#include "FileHelper.h"

bool comp(pair<char, int> a, pair<char, int> b) {
    return a.second > b.second;
}

vector<string> FileHelper::open(const char* filename) {
    streamsize size = -1;

    vector<string> text;
    vector<pair<char, int>> chars;
    size = this->proccessFile(filename, &text, &chars);

    int c = 1;
    for (auto it : chars) {
        map.insert(make_pair(it.first, c));
        c++;
    }

    return text;
}

streamsize FileHelper::save(const char* filename, vector<char> &text) {
    ofstream os(filename);

    for (auto ch : text) {
        os << ch;
    }
    os.close();

    return 0;
}

void FileHelper::loadReverseTable(const char* filename) {
    vector<pair<char, int>> chars;
    proccessFile(filename, nullptr, &chars);

    for (auto it : chars) {
        reverse_map.push_back(it.first);
    }
}

streamsize FileHelper::proccessFile(const char* filename, vector<string>* text, vector<pair<char, int>>* chars) {
    ifstream io(filename);

    io.seekg(0, io.end);
    streamsize size = io.tellg();
    io.seekg(0, io.beg);

    unordered_map<char, int> charmap;
    string line;

    totalChars = 0;

    while (getline(io, line)) {
        line.append("\n");
        for (auto c : line) {
            auto it = charmap.find(c);
            if (it != charmap.end()) {
                charmap.at(c) += 1;
            }
            else {
                charmap.insert(make_pair(c, 1));
            }


            totalChars++;
        }
        if (text != nullptr) {
            text->push_back(line);
        }
    }

    float entropy = 0.f;
    for (auto it : charmap) {
        float p = it.second / float(totalChars);

        if (p == 0.f) {
            continue;
        }

        entropy += (-p * log2(p));
    }
    printf("Entropy of %s: %f\n", filename, entropy);

    if (chars != nullptr) {
        chars->assign(charmap.begin(), charmap.end());
        sort(chars->begin(), chars->end(), comp);
    }

    io.close();
    return 0;
}