#include "pistring.h"
#include "pivector2d.h"

#include "gtest/gtest.h"
#include <numeric>

size_t ROWS_COUNT_INIT  = 31;
size_t COLS_COUNT_INIT  = 34;
int ROWS_COUNT_INCREASE = 41;
int COLS_COUNT_INCREASE = 44;
int ROWS_COUNT_REDUCE   = 22;
int COLS_COUNT_REDUCE   = 13;

void fill_with_sequential(PIVector2D<int> & vec, int rows, int cols) {
	for (int r = 0; r < rows; ++r) {
		for (int c = 0; c < cols; ++c) {
			vec.element(r, c) = r * cols + c;
		}
	}
}

void assert_fill_with_sequential(const PIVector2D<int> & vec, int rows, int cols) {
	ASSERT_EQ(vec.rows(), rows);
	ASSERT_EQ(vec.cols(), cols);
	for (int r = 0; r < rows; ++r) {
		for (int c = 0; c < cols; ++c) {
			ASSERT_EQ(vec.element(r, c), r * cols + c);
		}
	}
}

class Vector2DTest: public ::testing::Test {
protected:
	PIVector2D<int> vec = PIVector2D<int>(ROWS_COUNT_INIT, COLS_COUNT_INIT);

	void SetUp() override { fill_with_sequential(vec, ROWS_COUNT_INIT, COLS_COUNT_INIT); }
};

// ==================== CONSTRUCTOR TESTS ====================
TEST_F(Vector2DTest, defaultConstructor_createsEmptyVector) {
	PIVector2D<int> emptyVec;
	EXPECT_TRUE(emptyVec.isEmpty());
	EXPECT_EQ(emptyVec.rows(), 0);
	EXPECT_EQ(emptyVec.cols(), 0);
	EXPECT_EQ(emptyVec.size(), 0);
}

TEST_F(Vector2DTest, sizedConstructor_createsCorrectDimensions) {
	PIVector2D<int> testVec(5, 3, 42);
	EXPECT_EQ(testVec.rows(), 5);
	EXPECT_EQ(testVec.cols(), 3);
	EXPECT_EQ(testVec.size(), 15);

	for (size_t r = 0; r < 5; ++r) {
		for (size_t c = 0; c < 3; ++c) {
			EXPECT_EQ(testVec.element(r, c), 42);
		}
	}
}

TEST_F(Vector2DTest, fromPlainVector_constructor_reshapesCorrectly) {
	PIVector<int> plain(20);
	std::iota(plain.data(), plain.data() + 20, 0);

	PIVector2D<int> vec2d(4, 5, plain);
	EXPECT_EQ(vec2d.rows(), 4);
	EXPECT_EQ(vec2d.cols(), 5);

	for (size_t r = 0; r < 4; ++r) {
		for (size_t c = 0; c < 5; ++c) {
			EXPECT_EQ(vec2d.element(r, c), static_cast<int>(r * 5 + c));
		}
	}
}

TEST_F(Vector2DTest, fromPlainVector_move_constructor_reshapesCorrectly) {
	PIVector<int> plain(20);
	std::iota(plain.data(), plain.data() + 20, 0);

	PIVector2D<int> vec2d(4, 5, std::move(plain));
	EXPECT_EQ(vec2d.rows(), 4);
	EXPECT_EQ(vec2d.cols(), 5);
	EXPECT_TRUE(plain.isEmpty()); // Moved-from state

	for (size_t r = 0; r < 4; ++r) {
		for (size_t c = 0; c < 5; ++c) {
			EXPECT_EQ(vec2d.element(r, c), static_cast<int>(r * 5 + c));
		}
	}
}

TEST_F(Vector2DTest, fromVectorOfVectors_constructor_reshapesCorrectly) {
	PIVector<PIVector<int>> vectors;
	vectors << PIVector<int>({1, 2, 3}) << PIVector<int>({4, 5, 6}) << PIVector<int>({7, 8, 9});

	PIVector2D<int> vec2d(vectors);
	EXPECT_EQ(vec2d.rows(), 3);
	EXPECT_EQ(vec2d.cols(), 3);

	EXPECT_EQ(vec2d.element(0, 0), 1);
	EXPECT_EQ(vec2d.element(1, 1), 5);
	EXPECT_EQ(vec2d.element(2, 2), 9);
}

