/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
   file LICENSE.rst or https://cmake.org/licensing for details.  */
#include "cmGraphVizWriter.h"

#include <algorithm>
#include <iostream>
#include <memory>
#include <set>
#include <unordered_set>
#include <utility>

#include <cm/memory>

#include "cmsys/RegularExpression.hxx"
#include "cmsys/String.h"

#include "cmGeneratedFileStream.h"
#include "cmGeneratorTarget.h"
#include "cmGlobalGenerator.h"
#include "cmLinkItem.h"
#include "cmList.h"
#include "cmLocalGenerator.h"
#include "cmMakefile.h"
#include "cmState.h"
#include "cmStateSnapshot.h"
#include "cmStringAlgorithms.h"
#include "cmSystemTools.h"
#include "cmTargetTypes.h"
#include "cmValue.h"
#include "cmake.h"

namespace {

char const* const GRAPHVIZ_EDGE_STYLE_PUBLIC = "solid";
char const* const GRAPHVIZ_EDGE_STYLE_INTERFACE = "dashed";
char const* const GRAPHVIZ_EDGE_STYLE_PRIVATE = "dotted";

char const* const GRAPHVIZ_NODE_SHAPE_EXECUTABLE = "egg"; // egg-xecutable

// Normal libraries.
char const* const GRAPHVIZ_NODE_SHAPE_LIBRARY_STATIC = "octagon";
char const* const GRAPHVIZ_NODE_SHAPE_LIBRARY_SHARED = "doubleoctagon";
char const* const GRAPHVIZ_NODE_SHAPE_LIBRARY_MODULE = "tripleoctagon";

char const* const GRAPHVIZ_NODE_SHAPE_LIBRARY_INTERFACE = "pentagon";
char const* const GRAPHVIZ_NODE_SHAPE_LIBRARY_OBJECT = "hexagon";
char const* const GRAPHVIZ_NODE_SHAPE_LIBRARY_UNKNOWN = "septagon";

char const* const GRAPHVIZ_NODE_SHAPE_UTILITY = "box";

char const* getShapeForTarget(cmLinkItem const& item)
{
  if (!item.Target) {
    return GRAPHVIZ_NODE_SHAPE_LIBRARY_UNKNOWN;
  }

  switch (item.Target->GetType()) {
    case cm::TargetType::EXECUTABLE:
      return GRAPHVIZ_NODE_SHAPE_EXECUTABLE;
    case cm::TargetType::STATIC_LIBRARY:
      return GRAPHVIZ_NODE_SHAPE_LIBRARY_STATIC;
    case cm::TargetType::SHARED_LIBRARY:
      return GRAPHVIZ_NODE_SHAPE_LIBRARY_SHARED;
    case cm::TargetType::MODULE_LIBRARY:
      return GRAPHVIZ_NODE_SHAPE_LIBRARY_MODULE;
    case cm::TargetType::OBJECT_LIBRARY:
      return GRAPHVIZ_NODE_SHAPE_LIBRARY_OBJECT;
    case cm::TargetType::UTILITY:
      return GRAPHVIZ_NODE_SHAPE_UTILITY;
    case cm::TargetType::INTERFACE_LIBRARY:
      return GRAPHVIZ_NODE_SHAPE_LIBRARY_INTERFACE;
    case cm::TargetType::UNKNOWN_LIBRARY:
    default:
      return GRAPHVIZ_NODE_SHAPE_LIBRARY_UNKNOWN;
  }
}

struct DependeesDir
{
  template <typename T>
  static cmLinkItem const& src(T const& con)
  {
    return con.src;
  }

  template <typename T>
  static cmLinkItem const& dst(T const& con)
  {
    return con.dst;
  }
};

struct DependersDir
{
  template <typename T>
  static cmLinkItem const& src(T const& con)
  {
    return con.dst;
  }

  template <typename T>
  static cmLinkItem const& dst(T const& con)
  {
    return con.src;
  }
};
}

