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#include "defines.h"

#include "CONTROLLERS.h"

#include "SNAKE.h"

static SNAKE_DATA *data_p;

static uint32_t rand_value __attribute__((persistent));

void Snake_Init(SNAKE_DATA *data) {

    data_p = data;

    // Set starting point

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

    data_p->pos_head = 0;

    data_p->pos_tail = 0;

    data_p->length = 1;

    data_p->level = 1;

    data_p->delay = 800;

    srand(rand_value);

    // Generate a starting location for the candy

    data_p->candy_loc = Snake_Generate_Candy();

    // Draw the snake (head)

    Cube_Clear();

    uint32_t index = data_p->pos_head;

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

    while (index != data_p->pos_tail) {

        if (data_p->length > 1) {

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

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

        }

    }

}

void Snake_Main(void) {

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

    Delay_MS(2000);

    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(data_p->delay);

    }

}

void Snake_Update_Direction(uint8_t p1, uint8_t p2) {

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

    SNAKE_DIRECTION dir;

    dir.value = p1 | p2;

    data_p->last_direction = dir.value;

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

    if (dir.up) {

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

    } else if (dir.down) {

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

    } else if (dir.forward) {

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

    } else if (dir.right) {

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

    } else if (dir.backward) {

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

    } else if (dir.left) {

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

    }

    data_p->direction = point;

    // Update the overlay with the candy location

    Cube_Overlay_Clear();

    Cube_Overlay_Set_Pixel(data_p->candy_loc.z, data_p->candy_loc.x, 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 (data_p->direction.x == data_p->candy_loc.x &&

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

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

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

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

        data_p->length++;

        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 = data_p->pos_tail;

    while (pos != data_p->pos_head) {

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

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

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

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

            Cube_Set_Pixel(data_p->direction.z, data_p->direction.x, 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) {

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

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

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

    }

    // Draw updated snake location

    Cube_Clear();

    uint32_t index = data_p->pos_head;

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

    while (index != data_p->pos_tail) {

        if (data_p->length > 1) {

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

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

        }

    }

    // Determine the next direction to take

    Snake_Update_Direction(data_p->last_direction, 0x0);

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

    if (om_nom_nom) {

        // Increase the level by one, show on controller if necessary

        data_p->level += 1;

        if (data_p->level % SNAKE_LEVEL_STEP == 0) {

            uint8_t tier = data_p->level / SNAKE_LEVEL_STEP;

            Controller_Set_Leds(tier, tier);

        }

        // Decrease the delay between frame updates by 5ms

        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 (data_p->length != 1) {

            uint32_t pos = data_p->pos_tail;

            uint32_t overlap = 0;

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

            while (pos != data_p->pos_head) {

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

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

                        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 = data_p->pos_tail;

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

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

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

                brk = 1;

            }

        }

        if (brk)

            break;

    }

    ret.x = x;

    ret.y = y;

    ret.z = z;

    return ret;

}