#!/usr/bin/env python -u

# Copyright (C) 2019 Apple Inc. All rights reserved.
#
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# are met:
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# 1.  Redistributions of source code must retain the above copyright
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# 3.  Neither the name of Apple Inc. ("Apple") nor the names of
#     its contributors may be used to endorse or promote products derived
#     from this software without specific prior written permission. 
#
# THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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
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# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import sys
import argparse
import json

try:
    from scipy import stats
except:
    print "ERROR: scipy package is not installed. Run `pip install scipy`"
    sys.exit(1)

try:
    import numpy
except:
    print "ERROR: numpy package is not installed. Run `pip install numpy`"
    sys.exit(1)

def readJSONFile(path):
    with open(path, 'r') as contents:
        return json.loads(contents.read())

Speedometer2 = "Speedometer2"
JetStream2 = "JetStream2"
PLT5 = "PLT5"
MotionMark = "MotionMark"
MotionMark1_1 = "MotionMark-1.1"

def detectJetStream2(payload):
    return "JetStream2.0" in payload

def JetStream2Results(payload):
    assert detectJetStream2(payload)

    js = payload["JetStream2.0"]
    iterations = len(js["tests"]["gaussian-blur"]["metrics"]["Score"]["current"])
    results = []
    for i in range(iterations):
        scores = []
        for test in js["tests"].keys():
            scores.append(js["tests"][test]["metrics"]["Score"]["current"][i])
        geomean = stats.gmean(scores)
        
        results.append(geomean)

    return results

def detectSpeedometer2(payload):
    return "Speedometer-2" in payload

def Speedometer2Results(payload):
    assert detectSpeedometer2(payload)
    results = []
    for arr in payload["Speedometer-2"]["metrics"]["Score"]["current"]:
        results.append(numpy.mean(arr))
    return results

def detectPLT5(payload):
    if "iterations" not in payload:
        return False
    iterations = payload["iterations"]
    if not isinstance(iterations, list):
        return False
    if not len(iterations):
        return False
    if "cold" not in iterations[0]:
        return False
    if "warm" not in iterations[0]:
        return False
    if "Geometric" not in iterations[0]:
        return False
    return True

def PLT5Results(payload):
    assert detectPLT5(payload)
    results = []
    for obj in payload["iterations"]:
        results.append(obj["Geometric"])
    return results

def detectMotionMark(payload):
    return "MotionMark" in payload

def detectMotionMark1_1(payload):
    return "MotionMark-1.1" in payload

def motionMarkResults(payload):
    assert detectMotionMark(payload) or detectMotionMark1_1(payload)
    if detectMotionMark(payload):
        payload = payload["MotionMark"]
    else:
        payload = payload["MotionMark-1.1"]
    testNames = payload["tests"].keys()
    numTests = len(payload["tests"][testNames[0]]["metrics"]["Score"]["current"])
    results = []
    for i in range(numTests):
        scores = []
        for test in testNames:
            scores.append(payload["tests"][test]["metrics"]["Score"]["current"][i])
        results.append(stats.gmean(scores))

    return results

def motionMark1_1Results(payload):
    return motionMarkResults(payload)

def detectBenchmark(payload):
    if detectJetStream2(payload):
        return JetStream2
    if detectSpeedometer2(payload):
        return Speedometer2
    if detectPLT5(payload):
        return PLT5
    if detectMotionMark(payload):
        return MotionMark
    if detectMotionMark1_1(payload):
        return MotionMark1_1
    return None

def biggerIsBetter(benchmarkType):
    if benchmarkType == JetStream2:
        return True
    if benchmarkType == Speedometer2:
        return True
    if benchmarkType == MotionMark:
        return True
    if benchmarkType == MotionMark1_1:
        return True
    if benchmarkType == PLT5:
        return False

    print "Should not be reached."
    assert False

def ttest(benchmarkType, a, b):
    # We use two-tailed Welch's
    (tStatistic, pValue) = stats.ttest_ind(a, b, equal_var=False)
    aMean = numpy.mean(a)
    bMean = numpy.mean(b)
    print "a mean = {:.5f}".format(aMean)
    print "b mean = {:.5f}".format(bMean)

    print "pValue = {:.10f}".format(pValue)

    if biggerIsBetter(benchmarkType):
        print "(Bigger means are better.)"
        if aMean > bMean:
            print "{:.3f} times worse".format((aMean / bMean))
        else:
            print "{:.3f} times better".format((bMean / aMean))
    else:
        print "(Smaller means are better.)"
        if aMean > bMean:
            print "{:.3f} times better".format((aMean / bMean))
        else:
            print "{:.3f} times worse".format((bMean / aMean))

    if pValue <= 0.05:
        print "Results ARE significant"
    else:
        print "Results ARE NOT significant"

def getOptions():
    parser = argparse.ArgumentParser(description="Compare two WebKit benchmark results. Pass in two JSON result files to compare them. This script prints the pValue along with the magnitude of the change.")

    parser.add_argument("-a",
        type=str,
        required=True,
        help="a of a/b. Path to JSON results file.")

    parser.add_argument("-b",
        type=str,
        required=True,
        help="b of a/b. Path to JSON results file.")

    return parser.parse_known_args()[0]


def main():
    args = getOptions()

    a = readJSONFile(args.a)
    b = readJSONFile(args.b)

    typeA = detectBenchmark(a)
    typeB = detectBenchmark(b)

    if typeA != typeB:
        print "-a and -b are not the same benchmark. a={} b={}".format(typeA, typeB)
        sys.exit(1)

    if not (typeA and typeB):
        print "Unknown benchmark type. a={} b={}".format(typeA, typeB)
        sys.exit(1)
    
    if typeA == JetStream2:
        ttest(typeA, JetStream2Results(a), JetStream2Results(b))
    elif typeA == Speedometer2:
        ttest(typeA, Speedometer2Results(a), Speedometer2Results(b))
    elif typeA == MotionMark:
        ttest(typeA, motionMarkResults(a), motionMarkResults(b))
    elif typeA == MotionMark1_1:
        ttest(typeA, motionMark1_1Results(a), motionMark1_1Results(b))
    elif typeA == PLT5:
        ttest(typeA, PLT5Results(a), PLT5Results(b))
    else:
        print "Unknown benchmark type"
        sys.exit(1)


if __name__ == "__main__":
    main()