//===--- Diagnostics.cpp - Helper class for error diagnostics ---*- C++ -*-===//
//
// 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 "clang/ASTMatchers/Dynamic/Diagnostics.h"

namespace clang {
namespace ast_matchers {
namespace dynamic {
Diagnostics::ArgStream Diagnostics::pushContextFrame(ContextType Type,
                                                     SourceRange Range) {
  ContextStack.emplace_back();
  ContextFrame& data = ContextStack.back();
  data.Type = Type;
  data.Range = Range;
  return ArgStream(&data.Args);
}

Diagnostics::Context::Context(ConstructMatcherEnum, Diagnostics *Error,
                              StringRef MatcherName,
                              SourceRange MatcherRange)
    : Error(Error) {
  Error->pushContextFrame(CT_MatcherConstruct, MatcherRange) << MatcherName;
}

Diagnostics::Context::Context(MatcherArgEnum, Diagnostics *Error,
                              StringRef MatcherName,
                              SourceRange MatcherRange,
                              unsigned ArgNumber)
    : Error(Error) {
  Error->pushContextFrame(CT_MatcherArg, MatcherRange) << ArgNumber
                                                       << MatcherName;
}

Diagnostics::Context::~Context() { Error->ContextStack.pop_back(); }

Diagnostics::OverloadContext::OverloadContext(Diagnostics *Error)
    : Error(Error), BeginIndex(Error->Errors.size()) {}

Diagnostics::OverloadContext::~OverloadContext() {
  // Merge all errors that happened while in this context.
  if (BeginIndex < Error->Errors.size()) {
    Diagnostics::ErrorContent &Dest = Error->Errors[BeginIndex];
    for (size_t i = BeginIndex + 1, e = Error->Errors.size(); i < e; ++i) {
      Dest.Messages.push_back(Error->Errors[i].Messages[0]);
    }
    Error->Errors.resize(BeginIndex + 1);
  }
}

void Diagnostics::OverloadContext::revertErrors() {
  // Revert the errors.
  Error->Errors.resize(BeginIndex);
}

Diagnostics::ArgStream &Diagnostics::ArgStream::operator<<(const Twine &Arg) {
  Out->push_back(Arg.str());
  return *this;
}

Diagnostics::ArgStream Diagnostics::addError(SourceRange Range,
                                             ErrorType Error) {
  Errors.emplace_back();
  ErrorContent &Last = Errors.back();
  Last.ContextStack = ContextStack;
  Last.Messages.emplace_back();
  Last.Messages.back().Range = Range;
  Last.Messages.back().Type = Error;
  return ArgStream(&Last.Messages.back().Args);
}

static StringRef contextTypeToFormatString(Diagnostics::ContextType Type) {
  switch (Type) {
    case Diagnostics::CT_MatcherConstruct:
      return "Error building matcher $0.";
    case Diagnostics::CT_MatcherArg:
      return "Error parsing argument $0 for matcher $1.";
  }
  llvm_unreachable("Unknown ContextType value.");
}

static StringRef errorTypeToFormatString(Diagnostics::ErrorType Type) {
  switch (Type) {
  case Diagnostics::ET_RegistryMatcherNotFound:
    return "Matcher not found: $0";
  case Diagnostics::ET_RegistryWrongArgCount:
    return "Incorrect argument count. (Expected = $0) != (Actual = $1)";
  case Diagnostics::ET_RegistryWrongArgType:
    return "Incorrect type for arg $0. (Expected = $1) != (Actual = $2)";
  case Diagnostics::ET_RegistryNotBindable:
    return "Matcher does not support binding.";
  case Diagnostics::ET_RegistryAmbiguousOverload:
    // TODO: Add type info about the overload error.
    return "Ambiguous matcher overload.";
  case Diagnostics::ET_RegistryValueNotFound:
    return "Value not found: $0";
  case Diagnostics::ET_RegistryUnknownEnumWithReplace:
    return "Unknown value '$1' for arg $0; did you mean '$2'";

