/*
 * Copyright 2017 Graz University of Technology EAAF-Core Components has been developed in a
 * cooperation between EGIZ, A-SIT Plus, A-SIT, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by the European
 * Commission - subsequent versions of the EUPL (the "Licence"); You may not use this work except in
 * compliance with the Licence. You may obtain a copy of the Licence at:
 * https://joinup.ec.europa.eu/news/understanding-eupl-v12
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the Licence
 * is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the Licence for the specific language governing permissions and limitations under
 * the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text file for details on the
 * various modules and licenses. The "NOTICE" text file is part of the distribution. Any derivative
 * works that you distribute must include a readable copy of the "NOTICE" text file.
*/

package at.gv.egiz.eaaf.core.impl.idp.auth.data;

import java.io.Serializable;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.Date;
import java.util.Map;
import java.util.Map.Entry;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import javax.annotation.Nullable;

import org.apache.commons.lang3.StringUtils;

import at.gv.egiz.eaaf.core.api.data.EaafConstants;
import at.gv.egiz.eaaf.core.api.idp.EaafAuthProcessDataConstants;
import at.gv.egiz.eaaf.core.api.idp.auth.data.IAuthProcessDataContainer;
import at.gv.egiz.eaaf.core.api.idp.auth.data.IIdentityLink;
import at.gv.egiz.eaaf.core.exceptions.EaafJsonMapperException;
import at.gv.egiz.eaaf.core.exceptions.EaafStorageException;
import at.gv.egiz.eaaf.core.impl.utils.DefaultJsonMapper;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.extern.slf4j.Slf4j;

@Slf4j
public class AuthProcessDataWrapper
    implements IAuthProcessDataContainer, EaafAuthProcessDataConstants {

  public static final String GENERIC_DATA_PREFIX = "$GENERIC$_";
  public static final String PATTERN_ISSUE_INSTANT = "yyyy-MM-dd'T'HH:mm:ss'Z'";

  protected Map<String, Object> authProcessData;

  public AuthProcessDataWrapper(final Map<String, Object> authProcessData) {
    this.authProcessData = authProcessData;

  }

  @Override
  public Instant getIssueInstant() {
    return buildDateTimeUtcDate(wrapStoredObject(VALUE_ISSUEINSTANT, null, String.class));
  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#getIssueInstant()
   */
  @Override
  public String getIssueInstantString() {
    return wrapStoredObject(VALUE_ISSUEINSTANT, null, String.class);
  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#setIssueInstant(
   * java.lang.String)
   */
  @Override
  public void setIssueInstant(final String issueInstant) {
    if (buildDateTimeUtcDate(issueInstant) != null) {
      authProcessData.put(VALUE_ISSUEINSTANT, issueInstant);

    } else if (StringUtils.isNotEmpty(issueInstant)) {
      log.warn("Can not parse IssueInstant of authentication: {}", issueInstant);

    }
  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#setIssueInstant(
   * java.lang.String)
   */
  @Override
  public void setIssueInstant(final Instant issueInstant) {
    authProcessData.put(VALUE_ISSUEINSTANT, buildDateTimeUtcString(issueInstant));

  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#isAuthenticated()
   */
  @Override
  public boolean isAuthenticated() {
    return wrapStoredObject(FLAG_IS_AUTHENTICATED, false, Boolean.class);

  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#setAuthenticated(
   * boolean)
   */
  @Override
  public void setAuthenticated(final boolean authenticated) {
    authProcessData.put(FLAG_IS_AUTHENTICATED, authenticated);

  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#getIdentityLink()
   */
  @Override
  public IIdentityLink getIdentityLink() {
    return wrapStoredObject(VALUE_IDENTITYLINK, null, IIdentityLink.class);

  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#setIdentityLink(at.
   * gv.egovernment.moa .id.auth.data.IdentityLink)
   */
  @Override
  public void setIdentityLink(final IIdentityLink identityLink) {
    authProcessData.put(VALUE_IDENTITYLINK, identityLink);

  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#isMandateUsed()
   */
  @Override
  public boolean isMandateUsed() {
    return wrapStoredObject(FLAG_USE_MANDATE, false, Boolean.class);
  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#setUseMandates(
   * boolean)
   */
  @Override
  public void setUseMandates(final boolean useMandates) {
    authProcessData.put(FLAG_USE_MANDATE, useMandates);