cmGraphVizWriter::cmGraphVizWriter(std::string const& fileName,
                                   cmGlobalGenerator const* globalGenerator)
  : FileName(fileName)
  , GlobalFileStream(fileName)
  , GraphName(globalGenerator->GetSafeGlobalSetting("CMAKE_PROJECT_NAME"))
  , GraphHeader("node [\n  fontsize = \"12\"\n];")
  , GraphNodePrefix("node")
  , GlobalGenerator(globalGenerator)
{
}

cmGraphVizWriter::~cmGraphVizWriter()
{
  this->WriteFooter(this->GlobalFileStream);
}

void cmGraphVizWriter::VisitGraph(std::string const&)
{
  this->WriteHeader(this->GlobalFileStream, this->GraphName);
  this->WriteLegend(this->GlobalFileStream);
}

void cmGraphVizWriter::OnItem(cmLinkItem const& item)
{
  if (this->ItemExcluded(item)) {
    return;
  }

  this->NodeNames[item.AsStr()] =
    cmStrCat(this->GraphNodePrefix, this->NextNodeId);
  ++this->NextNodeId;

  this->WriteNode(this->GlobalFileStream, item);
}

std::unique_ptr<cmGeneratedFileStream> cmGraphVizWriter::CreateTargetFile(
  cmLinkItem const& item, std::string const& fileNameSuffix)
{
  auto const pathSafeItemName = PathSafeString(item.AsStr());
  auto const perTargetFileName =
    cmStrCat(this->FileName, '.', pathSafeItemName, fileNameSuffix);
  auto perTargetFileStream =
    cm::make_unique<cmGeneratedFileStream>(perTargetFileName);

  this->WriteHeader(*perTargetFileStream, item.AsStr());
  this->WriteNode(*perTargetFileStream, item);

  return perTargetFileStream;
}

void cmGraphVizWriter::OnDirectLink(cmLinkItem const& depender,
                                    cmLinkItem const& dependee,
                                    DependencyType dt)
{
  this->VisitLink(depender, dependee, true, GetEdgeStyle(dt));
}

void cmGraphVizWriter::OnIndirectLink(cmLinkItem const& depender,
                                      cmLinkItem const& dependee)
{
  this->VisitLink(depender, dependee, false);
}

void cmGraphVizWriter::VisitLink(cmLinkItem const& depender,
                                 cmLinkItem const& dependee, bool isDirectLink,
                                 std::string const& scopeType)
{
  if (this->ItemExcluded(depender) || this->ItemExcluded(dependee)) {
    return;
  }

  if (!isDirectLink) {
    return;
  }

  // write global data directly
  this->WriteConnection(this->GlobalFileStream, depender, dependee, scopeType);

  if (this->GeneratePerTarget) {
    this->PerTargetConnections[depender].emplace_back(depender, dependee,
                                                      scopeType);
  }

  if (this->GenerateDependers) {
    this->TargetDependersConnections[dependee].emplace_back(dependee, depender,
                                                            scopeType);
  }
}

void cmGraphVizWriter::ReadSettings(
  std::string const& settingsFileName,
  std::string const& fallbackSettingsFileName)
{
  cmake cm(cmState::Role::Script);
  cm.GetCurrentSnapshot().SetDefaultDefinitions();
  cmGlobalGenerator ggi(&cm);
  cmMakefile mf(&ggi, cm.GetCurrentSnapshot());
  std::unique_ptr<cmLocalGenerator> lg(ggi.CreateLocalGenerator(&mf));

  std::string inFileName = settingsFileName;
  if (!cmSystemTools::FileExists(inFileName)) {
    inFileName = fallbackSettingsFileName;
    if (!cmSystemTools::FileExists(inFileName)) {
      return;
    }
  }

  if (!mf.ReadListFile(inFileName)) {
    cmSystemTools::Error("Problem opening GraphViz options file: " +
                         inFileName);
    return;
  }

  std::cout << "Reading GraphViz options file: " << inFileName << std::endl;

