#include <stdio.h>
#include <stdlib.h>
#include "snake.h"

/*typedef struct Snake {
    int x;
    int y;
    struct Snake *next;
} Snake;


typedef struct State {
    Snake *snake;
    int food[2]; 
    int foodCount; 
    int height;
    int width;
    int speedX;
    int speedY;
} State;*/


/*enum endgame {
    END_CONTINUE,
    END_SNAKE,
    END_FOOD
};*/


void calculateNewSnakeHeadPosition(State *state, int *newX, int *newY) {
    *newX = state->snake->x + state->speedX;
    *newY = state->snake->y + state->speedY;
}


int isPointInsideSnake(Snake *snake, int x, int y) {
    Snake *current = snake;
    while (current != NULL) {
        if (current->x == x && current->y == y) {
            return 1; 
        }
        current = current->next;
    }
    return 0; 
}


void removeLastSnakePart(Snake *snake) {
    Snake *current = snake;
    Snake *previous = NULL;
    while (current->next != NULL) {
        previous = current;
        current = current->next;
    }
    free(current);
    if (previous != NULL) {
        previous->next = NULL;
    }
}


void addNewSnakePart(Snake *snake, int x, int y) {
    Snake *newPart = (Snake*)malloc(sizeof(Snake));
    if (newPart == NULL) {
        printf("Error\n");
        exit(1);
    }
    newPart->x = x;
    newPart->y = y;
    newPart->next = NULL;

    Snake *current = snake;
    while (current->next != NULL) {
        current = current->next;
    }
    current->next = newPart;
}


/*int step_state(struct state* state) {
    int newX, newY;
    calculateNewSnakeHeadPosition(state, &newX, &newY);

    if (isPointInsideSnake(state->snake, newX, newY)) {
        return END_SNAKE; 
    }

    
    if (newX == state->foodx[0] && newY == state->foody[1]) {
        
        state->foodx[0] = -1;
        state->foody[1] = -1;
        addNewSnakePart(state->snake, newX, newY);
        state->foodCount--;

        if (state->foodCount == 0) {
            return END_FOOD; 
        } else {
            return END_CONTINUE; 
        }
    }

   
    if (newX >= 0 && newX < state->width && newY >= 0 && newY < state->height) {
       
        addNewSnakePart(state->snake, newX, newY);
        removeLastSnakePart(state->snake);
        return END_CONTINUE;
    } else {
        return END_SNAKE; 
    }
}*/
int step_state(struct state* state) {
    // Рассчитываем новые координаты головы змеи
    int newHeadX = state->snake->x + state->sx;
    int newHeadY = state->snake->y + state->sy;

    // Проверяем, находится ли новая позиция головы змеи на змее
    struct snake *current = state->snake->next;
    while (current != NULL) {
        if (current->x == newHeadX && current->y == newHeadY) {
            return END_SNAKE; // Игра завершается из-за столкновения со змеей
        }
        current = current->next;
    }

    // Проверяем, находится ли новая позиция головы змеи на еде
    for (int i = 0; i < FOOD_COUNT; ++i) {
        if (newHeadX == state->foodx[i] && newHeadY == state->foody[i]) {
            // Помечаем еду как съеденную и добавляем новый элемент змеи
            state->foodx[i] = -1;
            state->foody[i] = -1;
            struct snake *newPart = (struct snake*)malloc(sizeof(struct snake));
            if (newPart == NULL) {
                printf("Ошибка выделения памяти\n");
                exit(1);
            }
            newPart->x = newHeadX;
            newPart->y = newHeadY;
            newPart->next = state->snake;
            state->snake = newPart;
            return (i == FOOD_COUNT - 1) ? END_FOOD : END_CONTINUE;
        }
    }

    // Проверяем, находится ли новая позиция головы змеи в пределах поля
    if (newHeadX >= 0 && newHeadX < state->width && newHeadY >= 0 && newHeadY < state->height) {
        // Добавляем новую часть змеи и удаляем последнюю
        struct snake *newHead = (struct snake*)malloc(sizeof(struct snake));
        if (newHead == NULL) {
            printf("Ошибка выделения памяти\n");
            exit(1);
        }
        newHead->x = newHeadX;
        newHead->y = newHeadY;
        newHead->next = state->snake;
        state->snake = newHead;

        // Удаляем последнюю часть змеи
        struct snake *tail = state->snake;
        while (tail->next->next != NULL) {
            tail = tail->next;
        }
        free(tail->next);
        tail->next = NULL;

        return END_CONTINUE; // Игра продолжается после перемещения змеи
    } else {
        return END_SNAKE; // Игра завершается из-за выхода за пределы поля
    }
}

/*int main() {
    
    State *gameState = (State*)malloc(sizeof(State));
    if (gameState == NULL) {
        printf("Error\n");
        return 1;
    }

    
    gameState->snake = (Snake*)malloc(sizeof(Snake));
    if (gameState->snake == NULL) {
        printf("Error\n");
        return 1;
    }
    gameState->snake->x = 0;
    gameState->snake->y = 0;
    gameState->snake->next = NULL;
    gameState->food[0] = 5;
    gameState->food[1] = 5;
    gameState->foodCount = 1;
    gameState->height = 10;
    gameState->width = 10;
    gameState->speedX = 1;
    gameState->speedY = 0;


    int endGameReason = step_state(gameState);
    
    switch (endGameReason) {
        case END_CONTINUE:
            printf("Game continue.\n");
            break;
        case END_SNAKE:
            printf("Game is finished due to colision.\n");
            break;
        case END_FOOD:
            printf("Game is finished due to lack of food.\n");
            break;
    }

    
    free(gameState->snake);
    free(gameState);

    return 0;
}*/