  }

  /*
   * (non-Javadoc)
   *
   * @see at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#getQAALevel()
   */
  @Override
  public String getQaaLevel() {
    return wrapStoredObject(VALUE_QAALEVEL, null, String.class);
  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#setQAALevel(java.
   * lang.String)
   */
  @Override
  public void setQaaLevel(final String qaaLevel) {
    authProcessData.put(VALUE_QAALEVEL, qaaLevel);

  }

  /*
   * (non-Javadoc)
   *
   * @see at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#isForeigner()
   */
  @Override
  public boolean isForeigner() {
    return wrapStoredObject(FLAG_IS_FOREIGNER, false, Boolean.class);
  }

  /*
   * (non-Javadoc)
   *
   * @see at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#setForeigner(
   * boolean)
   */
  @Override
  public void setForeigner(final boolean isForeigner) {
    authProcessData.put(FLAG_IS_FOREIGNER, isForeigner);

  }

  /*
   * (non-Javadoc)
   *
   * @see at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#isOW()
   */
  @Override
  public boolean isOW() {
    return wrapStoredObject(FLAG_IS_ORGANWALTER, false, Boolean.class);
  }

  /*
   * (non-Javadoc)
   *
   * @see at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#setOW(boolean)
   */
  @Override
  public void setOW(final boolean isOW) {
    authProcessData.put(FLAG_IS_ORGANWALTER, isOW);

  }

  @Override
  public boolean isEidProcess() {
    return wrapStoredObject(FLAG_IS_NEW_EID_PROCESS, false, Boolean.class);
  }

  @Override
  public void setEidProcess(final boolean value) {
    authProcessData.put(FLAG_IS_NEW_EID_PROCESS, value);

  }

  /*
   * (non-Javadoc)
   *
   * @see
   * at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#getSessionCreated()
   */
  @Override
  public Instant getSessionCreated() {
    return buildDateTimeUtcDate(wrapStoredObject(EaafConstants.AUTH_DATA_CREATED, null, String.class));
  }

  /*
   * (non-Javadoc)
   *
   * @see at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#
   * getGenericSessionDataStorage()
   */
  @Override
  public Map<String, Object> getGenericSessionDataStorage() {    
    return authProcessData.entrySet().stream()
        .filter(el -> el.getKey().startsWith(GENERIC_PREFIX))
        .map(el -> {
          Object obj = el.getValue();
          if (obj instanceof String && ((String) obj).startsWith(GENERIC_DATA_PREFIX)) {
            log.trace("Find generic JSON serialized data. Starting de-serialization ... ");
            el.setValue(objectSaveJsonDeserialization(obj));

          }
          return el;
        })
        .collect(
            Collectors.toMap(
                el -> el.getKey().substring(GENERIC_PREFIX.length()), 
                value -> value.getValue()));
    
  }
  
  @Override
  public Stream<Entry<String, Object>> getGenericSessionDataStream() {
    return getGenericSessionDataStorage().entrySet().stream();
    
  }

  /*
   * (non-Javadoc)
   *
   * @see at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#
   * getGenericDataFromSession(java.lang. String)
   */
  @Override
  public Object getGenericDataFromSession(final String key) {
    return wrapStoredObject(GENERIC_PREFIX + key, null, Object.class);

  }

  /*
   * (non-Javadoc)
   *
   * @see at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#
   * getGenericDataFromSession(java.lang. String, java.lang.Class)
   */
  @Override
  public <T> T getGenericDataFromSession(final String key, final Class<T> clazz) {
    return wrapStoredObject(GENERIC_PREFIX + key, null, clazz);

  }

  /*
   * (non-Javadoc)
   *
   * @see at.gv.egovernment.moa.id.auth.data.IAuthenticationSession#
   * setGenericDataToSession(java.lang. String, java.lang.Object)
   */
  @Override
  public void setGenericDataToSession(final String key, final Object object)
      throws EaafStorageException {
    authProcessData.put(GENERIC_PREFIX + key, objectSaveJsonSerialization(object));

  }

  protected <T> T wrapStoredObject(final String key, final Object defaultValue,
      final Class<T> clazz) {
    if (StringUtils.isNotEmpty(key)) {
      final Object obj = authProcessData.get(key);

      // check if it is a generic container
      if (obj instanceof String && ((String) obj).startsWith(GENERIC_DATA_PREFIX)) {
        log.trace("Find generic JSON serialized data. Starting de-serialization ... ");
        return (T) objectSaveJsonDeserialization(obj);

      // check if object is already of valid type
      } else if (obj != null && clazz.isInstance(obj)) {
        return (T) obj;

