//
//  Convolutions.cpp
//
//  Created by Marc Melikyan on 4/6/21.
//

#include "../convolutions/convolutions.h"
#include "../lin_alg/lin_alg.h"
#include "../stat/stat.h"
#include <cmath>
#include <iostream>

/*
std::vector<std::vector<real_t>> MLPPConvolutions::convolve_2d(std::vector<std::vector<real_t>> input, std::vector<std::vector<real_t>> filter, int S, int P) {
	MLPPLinAlg alg;
	std::vector<std::vector<real_t>> feature_map;
	uint32_t N = input.size();
	uint32_t F = filter.size();
	uint32_t map_size = (N - F + 2 * P) / S + 1; // This is computed as ⌊map_size⌋ by def- thanks C++!

	if (P != 0) {
		std::vector<std::vector<real_t>> padded_input;
		padded_input.resize(N + 2 * P);
		for (uint32_t i = 0; i < padded_input.size(); i++) {
			padded_input[i].resize(N + 2 * P);
		}
		for (uint32_t i = 0; i < padded_input.size(); i++) {
			for (uint32_t j = 0; j < padded_input[i].size(); j++) {
				if (i - P < 0 || j - P < 0 || i - P > input.size() - 1 || j - P > input[0].size() - 1) {
					padded_input[i][j] = 0;
				} else {
					padded_input[i][j] = input[i - P][j - P];
				}
			}
		}
		input.resize(padded_input.size());
		for (uint32_t i = 0; i < padded_input.size(); i++) {
			input[i].resize(padded_input[i].size());
		}
		input = padded_input;
	}

	feature_map.resize(map_size);
	for (uint32_t i = 0; i < map_size; i++) {
		feature_map[i].resize(map_size);
	}

	for (uint32_t i = 0; i < map_size; i++) {
		for (uint32_t j = 0; j < map_size; j++) {
			std::vector<real_t> convolving_input;
			for (uint32_t k = 0; k < F; k++) {
				for (uint32_t p = 0; p < F; p++) {
					if (i == 0 && j == 0) {
						convolving_input.push_back(input[i + k][j + p]);
					} else if (i == 0) {
						convolving_input.push_back(input[i + k][j + (S - 1) + p]);
					} else if (j == 0) {
						convolving_input.push_back(input[i + (S - 1) + k][j + p]);
					} else {
						convolving_input.push_back(input[i + (S - 1) + k][j + (S - 1) + p]);
					}
				}
			}
			feature_map[i][j] = alg.dot(convolving_input, alg.flatten(filter));
		}
	}
	return feature_map;
}

std::vector<std::vector<std::vector<real_t>>> MLPPConvolutions::convolve_3d(std::vector<std::vector<std::vector<real_t>>> input, std::vector<std::vector<std::vector<real_t>>> filter, int S, int P) {
	MLPPLinAlg alg;
	std::vector<std::vector<std::vector<real_t>>> feature_map;
	uint32_t N = input[0].size();
	uint32_t F = filter[0].size();
	uint32_t C = filter.size() / input.size();
	uint32_t map_size = (N - F + 2 * P) / S + 1; // This is computed as ⌊map_size⌋ by def.

	if (P != 0) {
		for (uint32_t c = 0; c < input.size(); c++) {
			std::vector<std::vector<real_t>> padded_input;
			padded_input.resize(N + 2 * P);
			for (uint32_t i = 0; i < padded_input.size(); i++) {
				padded_input[i].resize(N + 2 * P);
			}
			for (uint32_t i = 0; i < padded_input.size(); i++) {
				for (uint32_t j = 0; j < padded_input[i].size(); j++) {
					if (i - P < 0 || j - P < 0 || i - P > input[c].size() - 1 || j - P > input[c][0].size() - 1) {
						padded_input[i][j] = 0;
					} else {
						padded_input[i][j] = input[c][i - P][j - P];
					}
				}
			}
			input[c].resize(padded_input.size());
			for (uint32_t i = 0; i < padded_input.size(); i++) {
				input[c][i].resize(padded_input[i].size());
			}
			input[c] = padded_input;
		}
	}

	feature_map.resize(C);
	for (uint32_t i = 0; i < feature_map.size(); i++) {
		feature_map[i].resize(map_size);
		for (uint32_t j = 0; j < feature_map[i].size(); j++) {
			feature_map[i][j].resize(map_size);
		}
	}