#define set_if_set(var, cmakeDefinition)                                      \
  do {                                                                        \
    cmValue value = mf.GetDefinition(cmakeDefinition);                        \
    if (value) {                                                              \
      (var) = *value;                                                         \
    }                                                                         \
  } while (false)

  set_if_set(this->GraphName, "GRAPHVIZ_GRAPH_NAME");
  set_if_set(this->GraphHeader, "GRAPHVIZ_GRAPH_HEADER");
  set_if_set(this->GraphNodePrefix, "GRAPHVIZ_NODE_PREFIX");

#define set_bool_if_set(var, cmakeDefinition)                                 \
  do {                                                                        \
    cmValue value = mf.GetDefinition(cmakeDefinition);                        \
    if (value) {                                                              \
      (var) = cmIsOn(*value);                                                 \
    }                                                                         \
  } while (false)

  set_bool_if_set(this->GenerateForExecutables, "GRAPHVIZ_EXECUTABLES");
  set_bool_if_set(this->GenerateForStaticLibs, "GRAPHVIZ_STATIC_LIBS");
  set_bool_if_set(this->GenerateForSharedLibs, "GRAPHVIZ_SHARED_LIBS");
  set_bool_if_set(this->GenerateForModuleLibs, "GRAPHVIZ_MODULE_LIBS");
  set_bool_if_set(this->GenerateForInterfaceLibs, "GRAPHVIZ_INTERFACE_LIBS");
  set_bool_if_set(this->GenerateForObjectLibs, "GRAPHVIZ_OBJECT_LIBS");
  set_bool_if_set(this->GenerateForUnknownLibs, "GRAPHVIZ_UNKNOWN_LIBS");
  set_bool_if_set(this->GenerateForCustomTargets, "GRAPHVIZ_CUSTOM_TARGETS");
  set_bool_if_set(this->GenerateForExternals, "GRAPHVIZ_EXTERNAL_LIBS");
  set_bool_if_set(this->GeneratePerTarget, "GRAPHVIZ_GENERATE_PER_TARGET");
  set_bool_if_set(this->GenerateDependers, "GRAPHVIZ_GENERATE_DEPENDERS");

  std::string ignoreTargetsRegexes;
  set_if_set(ignoreTargetsRegexes, "GRAPHVIZ_IGNORE_TARGETS");

  this->TargetsToIgnoreRegex.clear();
  if (!ignoreTargetsRegexes.empty()) {
    cmList ignoreTargetsRegExList{ ignoreTargetsRegexes };
    for (std::string const& currentRegexString : ignoreTargetsRegExList) {
      cmsys::RegularExpression currentRegex;
      if (!currentRegex.compile(currentRegexString)) {
        std::cerr << "Could not compile bad regex \"" << currentRegexString
                  << "\"" << std::endl;
      }
      this->TargetsToIgnoreRegex.push_back(std::move(currentRegex));
    }
  }
}

void cmGraphVizWriter::Write()
{
  auto const* gg = this->GlobalGenerator;

  this->VisitGraph(gg->GetName());

  // We want to traverse in a determined order, such that the output is always
  // the same for a given project (this makes tests reproducible, etc.)
  std::set<cmGeneratorTarget const*, cmGeneratorTarget::StrictTargetComparison>
    sortedGeneratorTargets;

  for (auto const& lg : gg->GetLocalGenerators()) {
    for (auto const& gt : lg->GetGeneratorTargets()) {
      // Reserved targets have inconsistent names across platforms (e.g. 'all'
      // vs. 'ALL_BUILD'), which can disrupt the traversal ordering.
      // We don't need or want them anyway.
      if (!cmGlobalGenerator::IsReservedTarget(gt->GetName()) &&
          !cmHasLiteralPrefix(gt->GetName(), "__cmake_")) {
        sortedGeneratorTargets.insert(gt.get());
      }
    }
  }

