#pragma once

#include "fesa/Core/Dof.hpp"
#include "fesa/Core/Domain.hpp"
#include "fesa/Util/Diagnostics.hpp"
#include "fesa/Util/String.hpp"

#include <algorithm>
#include <cmath>
#include <optional>
#include <set>
#include <string>
#include <utility>
#include <vector>

namespace fesa {

inline std::optional<GlobalId> numericTarget(const std::string& target) {
  return parseInt64(target);
}

inline std::vector<GlobalId> resolveNodeTarget(const Domain& domain, const std::string& target, std::vector<Diagnostic>* diagnostics = nullptr,
                                               const std::string& diagnostic_keyword = "node target") {
  if (auto node_id = numericTarget(target)) {
    if (domain.nodes.count(*node_id) == 0) {
      if (diagnostics != nullptr) {
        diagnostics->push_back(
            makeDiagnostic(Severity::Error, "FESA-VALIDATION-MISSING-NODE", "Missing node target: " + target, diagnostic_keyword));
      }
      return {};
    }
    return {*node_id};
  }
  auto set_it = domain.node_sets.find(Domain::key(target));
  if (set_it == domain.node_sets.end()) {
    if (diagnostics != nullptr) {
      diagnostics->push_back(
          makeDiagnostic(Severity::Error, "FESA-VALIDATION-MISSING-NSET", "Missing node set: " + target, diagnostic_keyword));
    }
    return {};
  }
  return set_it->second.node_ids;
}

inline const ShellSection* shellSectionForElement(const Domain& domain, GlobalId element_id) {
  for (const ShellSection& section : domain.shell_sections) {
    auto set_it = domain.element_sets.find(Domain::key(section.element_set));
    if (set_it == domain.element_sets.end()) {
      continue;
    }
    if (std::find(set_it->second.element_ids.begin(), set_it->second.element_ids.end(), element_id) != set_it->second.element_ids.end()) {
      return &section;
    }
  }
  return nullptr;
}

inline std::string dofNameOrNumber(int abaqus_dof) {
  auto dof = dofFromAbaqus(abaqus_dof);
  if (dof) {
    return dofLabel(*dof);
  }
  return "DOF " + std::to_string(abaqus_dof);
}

inline bool validAbaqusDofRange(int first, int last) {
  return dofFromAbaqus(first).has_value() && dofFromAbaqus(last).has_value() && first <= last;
}

inline std::vector<Diagnostic> validateDomain(const Domain& domain) {
  std::vector<Diagnostic> diagnostics;
  if (domain.elements.empty()) {
    diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-SINGULAR-NO-ACTIVE-ELEMENTS",
                                         "No active elements exist in the current model", "analysis model"));
  }
  if (domain.boundary_conditions.empty()) {
    diagnostics.push_back(makeDiagnostic(Severity::Warning, "FESA-SINGULAR-NO-BOUNDARY", "No boundary constraints are defined", "boundary"));
  }
  for (const auto& [set_key, set] : domain.node_sets) {
    (void)set_key;
    for (GlobalId node_id : set.node_ids) {
      if (domain.nodes.count(node_id) == 0) {
        diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-NSET-MISSING-NODE",
                                             "Node set " + set.name + " references missing node " + std::to_string(node_id),
                                             "nset"));
      }
    }
  }
  for (const auto& [set_key, set] : domain.element_sets) {
    (void)set_key;
    for (GlobalId element_id : set.element_ids) {
      if (domain.elements.count(element_id) == 0) {
        diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-ELSET-MISSING-ELEMENT",
                                             "Element set " + set.name + " references missing element " + std::to_string(element_id),
                                             "elset"));
      }
    }
  }
  for (const auto& [id, element] : domain.elements) {
    for (GlobalId node_id : element.node_ids) {
      if (domain.nodes.count(node_id) == 0) {
        diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-ELEMENT-MISSING-NODE",
                                             "Element " + std::to_string(id) + " references missing node " + std::to_string(node_id),
                                             "element"));
      }
    }
    const ShellSection* section = shellSectionForElement(domain, id);
    if (section == nullptr) {
      diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-MISSING-PROPERTY",
                                           "Element " + std::to_string(id) + " has no assigned shell section", "element"));
    }
  }
  for (const ShellSection& section : domain.shell_sections) {
    if (section.thickness <= 0.0 || !std::isfinite(section.thickness)) {
      diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-NONPOSITIVE-THICKNESS",
                                           "Shell section for element set " + section.element_set + " has non-positive thickness",
                                           "shell section"));
    }
    if (domain.element_sets.count(Domain::key(section.element_set)) == 0) {
      diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-MISSING-ELSET",
                                           "Shell section references missing element set: " + section.element_set, "shell section"));
    }
    auto material_it = domain.materials.find(Domain::key(section.material));
    if (material_it == domain.materials.end()) {
      diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-MISSING-MATERIAL",
                                           "Shell section references missing material: " + section.material, "shell section"));
    } else if (material_it->second.elastic_modulus <= 0.0) {
      diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-INCOMPLETE-MATERIAL",
                                           "Material has no valid elastic constants: " + section.material, "material"));
    }
  }
  for (const BoundaryCondition& boundary : domain.boundary_conditions) {
    if (!validAbaqusDofRange(boundary.first_dof, boundary.last_dof)) {
      diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-BOUNDARY-DOF",
                                           "Boundary target " + boundary.target + " has invalid DOF range " +
                                               dofNameOrNumber(boundary.first_dof) + " to " + dofNameOrNumber(boundary.last_dof),
                                           "boundary"));
    }
    (void)resolveNodeTarget(domain, boundary.target, &diagnostics, "boundary");
  }
  for (const NodalLoad& load : domain.loads) {
    if (!dofFromAbaqus(load.dof)) {
      diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-VALIDATION-CLOAD-DOF",
                                           "Load target " + load.target + " has invalid " + dofNameOrNumber(load.dof), "cload"));
    }
    (void)resolveNodeTarget(domain, load.target, &diagnostics, "cload");
  }
  const bool any_nonzero_load = std::any_of(domain.loads.begin(), domain.loads.end(), [](const NodalLoad& load) {
    return std::fabs(load.magnitude) > 0.0;
  });
  if (!any_nonzero_load) {
    diagnostics.push_back(makeDiagnostic(Severity::Warning, "FESA-SINGULAR-NO-NONZERO-LOAD", "No nonzero load is defined", "cload"));
  }

