#include "fracture.h"

bool break_edge(finst *instance, unsigned int edge, cholmod_common *c) {
	instance->fuses[edge] = true;
	instance->num_remaining_edges--;

	unsigned int v1 = instance->network->edges_to_verts_break[2 * edge];
	unsigned int v2 = instance->network->edges_to_verts_break[2 * edge + 1];

	update_factor(instance->factor, v1, v2, c);


	unsigned int w1 = instance->network->edges_to_verts[2 * edge];
	unsigned int w2 = instance->network->edges_to_verts[2 * edge + 1];
	unsigned int dw1 = instance->network->dual_edges_to_verts[2 * edge];
	unsigned int dw2 = instance->network->dual_edges_to_verts[2 * edge + 1];

	if (instance->network->boundary != TORUS_BOUND) {

		unsigned int tw1 = w1 > w2 ? w1 : w2;
		unsigned int tw2 = w1 > w2 ? w2 : w1;

		CHOL_INT *lap_p = (CHOL_INT *)instance->adjacency->p;
		CHOL_INT *lap_i = (CHOL_INT *)instance->adjacency->i;
		double *lap_x = (double *)instance->adjacency->x;

		for (int i = 0; i < lap_p[tw1 + 1] - lap_p[tw1]; i++) {
			if (lap_i[lap_p[tw1] + i] == tw2)
				lap_x[lap_p[tw1] + i] = 0;
		}
		for (int i = 0; i < lap_p[tw2 + 1] - lap_p[tw2]; i++) {
			if (lap_i[lap_p[tw2] + i] == tw1)
				lap_x[lap_p[tw2] + i] = 0;
		}

		int old_num_components = instance->num_components;

		instance->num_components = update_components(
				instance->adjacency, instance->marks, old_num_components, (int)tw1,
				(int)tw2, 0);
	}

	if (instance->network->boundary == TORUS_BOUND) {
		if (instance->dual_marks[dw1] == instance->dual_marks[dw2]) {
			int **cycles = (int **)malloc(2*instance->network->num_edges * sizeof(int *));
			unsigned int num_cycles = find_cycles(instance->network->num_edges, instance->fuses, instance->network->dual_edges_to_verts, instance->network->dual_verts_to_edges_ind, instance->network->dual_verts_to_edges, cycles);

			for (unsigned int i = 0; i < num_cycles; i++) {
				int x_num_crossings = 0;
				int y_num_crossings = 0;
				int ee; unsigned int j = 0;
				while ((ee = cycles[2*i][j]) >= 0) {
					int side = cycles[2*i+1][j];
					j++;
					unsigned int v1, v2;
					double v1x, v1y, v2x, v2y;
					v1 = instance->network->dual_edges_to_verts[2 * ee + !side];
					v2 = instance->network->dual_edges_to_verts[2 * ee + side];
					v1x = instance->network->dual_vert_coords[2 * v1];
					v1y = instance->network->dual_vert_coords[2 * v1 + 1];
					v2x = instance->network->dual_vert_coords[2 * v2];
					v2y = instance->network->dual_vert_coords[2 * v2 + 1];
					double dx = v1x - v2x;
					double dy = v1y - v2y;
					if (((v1x > 0.5 && v2x < 0.5) || (v1x < 0.5 && v2x > 0.5)) && fabs(dx) < 0.5) {
						x_num_crossings += dx > 0 ? 1 : -1;
					}
					if (((v1y > 0.5 && v2y < 0.5) || (v1y < 0.5 && v2y > 0.5)) && fabs(dy) < 0.5) {
						y_num_crossings += dy > 0 ? 1 : -1;
					}
				}
				if ((abs(y_num_crossings) == 0 && abs(x_num_crossings) > 0) || (abs(y_num_crossings) > 0 && abs(x_num_crossings) > 0 && num_cycles > 1)) {
					instance->num_components = 2;
				}
				free(cycles[2*i]);
				free(cycles[2*i+1]);
			}
			free(cycles);
		}

		unsigned int *tmp_marks = get_clusters(instance, c);
		free(instance->dual_marks);
		instance->dual_marks = tmp_marks;
	}


	return true;
}