/*
 * Copyright 2017 Kuelap, Inc.
 *
 * Licensed 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 io.mifos.individuallending.internal.service.costcomponent;

import io.mifos.core.lang.ServiceException;
import io.mifos.individuallending.api.v1.domain.product.AccountDesignators;
import io.mifos.individuallending.api.v1.domain.workflow.Action;
import io.mifos.individuallending.internal.service.DataContextOfAction;
import io.mifos.individuallending.internal.service.DesignatorToAccountIdentifierMapper;
import io.mifos.portfolio.api.v1.domain.ChargeDefinition;
import io.mifos.portfolio.service.internal.util.AccountingAdapter;
import net.jodah.expiringmap.ExpirationPolicy;
import net.jodah.expiringmap.ExpiringMap;

import java.math.BigDecimal;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.Optional;
import java.util.concurrent.TimeUnit;

/**
 * @author Myrle Krantz
 */
public class RealRunningBalances implements RunningBalances {
  private final DesignatorToAccountIdentifierMapper designatorToAccountIdentifierMapper;
  private final AccountingAdapter accountingAdapter;
  private final ExpiringMap<String, BigDecimal> realAccountBalanceCache;

  RealRunningBalances(
      final AccountingAdapter accountingAdapter,
      final DesignatorToAccountIdentifierMapper designatorToAccountIdentifierMapper) {
    this.accountingAdapter = accountingAdapter;
    this.designatorToAccountIdentifierMapper = designatorToAccountIdentifierMapper;
    this.realAccountBalanceCache = ExpiringMap.builder()
        .maxSize(20)
        .expirationPolicy(ExpirationPolicy.CREATED)
        .expiration(30,TimeUnit.SECONDS)
        .entryLoader((String accountDesignator) -> {
          final Optional<String> accountIdentifier;
          if (accountDesignator.equals(AccountDesignators.ENTRY)) {
            accountIdentifier = designatorToAccountIdentifierMapper.map(accountDesignator);
          }
          else {
            accountIdentifier = Optional.of(designatorToAccountIdentifierMapper.mapOrThrow(accountDesignator));
          }
          return accountIdentifier.map(accountingAdapter::getCurrentAccountBalance).orElse(BigDecimal.ZERO);
        })
        .build();
  }

  @Override
  public BigDecimal getAccountBalance(final String accountDesignator) {
    return realAccountBalanceCache.get(accountDesignator);
  }

  @Override
  public BigDecimal getAccruedBalanceForCharge(
      final DataContextOfAction dataContextOfAction,
      final LocalDate startOfTerm,
      final ChargeDefinition chargeDefinition) {
    final String accrualAccountIdentifier = designatorToAccountIdentifierMapper.mapOrThrow(chargeDefinition.getAccrualAccountDesignator());

    final BigDecimal amountAccrued = accountingAdapter.sumMatchingEntriesSinceDate(
        accrualAccountIdentifier,
        startOfTerm,
        dataContextOfAction.getMessageForCharge(Action.valueOf(chargeDefinition.getAccrueAction())));
    final BigDecimal amountApplied = accountingAdapter.sumMatchingEntriesSinceDate(
        accrualAccountIdentifier,
        startOfTerm,
        dataContextOfAction.getMessageForCharge(Action.valueOf(chargeDefinition.getChargeAction())));
    return amountAccrued.subtract(amountApplied);
  }

  @Override
  public LocalDate getStartOfTermOrThrow(final DataContextOfAction dataContextOfAction) {

    final String customerLoanPrincipalAccountIdentifier = designatorToAccountIdentifierMapper.mapOrThrow(AccountDesignators.CUSTOMER_LOAN_PRINCIPAL);

    final Optional<LocalDateTime> firstDisbursalDateTime = accountingAdapter.getDateOfOldestEntryContainingMessage(
        customerLoanPrincipalAccountIdentifier,
        dataContextOfAction.getMessageForCharge(Action.DISBURSE));

    return firstDisbursalDateTime.map(LocalDateTime::toLocalDate)
        .orElseThrow(() -> ServiceException.internalError(
            "Start of term for loan ''{0}'' could not be acquired from accounting.",
            dataContextOfAction.getCompoundIdentifer()));
  }
}