	for (uint32_t c = 0; c < C; c++) {
		for (uint32_t i = 0; i < map_size; i++) {
			for (uint32_t j = 0; j < map_size; j++) {
				std::vector<real_t> convolving_input;
				for (uint32_t t = 0; t < input.size(); t++) {
					for (uint32_t k = 0; k < F; k++) {
						for (uint32_t p = 0; p < F; p++) {
							if (i == 0 && j == 0) {
								convolving_input.push_back(input[t][i + k][j + p]);
							} else if (i == 0) {
								convolving_input.push_back(input[t][i + k][j + (S - 1) + p]);
							} else if (j == 0) {
								convolving_input.push_back(input[t][i + (S - 1) + k][j + p]);
							} else {
								convolving_input.push_back(input[t][i + (S - 1) + k][j + (S - 1) + p]);
							}
						}
					}
				}
				feature_map[c][i][j] = alg.dot(convolving_input, alg.flatten(filter));
			}
		}
	}
	return feature_map;
}

std::vector<std::vector<real_t>> MLPPConvolutions::pool_2d(std::vector<std::vector<real_t>> input, int F, int S, std::string type) {
	MLPPLinAlg alg;
	std::vector<std::vector<real_t>> pooled_map;
	uint32_t N = input.size();
	uint32_t map_size = floor((N - F) / S + 1);

	pooled_map.resize(map_size);
	for (uint32_t i = 0; i < map_size; i++) {
		pooled_map[i].resize(map_size);
	}

	for (uint32_t i = 0; i < map_size; i++) {
		for (uint32_t j = 0; j < map_size; j++) {
			std::vector<real_t> pooling_input;
			for (int k = 0; k < F; k++) {
				for (int p = 0; p < F; p++) {
					if (i == 0 && j == 0) {
						pooling_input.push_back(input[i + k][j + p]);
					} else if (i == 0) {
						pooling_input.push_back(input[i + k][j + (S - 1) + p]);
					} else if (j == 0) {
						pooling_input.push_back(input[i + (S - 1) + k][j + p]);
					} else {
						pooling_input.push_back(input[i + (S - 1) + k][j + (S - 1) + p]);
					}
				}
			}
			if (type == "Average") {
				MLPPStat stat;
				pooled_map[i][j] = stat.mean(pooling_input);
			} else if (type == "Min") {
				pooled_map[i][j] = alg.min(pooling_input);
			} else {
				pooled_map[i][j] = alg.max(pooling_input);
			}
		}
	}
	return pooled_map;
}

std::vector<std::vector<std::vector<real_t>>> MLPPConvolutions::pool_3d(std::vector<std::vector<std::vector<real_t>>> input, int F, int S, std::string type) {
	std::vector<std::vector<std::vector<real_t>>> pooled_map;
	for (uint32_t i = 0; i < input.size(); i++) {
		pooled_map.push_back(pool_2d(input[i], F, S, type));
	}
	return pooled_map;
}

real_t MLPPConvolutions::global_pool_2d(std::vector<std::vector<real_t>> input, std::string type) {
	MLPPLinAlg alg;
	if (type == "Average") {
		MLPPStat stat;
		return stat.mean(alg.flatten(input));
	} else if (type == "Min") {
		return alg.min(alg.flatten(input));
	} else {
		return alg.max(alg.flatten(input));
	}
}

std::vector<real_t> MLPPConvolutions::global_pool_3d(std::vector<std::vector<std::vector<real_t>>> input, std::string type) {
	std::vector<real_t> pooled_map;
	for (uint32_t i = 0; i < input.size(); i++) {
		pooled_map.push_back(global_pool_2d(input[i], type));
	}
	return pooled_map;
}

real_t MLPPConvolutions::gaussian_2d(real_t x, real_t y, real_t std) {
	real_t std_sq = std * std;
	return 1 / (2 * Math_PI * std_sq) * std::exp(-(x * x + y * y) / 2 * std_sq);
}

std::vector<std::vector<real_t>> MLPPConvolutions::gaussian_filter_2d(int size, real_t std) {
	std::vector<std::vector<real_t>> filter;
	filter.resize(size);
	for (uint32_t i = 0; i < filter.size(); i++) {
		filter[i].resize(size);
	}
	for (int i = 0; i < size; i++) {
		for (int j = 0; j < size; j++) {
			filter[i][j] = gaussian_2d(i - (size - 1) / 2, (size - 1) / 2 - j, std);
		}
	}
	return filter;
}


