// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: MIT-0
package com.socalcat.lambda.transferauth;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.Date;
import java.util.List;
import java.util.Map;

import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormatter;
import org.joda.time.format.ISODateTimeFormat;
import org.joda.time.tz.FixedDateTimeZone;

import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.Record;
import com.amazonaws.services.dynamodbv2.model.StreamRecord;
import com.amazonaws.services.lambda.runtime.events.DynamodbEvent;
import com.amazonaws.services.lambda.runtime.events.S3Event;
import com.amazonaws.services.lambda.runtime.events.SNSEvent;
import com.amazonaws.services.s3.event.S3EventNotification;
import com.amazonaws.util.IOUtils;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.PropertyNamingStrategy;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.module.SimpleModule;

/**
 * Helper utilities for testing Lambda functions.
 */
public class TestUtils {

    private static final ObjectMapper mapper = new ObjectMapper();
    private static final ObjectMapper snsEventMapper = new ObjectMapper();
    private static final ObjectMapper dynamodbEventMapper = new ObjectMapper();

    static {
        mapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
        mapper.setPropertyNamingStrategy(new UpperCaseRecordsPropertyNamingStrategy());
        mapper.registerModule(new TestJacksonMapperModule());

        snsEventMapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
        snsEventMapper.setPropertyNamingStrategy(PropertyNamingStrategy.PASCAL_CASE_TO_CAMEL_CASE);
        snsEventMapper.registerModule(new TestJacksonMapperModule());

        dynamodbEventMapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
        dynamodbEventMapper.setPropertyNamingStrategy(new UpperCaseRecordsPropertyNamingStrategy());
        dynamodbEventMapper.registerModule(new TestJacksonMapperModule());
        dynamodbEventMapper.addMixIn(Record.class, DynamodbEventMixin.RecordMixin.class);
        dynamodbEventMapper.addMixIn(StreamRecord.class, DynamodbEventMixin.StreamRecordMixin.class);
        dynamodbEventMapper.addMixIn(AttributeValue.class, DynamodbEventMixin.AttributeValueMixIn.class);
    }

    private static final DateTimeFormatter dateTimeFormatter = ISODateTimeFormat.dateTime()
            .withZone(new FixedDateTimeZone("GMT", "GMT", 0, 0));

    /**
     * Helper method that parses a JSON object from a resource on the classpath
     * as an instance of the provided type.
     *
     * @param resource the path to the resource (relative to this class)
     * @param clazz    the type to parse the JSON into
     */
    public static <T> T parse(String resource, Class<T> clazz)
            throws IOException {

        InputStream stream = TestUtils.class.getResourceAsStream(resource);
        try {
            if (clazz == S3Event.class) {
                String json = IOUtils.toString(stream);
                S3EventNotification event = S3EventNotification.parseJson(json);

                @SuppressWarnings("unchecked")
                T result = (T) new S3Event(event.getRecords());
                return result;

            } else if (clazz == SNSEvent.class) {
                return snsEventMapper.readValue(stream, clazz);
            } else if (clazz == DynamodbEvent.class) {
                return dynamodbEventMapper.readValue(stream, clazz);
            } else {
                return mapper.readValue(stream, clazz);
            }
        } finally {
            stream.close();
        }
    }

    private static class TestJacksonMapperModule extends SimpleModule {

        private static final long serialVersionUID = 1L;

        public TestJacksonMapperModule() {
            super("TestJacksonMapperModule");

            super.addSerializer(DateTime.class, new DateTimeSerializer());
            super.addDeserializer(DateTime.class, new DateTimeDeserializer());
        }
    }

    private static class DateTimeSerializer extends JsonSerializer<DateTime> {

        @Override
        public void serialize(
                DateTime value,
                JsonGenerator gen,
                SerializerProvider provider) throws IOException {

            gen.writeString(dateTimeFormatter.print(value));
        }
    }

    private static class DateTimeDeserializer
            extends JsonDeserializer<DateTime> {

        @Override
        public DateTime deserialize(
                JsonParser parser,
                DeserializationContext context) throws IOException {

            return dateTimeFormatter.parseDateTime(parser.getText());
        }
    }

    private static class UpperCaseRecordsPropertyNamingStrategy
            extends PropertyNamingStrategy.PropertyNamingStrategyBase {

        private static final long serialVersionUID = 1L;

