#include <stdlib.h>
#include <stdio.h>
#include "matrix_io.h"

int call_dgels(matrix_t * A, vector_t * b);

int main(int argc, char *argv[]) {

  /* Number of input arguments: /.lwork argv[1] argv[2] argv[3] */
  if (argc != 4) {
    fprintf(stderr,"Usage: %s A b x\n", argv[0]);
    return EXIT_FAILURE;
  }

  /* Read the text files */
  matrix_t * A = read_matrix(argv[1]);
  vector_t * b = read_vector(argv[2]);

  /* Input checks: If pointers is NULL */
  if((A == NULL) || (b == NULL)){
    if(A == NULL){
      FILE_ERR(argv[1]);
      free(b);
    }
    else{
      FILE_ERR(argv[2]);
      free(A);
    }
    return EXIT_FAILURE;
  }

  /* Using dgels() to solve LU and get info */
  int info = call_dgels(A,b);

  /* Input checks: For invalid info values */
  switch(info){
    case -12:
      INPUT_ERR;
      free(A);
      free(b);
      return EXIT_FAILURE;

    case -13:
      fprintf(stderr,"Matrix A is not a tall matrix, so m<n");
      free(A);
      free(b);
      return EXIT_FAILURE;

    case -14:
      fprintf(stderr, "The dimensions of A and b are incompatible");
      free(A);
      free(b);
      return EXIT_FAILURE;

    case -15:
      MEM_ERR;
      free(A);
      free(b);
      return EXIT_FAILURE;
  }

  /* Input checks taken from doc of dgels_() */
  if(info != 0){
    if(info < 0){
      fprintf(stderr,"INFO = %d, the %d-th argument had an illegal value\n", info, info);
    }
    else{
      fprintf(stderr,"INFO = %d and because of that, A does not have full rank\n", info);
    }
    free(A);
    free(b);
    return EXIT_FAILURE;
  }

  /* Allocation of x */
  vector_t * x = malloc_vector(A->n);
  if(x == NULL){
		MEM_ERR;
    free(A);
    free(b);
  	return EXIT_FAILURE;
	}

  /* Write values of b into x. Vector x should be n long */
  for(int i=0; i<A->n; i++){
    x->v[i] = b->v[i];
  }

  /* Making the output file */
  if(write_vector(argv[3], x) != 0){
    fprintf(stderr,"%s: failed to write file %s\n",__func__,argv[3]);
    free(A);
    free(b);
    free(x);
    return EXIT_FAILURE;
  }

  /* Free the memory */
  free(A);
  free(b);
  free(x);

  return EXIT_SUCCESS;
}