/*
 * [The "BSD license"]
 *  Copyright (c) 2014 Terence Parr
 *  Copyright (c) 2014 Sam Harwell
 *  Copyright (c) 2017 Egbert Voigt
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

module antlr.v4.runtime.atn.ParseInfo;

import std.conv;
import antlr.v4.runtime.dfa.DFA;
import antlr.v4.runtime.atn.DecisionInfo;
import antlr.v4.runtime.atn.ProfilingATNSimulator;

/**
 * This class provides access to specific and aggregate statistics gathered
 * during profiling of a parser.
 */
class ParseInfo
{

    protected ProfilingATNSimulator atnSimulator;

    public this(ProfilingATNSimulator atnSimulator)
    {
	this.atnSimulator = atnSimulator;
    }

    /**
     * Gets an array of {@link DecisionInfo} instances containing the profiling
     * information gathered for each decision in the ATN.
     *
     * @return An array of {@link DecisionInfo} instances, indexed by decision
     * number.
     */
    public DecisionInfo[] getDecisionInfo()
    {
	return atnSimulator.getDecisionInfo();
    }

    /**
     * Gets the decision numbers for decisions that required one or more
     * full-context predictions during parsing. These are decisions for which
     * {@link DecisionInfo#LL_Fallback} is non-zero.
     *
     * @return A list of decision numbers which required one or more
     * full-context predictions during parsing.
     */
    public int[] getLLDecisions()
    {
	DecisionInfo[] decisions = atnSimulator.getDecisionInfo();
        int[] LL;
        for (int i=0; i<decisions.length; i++) {
            long fallBack = decisions[i].LL_Fallback;
            if ( fallBack>0 ) LL ~= i;
        }
        return LL;
    }

    /**
     * Gets the total time spent during prediction across all decisions made
     * during parsing. This value is the sum of
     * {@link DecisionInfo#timeInPrediction} for all decisions.
     */
    public long getTotalTimeInPrediction()
    {
	DecisionInfo[] decisions = atnSimulator.getDecisionInfo();
        long t = 0;
        for (int i=0; i<decisions.length; i++) {
            t += decisions[i].timeInPrediction;
        }
        return t;
    }

    /**
     * Gets the total number of SLL lookahead operations across all decisions
     * made during parsing. This value is the sum of
     * {@link DecisionInfo#SLL_TotalLook} for all decisions.
     */
    public long getTotalSLLLookaheadOps()
    {

        DecisionInfo[] decisions = atnSimulator.getDecisionInfo();
        long k = 0;
        for (int i = 0; i < decisions.length; i++) {
            k += decisions[i].SLL_TotalLook;
        }
        return k;
    }

    /**
     * Gets the total number of LL lookahead operations across all decisions
     * made during parsing. This value is the sum of
     * {@link DecisionInfo#LL_TotalLook} for all decisions.
     */
    public long getTotalLLLookaheadOps()
    {
        DecisionInfo[] decisions = atnSimulator.getDecisionInfo();
        long k = 0;
        for (int i = 0; i < decisions.length; i++) {
            k += decisions[i].LL_TotalLook;
        }
        return k;
    }

    /**
     * Gets the total number of ATN lookahead operations for SLL prediction
     * across all decisions made during parsing.
     */
    public long getTotalSLLATNLookaheadOps()
    {
        DecisionInfo[] decisions = atnSimulator.getDecisionInfo();
        long k = 0;
        for (int i = 0; i < decisions.length; i++) {
            k += decisions[i].SLL_ATNTransitions;
        }
        return k;
    }

    /**
     * Gets the total number of ATN lookahead operations for LL prediction
     * across all decisions made during parsing.
     */
    public long getTotalLLATNLookaheadOps()
    {
	DecisionInfo[] decisions = atnSimulator.getDecisionInfo();
        long k = 0;
        for (int i = 0; i < decisions.length; i++) {
            k += decisions[i].LL_ATNTransitions;
        }
        return k;
    }

    /**
     * Gets the total number of ATN lookahead operations for SLL and LL
     * prediction across all decisions made during parsing.
     *
     * <p>
     * This value is the sum of {@link #getTotalSLLATNLookaheadOps} and
     * {@link #getTotalLLATNLookaheadOps}.</p>
     */
    public long getTotalATNLookaheadOps()
    {
	DecisionInfo[] decisions = atnSimulator.getDecisionInfo();
        long k = 0;
        for (int i = 0; i < decisions.length; i++) {
            k += decisions[i].SLL_ATNTransitions;
            k += decisions[i].LL_ATNTransitions;
        }
        return k;
    }

    /**
     * Gets the total number of DFA states stored in the DFA cache for all
     * decisions in the ATN.
     */
    public int getDFASize()
    {
	int n = 0;
        DFA[] decisionToDFA = atnSimulator.decisionToDFA;
        for (int i = 0; i < decisionToDFA.length; i++) {
            n += getDFASize(i);
        }
        return n;
    }

    /**
     * Gets the total number of DFA states stored in the DFA cache for a
     * particular decision.
     */
    public int getDFASize(int decision)
    {
        DFA decisionToDFA = atnSimulator.decisionToDFA[decision];
        return to!int(decisionToDFA.states.length);
    }

}