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#include "defines.h"

#include "CONTROLLERS.h"

#include "SNAKE.h"

#include "TIMER4.h"

static SNAKE_DATA *snake_data_p;

static uint32_t rand_value __attribute__((persistent));

void Snake_Init(SNAKE_DATA *data) {

    snake_data_p = data;

    // Set starting point

    snake_data_p->body[0] = (SNAKE_POINT){0,0,7};

    snake_data_p->pos_head = 0;

    snake_data_p->pos_tail = 0;

    snake_data_p->length = 1;

    snake_data_p->level = 0;

    snake_data_p->delay = SNAKE_MAXIMUM_DELAY;

    // Initialize the starting direction

    snake_data_p->direction = (SNAKE_POINT){1,0,7};

    snake_data_p->last_direction = 0x08;

    srand(rand_value);

    // Generate a starting location for the candy

    snake_data_p->candy_loc = Snake_Generate_Candy();

    // Draw the snake (head)

    Cube_Clear();

    uint32_t index = snake_data_p->pos_head;

    Cube_Set_Pixel(snake_data_p->body[index].z, snake_data_p->body[index].x, snake_data_p->body[index].y, SNAKE_HEAD_COLOR);

    while (index != snake_data_p->pos_tail) {

        if (snake_data_p->length > 1) {

            index = (index == 0) ? CUBE_PIXELS - 1 : index - 1;

            Cube_Set_Pixel(snake_data_p->body[index].z, snake_data_p->body[index].x, snake_data_p->body[index].y, SNAKE_BODY_COLOR);

        }

    }

}

void Snake_Main(void) {

    // Main function, loops and delays while updating the frame every x milliseconds

    // Ensure that a controller is connected before starting

    while(!Controller_Get_Connected()) {

        Delay_MS(100);

        Controller_Poll_Connected();

    }

    // Set the first controller as active and indicate it on its LEDs

    Controller_Set_Active(0);

    Delay_MS(20);

    Controller_Set_Left_Leds(0, 0x1);

    TIMER4_Start();

    Delay_MS(1000);

    while (1) {

        // Regenerate the seed upon each update so that the candy starts somewhere new every time

        rand_value = rand();

        Snake_Update_Frame();

        Delay_MS(snake_data_p->delay);

    }

}

void Snake_Update_Direction(uint8_t controller, CTRL_BTN_STATUS value) {

    // Determine the next direction for the snake based off the last button press

    if (controller == 0) {

        snake_data_p->last_direction = value.w;

        SNAKE_POINT point = snake_data_p->body[snake_data_p->pos_head];

        if (value.BTN_L_N || value.BTN_L_E) {    // Up

            point.z = (point.z == CUBE_LAYER_COUNT - 1) ? 0 : point.z + 1;

        } else if (value.BTN_L_W || value.BTN_L_S) { // Down

            point.z = (point.z == 0) ? CUBE_LAYER_COUNT - 1 : point.z - 1;

        } else if (value.BTN_R_N) { // Forward

            point.x = (point.x == CUBE_ROW_COUNT - 1) ? 0 : point.x + 1;

        } else if (value.BTN_R_W) { // Right

            point.y = (point.y == CUBE_COLUMN_COUNT - 1) ? 0 : point.y + 1;

        } else if (value.BTN_R_S) { // Backward

            point.x = (point.x == 0) ? CUBE_ROW_COUNT - 1 : point.x - 1;

        } else if (value.BTN_R_E) { // Left

            point.y = (point.y== 0) ? CUBE_COLUMN_COUNT - 1 : point.y - 1;

        }

        snake_data_p->direction = point;

    }

    // Update the overlay with the candy location

    Cube_Overlay_Clear();

    Cube_Overlay_Set_Pixel(snake_data_p->candy_loc.z, snake_data_p->candy_loc.x, snake_data_p->candy_loc.y, SNAKE_CANDY_COLOR);

}

void Snake_Update_Frame(void) {

    uint8_t om_nom_nom = 0;

    // Check if we are moving onto a candy, if so extend body

    if (snake_data_p->direction.x == snake_data_p->candy_loc.x &&

            snake_data_p->direction.y == snake_data_p->candy_loc.y &&

            snake_data_p->direction.z == snake_data_p->candy_loc.z) {

        snake_data_p->pos_head = (snake_data_p->pos_head == CUBE_PIXELS - 1) ? 0 : snake_data_p->pos_head + 1;

        snake_data_p->body[snake_data_p->pos_head] = snake_data_p->direction;

        snake_data_p->length++;

        snake_data_p->candy_loc = Snake_Generate_Candy();

        om_nom_nom = 1;

