/*
 * Copyright 2010-2011 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 com.ning.billing.catalog;

import java.net.URI;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.Iterator;
import java.util.List;

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

import org.joda.time.DateTime;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.ning.billing.ErrorCode;
import com.ning.billing.catalog.api.ActionPolicy;
import com.ning.billing.catalog.api.BillingAlignment;
import com.ning.billing.catalog.api.BillingPeriod;
import com.ning.billing.catalog.api.Catalog;
import com.ning.billing.catalog.api.CatalogApiException;
import com.ning.billing.catalog.api.Currency;
import com.ning.billing.catalog.api.Plan;
import com.ning.billing.catalog.api.PlanAlignmentChange;
import com.ning.billing.catalog.api.PlanAlignmentCreate;
import com.ning.billing.catalog.api.PlanChangeResult;
import com.ning.billing.catalog.api.PlanPhase;
import com.ning.billing.catalog.api.PlanPhaseSpecifier;
import com.ning.billing.catalog.api.PlanSpecifier;
import com.ning.billing.catalog.api.PriceList;
import com.ning.billing.catalog.api.Product;
import com.ning.billing.catalog.api.StaticCatalog;
import com.ning.billing.util.clock.Clock;
import com.ning.billing.util.config.ValidatingConfig;
import com.ning.billing.util.config.ValidationErrors;


@XmlRootElement(name="catalog")
@XmlAccessorType(XmlAccessType.NONE)
public class VersionedCatalog extends ValidatingConfig<StandaloneCatalog> implements Catalog, StaticCatalog {
	private static final Logger log = LoggerFactory.getLogger(VersionedCatalog.class);
	
	final private Clock clock;
	private String catalogName;
	
	@XmlElement(name="catalogVersion", required=true)
	private final List<StandaloneCatalog> versions = new ArrayList<StandaloneCatalog>();

	public VersionedCatalog(Clock clock) {
		this.clock = clock;
	}

	//
	// Private methods
	//
	private StandaloneCatalog versionForDate(DateTime date) throws CatalogApiException {
		return versions.get(indexOfVersionForDate(date.toDate()));
	}

	private List<StandaloneCatalog> versionsBeforeDate(Date date) throws CatalogApiException {
		List<StandaloneCatalog> result = new ArrayList<StandaloneCatalog>();
		int index = indexOfVersionForDate(date);
		for(int i = 0; i <= index; i++) {
			result.add(versions.get(i));
		}
		return result;
	}

	private int indexOfVersionForDate(Date date) throws CatalogApiException {
		for(int i = versions.size() - 1; i >= 0; i--) {
			StandaloneCatalog c = versions.get(i);
			if(c.getEffectiveDate().getTime() < date.getTime()) {
				return i;
			}
		}
		throw new CatalogApiException(ErrorCode.CAT_NO_CATALOG_FOR_GIVEN_DATE, date.toString());
	}
	
	private class PlanRequestWrapper {
		String name;
		String productName;
		BillingPeriod bp;
		String priceListName;
		
		public PlanRequestWrapper(String name) {
			super();
			this.name = name;
		}

		public PlanRequestWrapper(String productName, BillingPeriod bp,
				String priceListName) {
			super();
			this.productName = productName;
			this.bp = bp;
			this.priceListName = priceListName;
		}
		
		public Plan findPlan(StandaloneCatalog catalog) throws CatalogApiException {
			if(name != null) {
				return catalog.findCurrentPlan(name);
			} else {
				return catalog.findCurrentPlan(productName, bp, priceListName);
			}
		}
	}
	
	private Plan findPlan(PlanRequestWrapper wrapper, 
			DateTime requestedDate,
			DateTime subscriptionStartDate) 
					throws CatalogApiException {
		List<StandaloneCatalog> catalogs = versionsBeforeDate(requestedDate.toDate());
		if(catalogs.size() == 0) {
			throw new CatalogApiException(ErrorCode.CAT_NO_CATALOG_FOR_GIVEN_DATE, requestedDate.toDate().toString());
		}
		
		for(int i = catalogs.size() - 1; i >= 0 ; i--) { // Working backwards to find the latest applicable plan
			StandaloneCatalog c = catalogs.get(i);
			Plan plan = null;
			try {
				 plan = wrapper.findPlan(c);
			} catch (CatalogApiException e) {
				if(e.getCode() != ErrorCode.CAT_NO_SUCH_PLAN.getCode()) {
					throw e;
				} else { 
					break;
				}
			}
				
