/*
 * Copyright 2010-2013 Ning, Inc.
 *
 * Ning licenses this file to you 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.killbill.billing.catalog.rules;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;

import org.killbill.billing.catalog.DefaultPriceList;
import org.killbill.billing.catalog.StandaloneCatalog;
import org.killbill.billing.catalog.api.BillingActionPolicy;
import org.killbill.billing.catalog.api.BillingAlignment;
import org.killbill.billing.catalog.api.CatalogApiException;
import org.killbill.billing.catalog.api.IllegalPlanChange;
import org.killbill.billing.catalog.api.PlanAlignmentChange;
import org.killbill.billing.catalog.api.PlanAlignmentCreate;
import org.killbill.billing.catalog.api.PlanChangeResult;
import org.killbill.billing.catalog.api.PlanPhaseSpecifier;
import org.killbill.billing.catalog.api.PlanSpecifier;
import org.killbill.billing.util.config.catalog.ValidatingConfig;
import org.killbill.billing.util.config.catalog.ValidationErrors;

@XmlAccessorType(XmlAccessType.NONE)
public class PlanRules extends ValidatingConfig<StandaloneCatalog> {

    @XmlElementWrapper(name = "changePolicy")
    @XmlElement(name = "changePolicyCase", required = false)
    private CaseChangePlanPolicy[] changeCase;

    @XmlElementWrapper(name = "changeAlignment")
    @XmlElement(name = "changeAlignmentCase", required = false)
    private CaseChangePlanAlignment[] changeAlignmentCase;

    @XmlElementWrapper(name = "cancelPolicy")
    @XmlElement(name = "cancelPolicyCase", required = false)
    private CaseCancelPolicy[] cancelCase;

    @XmlElementWrapper(name = "createAlignment")
    @XmlElement(name = "createAlignmentCase", required = false)
    private CaseCreateAlignment[] createAlignmentCase;

    @XmlElementWrapper(name = "billingAlignment")
    @XmlElement(name = "billingAlignmentCase", required = false)
    private CaseBillingAlignment[] billingAlignmentCase;

    @XmlElementWrapper(name = "priceList")
    @XmlElement(name = "priceListCase", required = false)
    private CasePriceList[] priceListCase;

    public PlanAlignmentCreate getPlanCreateAlignment(final PlanSpecifier specifier, final StandaloneCatalog catalog) throws CatalogApiException {
        return Case.getResult(createAlignmentCase, specifier, catalog);
    }

    public BillingActionPolicy getPlanCancelPolicy(final PlanPhaseSpecifier planPhase, final StandaloneCatalog catalog) throws CatalogApiException {
        return CasePhase.getResult(cancelCase, planPhase, catalog);
    }

    public BillingAlignment getBillingAlignment(final PlanPhaseSpecifier planPhase, final StandaloneCatalog catalog) throws CatalogApiException {
        return CasePhase.getResult(billingAlignmentCase, planPhase, catalog);
    }

    public PlanChangeResult planChange(final PlanPhaseSpecifier from, PlanSpecifier to, final StandaloneCatalog catalog) throws CatalogApiException {
        final DefaultPriceList toPriceList;
        if (to.getPriceListName() == null) { // Pricelist may be null because it is unspecified this is the principal use-case
            toPriceList = findPriceList(from.toPlanSpecifier(), catalog);
            to = new PlanSpecifier(to.getProductName(), to.getProductCategory(), to.getBillingPeriod(), toPriceList.getName());
        } else {
            toPriceList = catalog.findCurrentPriceList(to.getPriceListName());
        }

        final BillingActionPolicy policy = getPlanChangePolicy(from, to, catalog);
        if (policy == BillingActionPolicy.ILLEGAL) {
            throw new IllegalPlanChange(from, to);
        }

        final PlanAlignmentChange alignment = getPlanChangeAlignment(from, to, catalog);

        return new PlanChangeResult(toPriceList, policy, alignment);
    }

    public PlanAlignmentChange getPlanChangeAlignment(final PlanPhaseSpecifier from,
                                                      final PlanSpecifier to, final StandaloneCatalog catalog) throws CatalogApiException {
        return CaseChange.getResult(changeAlignmentCase, from, to, catalog);
    }

    public BillingActionPolicy getPlanChangePolicy(final PlanPhaseSpecifier from,
                                            final PlanSpecifier to, final StandaloneCatalog catalog) throws CatalogApiException {
        if (from.getProductName().equals(to.getProductName()) &&
                from.getBillingPeriod() == to.getBillingPeriod() &&
                from.getPriceListName().equals(to.getPriceListName())) {
            return BillingActionPolicy.ILLEGAL;
        }
        //Plan toPlan = catalog.findPlan()

        return CaseChange.getResult(changeCase, from, to, catalog);
    }

    private DefaultPriceList findPriceList(final PlanSpecifier specifier, final StandaloneCatalog catalog) throws CatalogApiException {
        DefaultPriceList result = Case.getResult(priceListCase, specifier, catalog);
        if (result == null) {
            result = catalog.findCurrentPriceList(specifier.getPriceListName());
        }
        return result;
    }


    @Override
    public ValidationErrors validate(final StandaloneCatalog catalog, final ValidationErrors errors) {
        //TODO: MDW - Validation: check that the plan change special case pairs are unique!
        //TODO: MDW - Validation: check that the each product appears in at most one tier.
        //TODO: MDW - Unit tests for rules
        //TODO: MDW - validate that there is a default policy for change AND cancel

        return errors;
    }


    /////////////////////////////////////////////////////////////////////////////////////
    // Setters for testing
    /////////////////////////////////////////////////////////////////////////////////////

    protected PlanRules setChangeCase(final CaseChangePlanPolicy[] changeCase) {
        this.changeCase = changeCase;
        return this;
    }

    protected PlanRules setChangeAlignmentCase(
            final CaseChangePlanAlignment[] changeAlignmentCase) {
        this.changeAlignmentCase = changeAlignmentCase;
        return this;
    }

    protected PlanRules setCancelCase(final CaseCancelPolicy[] cancelCase) {
        this.cancelCase = cancelCase;
        return this;
    }

    protected PlanRules setCreateAlignmentCase(final CaseCreateAlignment[] createAlignmentCase) {
        this.createAlignmentCase = createAlignmentCase;
        return this;
    }

    protected PlanRules setBillingAlignmentCase(
            final CaseBillingAlignment[] billingAlignmentCase) {
        this.billingAlignmentCase = billingAlignmentCase;
        return this;
    }

    protected PlanRules setPriceListCase(final CasePriceList[] priceListCase) {
        this.priceListCase = priceListCase;
        return this;
    }

}