// ==================== CAPACITY TESTS ====================
TEST_F(Vector2DTest, sizeMethods_returnCorrectValues) {
	EXPECT_EQ(vec.rows(), ROWS_COUNT_INIT);
	EXPECT_EQ(vec.cols(), COLS_COUNT_INIT);
	EXPECT_EQ(vec.size(), ROWS_COUNT_INIT * COLS_COUNT_INIT);
	EXPECT_EQ(vec.size_s(), static_cast<ssize_t>(ROWS_COUNT_INIT * COLS_COUNT_INIT));
	EXPECT_EQ(vec.length(), ROWS_COUNT_INIT * COLS_COUNT_INIT);
	EXPECT_FALSE(vec.isEmpty());
	EXPECT_TRUE(vec.isNotEmpty());
	EXPECT_GE(vec.capacity(), vec.size());
}

// ==================== ELEMENT ACCESS TESTS ====================
TEST_F(Vector2DTest, element_access_returnsCorrectValues) {
	EXPECT_EQ(vec.element(5, 7), 5 * COLS_COUNT_INIT + 7);
	EXPECT_EQ(vec.at(10, 20), 10 * COLS_COUNT_INIT + 20);

	vec.element(15, 15) = 999;
	EXPECT_EQ(vec.element(15, 15), 999);
}

TEST_F(Vector2DTest, row_proxy_allows_elementAccess) {
	auto row = vec[5];
	EXPECT_EQ(row.size(), COLS_COUNT_INIT);
	EXPECT_EQ(row[7], 5 * COLS_COUNT_INIT + 7);

	row[10] = 123;
	EXPECT_EQ(vec.element(5, 10), 123);
}

TEST_F(Vector2DTest, row_proxy_data_pointer_works) {
	auto row  = vec[10];
	int * ptr = row.data();
	EXPECT_EQ(ptr, vec.data(10 * COLS_COUNT_INIT));

	ptr[5] = 777;
	EXPECT_EQ(vec.element(10, 5), 777);
}

TEST_F(Vector2DTest, row_proxy_const_access_works) {
	const auto & constVec = vec;
	auto row              = constVec[5];
	EXPECT_EQ(row[7], 5 * COLS_COUNT_INIT + 7);

	// Compilation test - uncommenting should fail
	// row[10] = 123;
}

TEST_F(Vector2DTest, row_proxy_assignment_works) {
	PIVector2D<int> other(ROWS_COUNT_INIT, COLS_COUNT_INIT, 42);

	vec[10] = other[10];
	for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
		EXPECT_EQ(vec.element(10, c), 42);
	}

	PIVector<int> newRow(COLS_COUNT_INIT, 99);
	vec[15] = newRow;
	for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
		EXPECT_EQ(vec.element(15, c), 99);
	}
}

TEST_F(Vector2DTest, row_proxy_toVector_conversion_works) {
	auto rowVec = vec[7].toVector();
	EXPECT_EQ(rowVec.size(), COLS_COUNT_INIT);
	for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
		EXPECT_EQ(rowVec[c], vec.element(7, c));
	}
}

TEST_F(Vector2DTest, col_proxy_allows_elementAccess) {
	auto col = vec.col(5);
	EXPECT_EQ(col.size(), ROWS_COUNT_INIT);
	EXPECT_EQ(col[10], 10 * COLS_COUNT_INIT + 5);

	col[15] = 456;
	EXPECT_EQ(vec.element(15, 5), 456);
}

TEST_F(Vector2DTest, col_proxy_data_pointer_works) {
	auto col  = vec.col(8);
	int * ptr = col.data(5); // Start from row 5
	EXPECT_EQ(ptr, &vec.element(5, 8));

	col[2] = 888; // This should affect row 7
	EXPECT_EQ(vec.element(2, 8), 888);
}

TEST_F(Vector2DTest, col_proxy_assignment_works) {
	PIVector2D<int> other(ROWS_COUNT_INIT, COLS_COUNT_INIT, 42);

	vec.col(12) = other.col(12);
	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		EXPECT_EQ(vec.element(r, 12), 42);
	}

	PIVector<int> newCol(ROWS_COUNT_INIT, 77);
	vec.col(20) = newCol;
	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		EXPECT_EQ(vec.element(r, 20), 77);
	}
}

TEST_F(Vector2DTest, col_proxy_toVector_conversion_works) {
	auto colVec = vec.col(9).toVector();
	EXPECT_EQ(colVec.size(), ROWS_COUNT_INIT);
	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		EXPECT_EQ(colVec[r], vec.element(r, 9));
	}
}

TEST_F(Vector2DTest, row_and_col_methods_return_same_as_operator) {
	auto row1 = vec.row(10);
	auto row2 = vec[10];
	EXPECT_EQ(row1[0], row2[0]);

	auto col1 = vec.col(15);
	auto col2 = vec.col(15); // No operator[] for col
	EXPECT_EQ(col1[5], col2[5]);
}