			DateTime catalogEffectiveDate = new DateTime(c.getEffectiveDate());
			if(subscriptionStartDate.isAfter(catalogEffectiveDate)) { // Its a new subscription this plan always applies
				return plan;
			} else { //Its an existing subscription
				if(plan.getEffectiveDateForExistingSubscriptons() != null) { //if it is null any change to this does not apply to existing subscriptions
					DateTime existingSubscriptionDate = new DateTime(plan.getEffectiveDateForExistingSubscriptons());
					if(requestedDate.isAfter(existingSubscriptionDate)){ // this plan is now applicable to existing subs
						return plan;
					}
				}
			}
		}
		
		throw new CatalogApiException(ErrorCode.CAT_NO_CATALOG_FOR_GIVEN_DATE, requestedDate.toDate().toString());
	}
	
	
	
	//
	// Public methods not exposed in interface
	//
	public void add(StandaloneCatalog e) throws CatalogApiException {
		if(catalogName == null) {
			catalogName = e.getCatalogName();
		} else {
			if(!catalogName.equals(getCatalogName())) {
				throw new CatalogApiException(ErrorCode.CAT_CATALOG_NAME_MISMATCH,catalogName, e.getCatalogName());
			}
		}
		versions.add(e);
		Collections.sort(versions,new Comparator<StandaloneCatalog>() {
			@Override
			public int compare(StandaloneCatalog c1, StandaloneCatalog c2) {
				return c1.getEffectiveDate().compareTo(c2.getEffectiveDate());
			}
		});
	}
		
	public Iterator<StandaloneCatalog> iterator() {
		return versions.iterator();
	}

	public int size() {
		return versions.size();
	}

	//
    // Simple getters
    //
	@Override
	public String getCatalogName() {
		return catalogName;
	}

	@Override
	public DefaultProduct[] getProducts(DateTime requestedDate) throws CatalogApiException {
		return versionForDate(requestedDate).getCurrentProducts();
	}

	@Override
	public Currency[] getSupportedCurrencies(DateTime requestedDate) throws CatalogApiException {
		return versionForDate(requestedDate).getCurrentSupportedCurrencies();
	}

	@Override
	public DefaultPlan[] getPlans(DateTime requestedDate) throws CatalogApiException {
		return versionForDate(requestedDate).getCurrentPlans();
	}

	//
	// Find a plan
	//
	@Override
	public Plan findPlan(String name, 
			DateTime requestedDate) 
					throws CatalogApiException {
		return versionForDate(requestedDate).findCurrentPlan(name);
	}

	@Override
	public Plan findPlan(String productName, 
			BillingPeriod term,
			String priceListName,
			DateTime requestedDate) 
					throws CatalogApiException {
		return versionForDate(requestedDate).findCurrentPlan(productName, term, priceListName);
	}

	@Override
	public Plan findPlan(String name, 
			DateTime requestedDate,
			DateTime subscriptionStartDate) 
					throws CatalogApiException {
		return findPlan(new PlanRequestWrapper(name), requestedDate, subscriptionStartDate);
	}

	@Override
	public Plan findPlan(String productName, 
			BillingPeriod term,
			String priceListName,
			DateTime requestedDate,
			DateTime subscriptionStartDate) 
					throws CatalogApiException {
		return findPlan(new PlanRequestWrapper(productName, term, priceListName), requestedDate, subscriptionStartDate);
	}

	//
	// Find a product
	//
	@Override
	public Product findProduct(String name, DateTime requestedDate) throws CatalogApiException {
		return versionForDate(requestedDate).findCurrentProduct(name);
	}


    //
    // Find a phase
    //
	@Override
	public PlanPhase findPhase(String phaseName, 
			DateTime requestedDate,
			DateTime subscriptionStartDate) 
					throws CatalogApiException {
		String planName = DefaultPlanPhase.planName(phaseName);
		Plan plan = findPlan(planName, requestedDate, subscriptionStartDate);
		return plan.findPhase(phaseName);
	}
	
	
	//
    // Find a price list
    //
    @Override
    public PriceList findPriceList(String name, DateTime requestedDate)
            throws CatalogApiException {
        return versionForDate(requestedDate).findCurrentPriceList(name);
    }

 
    //
    // Rules
    //
	@Override
	public ActionPolicy planChangePolicy(PlanPhaseSpecifier from,
			PlanSpecifier to, DateTime requestedDate) throws CatalogApiException {
		return versionForDate(requestedDate).planChangePolicy(from, to);
	}

