//===- Class.cpp - Helper classes for Op C++ code emission --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "mlir/TableGen/Class.h"
#include "mlir/TableGen/Format.h"
#include "llvm/ADT/Sequence.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/Debug.h"

using namespace mlir;
using namespace mlir::tblgen;

/// Returns space to be emitted after the given C++ `type`. return "" if the
/// ends with '&' or '*', or is empty, else returns " ".
static StringRef getSpaceAfterType(StringRef type) {
  return (type.empty() || type.endswith("&") || type.endswith("*")) ? "" : " ";
}

//===----------------------------------------------------------------------===//
// MethodParameter definitions
//===----------------------------------------------------------------------===//

void MethodParameter::writeDeclTo(raw_indented_ostream &os) const {
  if (optional)
    os << "/*optional*/";
  os << type << getSpaceAfterType(type) << name;
  if (hasDefaultValue())
    os << " = " << defaultValue;
}

void MethodParameter::writeDefTo(raw_indented_ostream &os) const {
  if (optional)
    os << "/*optional*/";
  os << type << getSpaceAfterType(type) << name;
}

//===----------------------------------------------------------------------===//
// MethodParameters definitions
//===----------------------------------------------------------------------===//

void MethodParameters::writeDeclTo(raw_indented_ostream &os) const {
  llvm::interleaveComma(parameters, os,
                        [&os](auto &param) { param.writeDeclTo(os); });
}
void MethodParameters::writeDefTo(raw_indented_ostream &os) const {
  llvm::interleaveComma(parameters, os,
                        [&os](auto &param) { param.writeDefTo(os); });
}

bool MethodParameters::subsumes(const MethodParameters &other) const {
  // These parameters do not subsume the others if there are fewer parameters
  // or their types do not match.
  if (parameters.size() < other.parameters.size())
    return false;
  if (!std::equal(
          other.parameters.begin(), other.parameters.end(), parameters.begin(),
          [](auto &lhs, auto &rhs) { return lhs.getType() == rhs.getType(); }))
    return false;

  // If all the common parameters have the same type, we can elide the other
  // method if this method has the same number of parameters as other or if the
  // first paramater after the common parameters has a default value (and, as
  // required by C++, subsequent parameters will have default values too).
  return parameters.size() == other.parameters.size() ||
         parameters[other.parameters.size()].hasDefaultValue();
}

//===----------------------------------------------------------------------===//
// MethodSignature definitions
//===----------------------------------------------------------------------===//

bool MethodSignature::makesRedundant(const MethodSignature &other) const {
  return methodName == other.methodName &&
         parameters.subsumes(other.parameters);
}

void MethodSignature::writeDeclTo(raw_indented_ostream &os) const {
  os << returnType << getSpaceAfterType(returnType) << methodName << "(";
  parameters.writeDeclTo(os);
  os << ")";
}

void MethodSignature::writeDefTo(raw_indented_ostream &os,
                                 StringRef namePrefix) const {
  os << returnType << getSpaceAfterType(returnType) << namePrefix
     << (namePrefix.empty() ? "" : "::") << methodName << "(";
  parameters.writeDefTo(os);
  os << ")";
}

//===----------------------------------------------------------------------===//
// MethodBody definitions
//===----------------------------------------------------------------------===//

MethodBody::MethodBody(bool declOnly)
    : declOnly(declOnly), stringOs(body), os(stringOs) {}

void MethodBody::writeTo(raw_indented_ostream &os) const {
  auto bodyRef = StringRef(body).drop_while([](char c) { return c == '\n'; });
  os << bodyRef;
  if (bodyRef.empty())
    return;
  if (bodyRef.back() != '\n')
    os << "\n";
}