  // write global data and collect all connection data for per target graphs
  for (auto const* const gt : sortedGeneratorTargets) {
    auto item = cmLinkItem(gt, false, gt->GetBacktrace());
    this->VisitItem(item);
  }

  if (this->GeneratePerTarget) {
    this->WritePerTargetConnections<DependeesDir>(this->PerTargetConnections);
  }

  if (this->GenerateDependers) {
    this->WritePerTargetConnections<DependersDir>(
      this->TargetDependersConnections, ".dependers");
  }
}

void cmGraphVizWriter::FindAllConnections(ConnectionsMap const& connectionMap,
                                          cmLinkItem const& rootItem,
                                          Connections& extendedCons,
                                          std::set<cmLinkItem>& visitedItems)
{
  // some "targets" are not in map, e.g. linker flags as -lm or
  // targets without dependency.
  // in both cases we are finished with traversing the graph
  if (connectionMap.find(rootItem) == connectionMap.cend()) {
    return;
  }

  Connections const& origCons = connectionMap.at(rootItem);

  for (Connection const& con : origCons) {
    extendedCons.emplace_back(con);
    cmLinkItem const& dstItem = con.dst;
    bool const visited = visitedItems.find(dstItem) != visitedItems.cend();
    if (!visited) {
      visitedItems.insert(dstItem);
      this->FindAllConnections(connectionMap, dstItem, extendedCons,
                               visitedItems);
    }
  }
}

void cmGraphVizWriter::FindAllConnections(ConnectionsMap const& connectionMap,
                                          cmLinkItem const& rootItem,
                                          Connections& extendedCons)
{
  std::set<cmLinkItem> visitedItems = { rootItem };
  this->FindAllConnections(connectionMap, rootItem, extendedCons,
                           visitedItems);
}

template <typename DirFunc>
void cmGraphVizWriter::WritePerTargetConnections(
  ConnectionsMap const& connections, std::string const& fileNameSuffix)
{
  // the per target connections must be extended by indirect dependencies
  ConnectionsMap extendedConnections;
  for (auto const& conPerTarget : connections) {
    cmLinkItem const& rootItem = conPerTarget.first;
    Connections& extendedCons = extendedConnections[conPerTarget.first];
    this->FindAllConnections(connections, rootItem, extendedCons);
  }

  for (auto const& conPerTarget : extendedConnections) {
    cmLinkItem const& rootItem = conPerTarget.first;

    // some of the nodes are excluded completely and are not written
    if (this->ItemExcluded(rootItem)) {
      continue;
    }

    Connections const& cons = conPerTarget.second;

    std::unique_ptr<cmGeneratedFileStream> fileStream =
      this->CreateTargetFile(rootItem, fileNameSuffix);

    // avoid write same node multiple times
    std::unordered_set<std::string> writtenNodes = { rootItem.AsStr() };
    for (Connection const& con : cons) {
      cmLinkItem const& src = DirFunc::src(con);
      cmLinkItem const& dst = DirFunc::dst(con);
      if (writtenNodes.emplace(con.dst.AsStr()).second) {
        this->WriteNode(*fileStream, con.dst);
      }
      this->WriteConnection(*fileStream, src, dst, con.scopeType);
    }

    this->WriteFooter(*fileStream);
  }
}

void cmGraphVizWriter::WriteHeader(cmGeneratedFileStream& fs,
                                   std::string const& name)
{
  auto const escapedGraphName = EscapeForDotFile(name);
  fs << "digraph \"" << escapedGraphName << "\" {\n"
     << this->GraphHeader << '\n';
}