// ==================== MODIFIER TESTS ====================
TEST_F(Vector2DTest, setRow_replaces_row_correctly) {
	PIVector<int> newRow(COLS_COUNT_INIT);
	std::iota(newRow.data(), newRow.data() + COLS_COUNT_INIT, 100);

	vec.setRow(12, newRow);
	for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
		EXPECT_EQ(vec.element(12, c), static_cast<int>(100 + c));
	}
}

TEST_F(Vector2DTest, setRow_with_shorter_vector_truncates) {
	PIVector<int> shortRow(COLS_COUNT_INIT - 5, 999);
	vec.setRow(8, shortRow);

	for (size_t c = 0; c < COLS_COUNT_INIT - 5; ++c) {
		EXPECT_EQ(vec.element(8, c), 999);
	}
	// Rest unchanged
	EXPECT_EQ(vec.element(8, COLS_COUNT_INIT - 5), 8 * COLS_COUNT_INIT + COLS_COUNT_INIT - 5);
}

TEST_F(Vector2DTest, addRow_appends_row_to_empty) {
	PIVector2D<int> empty;
	PIVector<int> newRow(5, 42);

	empty.addRow(newRow);
	EXPECT_EQ(empty.rows(), 1);
	EXPECT_EQ(empty.cols(), 5);
	for (size_t c = 0; c < 5; ++c) {
		EXPECT_EQ(empty.element(0, c), 42);
	}
}

TEST_F(Vector2DTest, addRow_appends_row_to_existing) {
	size_t oldRows = vec.rows();
	PIVector<int> newRow(COLS_COUNT_INIT, 999);

	vec.addRow(newRow);
	EXPECT_EQ(vec.rows(), oldRows + 1);
	EXPECT_EQ(vec.cols(), COLS_COUNT_INIT);

	for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
		EXPECT_EQ(vec.element(oldRows, c), 999);
	}
}

TEST_F(Vector2DTest, addRow_with_shorter_vector_uses_min) {
	size_t oldRows   = vec.rows();
	size_t shortCols = COLS_COUNT_INIT - 10;
	PIVector<int> shortRow(shortCols, 777);

	vec.addRow(shortRow);
	EXPECT_EQ(vec.rows(), oldRows + 1);
	EXPECT_EQ(vec.cols(), COLS_COUNT_INIT); // cols unchanged

	for (size_t c = 0; c < shortCols; ++c) {
		EXPECT_EQ(vec.element(oldRows, c), 777);
	}
	for (size_t c = shortCols; c < COLS_COUNT_INIT; ++c) {
		EXPECT_EQ(vec.element(oldRows, c), 0); // default initialized
	}
}

// ==================== RESIZE TESTS ====================
class Vector2DResizeTest: public Vector2DTest {
protected:
	void assert_resize_reduce_preserves_data(int newRows, int newCols) {
		vec.resize(newRows, newCols, 0);
		ASSERT_EQ(vec.rows(), newRows);
		ASSERT_EQ(vec.cols(), newCols);

		for (int r = 0; r < newRows; ++r) {
			for (int c = 0; c < newCols; ++c) {
				EXPECT_EQ(vec.element(r, c), r * COLS_COUNT_INIT + c);
			}
		}
	}

	void assert_resize_increase_initializes_new(size_t newRows, size_t newCols) {
		vec.resize(newRows, newCols, 0);
		ASSERT_EQ(vec.rows(), newRows);
		ASSERT_EQ(vec.cols(), newCols);

		// Check old data preserved
		for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
			for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
				EXPECT_EQ(vec.element(r, c), r * COLS_COUNT_INIT + c);
			}
		}

		// Check new elements initialized to 0
		for (size_t r = 0; r < newRows; ++r) {
			for (size_t c = 0; c < newCols; ++c) {
				if (r >= ROWS_COUNT_INIT || c >= COLS_COUNT_INIT) {
					EXPECT_EQ(vec.element(r, c), 0);
				}
			}
		}
	}
};

TEST_F(Vector2DResizeTest, resize_increase_both_preserves_data) {
	assert_resize_increase_initializes_new(ROWS_COUNT_INCREASE, COLS_COUNT_INCREASE);
}

TEST_F(Vector2DResizeTest, resize_increase_rows_only_preserves_data) {
	assert_resize_increase_initializes_new(ROWS_COUNT_INCREASE, COLS_COUNT_INIT);
}

TEST_F(Vector2DResizeTest, resize_increase_cols_only_preserves_data) {
	assert_resize_increase_initializes_new(ROWS_COUNT_INIT, COLS_COUNT_INCREASE);
}

TEST_F(Vector2DResizeTest, resize_reduce_both_preserves_data) {
	assert_resize_reduce_preserves_data(ROWS_COUNT_REDUCE, COLS_COUNT_REDUCE);
}

TEST_F(Vector2DResizeTest, resize_reduce_rows_only_preserves_data) {
	assert_resize_reduce_preserves_data(ROWS_COUNT_REDUCE, COLS_COUNT_INIT);
}