// Indeed a filter could have been used for this purpose, but I decided that it would've just
// been easier to carry out the calculation explicitly, mainly because it is more informative,
// and also because my convolution algorithm is only built for filters with equally sized
// heights and widths.

std::vector<std::vector<real_t>> MLPPConvolutions::dx(std::vector<std::vector<real_t>> input) {
	std::vector<std::vector<real_t>> deriv; // We assume a gray scale image.
	deriv.resize(input.size());
	for (uint32_t i = 0; i < deriv.size(); i++) {
		deriv[i].resize(input[i].size());
	}

	for (uint32_t i = 0; i < input.size(); i++) {
		for (uint32_t j = 0; j < input[i].size(); j++) {
			if (j != 0 && j != input.size() - 1) {
				deriv[i][j] = input[i][j + 1] - input[i][j - 1];
			} else if (j == 0) {
				deriv[i][j] = input[i][j + 1] - 0; // Implicit zero-padding
			} else {
				deriv[i][j] = 0 - input[i][j - 1]; // Implicit zero-padding
			}
		}
	}
	return deriv;
}

std::vector<std::vector<real_t>> MLPPConvolutions::dy(std::vector<std::vector<real_t>> input) {
	std::vector<std::vector<real_t>> deriv;
	deriv.resize(input.size());
	for (uint32_t i = 0; i < deriv.size(); i++) {
		deriv[i].resize(input[i].size());
	}

	for (uint32_t i = 0; i < input.size(); i++) {
		for (uint32_t j = 0; j < input[i].size(); j++) {
			if (i != 0 && i != input.size() - 1) {
				deriv[i][j] = input[i - 1][j] - input[i + 1][j];
			} else if (i == 0) {
				deriv[i][j] = 0 - input[i + 1][j]; // Implicit zero-padding
			} else {
				deriv[i][j] = input[i - 1][j] - 0; // Implicit zero-padding
			}
		}
	}
	return deriv;
}

std::vector<std::vector<real_t>> MLPPConvolutions::grad_magnitude(std::vector<std::vector<real_t>> input) {
	MLPPLinAlg alg;
	std::vector<std::vector<real_t>> x_deriv_2 = alg.hadamard_product(dx(input), dx(input));
	std::vector<std::vector<real_t>> y_deriv_2 = alg.hadamard_product(dy(input), dy(input));
	return alg.sqrt(alg.addition(x_deriv_2, y_deriv_2));
}

std::vector<std::vector<real_t>> MLPPConvolutions::grad_orientation(std::vector<std::vector<real_t>> input) {
	std::vector<std::vector<real_t>> deriv;
	deriv.resize(input.size());
	for (uint32_t i = 0; i < deriv.size(); i++) {
		deriv[i].resize(input[i].size());
	}

	std::vector<std::vector<real_t>> x_deriv = dx(input);
	std::vector<std::vector<real_t>> y_deriv = dy(input);
	for (uint32_t i = 0; i < deriv.size(); i++) {
		for (uint32_t j = 0; j < deriv[i].size(); j++) {
			deriv[i][j] = std::atan2(y_deriv[i][j], x_deriv[i][j]);
		}
	}
	return deriv;
}

std::vector<std::vector<std::vector<real_t>>> MLPPConvolutions::compute_m(std::vector<std::vector<real_t>> input) {
	real_t const SIGMA = 1;
	real_t const GAUSSIAN_SIZE = 3;

	real_t const GAUSSIAN_PADDING = ((input.size() - 1) + GAUSSIAN_SIZE - input.size()) / 2; // Convs must be same.
	std::cout << GAUSSIAN_PADDING << std::endl;
	MLPPLinAlg alg;
	std::vector<std::vector<real_t>> x_deriv = dx(input);
	std::vector<std::vector<real_t>> y_deriv = dy(input);

