#include "include/raylib.h"
#include <stdio.h>

//-------------------------------------------------------------------------------------------------------------------------------------
typedef struct Block {
    Vector2 position, size;
    int form, onGround;
    float speed, step;

    struct Block *next;
} Block;


void createBlock(Block **head) {
    Block *block = MemAlloc(sizeof(Block));
    block->position = (Vector2){ 400, -40 };
    block->size = (Vector2){ 20, 20 };
    block->form = 1;
    block->onGround = 0;
    block->speed = 4;
    block->step = 20;
    block->next = NULL;

    // Falls die Liste leer ist
    if (*head == NULL) {
        *head = block;
        return;
    }

    // Durch alle Blöcke iterieren und den neuesten am Schluss hinzufügen
    Block *currentBlock = *head;
    while (currentBlock->next != NULL) {
        currentBlock = currentBlock->next;
    }

    currentBlock->next = block;
}


int main(void) {

    // INIT
    const int screenWidth = 800;
    const int screenHeight = 450;
    InitWindow(screenWidth, screenHeight, "Tetris-C");
    
    Block *block = { 0 };
    createBlock(&block);
    int blockMoving = 1;
    int blockCounter = 1;

    SetTargetFPS(60);

    while (!WindowShouldClose()) {
        //-------------------------------------------------------------------------------------------------------------------------------------
        // UPDATE GAME LOGIC
        // INPUT
        Block *currentBlock = block;
        // Alle Blöcke fallen lassen
        while (currentBlock != NULL) {
            // Wenn Block noch nicht auf Boden, dann fallen
            if (currentBlock->onGround == 0) {

                // MOVEMENT -------------------------------------------------
                if (IsKeyPressed(KEY_LEFT)) {
                    currentBlock->position.x -= currentBlock->step;
                }

                if (IsKeyPressed(KEY_RIGHT)) {
                    currentBlock->position.x += currentBlock->step;
                }
                // ----------------------------------------------------------
                // Kollision gegen anderen Block checken

                float nextY = currentBlock->position.y + currentBlock->speed;

                if (nextY > screenHeight - currentBlock->size.y) {
                    currentBlock->position.y = screenHeight - currentBlock->size.y;
                    blockMoving = 0;
                    currentBlock->onGround = 1;
                }
                else {
                    Rectangle nextRect = { currentBlock->position.x, nextY, currentBlock->size.x, currentBlock->size.y };

                    int collided = 0;
                    Block *collisionCheck = block;
                    while (collisionCheck != NULL) {
                        // Nur gegen andere, bereits gelandete Blöcke prüfen (und nicht gegen sich selbst!)
                        if (collisionCheck != currentBlock && collisionCheck->onGround == 1) {
                            Rectangle otherRect = { collisionCheck->position.x, collisionCheck->position.y, collisionCheck->size.x, collisionCheck->size.y };
                            
                            if (CheckCollisionRecs(nextRect, otherRect)) {
                                collided = 1;
                                break;
                            }
                        }
                        collisionCheck = collisionCheck->next;
                    }

                    if (collided) {
                        blockMoving = 0;
                        currentBlock->onGround = 1;
                    }
                    else {
                        currentBlock->position.y = nextY;
                    }
                }              

            }

            currentBlock = currentBlock->next;
        }

        // Wenn sich kein Block mehr bewegt, einen neuen erstellen
        if (blockMoving == 0) {
            createBlock(&block);
            blockCounter++;
            blockMoving = 1;
        }

        //-------------------------------------------------------------------------------------------------------------------------------------
        // ZEICHNEN
        BeginDrawing();
            ClearBackground(RAYWHITE);
            
            DrawFPS(20, 20);
            DrawText(TextFormat("Blocks: %i", blockCounter), 20, 40, 20, GREEN);

            // BLOCK ZEICHNEN
            currentBlock = block;
            while (currentBlock != NULL) {
                DrawRectangleV(currentBlock->position, currentBlock->size, BLUE);
                currentBlock = currentBlock->next;
            }

        EndDrawing();
        //-------------------------------------------------------------------------------------------------------------------------------------
    }


    // Alle Blöcke im Speicher freigeben
    Block *currentBlock = block;
    while (currentBlock != NULL) {
        Block *nextBlock = currentBlock->next;
        MemFree(currentBlock);
        currentBlock = nextBlock;
    }

    CloseWindow();
    return 0;
}