void cmGraphVizWriter::WriteFooter(cmGeneratedFileStream& fs)
{
  fs << "}\n";
}

void cmGraphVizWriter::WriteLegend(cmGeneratedFileStream& fs)
{
  // Note that the subgraph name must start with "cluster", as done here, to
  // make Graphviz layout engines do the right thing and keep the nodes
  // together.
  /* clang-format off */
  fs << "subgraph clusterLegend {\n"
        "  label = \"Legend\";\n"
        // Set the color of the box surrounding the legend.
        "  color = black;\n"
        // We use invisible edges just to enforce the layout.
        "  edge [ style = invis ];\n"
        // Nodes.
        "  legendNode0 [ label = \"Executable\", shape = "
     << GRAPHVIZ_NODE_SHAPE_EXECUTABLE << " ];\n"
        "  legendNode1 [ label = \"Static Library\", shape = "
     << GRAPHVIZ_NODE_SHAPE_LIBRARY_STATIC << " ];\n"
        "  legendNode2 [ label = \"Shared Library\", shape = "
     << GRAPHVIZ_NODE_SHAPE_LIBRARY_SHARED << " ];\n"
        "  legendNode3 [ label = \"Module Library\", shape = "
     << GRAPHVIZ_NODE_SHAPE_LIBRARY_MODULE << " ];\n"
        "  legendNode4 [ label = \"Interface Library\", shape = "
     << GRAPHVIZ_NODE_SHAPE_LIBRARY_INTERFACE << " ];\n"
        "  legendNode5 [ label = \"Object Library\", shape = "
     << GRAPHVIZ_NODE_SHAPE_LIBRARY_OBJECT << " ];\n"
        "  legendNode6 [ label = \"Unknown Library\", shape = "
     << GRAPHVIZ_NODE_SHAPE_LIBRARY_UNKNOWN << " ];\n"
        "  legendNode7 [ label = \"Custom Target\", shape = "
     << GRAPHVIZ_NODE_SHAPE_UTILITY << " ];\n"
        // Edges.
        // Some of those are dummy (invisible) edges to enforce a layout.
        "  legendNode0 -> legendNode1 [ style = "
     << GRAPHVIZ_EDGE_STYLE_PUBLIC << " ];\n"
        "  legendNode0 -> legendNode2 [ style = "
     << GRAPHVIZ_EDGE_STYLE_PUBLIC << " ];\n"
        "  legendNode0 -> legendNode3;\n"
        "  legendNode1 -> legendNode4 [ label = \"Interface\", style = "
     << GRAPHVIZ_EDGE_STYLE_INTERFACE << " ];\n"
        "  legendNode2 -> legendNode5 [ label = \"Private\", style = "
     << GRAPHVIZ_EDGE_STYLE_PRIVATE << " ];\n"
        "  legendNode3 -> legendNode6 [ style = "
     << GRAPHVIZ_EDGE_STYLE_PUBLIC << " ];\n"
        "  legendNode0 -> legendNode7;\n"
        "}\n";
  /* clang-format off */
}

void cmGraphVizWriter::WriteNode(cmGeneratedFileStream& fs,
                                 cmLinkItem const& item)
{
  auto const& itemName = item.AsStr();
  auto const& nodeName = this->NodeNames[itemName];

  auto const itemNameWithAliases = this->ItemNameWithAliases(itemName);
  auto const escapedLabel = EscapeForDotFile(itemNameWithAliases);

  fs << "    \"" << nodeName << "\" [ label = \"" << escapedLabel
     << "\", shape = " << getShapeForTarget(item) << " ];\n";
}

void cmGraphVizWriter::WriteConnection(cmGeneratedFileStream& fs,
                                       cmLinkItem const& depender,
                                       cmLinkItem const& dependee,
                                       std::string const& edgeStyle)
{
  auto const& dependerName = depender.AsStr();
  auto const& dependeeName = dependee.AsStr();

  fs << "    \"" << this->NodeNames[dependerName] << "\" -> \""
     << this->NodeNames[dependeeName] << "\" "
     << edgeStyle
     << " // " << dependerName << " -> " << dependeeName << '\n';
}

bool cmGraphVizWriter::ItemExcluded(cmLinkItem const& item)
{
  auto const itemName = item.AsStr();