//===----------------------------------------------------------------------===//
// Method definitions
//===----------------------------------------------------------------------===//

void Method::writeDeclTo(raw_indented_ostream &os) const {
  if (isStatic())
    os << "static ";
  if (properties & ConstexprValue)
    os << "constexpr ";
  methodSignature.writeDeclTo(os);
  if (isConst())
    os << " const";
  if (!isInline()) {
    os << ";\n";
    return;
  }
  os << " {\n";
  methodBody.writeTo(os);
  os << "}\n\n";
}

void Method::writeDefTo(raw_indented_ostream &os, StringRef namePrefix) const {
  // The method has no definition to write if it is declaration only or inline.
  if (properties & Declaration || isInline())
    return;

  methodSignature.writeDefTo(os, namePrefix);
  if (isConst())
    os << " const";
  os << " {\n";
  methodBody.writeTo(os);
  os << "}\n\n";
}

//===----------------------------------------------------------------------===//
// Constructor definitions
//===----------------------------------------------------------------------===//

void Constructor::writeDeclTo(raw_indented_ostream &os) const {
  if (properties & ConstexprValue)
    os << "constexpr ";
  methodSignature.writeDeclTo(os);
  if (!isInline()) {
    os << ";\n\n";
    return;
  }
  os << ' ';
  if (!initializers.empty())
    os << ": ";
  llvm::interleaveComma(initializers, os,
                        [&](auto &initializer) { initializer.writeTo(os); });
  if (!initializers.empty())
    os << ' ';
  os << "{";
  methodBody.writeTo(os);
  os << "}\n\n";
}

void Constructor::writeDefTo(raw_indented_ostream &os,
                             StringRef namePrefix) const {
  // The method has no definition to write if it is declaration only or inline.
  if (properties & Declaration || isInline())
    return;

  methodSignature.writeDefTo(os, namePrefix);
  os << ' ';
  if (!initializers.empty())
    os << ": ";
  llvm::interleaveComma(initializers, os,
                        [&](auto &initializer) { initializer.writeTo(os); });
  if (!initializers.empty())
    os << ' ';
  os << "{";
  methodBody.writeTo(os);
  os << "}\n\n";
}

void Constructor::MemberInitializer::writeTo(raw_indented_ostream &os) const {
  os << name << '(' << value << ')';
}

//===----------------------------------------------------------------------===//
// Visibility definitions
//===----------------------------------------------------------------------===//

namespace mlir {
namespace tblgen {
raw_ostream &operator<<(raw_ostream &os, Visibility visibility) {
  switch (visibility) {
  case Visibility::Public:
    return os << "public";
  case Visibility::Protected:
    return os << "protected";
  case Visibility::Private:
    return os << "private";
  }
  return os;
}
} // namespace tblgen
} // namespace mlir

//===----------------------------------------------------------------------===//
// ParentClass definitions
//===----------------------------------------------------------------------===//

void ParentClass::writeTo(raw_indented_ostream &os) const {
  os << visibility << ' ' << name;
  if (!templateParams.empty()) {
    auto scope = os.scope("<", ">", /*indent=*/false);
    llvm::interleaveComma(templateParams, os,
                          [&](auto &param) { os << param; });
  }
}

//===----------------------------------------------------------------------===//
// UsingDeclaration definitions
//===----------------------------------------------------------------------===//

void UsingDeclaration::writeDeclTo(raw_indented_ostream &os) const {
  os << "using " << name;
  if (!value.empty())
    os << " = " << value;
  os << ";\n";
}

//===----------------------------------------------------------------------===//
// Field definitions
//===----------------------------------------------------------------------===//

void Field::writeDeclTo(raw_indented_ostream &os) const {
  os << type << ' ' << name << ";\n";
}

//===----------------------------------------------------------------------===//
// VisibilityDeclaration definitions
//===----------------------------------------------------------------------===//

void VisibilityDeclaration::writeDeclTo(raw_indented_ostream &os) const {
  os.unindent();
  os << visibility << ":\n";
  os.indent();
}

