#include "puzzle.hpp"
#include "gameplay.hpp"
#include "image_converter/resources.hpp"

#include <algorithm>
#include <stdlib.h>
#include <string>
#include <string.h>
#include <FL/Fl.H>
#include <FL/Fl_PNG_Image.H>
#include <FL/fl_ask.H>
#include <utility>
#include <memory>
#include <filesystem>
#include <random>

GameParams* GameParams::instance = nullptr;

void GameParams::CalculateStandardPuzzlePos()
{
    coordinates tmp;

    int i, j, k = 0;
    for(i = 0; i < puzzles_per_side; ++i)
        for(j = 0; j < puzzles_per_side; ++j, ++k) {
            tmp.x = i * (puzzle_size + spacing) + spacing;
            tmp.y = j * (puzzle_size + spacing) + spacing + 30;
            standard_puzzle_coordinates[k] = tmp;
        }
}

void GameParams::ResetFreePuzzles()
{
    for(int i = 0; i < puzzle_pieces; ++i)
        free_puzzles[i] = 1;
}

static void find_path_to_picture(std::string& path,
                                 const std::string& cur_directory, int number)
{
    path =
        cur_directory + std::to_string(number / puzzles_per_side) +
        std::to_string(number % puzzles_per_side) + ".png";
}

Fl_PNG_Image *GameParams::LoadPictureParts(std::unique_ptr<Puzzle>& tmp_puzzle)
{
    Fl_PNG_Image *img = nullptr;
    /*
     * if loading from Resources dir
     */
    if(cur_directory.size()) {
        find_path_to_picture(tmp_puzzle->path, cur_directory,
                             tmp_puzzle->sequence_number);
        img = new Fl_PNG_Image(tmp_puzzle->path.c_str());
        /*
         * loading a standard image from RAM (image_converter/resources.cpp)
         */
    } else  {
        int offset = 0;
        for(int i = 0; i < tmp_puzzle->sequence_number; ++i)
            offset += image_sizes[i];
        unsigned char *image_buffer = image_data + offset;
        img = new Fl_PNG_Image(nullptr, image_buffer,
                               image_sizes[tmp_puzzle->sequence_number]);
    }
    return img;
}

void GameParams::NextUntestedPuzzles()
{
    int idx_random_puzzle;
    std::unique_ptr<Puzzle> tmp_puzzle;
    /*
     * check if puzzles already were created
     */
    if(puzzles.size() != 0) {
        puzzles.clear();
        Fl::do_widget_deletion();
    }
    /*
     * ======== creating puzzles ===========
     */
    win->begin();
    for(int i = 0; i < puzzle_pieces; ++i) {
        idx_random_puzzle =
            0 + (int)((double)puzzle_pieces * rand()/(RAND_MAX + 1.0));
        while(!free_puzzles[idx_random_puzzle])
            idx_random_puzzle =
                0 + (int)((double)puzzle_pieces * rand()/(RAND_MAX + 1.0));
        free_puzzles[idx_random_puzzle] = 0;
        /* empty puzzle */
        if(idx_random_puzzle == puzzle_pieces-1) {
            SetXYEmptyBox(standard_puzzle_coordinates[i].x,
                          standard_puzzle_coordinates[i].y);
            continue;
        }
        /* common puzzle */
        tmp_puzzle =
            std::unique_ptr<Puzzle>(new Puzzle(standard_puzzle_coordinates[i].x,
                                standard_puzzle_coordinates[i].y));
        tmp_puzzle->sequence_number = idx_random_puzzle;
        Fl_PNG_Image *img = LoadPictureParts(tmp_puzzle);
        switch (img->fail()) {
            case Fl_Image::ERR_NO_IMAGE:
            case Fl_Image::ERR_FILE_ACCESS:
                fl_alert("%s: %s", tmp_puzzle->path.c_str(), strerror(errno));
                exit(1);
            case Fl_Image::ERR_FORMAT:
                fl_alert("couldn't decode image");
                exit(1);
        }
        tmp_puzzle->image(img);
        tmp_puzzle->stored_img_pointer = img;
        tmp_puzzle->callback(press_button_callback, this);
        puzzles.push_back(std::move(tmp_puzzle));
    }
    ResetFreePuzzles();
   /*
    * Checking image shuffling
    */
    bool shuffled_img = false;
    for(int i = 0; i < puzzle_pieces-1; ++i)
        if(puzzles[i]->sequence_number != i) {
            shuffled_img = true;
            break;
        }
    if(!shuffled_img)
        NextUntestedPuzzles();
    win->end();
}

bool GameParams::IsSolvability()
{
    int counter = 0;
    for(size_t i = 0; i < puzzles.size(); ++i)
        for(size_t j = i+1; j < puzzles.size(); ++j)
            if(puzzles[i]->sequence_number > puzzles[j]->sequence_number)
                ++counter;
    return counter % 2 == 0;
}

void GameParams::CreateNewPuzzles()
{
    do {
        NextUntestedPuzzles();
    } while(!IsSolvability());
}

void GameParams::SelectRandomPicture()
{
    std::filesystem::path res_path = std::string("resources");
    bool res_path_exists = std::filesystem::exists(res_path);
    if(res_path_exists) {
        std::vector<std::string> choices;
        for (const auto& entry : std::filesystem::directory_iterator("resources")) {
            choices.emplace_back(entry.path().string());
        }
        choices.emplace_back("standard");
        std::random_device rd;
        std::mt19937 g(rd());
        std::shuffle(choices.begin(), choices.end(), g);
        if(choices[0] == "standard")
            cur_directory.clear();
        else {
            cur_directory = choices[0];
#if defined(_WIN32)
            cur_directory.append("\\");
#else
            cur_directory.append("/");
        }
    }
#endif
}