TEST_F(Vector2DResizeTest, resize_reduce_cols_only_preserves_data) {
	assert_resize_reduce_preserves_data(ROWS_COUNT_INIT, COLS_COUNT_REDUCE);
}

TEST_F(Vector2DResizeTest, resize_to_zero_creates_empty) {
	vec.resize(0, 0, 42);
	EXPECT_TRUE(vec.isEmpty());
	EXPECT_EQ(vec.rows(), 0);
	EXPECT_EQ(vec.cols(), 0);
}

TEST_F(Vector2DResizeTest, resize_same_dimensions_does_nothing) {
	size_t oldRows        = vec.rows();
	size_t oldCols        = vec.cols();
	PIVector<int> oldData = vec.asPlainVector();

	vec.resize(oldRows, oldCols, 999);
	EXPECT_EQ(vec.rows(), oldRows);
	EXPECT_EQ(vec.cols(), oldCols);
	EXPECT_EQ(vec.asPlainVector(), oldData); // Data unchanged
}

// ==================== SEARCH AND LOOKUP TESTS ====================
TEST_F(Vector2DTest, contains_finds_element_in_flat_vector) {
	EXPECT_TRUE(vec.contains(5 * COLS_COUNT_INIT + 7));
	EXPECT_FALSE(vec.contains(-999));
	EXPECT_TRUE(vec.contains(0));                                     // first element
	EXPECT_TRUE(vec.contains(ROWS_COUNT_INIT * COLS_COUNT_INIT - 1)); // last element
}

TEST_F(Vector2DTest, contains_with_start_parameter_works) {
	int target = 10 * COLS_COUNT_INIT + 15;
	EXPECT_TRUE(vec.contains(target));
	EXPECT_TRUE(vec.contains(target, target));      // start exactly at target (inclusive)
	EXPECT_FALSE(vec.contains(target, target + 1)); // start after target
}

TEST_F(Vector2DTest, contains_vector_of_elements_works) {
	PIVector<int> searchFor;
	searchFor << 100 << 200 << 300;
	EXPECT_TRUE(vec.contains(searchFor));

	searchFor << -999;
	EXPECT_FALSE(vec.contains(searchFor));
}

TEST_F(Vector2DTest, entries_counts_occurrences) {
	// Add some duplicates
	vec.fill(0);
	vec.element(5, 5)   = 42;
	vec.element(10, 10) = 42;

	EXPECT_EQ(vec.entries(42), 2);
	EXPECT_EQ(vec.entries(-1), 0);
}

TEST_F(Vector2DTest, entries_with_predicate_counts_matches) {
	auto isEven   = [](const int & e) { return e % 2 == 0; };
	int evenCount = 0;
	for (size_t i = 0; i < vec.size(); ++i) {
		if (vec.asPlainVector()[i] % 2 == 0) evenCount++;
	}
	EXPECT_EQ(vec.entries(isEven), evenCount);
}

TEST_F(Vector2DTest, indexOf_finds_first_occurrence) {
	int firstTarget = 5 * COLS_COUNT_INIT + 10;
	EXPECT_EQ(vec.indexOf(firstTarget), static_cast<ssize_t>(firstTarget));

	// Add duplicate later
	vec.asPlainVector()[20 * COLS_COUNT_INIT + 15] = firstTarget;
	EXPECT_EQ(vec.indexOf(firstTarget), static_cast<ssize_t>(firstTarget)); // Still first
}

TEST_F(Vector2DTest, indexOf_with_start_works) {
	int target = 15 * COLS_COUNT_INIT + 20;
	EXPECT_EQ(vec.indexOf(target, target + 1), -1);
	EXPECT_EQ(vec.indexOf(target, target), static_cast<ssize_t>(target));
}

TEST_F(Vector2DTest, indexWhere_finds_first_match) {
	auto isLarge     = [](const int & e) { return e > 500; };
	ssize_t expected = 501; // First element > 500
	EXPECT_EQ(vec.indexWhere(isLarge), expected);
}

TEST_F(Vector2DTest, lastIndexOf_finds_last_occurrence) {
	// Add duplicate later
	int target                                     = 8 * COLS_COUNT_INIT + 8;
	vec.asPlainVector()[25 * COLS_COUNT_INIT + 25] = target;

	EXPECT_EQ(vec.lastIndexOf(target), static_cast<ssize_t>(25 * COLS_COUNT_INIT + 25));
}

TEST_F(Vector2DTest, lastIndexWhere_finds_last_match) {
	auto isLarge     = [](const int & e) { return e > 900; };
	ssize_t expected = vec.size() - 1; // Last element
	EXPECT_EQ(vec.lastIndexWhere(isLarge), expected);
}