  case Diagnostics::ET_ParserStringError:
    return "Error parsing string token: <$0>";
  case Diagnostics::ET_ParserNoOpenParen:
    return "Error parsing matcher. Found token <$0> while looking for '('.";
  case Diagnostics::ET_ParserNoCloseParen:
    return "Error parsing matcher. Found end-of-code while looking for ')'.";
  case Diagnostics::ET_ParserNoComma:
    return "Error parsing matcher. Found token <$0> while looking for ','.";
  case Diagnostics::ET_ParserNoCode:
    return "End of code found while looking for token.";
  case Diagnostics::ET_ParserNotAMatcher:
    return "Input value is not a matcher expression.";
  case Diagnostics::ET_ParserInvalidToken:
    return "Invalid token <$0> found when looking for a value.";
  case Diagnostics::ET_ParserMalformedBindExpr:
    return "Malformed bind() expression.";
  case Diagnostics::ET_ParserTrailingCode:
    return "Expected end of code.";
  case Diagnostics::ET_ParserNumberError:
    return "Error parsing numeric literal: <$0>";
  case Diagnostics::ET_ParserOverloadedType:
    return "Input value has unresolved overloaded type: $0";

  case Diagnostics::ET_None:
    return "<N/A>";
  }
  llvm_unreachable("Unknown ErrorType value.");
}

static void formatErrorString(StringRef FormatString,
                              ArrayRef<std::string> Args,
                              llvm::raw_ostream &OS) {
  while (!FormatString.empty()) {
    std::pair<StringRef, StringRef> Pieces = FormatString.split("$");
    OS << Pieces.first.str();
    if (Pieces.second.empty()) break;

    const char Next = Pieces.second.front();
    FormatString = Pieces.second.drop_front();
    if (Next >= '0' && Next <= '9') {
      const unsigned Index = Next - '0';
      if (Index < Args.size()) {
        OS << Args[Index];
      } else {
        OS << "<Argument_Not_Provided>";
      }
    }
  }
}

static void maybeAddLineAndColumn(SourceRange Range,
                                  llvm::raw_ostream &OS) {
  if (Range.Start.Line > 0 && Range.Start.Column > 0) {
    OS << Range.Start.Line << ":" << Range.Start.Column << ": ";
  }
}

static void printContextFrameToStream(const Diagnostics::ContextFrame &Frame,
                                      llvm::raw_ostream &OS) {
  maybeAddLineAndColumn(Frame.Range, OS);
  formatErrorString(contextTypeToFormatString(Frame.Type), Frame.Args, OS);
}

static void
printMessageToStream(const Diagnostics::ErrorContent::Message &Message,
                     const Twine Prefix, llvm::raw_ostream &OS) {
  maybeAddLineAndColumn(Message.Range, OS);
  OS << Prefix;
  formatErrorString(errorTypeToFormatString(Message.Type), Message.Args, OS);
}

static void printErrorContentToStream(const Diagnostics::ErrorContent &Content,
                                      llvm::raw_ostream &OS) {
  if (Content.Messages.size() == 1) {
    printMessageToStream(Content.Messages[0], "", OS);
  } else {
    for (size_t i = 0, e = Content.Messages.size(); i != e; ++i) {
      if (i != 0) OS << "\n";
      printMessageToStream(Content.Messages[i],
                           "Candidate " + Twine(i + 1) + ": ", OS);
    }
  }
}

void Diagnostics::printToStream(llvm::raw_ostream &OS) const {
  for (size_t i = 0, e = Errors.size(); i != e; ++i) {
    if (i != 0) OS << "\n";
    printErrorContentToStream(Errors[i], OS);
  }
}

std::string Diagnostics::toString() const {
  std::string S;
  llvm::raw_string_ostream OS(S);
  printToStream(OS);
  return OS.str();
}

void Diagnostics::printToStreamFull(llvm::raw_ostream &OS) const {
  for (size_t i = 0, e = Errors.size(); i != e; ++i) {
    if (i != 0) OS << "\n";
    const ErrorContent &Error = Errors[i];
    for (size_t i = 0, e = Error.ContextStack.size(); i != e; ++i) {
      printContextFrameToStream(Error.ContextStack[i], OS);
      OS << "\n";
    }
    printErrorContentToStream(Error, OS);
  }
}

std::string Diagnostics::toStringFull() const {
  std::string S;
  llvm::raw_string_ostream OS(S);
  printToStreamFull(OS);
  return OS.str();
}

}  // namespace dynamic
}  // namespace ast_matchers
}  // namespace clang
