#include "rb_lapack.h"

extern VOID cungqr_(integer* m, integer* n, integer* k, complex* a, integer* lda, complex* tau, complex* work, integer* lwork, integer* info);


static VALUE
rblapack_cungqr(int argc, VALUE *argv, VALUE self){
  VALUE rblapack_m;
  integer m; 
  VALUE rblapack_a;
  complex *a; 
  VALUE rblapack_tau;
  complex *tau; 
  VALUE rblapack_lwork;
  integer lwork; 
  VALUE rblapack_work;
  complex *work; 
  VALUE rblapack_info;
  integer info; 
  VALUE rblapack_a_out__;
  complex *a_out__;

  integer lda;
  integer n;
  integer k;

  VALUE rblapack_options;
  if (argc > 0 && TYPE(argv[argc-1]) == T_HASH) {
    argc--;
    rblapack_options = argv[argc];
    if (rb_hash_aref(rblapack_options, sHelp) == Qtrue) {
      printf("%s\n", "USAGE:\n  work, info, a = NumRu::Lapack.cungqr( m, a, tau, [:lwork => lwork, :usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n      SUBROUTINE CUNGQR( M, N, K, A, LDA, TAU, WORK, LWORK, INFO )\n\n*  Purpose\n*  =======\n*\n*  CUNGQR generates an M-by-N complex matrix Q with orthonormal columns,\n*  which is defined as the first N columns of a product of K elementary\n*  reflectors of order M\n*\n*        Q  =  H(1) H(2) . . . H(k)\n*\n*  as returned by CGEQRF.\n*\n\n*  Arguments\n*  =========\n*\n*  M       (input) INTEGER\n*          The number of rows of the matrix Q. M >= 0.\n*\n*  N       (input) INTEGER\n*          The number of columns of the matrix Q. M >= N >= 0.\n*\n*  K       (input) INTEGER\n*          The number of elementary reflectors whose product defines the\n*          matrix Q. N >= K >= 0.\n*\n*  A       (input/output) COMPLEX array, dimension (LDA,N)\n*          On entry, the i-th column must contain the vector which\n*          defines the elementary reflector H(i), for i = 1,2,...,k, as\n*          returned by CGEQRF in the first k columns of its array\n*          argument A.\n*          On exit, the M-by-N matrix Q.\n*\n*  LDA     (input) INTEGER\n*          The first dimension of the array A. LDA >= max(1,M).\n*\n*  TAU     (input) COMPLEX array, dimension (K)\n*          TAU(i) must contain the scalar factor of the elementary\n*          reflector H(i), as returned by CGEQRF.\n*\n*  WORK    (workspace/output) COMPLEX array, dimension (MAX(1,LWORK))\n*          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.\n*\n*  LWORK   (input) INTEGER\n*          The dimension of the array WORK. LWORK >= max(1,N).\n*          For optimum performance LWORK >= N*NB, where NB is the\n*          optimal blocksize.\n*\n*          If LWORK = -1, then a workspace query is assumed; the routine\n*          only calculates the optimal size of the WORK array, returns\n*          this value as the first entry of the WORK array, and no error\n*          message related to LWORK is issued by XERBLA.\n*\n*  INFO    (output) INTEGER\n*          = 0:  successful exit\n*          < 0:  if INFO = -i, the i-th argument has an illegal value\n*\n\n*  =====================================================================\n*\n\n");
      return Qnil;
    }
    if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
      printf("%s\n", "USAGE:\n  work, info, a = NumRu::Lapack.cungqr( m, a, tau, [:lwork => lwork, :usage => usage, :help => help])\n");
      return Qnil;
    } 
  } else
    rblapack_options = Qnil;
  if (argc != 3 && argc != 4)
    rb_raise(rb_eArgError,"wrong number of arguments (%d for 3)", argc);
  rblapack_m = argv[0];
  rblapack_a = argv[1];
  rblapack_tau = argv[2];
  if (argc == 4) {
    rblapack_lwork = argv[3];
  } else if (rblapack_options != Qnil) {
    rblapack_lwork = rb_hash_aref(rblapack_options, ID2SYM(rb_intern("lwork")));
  } else {
    rblapack_lwork = Qnil;
  }

  m = NUM2INT(rblapack_m);
  if (!NA_IsNArray(rblapack_tau))
    rb_raise(rb_eArgError, "tau (3th argument) must be NArray");
  if (NA_RANK(rblapack_tau) != 1)
    rb_raise(rb_eArgError, "rank of tau (3th argument) must be %d", 1);
  k = NA_SHAPE0(rblapack_tau);
  if (NA_TYPE(rblapack_tau) != NA_SCOMPLEX)
    rblapack_tau = na_change_type(rblapack_tau, NA_SCOMPLEX);
  tau = NA_PTR_TYPE(rblapack_tau, complex*);
  if (!NA_IsNArray(rblapack_a))
    rb_raise(rb_eArgError, "a (2th argument) must be NArray");
  if (NA_RANK(rblapack_a) != 2)
    rb_raise(rb_eArgError, "rank of a (2th argument) must be %d", 2);
  lda = NA_SHAPE0(rblapack_a);
  n = NA_SHAPE1(rblapack_a);
  if (NA_TYPE(rblapack_a) != NA_SCOMPLEX)
    rblapack_a = na_change_type(rblapack_a, NA_SCOMPLEX);
  a = NA_PTR_TYPE(rblapack_a, complex*);
  if (rblapack_lwork == Qnil)
    lwork = n;
  else {
    lwork = NUM2INT(rblapack_lwork);
  }
  {
    na_shape_t shape[1];
    shape[0] = MAX(1,lwork);
    rblapack_work = na_make_object(NA_SCOMPLEX, 1, shape, cNArray);
  }
  work = NA_PTR_TYPE(rblapack_work, complex*);
  {
    na_shape_t shape[2];
    shape[0] = lda;
    shape[1] = n;
    rblapack_a_out__ = na_make_object(NA_SCOMPLEX, 2, shape, cNArray);
  }
  a_out__ = NA_PTR_TYPE(rblapack_a_out__, complex*);
  MEMCPY(a_out__, a, complex, NA_TOTAL(rblapack_a));
  rblapack_a = rblapack_a_out__;
  a = a_out__;

  cungqr_(&m, &n, &k, a, &lda, tau, work, &lwork, &info);

  rblapack_info = INT2NUM(info);
  return rb_ary_new3(3, rblapack_work, rblapack_info, rblapack_a);
}

void
init_lapack_cungqr(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
  sHelp = sH;
  sUsage = sU;
  rblapack_ZERO = zero;

  rb_define_module_function(mLapack, "cungqr", rblapack_cungqr, -1);
}