// ==================== STATISTICS AND CONDITIONS TESTS ====================
TEST_F(Vector2DTest, any_returns_true_if_any_match) {
	auto isNegative = [](const int & e) { return e < 0; };
	auto isLarge    = [](const int & e) { return e > 1000000; };

	EXPECT_FALSE(vec.any(isNegative));
	EXPECT_FALSE(vec.any(isLarge));

	auto isPositive = [](const int & e) { return e >= 0; };
	EXPECT_TRUE(vec.any(isPositive));
}

TEST_F(Vector2DTest, every_returns_true_if_all_match) {
	auto isNonNegative = [](const int & e) { return e >= 0; };
	const int max      = ROWS_COUNT_INIT * COLS_COUNT_INIT;
	auto isLessThan    = [max](const int & e) { return e < max; };

	EXPECT_TRUE(vec.every(isNonNegative));
	EXPECT_TRUE(vec.every(isLessThan));

	auto isEven = [](const int & e) { return e % 2 == 0; };
	EXPECT_FALSE(vec.every(isEven));
}

// ==================== FILL AND ASSIGN TESTS ====================
TEST_F(Vector2DTest, fill_sets_all_elements_to_value) {
	vec.fill(42);
	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
			EXPECT_EQ(vec.element(r, c), 42);
		}
	}
}

TEST_F(Vector2DTest, fill_with_function_generates_values) {
	vec.fill([](size_t i) { return static_cast<int>(i * 2); });
	for (size_t i = 0; i < vec.size(); ++i) {
		EXPECT_EQ(vec.asPlainVector()[i], static_cast<int>(i * 2));
	}
}

TEST_F(Vector2DTest, assign_is_alias_for_fill) {
	vec.assign(99);
	for (size_t i = 0; i < vec.size(); ++i) {
		EXPECT_EQ(vec.asPlainVector()[i], 99);
	}
}

TEST_F(Vector2DTest, assign_with_size_resets_to_single_row) {
	vec.assign(10, 77);
	EXPECT_EQ(vec.rows(), 1);
	EXPECT_EQ(vec.cols(), 10);
	for (size_t c = 0; c < 10; ++c) {
		EXPECT_EQ(vec.element(0, c), 77);
	}
}

// ==================== COMPARISON TESTS ====================
TEST_F(Vector2DTest, equality_operator_works) {
	PIVector2D<int> same = vec;
	EXPECT_EQ(vec, same);

	PIVector2D<int> differentRows(ROWS_COUNT_INIT + 1, COLS_COUNT_INIT);
	EXPECT_NE(vec, differentRows);

	PIVector2D<int> differentCols(ROWS_COUNT_INIT, COLS_COUNT_INIT + 1);
	EXPECT_NE(vec, differentCols);

	PIVector2D<int> differentData(ROWS_COUNT_INIT, COLS_COUNT_INIT, 99);
	EXPECT_NE(vec, differentData);
}

// ==================== CONVERSION TESTS ====================
TEST_F(Vector2DTest, toVectors_converts_correctly) {
	auto vectors = vec.toVectors();
	EXPECT_EQ(vectors.size(), ROWS_COUNT_INIT);

	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		EXPECT_EQ(vectors[r].size(), COLS_COUNT_INIT);
		for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
			EXPECT_EQ(vectors[r][c], vec.element(r, c));
		}
	}
}

TEST_F(Vector2DTest, plainVector_returns_underlying_storage) {
	const auto & plain = vec.asPlainVector();
	EXPECT_EQ(plain.size(), vec.size());

	for (size_t i = 0; i < plain.size(); ++i) {
		EXPECT_EQ(plain[i], vec.asPlainVector()[i]);
	}
}

TEST_F(Vector2DTest, toPlainVector_returns_copy) {
	auto copy = vec.toPlainVector();
	EXPECT_EQ(copy.size(), vec.size());
	EXPECT_NE(copy.data(), vec.data()); // Different memory

	for (size_t i = 0; i < copy.size(); ++i) {
		EXPECT_EQ(copy[i], vec.asPlainVector()[i]);
	}
}

// ==================== SWAP TESTS ====================
TEST_F(Vector2DTest, swap_exchanges_contents) {
	PIVector2D<int> other(5, 5, 42);

	size_t oldRows        = vec.rows();
	size_t oldCols        = vec.cols();
	PIVector<int> oldData = vec.asPlainVector();

	vec.swap(other);

	EXPECT_EQ(vec.rows(), 5);
	EXPECT_EQ(vec.cols(), 5);
	for (size_t i = 0; i < vec.size(); ++i) {
		EXPECT_EQ(vec.asPlainVector()[i], 42);
	}

