//===--- Annotations.cpp - Annotated source code for unit tests --*- 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 "llvm/Testing/Annotations/Annotations.h"

#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/raw_ostream.h"

using namespace llvm;

// Crash if the assertion fails, printing the message and testcase.
// More elegant error handling isn't needed for unit tests.
static void require(bool Assertion, const char *Msg, llvm::StringRef Code) {
  if (!Assertion) {
    llvm::errs() << "Annotated testcase: " << Msg << "\n" << Code << "\n";
    llvm_unreachable("Annotated testcase assertion failed!");
  }
}

Annotations::Annotations(llvm::StringRef Text) {
  auto Require = [Text](bool Assertion, const char *Msg) {
    require(Assertion, Msg, Text);
  };
  std::optional<llvm::StringRef> Name;
  std::optional<llvm::StringRef> Payload;
  llvm::SmallVector<Annotation, 8> OpenRanges;

  Code.reserve(Text.size());
  while (!Text.empty()) {
    if (Text.consume_front("^")) {
      All.push_back(
          {Code.size(), size_t(-1), Name.value_or(""), Payload.value_or("")});
      Points[Name.value_or("")].push_back(All.size() - 1);
      Name = std::nullopt;
      Payload = std::nullopt;
      continue;
    }
    if (Text.consume_front("[[")) {
      OpenRanges.push_back(
          {Code.size(), size_t(-1), Name.value_or(""), Payload.value_or("")});
      Name = std::nullopt;
      Payload = std::nullopt;
      continue;
    }
    Require(!Name, "$name should be followed by ^ or [[");
    if (Text.consume_front("]]")) {
      Require(!OpenRanges.empty(), "unmatched ]]");

      const Annotation &NewRange = OpenRanges.back();
      All.push_back(
          {NewRange.Begin, Code.size(), NewRange.Name, NewRange.Payload});
      Ranges[NewRange.Name].push_back(All.size() - 1);

      OpenRanges.pop_back();
      continue;
    }
    if (Text.consume_front("$")) {
      Name =
          Text.take_while([](char C) { return llvm::isAlnum(C) || C == '_'; });
      Text = Text.drop_front(Name->size());

      if (Text.consume_front("(")) {
        Payload = Text.take_while([](char C) { return C != ')'; });
        Require(Text.size() > Payload->size(), "unterminated payload");
        Text = Text.drop_front(Payload->size() + 1);
      }

      continue;
    }
    Code.push_back(Text.front());
    Text = Text.drop_front();
  }
  Require(!Name, "unterminated $name");
  Require(OpenRanges.empty(), "unmatched [[");
}

size_t Annotations::point(llvm::StringRef Name) const {
  return pointWithPayload(Name).first;
}

std::pair<size_t, llvm::StringRef>
Annotations::pointWithPayload(llvm::StringRef Name) const {
  auto I = Points.find(Name);
  require(I != Points.end() && I->getValue().size() == 1,
          "expected exactly one point", Code);
  const Annotation &P = All[I->getValue()[0]];
  return {P.Begin, P.Payload};
}

std::vector<size_t> Annotations::points(llvm::StringRef Name) const {
  auto Pts = pointsWithPayload(Name);
  std::vector<size_t> Positions;
  Positions.reserve(Pts.size());
  for (const auto &[Point, Payload] : Pts)
    Positions.push_back(Point);
  return Positions;
}

std::vector<std::pair<size_t, llvm::StringRef>>
Annotations::pointsWithPayload(llvm::StringRef Name) const {
  auto Iter = Points.find(Name);
  if (Iter == Points.end())
    return {};

  std::vector<std::pair<size_t, llvm::StringRef>> Res;
  Res.reserve(Iter->getValue().size());
  for (size_t I : Iter->getValue())
    Res.push_back({All[I].Begin, All[I].Payload});

  return Res;
}

llvm::StringMap<llvm::SmallVector<size_t, 1>> Annotations::all_points() const {
  llvm::StringMap<llvm::SmallVector<size_t, 1>> Result;
  for (const auto &Name : Points.keys()) {
    auto Pts = points(Name);
    Result[Name] = {Pts.begin(), Pts.end()};
  }
  return Result;
}

Annotations::Range Annotations::range(llvm::StringRef Name) const {
  return rangeWithPayload(Name).first;
}

std::pair<Annotations::Range, llvm::StringRef>
Annotations::rangeWithPayload(llvm::StringRef Name) const {
  auto I = Ranges.find(Name);
  require(I != Ranges.end() && I->getValue().size() == 1,
          "expected exactly one range", Code);
  const Annotation &R = All[I->getValue()[0]];
  return {{R.Begin, R.End}, R.Payload};
}

std::vector<Annotations::Range>
Annotations::ranges(llvm::StringRef Name) const {
  auto WithPayload = rangesWithPayload(Name);
  std::vector<Annotations::Range> Res;
  Res.reserve(WithPayload.size());
  for (const auto &[Range, Payload] : WithPayload)
    Res.push_back(Range);
  return Res;
}
std::vector<std::pair<Annotations::Range, llvm::StringRef>>
Annotations::rangesWithPayload(llvm::StringRef Name) const {
  auto Iter = Ranges.find(Name);
  if (Iter == Ranges.end())
    return {};

  std::vector<std::pair<Annotations::Range, llvm::StringRef>> Res;
  Res.reserve(Iter->getValue().size());
  for (size_t I : Iter->getValue())
    Res.emplace_back(Annotations::Range{All[I].Begin, All[I].End},
                     All[I].Payload);

  return Res;
}

llvm::StringMap<llvm::SmallVector<Annotations::Range, 1>>
Annotations::all_ranges() const {
  llvm::StringMap<llvm::SmallVector<Annotations::Range, 1>> Res;
  for (const llvm::StringRef &Name : Ranges.keys()) {
    auto R = ranges(Name);
    Res[Name] = {R.begin(), R.end()};
  }
  return Res;
}

llvm::raw_ostream &llvm::operator<<(llvm::raw_ostream &O,
                                    const llvm::Annotations::Range &R) {
  return O << llvm::formatv("[{0}, {1})", R.Begin, R.End);
}