        // check if byte[] was requested and object is of type String in that case it's
        // B64 content
      } else if (obj instanceof String && clazz.equals(byte[].class)) {
        try {
          return (T) java.util.Base64.getDecoder().decode((String) obj);

        } catch (IllegalArgumentException e) {
          log.warn("Can not decode session-object with key: {}", key, e);

        }
      } else if (obj != null) {
        log.warn("Can not unwrap data object with key: {} because requires class: {} but  has: {}",
            key, clazz.getName(), obj.getClass().getName());

      }
    }

    // return default value if we get not other result
    if (defaultValue == null) {
      return null;

    } else if (clazz.isInstance(defaultValue)) {
      return (T) defaultValue;

    } else {
      log.error("DefaultValue: " + defaultValue.getClass().getName() + " is not of Type:"
          + clazz.getName());
      throw new IllegalStateException("DefaultValue: " + defaultValue.getClass().getName()
          + " is not of Type:" + clazz.getName());

    }
  }

  /**
   * Builds a {@link String} dateTime value in UTC from a {@link Date} value.
   *
   * @param date the {@link Date} that should be transformed
   * @return The {@link String} representation of the date in
   *     <code>yyyy-MM-dd'T'HH:mm:ss'Z'</code>, or <code>null</code> if {@link Date} was <code>null</code>
   */
  @Nullable
  public static String buildDateTimeUtcString(@Nullable final Instant date) {
    if (date == null) {
      return null;

    }
    
    return DateTimeFormatter
        .ofPattern(PATTERN_ISSUE_INSTANT)
        .withZone(ZoneId.of("UTC"))
        .format(date);
    
  }

  /**
   * Builds a {@link String} dateTime value in UTC from a {@link Date} value.
   *
   * @param date the {@link String} in <code>yyyy-MM-dd'T'HH:mm:ss'Z'</code>
   *     format that should be transformed
   * @return The {@link Date} representation of the date, otherwise <code>null</code>
   *     if input parameter was <code>null</code> or invalid
   */
  @Nullable
  public static Instant buildDateTimeUtcDate(@Nullable final String date) {
    if (date != null) {
      DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern(PATTERN_ISSUE_INSTANT);
      return LocalDateTime.parse(date, dateTimeFormatter).atZone(ZoneId.of("UTC")).toInstant();

    }

    return null;

  }
  
  /**
   * Object save JSON serialization of arbitrary objects.
   * 
   * @param object Element to store
   * @return Object for putting into cache
   * @throws EaafStorageException In case of a JSON serialization error
   */
  protected final Object objectSaveJsonSerialization(Object object) throws EaafStorageException {
    try {
      if (object == null || object instanceof String || object instanceof Boolean
          || object instanceof Integer) {
        return object;

      } else {
        return GENERIC_DATA_PREFIX + DefaultJsonMapper.serialize(RawDataHolder.builder()
            .object(DefaultJsonMapper.serialize(object))
            .clazzType(object.getClass().getName())
            .build());

      }
    } catch (EaafJsonMapperException e) {
      throw new EaafStorageException("Can no serialize object to JSON", e);

    }
  }

  /**
   * Object save JSON serialization of arbitrary objects.
   * 
   * @param object Element to store
   * @return Object for putting into cache
   */
  protected final Object failSaveObjectSaveJsonSerialization(Object object) {
    try {
      return objectSaveJsonSerialization(object);

    } catch (EaafStorageException e) {
      log.error("Can not store object: {} into session. Return null ... ", object.getClass().getName(), e);
      return null;

    }
  }

  private Object objectSaveJsonDeserialization(Object data) {
    try {
      if (data == null) {
        return null;

      } else if (data instanceof String) {
        RawDataHolder holder = (RawDataHolder) DefaultJsonMapper.deserialize(
            ((String) data).substring(GENERIC_DATA_PREFIX.length()), RawDataHolder.class);
        Class<?> clz = Class.forName(holder.getClazzType());
        return DefaultJsonMapper.deserialize(holder.getObject(), clz);

      } else {
        log.error("Can not deserialize: {} because it's not of type String", data.getClass().getName());

      }
    } catch (final Exception e) {
      log.warn("Generic request-data object can not be casted to requested type", e);

    }
    return null;

  }

  @Data
  @Builder
  @NoArgsConstructor
  @AllArgsConstructor
  private static class RawDataHolder implements Serializable {

    private static final long serialVersionUID = -3827971372737399528L;

    private String object;

    private String clazzType;

  }

}