/********************************************************************************
 * Copyright (c) 2015-2020 Contributors to the Eclipse Foundation
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 ********************************************************************************/
package org.eclipse.mdm.businessobjects.utils;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.apache.commons.lang3.StringUtils;
import org.eclipse.mdm.api.base.model.FileLink;
import org.eclipse.mdm.api.base.model.MimeType;
import org.eclipse.mdm.api.base.model.Value;
import org.eclipse.mdm.api.base.model.ValueType;
import org.eclipse.mdm.businessobjects.control.MDMEntityAccessException;
import org.eclipse.mdm.businessobjects.entity.MDMFileLink;

import com.google.common.base.Strings;

/**
 * Serializer for values.
 */
public final class Serializer {

	private static DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'");

	private Serializer() {
	}

	public static Object serializeValue(Value value) {
		if (value.getValueType().isDate()) {
			return formatter.format(value.extract());
		} else if (value.getValueType().isFileLink()) {
			return serializeFileLink(value.extract(ValueType.FILE_LINK));
		} else if (value.getValueType().isFileLinkSequence()) {
			return Stream.of(value.extract(ValueType.FILE_LINK_SEQUENCE)).map(Serializer::serializeFileLink)
					.collect(Collectors.toList());
		} else {
			return value.extract().toString();
		}
	}

	public static MDMFileLink serializeFileLink(FileLink fileLink) {
		return new MDMFileLink(fileLink.getRemotePath(), fileLink.getMimeType().toString(), fileLink.getDescription());
	}

	public static LocalDateTime parseDate(String value) {
		return LocalDateTime.from(formatter.parse(value));
	}

	public static void applyValue(org.eclipse.mdm.api.base.model.Value value, Object newValue) {
		value.set(deserializeValue(value.getValueType(), newValue));
	}

	public static Object deserializeValue(ValueType<?> type, Object newValue) {

		if (newValue == null || (!type.isString() && newValue instanceof String && "".equals((String) newValue))) {
			return null;
		}

		if (type.isBoolean()) {
			if (newValue instanceof Number) {
				return ((Number) newValue).intValue() == 1;
			} else if (newValue instanceof String) {
				String stringVal = (String) newValue;
				if (StringUtils.isNumeric(stringVal)) {
					return Integer.parseInt(stringVal) == 1;
				} else {
					return Boolean.valueOf(stringVal);
				}
			}
		} else if (type.isByte()) {
			if (newValue instanceof Number) {
				return (byte) ((Number) newValue).intValue();
			} else if (newValue instanceof String) {
				return Byte.parseByte((String) newValue);
			}
		} else if (type.isShort()) {
			if (newValue instanceof Number) {
				return (short) ((Number) newValue).intValue();
			} else if (newValue instanceof String) {
				return Short.parseShort((String) newValue);
			}
		} else if (type.isInteger()) {
			if (newValue instanceof Number) {
				return ((Number) newValue).intValue();
			} else if (newValue instanceof String) {
				return Integer.parseInt((String) newValue);
			}
		} else if (type.isLong()) {
			if (newValue instanceof Number) {
				return ((Number) newValue).longValue();
			} else if (newValue instanceof String) {
				return Long.parseLong((String) newValue);
			}
		} else if (type.isFloat()) {
			if (newValue instanceof Number) {
				return ((Number) newValue).floatValue();
			} else if (newValue instanceof String) {
				return Float.parseFloat((String) newValue);
			}
		} else if (type.isDouble()) {
			if (newValue instanceof Number) {
				return ((Number) newValue).doubleValue();
			} else if (newValue instanceof String) {
				return Double.parseDouble((String) newValue);
			}
		} else if (type.isDate()) {
			if (newValue instanceof Number) {
				return LocalDateTime.ofEpochSecond((long) newValue, 0, ZoneOffset.UTC);
			} else if (newValue instanceof String) {
				if (Strings.isNullOrEmpty((String) newValue)) {
					return null;
				} else {
					return Serializer.parseDate((String) newValue);
				}
			}
		} else if (type.isFileLink()) {
			if (newValue instanceof FileLink) {
				return newValue;
			} else {
				return deserializeFileLink(newValue);
			}
		} else if (type.isFileLinkSequence()) {
			if (newValue instanceof FileLink[]) {
				return newValue;
			} else if (newValue instanceof List) {
				if (((List<?>) newValue).isEmpty()) {
					return new FileLink[0];
				} else {
					List<FileLink> fileLinks = new ArrayList<>();
					for (Object o : (List<?>) newValue) {
						fileLinks.add(deserializeFileLink(o));
					}
					return fileLinks.toArray(new FileLink[0]);
				}
			}
		}
		// TODO mkoller on 2018-12-06: Missing ValueTypes: ByteStream, Blob,
		// FloatComplex, DoubleComplex, Enumeration and all sequence
		// ValueTypes
		return newValue;
	}

	private static FileLink deserializeFileLink(Object newValue) {

		if (newValue == null || newValue instanceof String && ((String) newValue).trim().isEmpty()) {
			return null;
		} else if (newValue instanceof Map<?, ?>) {
			Map<?, ?> map = (Map<?, ?>) newValue;
			String remotePath = Objects.toString(map.get("remotePath"));
			MimeType mimeType = new MimeType(Objects.toString(map.get("mimeType")));
			String description = Objects.toString(map.get("description"));
			return FileLink.newRemote(remotePath, mimeType, description);
		}

		throw new MDMEntityAccessException("Cannot deserialize FILE_LINK: " + newValue);
	}
}