/*
 *    This file is part of CasADi.
 *
 *    CasADi -- A symbolic framework for dynamic optimization.
 *    Copyright (C) 2010-2014 Joel Andersson, Joris Gillis, Moritz Diehl,
 *                            KU Leuven. All rights reserved.
 *    Copyright (C) 2011-2014 Greg Horn
 *
 *    CasADi is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation; either
 *    version 3 of the License, or (at your option) any later version.
 *
 *    CasADi is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public
 *    License along with CasADi; if not, write to the Free Software
 *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */


#include "linsol_internal.hpp"
#include "mx_node.hpp"
#include "filesystem_impl.hpp"

namespace casadi {

  Linsol::Linsol() {
  }

  Linsol::Linsol(const std::string& name, const std::string& solver,
                 const Sparsity& sp, const Dict& opts) {
    own(LinsolInternal::getPlugin(solver).creator(name, sp));
    (*this)->construct(opts);
  }

  LinsolInternal* Linsol::operator->() {
    return static_cast<LinsolInternal*>(SharedObject::operator->());
  }

  const LinsolInternal* Linsol::operator->() const {
    return static_cast<const LinsolInternal*>(SharedObject::operator->());
  }

  bool Linsol::test_cast(const SharedObjectInternal* ptr) {
    return dynamic_cast<const LinsolInternal*>(ptr)!=nullptr;
  }

  bool Linsol::has_plugin(const std::string& name) {
    return LinsolInternal::has_plugin(name);
  }

  void Linsol::load_plugin(const std::string& name) {
    LinsolInternal::load_plugin(name);
  }

  std::string Linsol::doc(const std::string& name) {
    return LinsolInternal::getPlugin(name).doc;
  }

  std::string Linsol::plugin_name() const {
    return (*this)->plugin_name();
  }

  const Sparsity& Linsol::sparsity() const {
    return (*this)->sp_;
  }

  DM Linsol::solve(const DM& A, const DM& B, bool tr) const {
    casadi_assert(A.size1()==B.size1(),
      "Linsol::solve: Dimension mismatch. A and b must have matching row count. "
      "Got " + A.dim() + " and " + B.dim() + ".");

    scoped_checkout<Linsol> mem(*this);
    auto m = static_cast<LinsolMemory*>((*this)->memory(mem));

    // Reset statistics
    for (auto&& s : m->fstats) s.second.reset();
    if (m->t_total) m->t_total->tic();
    // Symbolic factorization
    if (sfact(A.ptr(), mem)) casadi_error("Linsol::solve: 'sfact' failed");

    // Numeric factorization
    if (nfact(A.ptr(), mem)) casadi_error("Linsol::solve: 'nfact' failed");

    // Solve
    DM x = densify(B);
    if (solve(A.ptr(), x.ptr(), x.size2(), false, mem))
      casadi_error("Linsol::solve: 'solve' failed");
    // Show statistics
    if (m->t_total) m->t_total->toc();

    (*this)->print_time(m->fstats);
    return x;
  }

  MX Linsol::solve(const MX& A, const MX& B, bool tr) const {
    return A->get_solve(B, tr, *this);
  }

  void Linsol::sfact(const DM& A) const {
    if (A.sparsity()!=sparsity()) return sfact(project(A, sparsity()));
    if (sfact(A.ptr())) casadi_error("'sfact' failed");
  }

  int Linsol::sfact(const double* A, int mem) const {
    if (A==nullptr) return 1;
    auto m = static_cast<LinsolMemory*>((*this)->memory(mem));

    // Factorization will be needed after this step
    m->is_sfact = m->is_nfact = false;

    if (m->t_total) m->fstats.at("sfact").tic();
    // Perform pivoting
    if ((*this)->sfact(m, A)) return 1;
    if (m->t_total) m->fstats.at("sfact").toc();