	EXPECT_EQ(other.rows(), oldRows);
	EXPECT_EQ(other.cols(), oldCols);
	EXPECT_EQ(other.asPlainVector(), oldData);
}

// ==================== CLEAR TESTS ====================
TEST_F(Vector2DTest, clear_removes_all_elements) {
	vec.clear();
	EXPECT_TRUE(vec.isEmpty());
	EXPECT_EQ(vec.rows(), 0);
	EXPECT_EQ(vec.cols(), 0);
	EXPECT_EQ(vec.size(), 0);
}

// ==================== TRANSPOSE AND REVERSE TESTS ====================
TEST_F(Vector2DTest, transposed_returns_correct_dimensions) {
	auto transposed = vec.transposed();
	EXPECT_EQ(transposed.rows(), COLS_COUNT_INIT);
	EXPECT_EQ(transposed.cols(), ROWS_COUNT_INIT);

	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
			EXPECT_EQ(transposed.element(c, r), vec.element(r, c));
		}
	}
}

TEST_F(Vector2DTest, reverseRows_reverses_row_order) {
	auto original = vec;
	vec.reverseRows();

	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
			EXPECT_EQ(vec.element(r, c), original.element(ROWS_COUNT_INIT - 1 - r, c));
		}
	}
}

TEST_F(Vector2DTest, reverseColumns_reverses_column_order_in_each_row) {
	auto original = vec;
	vec.reverseColumns();

	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
			EXPECT_EQ(vec.element(r, c), original.element(r, COLS_COUNT_INIT - 1 - c));
		}
	}
}

TEST_F(Vector2DTest, reverseRows_and_reverseColumns_compose_correctly) {
	auto original = vec;
	vec.reverseRows();
	vec.reverseColumns();

	// This should be equivalent to 180-degree rotation
	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
			EXPECT_EQ(vec.element(r, c), original.element(ROWS_COUNT_INIT - 1 - r, COLS_COUNT_INIT - 1 - c));
		}
	}
}

// ==================== RANGE TESTS ====================
TEST_F(Vector2DTest, getRange_returns_submatrix) {
	auto sub = vec.getRange(5, 10, 8, 15);
	EXPECT_EQ(sub.rows(), 10);
	EXPECT_EQ(sub.cols(), 15);

	for (size_t r = 0; r < 10; ++r) {
		for (size_t c = 0; c < 15; ++c) {
			EXPECT_EQ(sub.element(r, c), vec.element(5 + r, 8 + c));
		}
	}
}

TEST_F(Vector2DTest, getRange_with_invalid_params_returns_empty) {
	auto sub1 = vec.getRange(ROWS_COUNT_INIT, 5, 0, 5);
	EXPECT_TRUE(sub1.isEmpty());

	auto sub2 = vec.getRange(0, 5, COLS_COUNT_INIT, 5);
	EXPECT_TRUE(sub2.isEmpty());
}

TEST_F(Vector2DTest, getRange_truncates_out_of_bounds) {
	auto sub = vec.getRange(ROWS_COUNT_INIT - 5, 10, COLS_COUNT_INIT - 5, 10);
	EXPECT_EQ(sub.rows(), 5);
	EXPECT_EQ(sub.cols(), 5);
}

// ==================== FUNCTIONAL PROGRAMMING TESTS ====================
TEST_F(Vector2DTest, map_transforms_elements) {
	auto doubled = vec.map<int>([](const int & e) { return e * 2; });
	EXPECT_EQ(doubled.rows(), vec.rows());
	EXPECT_EQ(doubled.cols(), vec.cols());

	for (size_t r = 0; r < vec.rows(); ++r) {
		for (size_t c = 0; c < vec.cols(); ++c) {
			EXPECT_EQ(doubled.element(r, c), vec.element(r, c) * 2);
		}
	}
}

TEST_F(Vector2DTest, map_changes_type) {
	auto asString = vec.map<PIString>([](const int & e) { return PIString::fromNumber(e); });
	EXPECT_EQ(asString.rows(), vec.rows());
	EXPECT_EQ(asString.cols(), vec.cols());

	for (size_t r = 0; r < vec.rows(); ++r) {
		for (size_t c = 0; c < vec.cols(); ++c) {
			EXPECT_EQ(asString.element(r, c), PIString::fromNumber(vec.element(r, c)));
		}
	}
}

TEST_F(Vector2DTest, mapIndexed_uses_indices) {
	auto indexed = vec.mapIndexed<int>([](size_t r, size_t c, const int & e) { return static_cast<int>(r * 1000 + c); });

	for (size_t r = 0; r < vec.rows(); ++r) {
		for (size_t c = 0; c < vec.cols(); ++c) {
			EXPECT_EQ(indexed.element(r, c), static_cast<int>(r * 1000 + c));
		}
	}
}

