/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.search.profile.query;

import org.apache.lucene.search.Query;
import org.elasticsearch.search.profile.AbstractProfiler;
import org.elasticsearch.search.profile.Timer;

import static java.util.Objects.requireNonNull;

/**
 * This class acts as a thread-local storage for profiling a query.  It also
 * builds a representation of the query tree which is built constructed
 * "online" as the weights are wrapped by ContextIndexSearcher.  This allows us
 * to know the relationship between nodes in tree without explicitly
 * walking the tree or pre-wrapping everything
 *
 * A Profiler is associated with every Search, not per Search-Request. E.g. a
 * request may execute two searches (query + global agg).  A Profiler just
 * represents one of those
 */
public final class QueryProfiler extends AbstractProfiler<QueryProfileBreakdown, Query> {

    /**
     * The root CollectorResult used in the search
     */
    private CollectorResult collectorResult;

    private long vectorOpsCount;

    public QueryProfiler() {
        super(new InternalQueryProfileTree());
    }

    /**
     * Adds a number of vector operations to the current count
     * @param vectorOpsCount number of vector ops to add to the profiler
     */
    public void addVectorOpsCount(long vectorOpsCount) {
        this.vectorOpsCount += vectorOpsCount;
    }

    /**
     * Retrieves the number of vector operations performed by the queries
     * @return number of vector operations performed by the queries
     */
    public long getVectorOpsCount() {
        return this.vectorOpsCount;
    }

    /** Set the collector result that is associated with this profiler. */
    public void setCollectorResult(CollectorResult collectorResult) {
        if (this.collectorResult != null) {
            throw new IllegalStateException("The collector result can only be set once.");
        }
        this.collectorResult = requireNonNull(collectorResult);
    }

    /**
     * Begin timing the rewrite phase of a request.  All rewrites are accumulated together into a
     * single metric
     */
    public Timer startRewriteTime() {
        return ((InternalQueryProfileTree) profileTree).startRewriteTime();
    }

    /**
     * Stop recording the current rewrite and add it's time to the total tally, returning the
     * cumulative time so far.
     *
     * @return cumulative rewrite time
     */
    public long stopAndAddRewriteTime(Timer rewriteTimer) {
        return ((InternalQueryProfileTree) profileTree).stopAndAddRewriteTime(requireNonNull(rewriteTimer));
    }

    /**
     * @return total time taken to rewrite all queries in this profile
     */
    public long getRewriteTime() {
        return ((InternalQueryProfileTree) profileTree).getRewriteTime();
    }

    /**
     * Return the current root Collector for this search
     */
    public CollectorResult getCollectorResult() {
        return this.collectorResult;
    }

}