	@Override
	public ActionPolicy planCancelPolicy(PlanPhaseSpecifier planPhase, DateTime requestedDate) throws CatalogApiException {
		return versionForDate(requestedDate).planCancelPolicy(planPhase);
	}

	@Override
	public PlanAlignmentChange planChangeAlignment(PlanPhaseSpecifier from,
			PlanSpecifier to, DateTime requestedDate) throws CatalogApiException {
		return versionForDate(requestedDate).planChangeAlignment(from, to);
	}

	@Override
	public PlanAlignmentCreate planCreateAlignment(PlanSpecifier specifier, DateTime requestedDate) throws CatalogApiException {
		return versionForDate(requestedDate).planCreateAlignment(specifier);
	}

	

	@Override
	public BillingAlignment billingAlignment(PlanPhaseSpecifier planPhase, DateTime requestedDate) throws CatalogApiException {
		return versionForDate(requestedDate).billingAlignment(planPhase);
	}

	@Override
	public PlanChangeResult planChange(PlanPhaseSpecifier from, PlanSpecifier to, DateTime requestedDate)
			throws CatalogApiException {
		return versionForDate(requestedDate).planChange(from, to);
	}

	@Override
	public boolean canCreatePlan(PlanSpecifier specifier, DateTime requestedDate)
			throws CatalogApiException {
		return versionForDate(requestedDate).canCreatePlan(specifier);
	}

	//
	// VerifiableConfig API
	//
	@Override
	public void initialize(StandaloneCatalog catalog, URI sourceURI) {
		for(StandaloneCatalog c : versions) {
			c.initialize(catalog, sourceURI);
		}
	}

	@Override
	public ValidationErrors validate(StandaloneCatalog catalog, ValidationErrors errors) {
		for(StandaloneCatalog c : versions) {
			errors.addAll(c.validate(c, errors));
		}
		//TODO MDW validation - ensure all catalog versions have a single name
		//TODO MDW validation - ensure effective dates are different (actually do we want this?)
		//TODO MDW validation - check that all products are there
		//TODO MDW validation - check that all plans are there
		//TODO MDW validation - check that all currencies are there
		//TODO MDW validation - check that all pricelists are there
		return errors;
	}

	//
	// Static catalog API
	//
	@Override
	public Date getEffectiveDate() throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).getEffectiveDate();
	}

	@Override
	public Currency[] getCurrentSupportedCurrencies() throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).getCurrentSupportedCurrencies();
	}

	@Override
	public Product[] getCurrentProducts() throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).getCurrentProducts() ;
	}

	@Override
	public Plan[] getCurrentPlans() throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).getCurrentPlans();
	}

	@Override
	public Plan findCurrentPlan(String productName, BillingPeriod term,
			String priceList) throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).findCurrentPlan(productName, term, priceList);
	}

	@Override
	public Plan findCurrentPlan(String name) throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).findCurrentPlan(name);
	}

	@Override
	public Product findCurrentProduct(String name) throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).findCurrentProduct(name);
	}

	@Override
	public PlanPhase findCurrentPhase(String name) throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).findCurrentPhase(name);
	}
	

    @Override
    public PriceList findCurrentPricelist(String name)
            throws CatalogApiException {
        return versionForDate(clock.getUTCNow()).findCurrentPriceList(name);
    }

	@Override
	public ActionPolicy planChangePolicy(PlanPhaseSpecifier from,
			PlanSpecifier to) throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).planChangePolicy(from, to);
	}

	@Override
	public PlanChangeResult planChange(PlanPhaseSpecifier from, PlanSpecifier to)
			throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).planChange(from, to);
	}

	@Override
	public ActionPolicy planCancelPolicy(PlanPhaseSpecifier planPhase)
			throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).planCancelPolicy(planPhase);
	}

	@Override
	public PlanAlignmentCreate planCreateAlignment(PlanSpecifier specifier)
			throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).planCreateAlignment(specifier);
	}

	@Override
	public BillingAlignment billingAlignment(PlanPhaseSpecifier planPhase)
			throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).billingAlignment(planPhase);
	}

	@Override
	public PlanAlignmentChange planChangeAlignment(PlanPhaseSpecifier from,
			PlanSpecifier to) throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).planChangeAlignment(from, to);
	}

	@Override
	public boolean canCreatePlan(PlanSpecifier specifier)
			throws CatalogApiException {
		return versionForDate(clock.getUTCNow()).canCreatePlan(specifier);
	}

}
