#include <iostream>
#include <Windows.h>
#include <vector>
#include <string>
#include <sstream>
#include <fstream>
#include <thread>
#include <cmath>

using namespace std;

const int max_size = 1000;

HANDLE threads[max_size];
vector<long double> threadsTime;
int priority = 0;

vector<string> words; // all words
vector<int> res; //max length values that every thread got

ifstream f;
string fileName;

int num; // number of threads
int n; //number of words
int ml = 0; // max length of word

LONG volatile progressCounter = 0;
double progressMax;
bool isWorking = true;

HANDLE ghSemaphore;

struct thr {
    int id;
    int step;
};

// знаходить найбільшу довжину слова зі всіх у масиві результатів
void findMax() {
    for (int i = 0; i < res.size(); i++) {
        if (res[i] > ml)ml = res[i];
    }
}
//записуємо результат
void writeRes2() {
    HANDLE file = CreateFile(TEXT(R"(C:\Users\BROS\source\repos\OSLab6\OSLab6\res.txt)"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

    string res = "";
    res += "Max length: " + to_string(ml) + '\n';

    for (int i = 0; i < threadsTime.size(); i++) {
        cout << "Thread #" << i << " time: " << threadsTime[i] << '\n';
    }
    for (int i = 0; i < threadsTime.size(); i++) {
        ostringstream strs;
        strs << threadsTime[i];
        string tT = strs.str();
        res += "Thread #" + to_string(i) + " time: " + tT + '\n';
    }

    const char* my_chars = res.c_str();

    HANDLE hMapping = CreateFileMapping(file, NULL, PAGE_READWRITE, 0, (strlen(my_chars) * sizeof(char)), NULL);

    LPSTR output = (LPSTR)MapViewOfFile(hMapping, FILE_MAP_ALL_ACCESS, 0, 0, (strlen(my_chars) * sizeof(char)));

    CopyMemory((LPVOID)output, (LPVOID)my_chars, (strlen(my_chars) * sizeof(char)));

    UnmapViewOfFile(output);
    CloseHandle(hMapping);
    CloseHandle(file);
}
// оскільки read2 повертає з файлу string, то цією функцією ми ту стрічку розділяємо на слова і тільки тоді запихуємо у масив
void split(string s) {
    char delim = ' ';
    size_t start, end = 0;
    while ((start = s.find_first_not_of(delim, end)) != string::npos) {
        end = s.find(delim, start);
        words.push_back(s.substr(start, end - start));
    }
}
// зчитує файл
void read2() {
    string path = "C:\\Users\\BROS\\source\\repos\\OSLab6\\OSLab6\\" + fileName;

    wstring tmp = wstring(path.begin(), path.end());
    const WCHAR* tmp2 = tmp.c_str();
    LPCWSTR p = const_cast<LPCWSTR>(tmp2);

    HANDLE hFile = CreateFile(p, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    HANDLE hMapping = CreateFileMapping(hFile, NULL, PAGE_READWRITE, 0, 0, NULL);
    LPSTR input = (LPSTR)MapViewOfFile(hMapping, FILE_MAP_READ, 0, 0, 0);

    split((string)input);

    UnmapViewOfFile(input);
    CloseHandle(hMapping);
    CloseHandle(hFile);
}
// вираховує кількість слів у файлі
int numOfWords() {
    ifstream file(fileName);

    int num = 0;
    string w;
    while (file >> w) {
        num++;
    }

    file.close();
    return num;
}
// функція, яку виконує кожен потік
DWORD WINAPI maxLen(LPVOID lpParameter) {
    WaitForSingleObject(ghSemaphore, 0L);

    thr* d = (thr*)lpParameter;

    if (d->id < words.size()) {
        chrono::steady_clock::time_point clockStart = chrono::steady_clock::now();

        res[d->id] = words[d->id].length();

        for (int i = d->id + d->step; i < words.size(); i += d->step) {
            if (res[d->id] < words[i].length()) res[d->id] = words[i].length();

            InterlockedIncrement(&progressCounter);
        }

        chrono::steady_clock::time_point clockEnd = chrono::steady_clock::now();

        chrono::steady_clock::duration timeSpan = clockEnd - clockStart;

        double nseconds = double(timeSpan.count()) * chrono::steady_clock::period::num / chrono::steady_clock::period::den;

        threadsTime[d->id] = nseconds;
    }


    ReleaseSemaphore(ghSemaphore, 1, NULL);

    ExitThread(0);
}
// функція для потоку, який показує нам прогрес
DWORD WINAPI showProgress(LPVOID lpParameter) {
    while (isWorking) {
        cout.precision(3);
        cout << progressCounter / progressMax * 100 << "%" << endl;

        int l = res[0];
        for (int j = 0; j < res.size(); j++) {
            if (l < res[j]) {
                l = res[j];
            }
        }

        if (l > 1) cout << "Len = " << l << endl;
    }

    ExitThread(0);
}

// створюємо потоки
bool aThr(int count) {
    n = words.size();
    progressMax = words.size();

    const unsigned pCount = 1U * num;
    res.resize(num, 0);
    threadsTime.resize(num, 0);

    ghSemaphore = CreateSemaphore(NULL, count, count, NULL);
    if (ghSemaphore == NULL) {
        cout << "\nWe got a problem with the Semaphore\n\n";
        return false;
    }

    HANDLE progr = CreateThread(NULL, 0, showProgress, NULL, 0, 0);
    if (progr == NULL) {
        cout << "\nWe got a problem with the Progress Thread\n\n";
        return false;
    }


    for (int i = 0; i < pCount; i++) {
        thr* d = new thr;
        d->id = i;
        d->step = pCount;

        threads[i] = CreateThread(0, 0, maxLen, (LPVOID)d, 0, 0);
    }

    SetThreadPriority(threads[0], priority);

    WaitForMultipleObjects(num, threads, TRUE, INFINITE);

    for (int i = 0; i < pCount; i++) {
        WaitForSingleObject(threads[i], INFINITE);
    }


    for (DWORD i = 0; i < pCount; ++i) {
        CloseHandle(threads[i]);
    }

    isWorking = false;
    WaitForSingleObject(progr, INFINITE);

    cout << "\nDone!\n";
    return true;
}

void changePriority() {
    cout << "Time critical - 15\n";
    cout << "Highest - 2\n";
    cout << "Above normal - 1\n";
    cout << "Normal - 0\n";
    cout << "Below normal - -1\n";
    cout << "Lowest - -2\n";
    cout << "Idle - -15\n";
    cin >> priority;
}

int main()
{
    cout << "Number of threads: ";
    cin >> num;

    int choice, maxCount = num;
    cout << "Would you like to limit the number of threads working at the same time? Yes - 1, No - 0 | ";
    cin >> choice;
    if (choice == 1) {
        cout << "Number of threads working at the same time: ";
        cin >> maxCount;
    }

    cout << "Would you like to change priority level of the first thread? Yes - 1, No - 0 | ";
    cin >> choice;
    if (choice == 1) changePriority();

    cout << "Name of file: ";
    cin >> fileName;

    read2();

    if (aThr(maxCount)) {
        findMax();
        cout << "Max length: " << ml << endl;
        writeRes2();
    }
}