  std::set<std::pair<GlobalId, int>> constrained_dofs;
  for (const BoundaryCondition& boundary : domain.boundary_conditions) {
    if (!validAbaqusDofRange(boundary.first_dof, boundary.last_dof)) {
      continue;
    }
    for (GlobalId node_id : resolveNodeTarget(domain, boundary.target)) {
      if (domain.nodes.count(node_id) == 0) {
        continue;
      }
      for (int dof = boundary.first_dof; dof <= boundary.last_dof; ++dof) {
        constrained_dofs.insert(std::make_pair(node_id, dof - 1));
      }
    }
  }

  std::set<GlobalId> active_connectivity_nodes;
  for (const auto& [element_id, element] : domain.elements) {
    (void)element_id;
    for (GlobalId node_id : element.node_ids) {
      if (domain.nodes.count(node_id) != 0) {
        active_connectivity_nodes.insert(node_id);
      }
    }
  }

  LocalIndex free_dof_count = 0;
  LocalIndex weak_drilling_count = 0;
  GlobalId weak_drilling_example = 0;
  for (const auto& [node_id, node] : domain.nodes) {
    (void)node;
    for (Dof dof : allDofs()) {
      const auto key = std::make_pair(node_id, dofIndex(dof));
      if (constrained_dofs.count(key) != 0) {
        continue;
      }
      ++free_dof_count;
      if (!domain.elements.empty() && active_connectivity_nodes.count(node_id) == 0) {
        diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-SINGULAR-DOF-UNTOUCHED",
                                             "Node " + std::to_string(node_id) + " DOF " + dofLabel(dof) +
                                                 " is free but is not touched by active element connectivity",
                                             "dof"));
      }
      if (!domain.elements.empty() && active_connectivity_nodes.count(node_id) != 0 && dof == Dof::RZ) {
        if (weak_drilling_count == 0) {
          weak_drilling_example = node_id;
        }
        ++weak_drilling_count;
      }
    }
  }
  if (!domain.nodes.empty() && free_dof_count == 0) {
    diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-SINGULAR-NO-FREE-DOFS",
                                         "No free DOFs exist after applying boundary constraints", "dof"));
  }
  if (weak_drilling_count > 0) {
    diagnostics.push_back(makeDiagnostic(Severity::Warning, "FESA-SINGULAR-WEAK-DRILLING-DOF",
                                         "Node " + std::to_string(weak_drilling_example) +
                                             " DOF RZ is free; drilling rotation is weakly stabilized in Phase 1 (" +
                                             std::to_string(weak_drilling_count) + " free drilling DOF(s))",
                                         "dof"));
  }
  return diagnostics;
}

}  // namespace fesa