	std::vector<std::vector<real_t>> gaussian_filter = gaussian_filter_2d(GAUSSIAN_SIZE, SIGMA); // Sigma of 1, size of 3.
	std::vector<std::vector<real_t>> xx_deriv = convolve_2d(alg.hadamard_product(x_deriv, x_deriv), gaussian_filter, 1, GAUSSIAN_PADDING);
	std::vector<std::vector<real_t>> yy_deriv = convolve_2d(alg.hadamard_product(y_deriv, y_deriv), gaussian_filter, 1, GAUSSIAN_PADDING);
	std::vector<std::vector<real_t>> xy_deriv = convolve_2d(alg.hadamard_product(x_deriv, y_deriv), gaussian_filter, 1, GAUSSIAN_PADDING);

	std::vector<std::vector<std::vector<real_t>>> M = { xx_deriv, yy_deriv, xy_deriv };
	return M;
}
std::vector<std::vector<std::string>> MLPPConvolutions::harris_corner_detection(std::vector<std::vector<real_t>> input) {
	real_t const k = 0.05; // Empirically determined wherein k -> [0.04, 0.06], though conventionally 0.05 is typically used as well.
	MLPPLinAlg alg;
	std::vector<std::vector<std::vector<real_t>>> M = compute_m(input);
	std::vector<std::vector<real_t>> det = alg.subtraction(alg.hadamard_product(M[0], M[1]), alg.hadamard_product(M[2], M[2]));
	std::vector<std::vector<real_t>> trace = alg.addition(M[0], M[1]);

	// The reason this is not a scalar is because xx_deriv, xy_deriv, yx_deriv, and yy_deriv are not scalars.
	std::vector<std::vector<real_t>> r = alg.subtraction(det, alg.scalarMultiply(k, alg.hadamard_product(trace, trace)));
	std::vector<std::vector<std::string>> imageTypes;
	imageTypes.resize(r.size());
	alg.printMatrix(r);
	for (uint32_t i = 0; i < r.size(); i++) {
		imageTypes[i].resize(r[i].size());
		for (uint32_t j = 0; j < r[i].size(); j++) {
			if (r[i][j] > 0) {
				imageTypes[i][j] = "C";
			} else if (r[i][j] < 0) {
				imageTypes[i][j] = "E";
			} else {
				imageTypes[i][j] = "N";
			}
		}
	}
	return imageTypes;
}

std::vector<std::vector<real_t>> MLPPConvolutions::get_prewitt_horizontal() {
	return _prewitt_horizontal;
}
std::vector<std::vector<real_t>> MLPPConvolutions::get_prewitt_vertical() {
	return _prewitt_vertical;
}
std::vector<std::vector<real_t>> MLPPConvolutions::get_sobel_horizontal() {
	return _sobel_horizontal;
}
std::vector<std::vector<real_t>> MLPPConvolutions::get_sobel_vertical() {
	return _sobel_vertical;
}
std::vector<std::vector<real_t>> MLPPConvolutions::get_scharr_horizontal() {
	return _scharr_horizontal;
}
std::vector<std::vector<real_t>> MLPPConvolutions::get_scharr_vertical() {
	return _scharr_vertical;
}
std::vector<std::vector<real_t>> MLPPConvolutions::get_roberts_horizontal() {
	return _roberts_horizontal;
}
std::vector<std::vector<real_t>> MLPPConvolutions::get_roberts_vertical() {
	return _roberts_vertical;
}
*/

MLPPConvolutions::MLPPConvolutions() {
	/*
	_prewitt_horizontal = { { 1, 1, 1 }, { 0, 0, 0 }, { -1, -1, -1 } };
	_prewitt_vertical = { { 1, 0, -1 }, { 1, 0, -1 }, { 1, 0, -1 } };
	_sobel_horizontal = { { 1, 2, 1 }, { 0, 0, 0 }, { -1, -2, -1 } };
	_sobel_vertical = { { -1, 0, 1 }, { -2, 0, 2 }, { -1, 0, 1 } };
	_scharr_horizontal = { { 3, 10, 3 }, { 0, 0, 0 }, { -3, -10, -3 } };
	_scharr_vertical = { { 3, 0, -3 }, { 10, 0, -10 }, { 3, 0, -3 } };
	_roberts_horizontal = { { 0, 1 }, { -1, 0 } };
	_roberts_vertical = { { 1, 0 }, { 0, -1 } };
	*/
}

void MLPPConvolutions::_bind_methods() {
}