var fs = require('fs');

var PNG = require('png-js');

var BENCHMARK_FILENAME = 'benchmark.json';

var PATH_PERF_TESTS = 'test/perf';

var PATH_BENCHMARK_FILE = 'test/assets/' + BENCHMARK_FILENAME;

var TEST_TIMES_RUN = 5;

var TIME_THRESHOLD = 30;

var Benchmark = {

/**

* Calls the setUp function for all performance tests.

* @param {function} done Function to be called when the set up is done.

*/

setUpAll: function(done) {

readTestFiles(function(files) {

Benchmark.files = files;

runAllSetUps(done);

});

},

/**

* Runs all the performance tests.

* @param {function} callback Function to be called when all tests finish running.

*/

runAll: function(callback) {

var results;

getBenchmarkContents(function(benchmark) {

results = runAllTests(benchmark);

fs.writeFile(PATH_BENCHMARK_FILE, JSON.stringify(benchmark), function() {

callback(results);

});

});

},

/**

* Creates a failure message for the given results.

* @param {array} results An array with the results of the performance tests.

*/

createFailureMessage: function(results) {

var message = '';

for(var i = 0; i < results.length; i++) {

if (results[i].failedTests.length > 0) {

message += '\n' + results[i].failedTests.length + ' failures for ' + results[i].filename + ':';

for (var j = 0; j < results[i].failedTests.length; j++) {

message += '\n\t' + results[i].failedTests[j];

}

}

}

return message;

}

};

/**

* Gets the contents of the benchmark json file.

* @param {function} callback Function to be called with the contents.

*/

function getBenchmarkContents(callback){

fs.exists(PATH_BENCHMARK_FILE, function (exists) {

if (exists) {

fs.readFile(PATH_BENCHMARK_FILE, 'utf8', function(error, data) {

callback(JSON.parse(data));

});

} else {

callback({});

}

});

}

/**

* Reads all performance test files.

* @param {function} callback Function to be called when all tests are read.

*/

function readTestFiles(callback) {

fs.readdir(PATH_PERF_TESTS, function(error, files_list) {

var files = [];

for (var i = 0; i < files_list.length; i++) {

var filename = files_list[i];

if (filename.match('.*.js$')) {

files.push({

filename: filename,

test: require('../../' + PATH_PERF_TESTS + '/' + filename)

});

}

}

callback(files);

});

}

/**

* Runs the setUp function for each performance test.

* @param {function} callback Function to be called when all set ups are done.

*/

function runAllSetUps(callback) {

Benchmark.totalDone = 0;

for (var i = 0; i < Benchmark.files.length; i++) {

test = Benchmark.files[i].test;

if (test.setUp) {

test.setUp(function() {

setUpDone(callback);

});

} else {

setUpDone(callback);

}

}

}

/**

* Runs all the performance tests.

* @param {object} benchmark Information about duration of previous test runs.

*/

function runAllTests(benchmark) {

var allResults = [];

var benchmarkTime;

var benchmarkTimes;

var currentResults;

var duration;

var filename;

var passed = true;

var test;

for (var i = 0; i < Benchmark.files.length; i++) {

filename = Benchmark.files[i].filename;

test = Benchmark.files[i].test;

if (!benchmark[filename]) {

benchmark[filename] = {};

}

currentResults = {

filename: filename,

failedTests: [],

passedTests: []

};

for (var key in test) {

if (test.hasOwnProperty(key) && (typeof test[key] === 'function') && key !== 'setUp') {

duration = runTest(test[key]);

benchmarkTimes = benchmark[filename][key];

if (benchmarkTimes && benchmarkTimes.length) {

benchmarkTime = benchmarkTimes[benchmarkTimes.length - 1];

if (duration > benchmarkTime + TIME_THRESHOLD) {

currentResults.failedTests.push(key);

passed = false;

}

else {

currentResults.passedTests.push(key);

benchmark[filename][key].push(duration);

}

}

else {

currentResults.passedTests.push(key);

benchmark[filename][key] = [duration];

}

}

}

allResults.push(currentResults);

}

return {

passed: passed,

resultDetails: allResults

};

}

/**

* Runs a single test.

* @param {object} test The test to be run.

*/

function runTest(test) {

var timeBefore;

var timeTotal = 0;

for (var i = 0; i < TEST_TIMES_RUN; i++) {

timeBefore = new Date().getTime();

test();

timeTotal += new Date().getTime() - timeBefore;

}

return timeTotal / TEST_TIMES_RUN;

}

/**

* Increments the number of setUp functions that are done, and invokes the callback when all

* have been finished.

* @param {function} callback The function to be called when the last setUp function is done

*/

function setUpDone(callback) {

Benchmark.totalDone++;

if (Benchmark.totalDone === Benchmark.files.length) {

callback();

}

}

module.exports = Benchmark;