From b1f20338809f8dc99eefda69a990ade3a1e29cd0 Mon Sep 17 00:00:00 2001
From: Gregor Klevze <gregor@klevze.si>
Date: Thu, 25 Dec 2025 10:15:23 +0100
Subject: [PATCH] Scaffold the pure game model

- Added a pure, SDL-free Board model implementing grid access and clearFullLines().
- Added a small standalone test at test_board.cpp (simple assert-based; not yet wired into CMake).
---
 src/logic/Board.cpp  | 59 ++++++++++++++++++++++++++++++++++++++++++++
 src/logic/Board.h    | 32 ++++++++++++++++++++++++
 tests/test_board.cpp | 31 +++++++++++++++++++++++
 3 files changed, 122 insertions(+)
 create mode 100644 src/logic/Board.cpp
 create mode 100644 src/logic/Board.h
 create mode 100644 tests/test_board.cpp

diff --git a/src/logic/Board.cpp b/src/logic/Board.cpp
new file mode 100644
index 0000000..ca6ef59
--- /dev/null
+++ b/src/logic/Board.cpp
@@ -0,0 +1,59 @@
+#include "Board.h"
+#include <algorithm>
+
+namespace logic {
+
+Board::Board()
+    : grid_(Width * Height, Cell::Empty)
+{
+}
+
+void Board::clear()
+{
+    std::fill(grid_.begin(), grid_.end(), Cell::Empty);
+}
+
+bool Board::inBounds(int x, int y) const
+{
+    return x >= 0 && x < Width && y >= 0 && y < Height;
+}
+
+Board::Cell Board::at(int x, int y) const
+{
+    if (!inBounds(x, y)) return Cell::Empty;
+    return grid_[y * Width + x];
+}
+
+void Board::set(int x, int y, Cell c)
+{
+    if (!inBounds(x, y)) return;
+    grid_[y * Width + x] = c;
+}
+
+int Board::clearFullLines()
+{
+    int cleared = 0;
+    // scan from bottom to top
+    for (int y = Height - 1; y >= 0; --y) {
+        bool full = true;
+        for (int x = 0; x < Width; ++x) {
+            if (at(x, y) == Cell::Empty) { full = false; break; }
+        }
+        if (full) {
+            // remove row y: move all rows above down by one
+            for (int yy = y; yy > 0; --yy) {
+                for (int x = 0; x < Width; ++x) {
+                    grid_[yy * Width + x] = grid_[(yy - 1) * Width + x];
+                }
+            }
+            // clear top row
+            for (int x = 0; x < Width; ++x) grid_[x] = Cell::Empty;
+            ++cleared;
+            // stay on same y to re-check the row that fell into place
+            ++y; // because next iteration decrements y
+        }
+    }
+    return cleared;
+}
+
+} // namespace logic
diff --git a/src/logic/Board.h b/src/logic/Board.h
new file mode 100644
index 0000000..6ed5a27
--- /dev/null
+++ b/src/logic/Board.h
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <vector>
+#include <cstdint>
+
+namespace logic {
+
+class Board {
+public:
+    static constexpr int Width = 10;
+    static constexpr int Height = 20;
+
+    enum class Cell : uint8_t { Empty = 0, Filled = 1 };
+
+    Board();
+
+    void clear();
+
+    Cell at(int x, int y) const;
+    void set(int x, int y, Cell c);
+    bool inBounds(int x, int y) const;
+
+    // Remove and return number of full lines cleared. Rows above fall down.
+    int clearFullLines();
+
+    const std::vector<Cell>& data() const { return grid_; }
+
+private:
+    std::vector<Cell> grid_; // row-major: y*Width + x
+};
+
+} // namespace logic
diff --git a/tests/test_board.cpp b/tests/test_board.cpp
new file mode 100644
index 0000000..babc08a
--- /dev/null
+++ b/tests/test_board.cpp
@@ -0,0 +1,31 @@
+#include "../src/logic/Board.h"
+#include <cassert>
+#include <iostream>
+
+int main()
+{
+    using logic::Board;
+    Board b;
+    // board starts empty
+    for (int y = 0; y < Board::Height; ++y)
+        for (int x = 0; x < Board::Width; ++x)
+            assert(b.at(x,y) == Board::Cell::Empty);
+
+    // fill a single full row at bottom
+    int y = Board::Height - 1;
+    for (int x = 0; x < Board::Width; ++x) b.set(x, y, Board::Cell::Filled);
+    int cleared = b.clearFullLines();
+    assert(cleared == 1);
+    // bottom row should be empty after clear
+    for (int x = 0; x < Board::Width; ++x) assert(b.at(x, Board::Height - 1) == Board::Cell::Empty);
+
+    // fill two non-adjacent rows and verify both clear
+    int y1 = Board::Height - 1;
+    int y2 = Board::Height - 3;
+    for (int x = 0; x < Board::Width; ++x) { b.set(x, y1, Board::Cell::Filled); b.set(x, y2, Board::Cell::Filled); }
+    cleared = b.clearFullLines();
+    assert(cleared == 2);
+
+    std::cout << "tests/test_board: all assertions passed\n";
+    return 0;
+}