  if (this->ItemNameFilteredOut(itemName)) {
    return true;
  }

  if (!item.Target) {
    return !this->GenerateForExternals;
  }

  if (item.Target->GetType() == cm::TargetType::UTILITY) {
    if (cmHasLiteralPrefix(itemName, "Nightly") ||
        cmHasLiteralPrefix(itemName, "Continuous") ||
        cmHasLiteralPrefix(itemName, "Experimental")) {
      return true;
    }
  }

  if (item.Target->IsImported() && !this->GenerateForExternals) {
    return true;
  }

  return !this->TargetTypeEnabled(item.Target->GetType());
}

bool cmGraphVizWriter::ItemNameFilteredOut(std::string const& itemName)
{
  if (itemName == ">") {
    // FIXME: why do we even receive such a target here?
    return true;
  }

  if (cmGlobalGenerator::IsReservedTarget(itemName)) {
    return true;
  }

  for (cmsys::RegularExpression& regEx : this->TargetsToIgnoreRegex) {
    if (regEx.is_valid()) {
      if (regEx.find(itemName)) {
        return true;
      }
    }
  }

  return false;
}

bool cmGraphVizWriter::TargetTypeEnabled(
  cm::TargetType targetType) const
{
  switch (targetType) {
    case cm::TargetType::EXECUTABLE:
      return this->GenerateForExecutables;
    case cm::TargetType::STATIC_LIBRARY:
      return this->GenerateForStaticLibs;
    case cm::TargetType::SHARED_LIBRARY:
      return this->GenerateForSharedLibs;
    case cm::TargetType::MODULE_LIBRARY:
      return this->GenerateForModuleLibs;
    case cm::TargetType::INTERFACE_LIBRARY:
      return this->GenerateForInterfaceLibs;
    case cm::TargetType::OBJECT_LIBRARY:
      return this->GenerateForObjectLibs;
    case cm::TargetType::UNKNOWN_LIBRARY:
      return this->GenerateForUnknownLibs;
    case cm::TargetType::UTILITY:
      return this->GenerateForCustomTargets;
    case cm::TargetType::GLOBAL_TARGET:
      // Built-in targets like edit_cache, etc.
      // We don't need/want those in the dot file.
      return false;
    default:
      break;
  }
  return false;
}

std::string cmGraphVizWriter::ItemNameWithAliases(
  std::string const& itemName) const
{
  std::vector<std::string> items;
  for (auto const& lg : this->GlobalGenerator->GetLocalGenerators()) {
    for (auto const& aliasTargets : lg->GetMakefile()->GetAliasTargets()) {
      if (aliasTargets.second == itemName) {
        items.push_back(aliasTargets.first);
      }
    }
  }

  std::sort(items.begin(), items.end());
  items.erase(std::unique(items.begin(), items.end()), items.end());

  auto nameWithAliases = itemName;
  for(auto const& item : items) {
    nameWithAliases = cmStrCat(std::move(nameWithAliases), "\\n(" , item , ')');
  }

  return nameWithAliases;
}

std::string cmGraphVizWriter::GetEdgeStyle(DependencyType dt)
{
  std::string style;
  switch (dt) {
    case DependencyType::LinkPrivate:
      style = cmStrCat("[ style = ", GRAPHVIZ_EDGE_STYLE_PRIVATE, " ]");
      break;
    case DependencyType::LinkInterface:
      style = cmStrCat("[ style = ", GRAPHVIZ_EDGE_STYLE_INTERFACE, " ]");
      break;
    default:
      break;
  }
  return style;
}

std::string cmGraphVizWriter::EscapeForDotFile(std::string const& str)
{
  return cmSystemTools::EscapeChars(str.data(), "\"");
}

std::string cmGraphVizWriter::PathSafeString(std::string const& str)
{
  std::string pathSafeStr;

  // We'll only keep alphanumerical characters, plus the following ones that
  // are common, and safe on all platforms:
  auto const extra_chars = std::set<char>{ '.', '-', '_' };

  for (char c : str) {
    if (cmsysString_isalnum(c) || extra_chars.find(c) != extra_chars.cend()) {
      pathSafeStr += c;
    }
  }

  return pathSafeStr;
}