEDDED_AVRO_SCHEMA);
        return allowableValues;
    }

    @Override
    protected SchemaAccessStrategy getSchemaAccessStrategy(String strategy, SchemaRegistry schemaRegistry, PropertyContext context) {
        if (EMBEDDED_AVRO_SCHEMA.getValue().equals(strategy)) {
            return new EmbeddedAvroSchemaAccessStrategy();
        } else {
            return super.getSchemaAccessStrategy(strategy, schemaRegistry, context);
        }
    }

    @Override
    public RecordReader createRecordReader(final Map<String, String> variables, final InputStream in, final long inputLength, final ComponentLog logger) throws IOException, SchemaNotFoundException {
        final String schemaAccessStrategy = getConfigurationContext().getProperty(getSchemaAccessStrategyDescriptor()).getValue();
        if (EMBEDDED_AVRO_SCHEMA.getValue().equals(schemaAccessStrategy)) {
            return new AvroReaderWithEmbeddedSchema(in, fastReaderEnabled);
        } else {
            final RecordSchema recordSchema = getSchema(variables, in, null);

            final Schema avroSchema;
            try {
                if (recordSchema.getSchemaFormat().isPresent() && recordSchema.getSchemaFormat().get().equals(AvroTypeUtil.AVRO_SCHEMA_FORMAT)) {
                    final Optional<String> textOption = recordSchema.getSchemaText();
                    if (textOption.isPresent()) {
                        avroSchema = compiledAvroSchemaCache.get(textOption.get());
                    } else {
                        avroSchema = AvroTypeUtil.extractAvroSchema(recordSchema);
                    }
                } else {
                    avroSchema = AvroTypeUtil.extractAvroSchema(recordSchema);
                }
            } catch (final Exception e) {
                throw new SchemaNotFoundException("Failed to compile Avro Schema", e);
            }

            return new AvroReaderWithExplicitSchema(in, recordSchema, avroSchema, fastReaderEnabled);
        }
    }

    @Override
    protected AllowableValue getDefaultSchemaAccessStrategy() {
        return EMBEDDED_AVRO_SCHEMA;
    }
}