        @Override
        public String translate(String propertyName) {
            if (propertyName.equals("records")) {
                return "Records";
            }
            return propertyName;
        }
    }

    private static interface DynamodbEventMixin {
        public static final String L = "L";
        public static final String M = "M";
        public static final String BS = "BS";
        public static final String NS = "NS";
        public static final String SS = "SS";
        public static final String BOOL = "BOOL";
        public static final String NULL = "NULL";
        public static final String B = "B";
        public static final String N = "N";
        public static final String S = "S";
        public static final String OLD_IMAGE = "OldImage";
        public static final String NEW_IMAGE = "NewImage";
        public static final String STREAM_VIEW_TYPE = "StreamViewType";
        public static final String SEQUENCE_NUMBER = "SequenceNumber";
        public static final String SIZE_BYTES = "SizeBytes";
        public static final String KEYS = "Keys";
        public static final String AWS_REGION = "awsRegion";
        public static final String DYNAMODB = "dynamodb";
        public static final String EVENT_ID = "eventID";
        public static final String EVENT_NAME = "eventName";
        public static final String EVENT_SOURCE = "eventSource";
        public static final String EVENT_VERSION = "eventVersion";
        public static final String EVENT_SOURCE_ARN = "eventSourceARN";
        public static final String APPROXIMATE_CREATION_DATE_TIME = "ApproximateCreationDateTime";

        @JsonProperty(value = "Records")
        public List<?> getRecords();

        static interface RecordMixin {
            @JsonProperty(AWS_REGION)
            public String getAwsRegion();

            @JsonProperty(AWS_REGION)
            public void setAwsRegion(String awsRegion);

            @JsonProperty(DYNAMODB)
            public Object getDynamodb();

            @JsonProperty(DYNAMODB)
            public void setDynamodb(Object dynamodb);

            @JsonProperty(EVENT_ID)
            public String getEventID();

            @JsonProperty(EVENT_ID)
            public void setEventID(String eventID);

            @JsonProperty(EVENT_NAME)
            public String getEventName();

            @JsonProperty(EVENT_NAME)
            public void setEventName(String eventName);

            @JsonProperty(EVENT_SOURCE)
            public String getEventSource();

            @JsonProperty(EVENT_SOURCE)
            public void setEventSource(String eventSource);

            @JsonProperty(EVENT_VERSION)
            public String getEventVersion();

            @JsonProperty(EVENT_VERSION)
            public void setEventVersion(String eventVersion);

            @JsonProperty(EVENT_SOURCE_ARN)
            public String getEventSourceArn();

            @JsonProperty(EVENT_SOURCE_ARN)
            public void setEventSourceArn(String eventSourceArn);
        }

        static interface StreamRecordMixin {

            @JsonProperty(KEYS)
            public Map<String, Object> getKeys();

            @JsonProperty(KEYS)
            public void setKeys(Map<String, Object> keys);

            @JsonProperty(SIZE_BYTES)
            public Long getSizeBytes();

            @JsonProperty(SIZE_BYTES)
            public void setSizeBytes(Long sizeBytes);

            @JsonProperty(SEQUENCE_NUMBER)
            public String getSequenceNumber();

            @JsonProperty(SEQUENCE_NUMBER)
            public void setSequenceNumber(String sequenceNumber);

            @JsonProperty(STREAM_VIEW_TYPE)
            public String getStreamViewType();

            @JsonProperty(STREAM_VIEW_TYPE)
            public void setStreamViewType(String streamViewType);

            @JsonProperty(NEW_IMAGE)
            public Map<String, Object> getNewImage();

            @JsonProperty(NEW_IMAGE)
            public void setNewImage(Map<String, Object> newImage);

            @JsonProperty(OLD_IMAGE)
            public Map<String, Object> getOldImage();

            @JsonProperty(OLD_IMAGE)
            public void setOldImage(Map<String, Object> oldImage);

            @JsonProperty(APPROXIMATE_CREATION_DATE_TIME)
            public Date getApproximateCreationDateTime();

            @JsonProperty(APPROXIMATE_CREATION_DATE_TIME)
            public void setApproximateCreationDateTime(Date approximateCreationDateTime);
        }

        static interface AttributeValueMixIn {
            @JsonProperty(S)
            public String getS();

            @JsonProperty(S)
            public void setS(String s);

            @JsonProperty(N)
            public String getN();

            @JsonProperty(N)
            public void setN(String n);

            @JsonProperty(B)
            public ByteBuffer getB();

            @JsonProperty(B)
            public void setB(ByteBuffer b);

            @JsonProperty(NULL)
            public Boolean isNULL();

            @JsonProperty(NULL)
            public void setNULL(Boolean nU);

            @JsonProperty(BOOL)
            public Boolean getBOOL();

            @JsonProperty(BOOL)
            public void setBOOL(Boolean bO);

            @JsonProperty(SS)
            public List<String> getSS();

            @JsonProperty(SS)
            public void setSS(List<String> sS);

            @JsonProperty(NS)
            public List<String> getNS();

            @JsonProperty(NS)
            public void setNS(List<String> nS);

            @JsonProperty(BS)
            public List<String> getBS();

            @JsonProperty(BS)
            public void setBS(List<String> bS);

            @JsonProperty(M)
            public Map<String, Object> getM();

            @JsonProperty(M)
            public void setM(Map<String, Object> val);

            @JsonProperty(L)
            public List<Object> getL();

            @JsonProperty(L)
            public void setL(List<Object> val);
        }
    }
}