TEST_F(Vector2DTest, forEach_readonly_visits_all_elements) {
	size_t count = 0;
	vec.asPlainVector().forEach([&count](const int &) { count++; });
	EXPECT_EQ(count, vec.size());
}

TEST_F(Vector2DTest, forEach_modifying_changes_elements) {
	vec.asPlainVector().forEach([](int & e) { e++; });

	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
			EXPECT_EQ(vec.element(r, c), r * COLS_COUNT_INIT + c + 1);
		}
	}
}

/*
TEST_F(Vector2DTest, forEachIndexed_readonly_uses_indices) {
    bool allCorrect = true;
    vec.forEachIndexed([&allCorrect](size_t r, size_t c, const int & e) {
        if (e != static_cast<int>(r * COLS_COUNT_INIT + c)) allCorrect = false;
    });
    EXPECT_TRUE(allCorrect);
}

TEST_F(Vector2DTest, forEachIndexed_modifying_uses_indices) {
    vec.forEachIndexed([](size_t r, size_t c, int & e) { e = static_cast<int>(r * 1000 + c); });

    for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
        for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
            EXPECT_EQ(vec.element(r, c), static_cast<int>(r * 1000 + c));
        }
    }
}
*/

TEST_F(Vector2DTest, reduce_accumulates_correctly) {
	int sum      = vec.reduce<int>([](const int & e, const int & acc) { return e + acc; });

	int expected = (vec.size() - 1) * vec.size() / 2;
	EXPECT_EQ(sum, expected);
}

TEST_F(Vector2DTest, reduce_with_initial_value) {
	int sum      = vec.reduce<int>([](const int & e, const int & acc) { return e + acc; }, 100);

	int expected = (vec.size() - 1) * vec.size() / 2 + 100;
	EXPECT_EQ(sum, expected);
}

TEST_F(Vector2DTest, reduceIndexed_uses_indices) {
	int sum =
		vec.reduceIndexed<int>([](size_t r, size_t c, const int & e, const int & acc) { return acc + static_cast<int>(r * 1000 + c); });

	int expected = 0;
	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
		for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
			expected += r * 1000 + c;
		}
	}
	EXPECT_EQ(sum, expected);
}

// ==================== REMOVAL TESTS ====================
TEST_F(Vector2DTest, removeRow_removes_specified_row) {
	size_t oldRows  = vec.rows();
	auto rowContent = vec[10].toVector();

	vec.removeRow(10);
	EXPECT_EQ(vec.rows(), oldRows - 1);

	// Check rows after 10 shifted up
	for (size_t r = 10; r < vec.rows(); ++r) {
		for (size_t c = 0; c < vec.cols(); ++c) {
			EXPECT_EQ(vec.element(r, c), (r + 1) * COLS_COUNT_INIT + c);
		}
	}
}

TEST_F(Vector2DTest, removeRow_invalid_index_does_nothing) {
	size_t oldRows = vec.rows();
	vec.removeRow(ROWS_COUNT_INIT + 10);
	EXPECT_EQ(vec.rows(), oldRows);
}

TEST_F(Vector2DTest, removeRow_last_row_works) {
	size_t oldRows = vec.rows();
	vec.removeRow(oldRows - 1);
	EXPECT_EQ(vec.rows(), oldRows - 1);
}

TEST_F(Vector2DTest, removeColumn_removes_specified_column) {
	size_t oldCols = vec.cols();
	vec.removeColumn(15);
	EXPECT_EQ(vec.cols(), oldCols - 1);

	for (size_t r = 0; r < vec.rows(); ++r) {
		for (size_t c = 0; c < 15; ++c) {
			EXPECT_EQ(vec.element(r, c), r * COLS_COUNT_INIT + c);
		}
		for (size_t c = 15; c < vec.cols(); ++c) {
			EXPECT_EQ(vec.element(r, c), r * COLS_COUNT_INIT + c + 1);
		}
	}
}

TEST_F(Vector2DTest, removeColumn_invalid_index_does_nothing) {
	size_t oldCols = vec.cols();
	vec.removeColumn(COLS_COUNT_INIT + 10);
	EXPECT_EQ(vec.cols(), oldCols);
}

TEST_F(Vector2DTest, removeColumn_last_column_works) {
	size_t oldCols = vec.cols();
	vec.removeColumn(oldCols - 1);
	EXPECT_EQ(vec.cols(), oldCols - 1);
}