    // Mark as (successfully) pivoted
    m->is_sfact = true;
    return 0;
  }

  void Linsol::nfact(const DM& A) const {
    if (A.sparsity()!=sparsity()) return nfact(project(A, sparsity()));
    if (nfact(A.ptr())) casadi_error("'nfact' failed");
  }

  int Linsol::nfact(const double* A, int mem) const {
    if (A==nullptr) return 1;
    auto m = static_cast<LinsolMemory*>((*this)->memory(mem));

    // Perform pivoting, if required
    if (!m->is_sfact) {
      if (sfact(A, mem)) return 1;
    }

    m->is_nfact = false;
    if (m->t_total) m->fstats.at("nfact").tic();
    int flag = (*this)->nfact(m, A);
    if (m->t_total) m->fstats.at("nfact").toc();
    if (flag && (*this)->regularity_check_) {
      // Collect nonzeros
      std::vector<std::string> nonzeros(sparsity().nnz());
      for (size_t nz = 0; nz < nonzeros.size(); ++nz)
        nonzeros[nz] = std::to_string(A[nz]);
      // Create .m file
      std::string fname = (*this)->class_name() + "_" + (*this)->name_ + "_debug.m";
      auto mfile_ptr = Filesystem::ofstream_ptr(fname);
      std::ostream& mfile = *mfile_ptr;
      Dict opts;
      opts["name"] = "A";
      opts["nonzeros"] = nonzeros;
      sparsity().export_code("matlab", mfile, opts);
      casadi_error("Numerical factorization failed for " + (*this)->name_
        + "[" + (*this)->class_name() + "]. Linear system saved to '" + fname + "'");
    }
    m->is_nfact = true;
    return flag;
  }

  casadi_int Linsol::neig(const DM& A) const {
    if (A.sparsity()!=sparsity()) return neig(project(A, sparsity()));
    casadi_int n = neig(A.ptr());
    casadi_assert(n>=0, "'neig' failed");
    return n;
  }

  casadi_int Linsol::neig(const double* A, int mem) const {
    return (*this)->neig((*this)->memory(mem), A);
  }

  casadi_int Linsol::rank(const DM& A) const {
    if (A.sparsity()!=sparsity()) return rank(project(A, sparsity()));
    casadi_int n = rank(A.ptr());
    casadi_assert(n>=0, "'rank' failed");
    return n;
  }

  casadi_int Linsol::rank(const double* A, int mem) const {
    return (*this)->rank((*this)->memory(mem), A);
  }

  int Linsol::solve(const double* A, double* x, casadi_int nrhs, bool tr, int mem) const {
    auto m = static_cast<LinsolMemory*>((*this)->memory(mem));
    casadi_assert(m->is_nfact, "Linear system has not been factorized");
    if (m->t_total) m->fstats.at("solve").tic();
    int ret = (*this)->solve(m, A, x, nrhs, tr);
    if (m->t_total) m->fstats.at("solve").toc();
    return ret;
  }

  casadi_int Linsol::checkout() const {
    return (*this)->checkout();
  }

  void Linsol::release(int mem) const {
    (*this)->release(mem);
  }


  bool has_linsol(const std::string& name) {
    return Linsol::has_plugin(name);
  }

  void load_linsol(const std::string& name) {
    Linsol::load_plugin(name);
  }

  std::string doc_linsol(const std::string& name) {
    return Linsol::doc(name);
  }

  Dict Linsol::stats(int mem) const {
    casadi_assert((*this)->has_memory(mem),
      "No stats available since Linsol did not solve a problem yet.");
    return (*this)->get_stats((*this)->memory(mem));
  }

  void Linsol::serialize(SerializingStream &s) const {
    // TODO(jgillis): I don't get why LinsolInternal:: this is necessary
    return (*this)->LinsolInternal::serialize(s);
  }

  Linsol Linsol::deserialize(DeserializingStream& s) {
    Linsol linsol;
    linsol.own(LinsolInternal::deserialize(s));
    linsol->finalize();
    return linsol;
  }

  Linsol Linsol::create(LinsolInternal* node) {
    Linsol ret;
    ret.own(node);
    return ret;
  }

} // namespace casadi
