/* dcel.c
 *
 * Created by Rory Healy (healyr@student.unimelb.edu.au)
 * Created on 25th August 2021
 * Last modified 25th August 2021
 *
 * Contains functions for the DCEL data structure, including creating, 
 * splitting an edge, and identifying towers in faces.
 *
 */

#ifndef DCEL_HEADER
#include "dcel.h"
#endif

#ifndef COMMON_HEADER
#include "common.h"
#endif

struct halfEdge {
    halfEdge_t *previous;
    halfEdge_t *next;
    halfEdge_t *twin;
    int face;
    int edge;
};

struct vertex {
    double x;
    double y;
};

struct edge {
    halfEdge_t halfEdge;
};

struct face {
    halfEdge_t start;
};

/* Reads the polygon file and stores the information in the vertices array. */
vertex_t **readPolygon(vertex_t **vertices, FILE *polygonFile, int *numVertices) {
    double currentX, currentY;
    int maxSizeVertices = 1;
    while ((fscanf(polygonFile, "%lf %lf", &currentX, &currentY)) != EOF) {
        /* Check if there enough space in the towers array */
        if (*numVertices == maxSizeVertices) {
            maxSizeVertices *= 2;
            vertex_t **temp = realloc(vertices, maxSizeVertices * sizeof(*vertices));
            checkNullPointer(temp);
            vertices = temp;
        }

        /* The current vertex being filled in with information */
        vertices[*numVertices] = malloc(sizeof(*vertices[*numVertices]));
        vertices[*numVertices]->x = currentX;
        vertices[*numVertices]->y = currentY;
        *numVertices += 1;
    }
    return vertices;
}

void freeVertices(vertex_t **vertices, int numVertices) {
    for (int i = 0; i < numVertices; i++) {
        free(vertices[i]);
    }
    free(vertices);
}