#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <random>
#include <thread>

#include "SearchJob.hpp"
#include "TestRunner.hpp"


// Type of our hay stack: a list of strings
typedef std::vector<std::string> WordList;

typedef SearchJob<WordList::const_iterator> WordSearchJob;

typedef std::vector<WordSearchJob> SearchJobList;


void create_testdata(WordList& words)
{
	const char start = 'A';
	const char end = 'Z';
	char str[4] = { 'A', 'A', 'A', 'A' };

	for (str[0] = start; str[0] <= end; str[0]++)
		for (str[1] = start; str[1] <= end; str[1]++)
			for (str[2] = start; str[2] <= end; str[2]++)
				for (str[3] = start; str[3] <= end; str[3]++)
					words.push_back(std::string(str, 4));

}

void shuffle_testdata(WordList& words)
{
	auto rng = std::default_random_engine{};
	std::shuffle(words.begin(), words.end(), rng);
}

void run_wordsearch(WordSearchJob& job)
{
	job.run();
}

void run_parallel_wordsearch(std::vector<WordSearchJob>& jobList)
{
	std::vector<std::thread> threads;

	for (WordSearchJob& job : jobList)
	{
		threads.push_back(std::thread(&WordSearchJob::run, &job));
	}

	for (std::thread& th : threads)
	{
		th.join();
	}
}

int main()
{
	double time_span;
	std::string pattern = "ABC";

	WordList test_data;

	std::cout << "Hello World." << std::endl;

	time_span = TestRunner(create_testdata, test_data);
	std::cout << "It took me " << time_span << " seconds to create " << test_data.size() << " words." << std::endl;

	time_span = TestRunner(shuffle_testdata, test_data);
	std::cout << "It took me " << time_span << " seconds to shuffle " << test_data.size() << " words." << std::endl;

	SearchJob<WordList::const_iterator> job(test_data.begin(), test_data.end(), pattern);

	time_span = TestRunner(run_wordsearch, job);
	std::cout << "It took me " << time_span << " seconds to find " << job.GetResult().size() << " matches." << std::endl;
	

	std::vector<WordSearchJob> jobList;

	unsigned coreCount = std::thread::hardware_concurrency();
	std::size_t bucketSize = test_data.size() / coreCount;
	std::size_t remains = test_data.size() % coreCount;

	std::cout << "Creating " << coreCount << " search jobs, bucketSize = " << bucketSize << std::endl;

	std::size_t offset = 0;
	while(offset < test_data.size())
	{
		// compute [first; last( iterators for sub-range
		std::size_t size = bucketSize + remains;
		WordList::const_iterator first = test_data.begin() + offset;
		WordList::const_iterator last  = first + bucketSize + remains;

		std::cout << "offset = " << offset << " size = " << size << std::endl;

		// add appropriate search job
		jobList.push_back(WordSearchJob(first, last, pattern));
		
		// increment offset
		offset += size;
		// clear remains (it has been added to first bucket)
		remains = 0;
	}

	

	time_span = TestRunner(run_parallel_wordsearch, jobList);

	// collect search results ...
	unsigned found = 0;
	for (WordSearchJob& job : jobList)
	{
		found += job.GetResult().size();
	}
	std::cout << "It took me " << time_span << " seconds to find " << found << " matches." << std::endl;



	std::cout << std::endl;
	
	return 0;
}