/*
  Copyright (c) 2012, 2018, Anatole Tresch, Werner Keil and others by the @author tag.

  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 org.javamoney.moneta.convert;

import javax.money.CurrencyUnit;
import javax.money.NumberValue;
import javax.money.convert.ConversionContext;
import javax.money.convert.ExchangeRate;
import javax.money.convert.RateType;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;

/**
 * Builder for creating new instances of {@link javax.money.convert.ExchangeRate}. Note that
 * instances of this class are not thread-safe.
 *
 * @author Anatole Tresch
 * @author Werner Keil
 */
public class ExchangeRateBuilder {
    /**
     * The {@link javax.money.convert.ConversionContext}.
     */
    ConversionContext conversionContext;
    /**
     * The base (source) currency.
     */
    CurrencyUnit base;
    /**
     * The term (target) currency.
     */
    CurrencyUnit term;
    /**
     * The conversion factor.
     */
    NumberValue factor;
    /**
     * The chain of involved rates.
     */
    List<ExchangeRate> rateChain = new ArrayList<>();

    /**
     * Sets the exchange rate type
     *
     * @param rateType the {@link javax.money.convert.RateType} contained
     */
    public ExchangeRateBuilder(String provider, RateType rateType) {
        this(ConversionContext.of(provider, rateType));
    }

    /**
     * Sets the exchange rate type
     *
     * @param context the {@link javax.money.convert.ConversionContext} to be applied
     */
    public ExchangeRateBuilder(ConversionContext context) {
        setContext(context);
    }

    /**
     * Sets the exchange rate type
     *
     * @param rate the {@link javax.money.convert.ExchangeRate} to be applied
     */
    public ExchangeRateBuilder(ExchangeRate rate) {
        setContext(rate.getContext());
        setFactor(rate.getFactor());
        setTerm(rate.getCurrency());
        setBase(rate.getBaseCurrency());
        setRateChain(rate.getExchangeRateChain());
    }

    /**
     * Sets the base {@link javax.money.CurrencyUnit}
     *
     * @param base to base (source) {@link javax.money.CurrencyUnit} to be applied
     * @return the builder instance
     */
    public ExchangeRateBuilder setBase(CurrencyUnit base) {
        this.base = base;
        return this;
    }

    /**
     * Sets the terminating (target) {@link javax.money.CurrencyUnit}
     *
     * @param term to terminating {@link javax.money.CurrencyUnit} to be applied
     * @return the builder instance
     */
    public ExchangeRateBuilder setTerm(CurrencyUnit term) {
        this.term = term;
        return this;
    }

    /**
     * Sets the {@link javax.money.convert.ExchangeRate} chain.
     *
     * @param exchangeRates the {@link javax.money.convert.ExchangeRate} chain to be applied
     * @return the builder instance
     */
    public ExchangeRateBuilder setRateChain(ExchangeRate... exchangeRates) {
        this.rateChain.clear();
        if (Objects.nonNull(exchangeRates)) {
            this.rateChain.addAll(Arrays.asList(exchangeRates.clone()));
        }
        return this;
    }

    /**
     * Sets the {@link javax.money.convert.ExchangeRate} chain.
     *
     * @param exchangeRates the {@link javax.money.convert.ExchangeRate} chain to be applied
     * @return the builder instance
     */
    public ExchangeRateBuilder setRateChain(List<ExchangeRate> exchangeRates) {
        this.rateChain.clear();
        if (Objects.nonNull(exchangeRates)) {
            this.rateChain.addAll(exchangeRates);
        }
        return this;
    }


    /**
     * Sets the conversion factor, as the factor
     * {@code base * factor = target}.
     *
     * @param factor the factor.
     * @return The builder instance.
     */
    public ExchangeRateBuilder setFactor(NumberValue factor) {
        this.factor = factor;
        return this;
    }

    /**
     * Sets the provider to be applied.
     *
     * @param conversionContext the {@link javax.money.convert.ConversionContext}, not null.
     * @return The builder.
     */
    public ExchangeRateBuilder setContext(ConversionContext conversionContext) {
        Objects.requireNonNull(conversionContext);
        this.conversionContext = conversionContext;
        return this;
    }

    /**
     * Builds a new instance of {@link javax.money.convert.ExchangeRate}.
     *
     * @return a new instance of {@link javax.money.convert.ExchangeRate}.
     * @throws IllegalArgumentException if the rate could not be built.
     */
    public ExchangeRate build() {
        return new DefaultExchangeRate(this);
    }

    /**
     * Initialize the {@link ExchangeRateBuilder} with an {@link javax.money.convert.ExchangeRate}. This is
     * useful for creating a new rate, reusing some properties from an
     * existing one.
     *
     * @param rate the base rate
     * @return the Builder, for chaining.
     */
    public ExchangeRateBuilder setRate(ExchangeRate rate) {
        this.base = rate.getBaseCurrency();
        this.term = rate.getCurrency();
        this.conversionContext = rate.getContext();
        this.factor = rate.getFactor();
        this.rateChain = rate.getExchangeRateChain();
        this.term = rate.getCurrency();
        return this;
    }

    @Override
    public String toString() {
        return "org.javamoney.moneta.ExchangeRateBuilder: " +
                "[conversionContext" + conversionContext + ',' +
                "base" + base + ',' +
                "term" + term + ',' +
                "factor" + factor + ',' +
                "rateChain" + rateChain + ']';
    }
}