    }

    // Check if the location that we are moving to is overlapping the body

    uint32_t pos = snake_data_p->pos_tail;

    while (pos != snake_data_p->pos_head) {

        if (snake_data_p->direction.x == snake_data_p->body[pos].x &&

                snake_data_p->direction.y == snake_data_p->body[pos].y &&

                snake_data_p->direction.z == snake_data_p->body[pos].z) {

            // Indicate the overlapping pixel, delay, then return to idle state

            Cube_Set_Pixel(snake_data_p->direction.z, snake_data_p->direction.x, snake_data_p->direction.y, SNAKE_COLLISION_COLOR);

            Delay_MS(3000);

            Cube_Overlay_Clear();

            Animation_Cube_In_Out(200, ORANGE);

            Reset_Board(BOARD_MODE_IDLE);

        }

        pos = (pos == CUBE_PIXELS - 1) ? 0 : pos + 1;

    }

    // If we didnt eat a candy, increment the frame to move the body along

    if (!om_nom_nom) {

        snake_data_p->pos_head = (snake_data_p->pos_head == CUBE_PIXELS - 1) ? 0 : snake_data_p->pos_head + 1;

        snake_data_p->pos_tail = (snake_data_p->pos_tail == CUBE_PIXELS - 1) ? 0 : snake_data_p->pos_tail + 1;

        snake_data_p->body[snake_data_p->pos_head] = snake_data_p->direction;

    }

    // Draw updated snake location

    Cube_Clear();

    uint32_t index = snake_data_p->pos_head;

    Cube_Set_Pixel(snake_data_p->body[index].z, snake_data_p->body[index].x, snake_data_p->body[index].y, SNAKE_HEAD_COLOR);

    while (index != snake_data_p->pos_tail) {

        if (snake_data_p->length > 1) {

            index = (index == 0) ? CUBE_PIXELS - 1 : index - 1;

            Cube_Set_Pixel(snake_data_p->body[index].z, snake_data_p->body[index].x, snake_data_p->body[index].y, SNAKE_BODY_COLOR);

        }

    }

    // Determine the next point to move to

    Snake_Update_Direction(0, (CTRL_BTN_STATUS)snake_data_p->last_direction);

    // If we ate a candy, delay for a bit to rest

    if (om_nom_nom) {

        // Increase the level by one

        snake_data_p->level += 1;

        TIMER4_Stop();

        Controller_Set_Middle_Leds(0, snake_data_p->level);

        if (snake_data_p->level >= 256)

            Controller_Set_Left_Leds(0, 0x9);

        TIMER4_Start();

        // Decrease the delay between frame updates by 5ms

        if (snake_data_p->delay > SNAKE_MINIMUM_DELAY)

            snake_data_p->delay -= 5;

        // Clear the watchdog timer to prevent resets in a middle of a game

        ClearWDT();

    }

}

SNAKE_POINT Snake_Generate_Candy(void) {

    // Generates a random position within the cube that doesnt overlap anything

    SNAKE_POINT ret;

    uint32_t x, y, z, brk = 0;

    while(1) {

        x = rand() % 8;

        y = rand() % 8;

        z = rand() % 8;

        if (snake_data_p->length != 1) {

            uint32_t pos = snake_data_p->pos_tail;

            uint32_t overlap = 0;

            // Iterate through the frame till we finish or find an overlap

            while (pos != snake_data_p->pos_head) {

                if (snake_data_p->body[pos].x == x &&

                        snake_data_p->body[pos].y == y &&

                        snake_data_p->body[pos].z == z) {

                    overlap = 1;

                    break;

                } else {

                    pos = (pos == CUBE_PIXELS - 1) ? 0 : pos + 1;

                }

            }

            if (!overlap)

                brk = 1;

        } else {

            uint32_t pos = snake_data_p->pos_tail;

            if (snake_data_p->body[pos].x != x &&

                    snake_data_p->body[pos].y != y &&

                    snake_data_p->body[pos].z != z) {

                brk = 1;

            }

        }

        if (brk)

            break;

    }

    ret.x = x;

    ret.y = y;

    ret.z = z;

    return ret;

}