#include "defs.h"

double computeGraph(graph* G, graphSDG* SDGdata) {

    VERT_T* endV;
    LONG_T *degree, *numEdges, *pos, *pSums;
    WEIGHT_T* w;
    double elapsed_time;

    elapsed_time = get_seconds();

    LONG_T i, j, u, n, m, tid, nthreads;

    tid = 0;
    nthreads = 1;

    n = N;
    m = M;
    
    if (tid == 0) {
        pos = (LONG_T *) malloc(m*sizeof(LONG_T));
        assert(pos != NULL);
        degree = (LONG_T *) calloc(m, sizeof(LONG_T));
        assert(degree != NULL);
    }
  
    for (i=0; i<m; i++) {
        u = SDGdata->startVertex[i];
        pos[i] = degree[u]++;
    } 
   
   
    if (tid == 0) {
        numEdges = (LONG_T *) malloc((n+1)*sizeof(LONG_T));
        pSums = (LONG_T *) malloc(nthreads*sizeof(LONG_T));
   }

    prefix_sums(degree, numEdges, pSums, n); 
    
    if (tid == 0) {
        free(degree);
        free(pSums);
        //w = (WEIGHT_T *) malloc(m*sizeof(WEIGHT_T));
        endV = (VERT_T *) malloc(m* sizeof(VERT_T));
    }

    for (i=0; i<m; i++) {
        u = SDGdata->startVertex[i];
        j = numEdges[u] + pos[i];
        endV[j] = SDGdata->endVertex[i];
        //w[j] = SDGdata->weight[i]; 
    }
    
 
    if (tid == 0) {
        free(pos);
        G->n = n;
        G->m = m;
        G->numEdges = numEdges;
        G->endV = endV;
        //G->weight = w;
		G->weight = NULL;
    }
    /* Verification */
#if 0 
    fprintf(stderr, "SDG data:\n");
    for (int i=0; i<SDGdata->m; i++) {
        fprintf(stderr, "[%ld %ld %ld] ", SDGdata->startVertex[i], 
                SDGdata->endVertex[i], SDGdata->weight[i]);
    }
 
    fprintf(stderr, "\n");

    for (int i=0; i<G->n + 1; i++) {
        fprintf(stderr, "[%ld] ", G->numEdges[i]);
    }
    
    fprintf(stderr, "\nGraph:\n");
    for (int i=0; i<G->n; i++) {
        for (int j=G->numEdges[i]; j<G->numEdges[i+1]; j++) {
            fprintf(stderr, "[%ld %ld %ld] ", i, G->endV[j], G->weight[j]);
        }
    }
#endif 
    
    free(SDGdata->startVertex);
    free(SDGdata->endVertex);
    free(SDGdata->weight);
    
    elapsed_time = get_seconds() - elapsed_time; 
    
    return elapsed_time;
}