TEST_F(Vector2DTest, removeRowsWhere_removes_matching_rows) {
	auto isSpecial = [](const PIVector2D<int>::RowConst & row) {
		return row[0] == 999; // First element is 999
	};

	const size_t rowsCont = 5;
	// Add some identifiable rows
	for (size_t r = 0; r < rowsCont; ++r) {
		vec.addRow(PIVector<int>(COLS_COUNT_INIT, 999));
	}
	EXPECT_EQ(vec.filterRows(isSpecial).rows(), rowsCont);

	vec.removeRowsWhere(isSpecial);
	EXPECT_EQ(vec.rows(), ROWS_COUNT_INIT);

	// Verify no rows with 999 remain
	auto res = vec.filterRows(isSpecial);
	EXPECT_TRUE(res.isEmpty());
}

TEST_F(Vector2DTest, removeColumnsWhere_removes_matching_columns) {
	// Make some columns have a distinctive first element
	for (size_t c = 0; c < 5; ++c) {
		vec.element(0, c) = 777;
	}

	auto isSpecial = [](const PIVector2D<int>::ColConst & col) {
		return col[0] == 777; // First element is 777
	};

	size_t oldCols = vec.cols();
	vec.removeColumnsWhere(isSpecial);
	EXPECT_EQ(vec.cols(), oldCols - 5);

	// Verify no columns with 777 in first row remain
	for (size_t c = 0; c < vec.cols(); ++c) {
		EXPECT_NE(vec.element(0, c), 777);
	}
}

// ==================== FILTER TESTS ====================
TEST_F(Vector2DTest, filterRows_returns_only_matching_rows) {
	auto rowsWithEvenFirst = vec.filterRows([](const PIVector2D<int>::RowConst & row) { return row[0] % 2 == 0; });

	// First element of row r is r * COLS_COUNT_INIT
	// This is even for all rows since COLS_COUNT_INIT is even (34)
	EXPECT_EQ(rowsWithEvenFirst.rows(), ROWS_COUNT_INIT);

	auto rowsWithLargeFirst = vec.filterRows([](const PIVector2D<int>::RowConst & row) { return row[0] > 500; });

	// First element > 500 means r * 34 > 500 -> r > 14.7
	EXPECT_EQ(rowsWithLargeFirst.rows(), ROWS_COUNT_INIT - 15);
}

TEST_F(Vector2DTest, filterColumns_returns_only_matching_columns) {
	auto colsWithEvenFirst = vec.filterColumns([](const PIVector2D<int>::ColConst & col) { return col[0] % 2 == 0; });

	// First element of column c is c
	EXPECT_EQ(colsWithEvenFirst.cols(), COLS_COUNT_INIT / 2);
}

TEST_F(Vector2DTest, filterColumns_empty_result_returns_empty) {
	auto noCols = vec.filterColumns([](const PIVector2D<int>::ColConst &) { return false; });
	EXPECT_TRUE(noCols.isEmpty());
}

// ==================== EDGE CASE TESTS ====================
TEST(Vector2DEdgeTest, empty_vector_operations) {
	PIVector2D<int> empty;

	EXPECT_TRUE(empty.isEmpty());
	EXPECT_EQ(empty.rows(), 0);
	EXPECT_EQ(empty.cols(), 0);

	// These should not crash
	empty.clear();
	empty.fill(42);
	empty.transposed();
	empty.reverseRows();
	empty.reverseColumns();

	auto range = empty.getRange(0, 5, 0, 5);
	EXPECT_TRUE(range.isEmpty());

	auto filtered = empty.filterRows([](const PIVector2D<int>::RowConst &) { return true; });
	EXPECT_TRUE(filtered.isEmpty());
}

TEST(Vector2DEdgeTest, single_element_vector) {
	PIVector2D<int> single(1, 1, 42);

	EXPECT_EQ(single.rows(), 1);
	EXPECT_EQ(single.cols(), 1);
	EXPECT_EQ(single.element(0, 0), 42);

	auto row = single[0];
	EXPECT_EQ(row.size(), 1);
	EXPECT_EQ(row[0], 42);

	auto col = single.col(0);
	EXPECT_EQ(col.size(), 1);
	EXPECT_EQ(col[0], 42);

	single.reverseRows(); // Should do nothing
	EXPECT_EQ(single.element(0, 0), 42);

	single.reverseColumns(); // Should do nothing
	EXPECT_EQ(single.element(0, 0), 42);
}

// ==================== OUTPUT TESTS ====================
TEST_F(Vector2DTest, picout_operator_works) {
	// Just test that it compiles and doesn't crash
	PICout s;
	s << vec;
	// No assertion, just ensure it runs
}

#ifdef PIP_STD_IOSTREAM
TEST_F(Vector2DTest, iostream_operator_works) {
	// PIVector2D doesn't have direct iostream operator,
	// but PIVector does, and we can test conversion
	std::stringstream ss;
	ss << vec.plainVector();
	// No assertion, just ensure it runs
}
#endif