//===----------------------------------------------------------------------===//
// ExtraClassDeclaration definitions
//===----------------------------------------------------------------------===//

void ExtraClassDeclaration::writeDeclTo(raw_indented_ostream &os) const {
  os.printReindented(extraClassDeclaration);
}

void ExtraClassDeclaration::writeDefTo(raw_indented_ostream &os,
                                       StringRef namePrefix) const {
  os.printReindented(extraClassDefinition);
}

//===----------------------------------------------------------------------===//
// Class definitions
//===----------------------------------------------------------------------===//

ParentClass &Class::addParent(ParentClass parent) {
  parents.push_back(std::move(parent));
  return parents.back();
}

void Class::writeDeclTo(raw_indented_ostream &os) const {
  // Declare the class.
  os << (isStruct ? "struct" : "class") << ' ' << className << ' ';

  // Declare the parent classes, if any.
  if (!parents.empty()) {
    os << ": ";
    llvm::interleaveComma(parents, os,
                          [&](auto &parent) { parent.writeTo(os); });
    os << ' ';
  }
  auto classScope = os.scope("{\n", "};\n", /*indent=*/true);

  // Print all the class declarations.
  for (auto &decl : declarations)
    decl->writeDeclTo(os);
}

void Class::writeDefTo(raw_indented_ostream &os) const {
  // Print all the definitions.
  for (auto &decl : declarations)
    decl->writeDefTo(os, className);
}

void Class::finalize() {
  // Sort the methods by public and private. Remove them from the pending list
  // of methods.
  SmallVector<std::unique_ptr<Method>> publicMethods, privateMethods;
  for (auto &method : methods) {
    if (method->isPrivate())
      privateMethods.push_back(std::move(method));
    else
      publicMethods.push_back(std::move(method));
  }
  methods.clear();

  // If the last visibility declaration wasn't `public`, add one that is. Then,
  // declare the public methods.
  if (!publicMethods.empty() && getLastVisibilityDecl() != Visibility::Public)
    declare<VisibilityDeclaration>(Visibility::Public);
  for (auto &method : publicMethods)
    declarations.push_back(std::move(method));

  // If the last visibility declaration wasn't `private`, add one that is. Then,
  // declare the private methods.
  if (!privateMethods.empty() && getLastVisibilityDecl() != Visibility::Private)
    declare<VisibilityDeclaration>(Visibility::Private);
  for (auto &method : privateMethods)
    declarations.push_back(std::move(method));

  // All fields added to the pending list are private and declared at the bottom
  // of the class. If the last visibility declaration wasn't `private`, add one
  // that is, then declare the fields.
  if (!fields.empty() && getLastVisibilityDecl() != Visibility::Private)
    declare<VisibilityDeclaration>(Visibility::Private);
  for (auto &field : fields)
    declare<Field>(std::move(field));
  fields.clear();
}

Visibility Class::getLastVisibilityDecl() const {
  auto reverseDecls = llvm::reverse(declarations);
  auto it = llvm::find_if(reverseDecls, [](auto &decl) {
    return isa<VisibilityDeclaration>(decl);
  });
  return it == reverseDecls.end()
             ? (isStruct ? Visibility::Public : Visibility::Private)
             : cast<VisibilityDeclaration>(*it).getVisibility();
}

Method *insertAndPruneMethods(std::vector<std::unique_ptr<Method>> &methods,
                              std::unique_ptr<Method> newMethod) {
  if (llvm::any_of(methods, [&](auto &method) {
        return method->makesRedundant(*newMethod);
      }))
    return nullptr;

  llvm::erase_if(methods, [&](auto &method) {
    return newMethod->makesRedundant(*method);
  });
  methods.push_back(std::move(newMethod));
  return methods.back().get();
}

Method *Class::addMethodAndPrune(Method &&newMethod) {
  return insertAndPruneMethods(methods,
                               std::make_unique<Method>(std::move(newMethod)));
}

Constructor *Class::addConstructorAndPrune(Constructor &&newCtor) {
  return dyn_cast_or_null<Constructor>(insertAndPruneMethods(
      methods, std::make_unique<Constructor>(std::move(newCtor))));
}