package io.prediction;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

import org.joda.time.DateTime;

import java.util.List;
import java.util.Map;

/**
 * Event class for PredictionIO Event objects.
 *
 * @author The PredictionIO Team (<a href="http://prediction.io">http://prediction.io</a>)
 * @version 0.8.0
 * @since 0.8.0
 */

public class Event {

    // mandatory fields
    private int appId;
    private String event;
    private String entityType;
    private String entityId;

    // optional fields
    private String targetEntityType;
    private String targetEntityId;
    private Map<String, Object> properties = Maps.newHashMap();
    private DateTime eventTime;

    /**
     * Instantiate an event object.
     */
    public Event() {
    }

    /**
     * Returns the appId.
     */
    public int getAppId() {
        return appId;
    }

    /**
     * Returns the name of the event.
     */
    public String getEvent() {
        return event;
    }

    /**
     * Returns the entity type. entityType-entityId forms the unique identifier of the entity.
     */
    public String getEntityType() {
        return entityType;
    }

    /**
     * Returns the entity id. entityType-entityId forms the unique identifier of the entity.
     */
    public String getEntityId() {
        return entityId;
    }

    /**
     * Returns the target entity type, or null if the field is not set.
     */
    public String getTargetEntityType() {
        return targetEntityType;
    }

    /**
     * Returns the target entity id, or null if the field is not set.
     */
    public String getTargetEntityId() {
        return targetEntityId;
    }

    /**
     * Returns the set of properties as a map.
     */
    public Map<String, Object> getProperties() {
        return properties;
    }

    /**
     * Returns the event time, or null if the field is not set.
     */
    public DateTime getEventTime() {
        return eventTime;
    }

    // builder methods for convenience

    /**
     * Sets the appId. Called by EventClient.
     */
    protected Event appId(int appId) {
        this.appId = appId;
        return this;
    }

    /**
     * Sets the name of the event.
     */
    public Event event(String event) {
        this.event = event;
        return this;
    }

    /**
     * Sets the entity type. entityType-entityId forms the unique identifier of the entity.
     */
    public Event entityType(String entityType) {
        this.entityType = entityType;
        return this;
    }

    /**
     * Sets the entity id. entityType-entityId forms the unique identifier of the entity.
     */
    public Event entityId(String entityId) {
        this.entityId = entityId;
        return this;
    }

    public Event targetEntityType(String targetEntityType) {
        this.targetEntityType = targetEntityType;
        return this;
    }

    public Event targetEntityId(String targetEntityId) {
        this.targetEntityId = targetEntityId;
        return this;
    }

    public Event property(String key, Object value) {
        this.properties.put(key, value);
        return this;
    }

    public Event properties(Map<String, Object> properties) {
        this.properties.putAll(properties);
        return this;
    }

    public Event eventTime(DateTime eventTime) {
        this.eventTime = eventTime;
        return this;
    }

    // toJsonString and toString methods

    public String toJsonString() {
        return toString();
    }

    @Override
    public String toString() {
        // handle DateTime separately
        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.registerTypeAdapter(DateTime.class, new DateTimeAdapter());
        Gson gson = gsonBuilder.create();
        return gson.toJson(this); // works when there are no generic types
    }
}