/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying

   file LICENSE.rst or https://cmake.org/licensing for details.  */

#include "cmGeneratorExpressionParser.h"

#include <cassert>

#include <cstddef>

#include <utility>

#include <cm/memory>

#include <cmext/algorithm>

#include <cmext/memory>

#include "cmGeneratorExpressionEvaluator.h"

#include "cmUnreachable.h"

cmGeneratorExpressionParser::cmGeneratorExpressionParser(

  std::vector<cmGeneratorExpressionToken> tokens)

  : Tokens(std::move(tokens))

{

}

void cmGeneratorExpressionParser::Parse(

  cmGeneratorExpressionEvaluatorVector& result)

{

  this->it = this->Tokens.begin();

  while (this->it != this->Tokens.end()) {

    this->ParseContent(result);

  }

}

static void extendText(

  cmGeneratorExpressionEvaluatorVector& result,

  std::vector<cmGeneratorExpressionToken>::const_iterator it)

{

  if (!result.empty() &&

      (*(result.end() - 1))->GetType() ==

        cmGeneratorExpressionEvaluator::Text) {

    cm::static_reference_cast<TextContent>(*(result.end() - 1))

      .Extend(it->Length);

  } else {

    auto textContent = cm::make_unique<TextContent>(it->Content, it->Length);

    result.push_back(std::move(textContent));

  }

}

static void extendResult(

  cmGeneratorExpressionParser::cmGeneratorExpressionEvaluatorVector& result,

  cmGeneratorExpressionParser::cmGeneratorExpressionEvaluatorVector&& contents)

{

  if (!result.empty() &&

      (*(result.end() - 1))->GetType() ==

        cmGeneratorExpressionEvaluator::Text &&

      contents.front()->GetType() == cmGeneratorExpressionEvaluator::Text) {

    cm::static_reference_cast<TextContent>(*(result.end() - 1))

      .Extend(

        cm::static_reference_cast<TextContent>(contents.front()).GetLength());

    contents.erase(contents.begin());

  }

  cm::append(result, std::move(contents));

}

void cmGeneratorExpressionParser::ParseGeneratorExpression(

  cmGeneratorExpressionEvaluatorVector& result)

{

  assert(this->it != this->Tokens.end());

  unsigned int nestedLevel = this->NestingLevel;

  ++this->NestingLevel;

  auto startToken = this->it - 1;

  cmGeneratorExpressionEvaluatorVector identifier;

  while (this->it->TokenType != cmGeneratorExpressionToken::EndExpression &&

         this->it->TokenType != cmGeneratorExpressionToken::ColonSeparator) {

    if (this->it->TokenType == cmGeneratorExpressionToken::CommaSeparator) {

      extendText(identifier, this->it);

      ++this->it;

    } else {

      this->ParseContent(identifier);

    }

    if (this->it == this->Tokens.end()) {

      break;

    }

  }

  if (identifier.empty()) {

    // ERROR

  }

  if (this->it != this->Tokens.end() &&

      this->it->TokenType == cmGeneratorExpressionToken::EndExpression) {

    auto content = cm::make_unique<GeneratorExpressionContent>(

      startToken->Content,

      this->it->Content - startToken->Content + this->it->Length);

    assert(this->it != this->Tokens.end());

    ++this->it;

    --this->NestingLevel;

    content->SetIdentifier(std::move(identifier));

    result.push_back(std::move(content));

    return;

  }

  std::vector<cmGeneratorExpressionEvaluatorVector> parameters;

  std::vector<std::vector<cmGeneratorExpressionToken>::const_iterator>

    commaTokens;

  std::vector<cmGeneratorExpressionToken>::const_iterator colonToken;

  bool emptyParamTermination = false;

  if (this->it != this->Tokens.end() &&

      this->it->TokenType == cmGeneratorExpressionToken::ColonSeparator) {

    colonToken = this->it;

    parameters.resize(parameters.size() + 1);

    assert(this->it != this->Tokens.end());

    ++this->it;

    if (this->it == this->Tokens.end()) {

      emptyParamTermination = true;

    }

    auto handleCommaOrColon = [this, &commaTokens, &parameters,

                               &emptyParamTermination]() -> void {

      if (this->it->TokenType == cmGeneratorExpressionToken::CommaSeparator) {

        commaTokens.push_back(this->it);

        parameters.resize(parameters.size() + 1);

        assert(this->it != this->Tokens.end());

        ++this->it;

        if (this->it == this->Tokens.end()) {

          emptyParamTermination = true;

        }

      } else if (this->it->TokenType ==

                 cmGeneratorExpressionToken::ColonSeparator) {

        extendText(*(parameters.end() - 1), this->it);

        assert(this->it != this->Tokens.end());

        ++this->it;

      }

    };

    while (

      this->it != this->Tokens.end() &&

      (this->it->TokenType == cmGeneratorExpressionToken::CommaSeparator ||

       this->it->TokenType == cmGeneratorExpressionToken::ColonSeparator)) {

      handleCommaOrColon();

    }

    while (this->it != this->Tokens.end() &&

           this->it->TokenType != cmGeneratorExpressionToken::EndExpression) {

      this->ParseContent(*(parameters.end() - 1));

      if (this->it == this->Tokens.end()) {

        break;

      }

      while (

        this->it != this->Tokens.end() &&

        (this->it->TokenType == cmGeneratorExpressionToken::CommaSeparator ||

         this->it->TokenType == cmGeneratorExpressionToken::ColonSeparator)) {

        handleCommaOrColon();

      }

    }

    if (this->it != this->Tokens.end() &&

        this->it->TokenType == cmGeneratorExpressionToken::EndExpression) {

      --this->NestingLevel;

      assert(this->it != this->Tokens.end());

      ++this->it;

    }

  }

  if (nestedLevel != this->NestingLevel) {

    // There was a '$<' in the text, but no corresponding '>'. Rebuild to

    // treat the '$<' as having been plain text, along with the

    // corresponding : and , tokens that might have been found.

    extendText(result, startToken);

    extendResult(result, std::move(identifier));

    if (!parameters.empty()) {

      extendText(result, colonToken);

      auto pit = parameters.begin();

      auto const pend = parameters.end();

      auto commaIt = commaTokens.begin();

      assert(parameters.size() > commaTokens.size());

      for (; pit != pend; ++pit, ++commaIt) {

        if (!pit->empty() && !emptyParamTermination) {

          extendResult(result, std::move(*pit));

        }

        if (commaIt != commaTokens.end()) {

          extendText(result, *commaIt);

        } else {

          break;

        }

      }

    }

    return;

  }

  size_t contentLength =

    ((this->it - 1)->Content - startToken->Content) + (this->it - 1)->Length;

  auto content = cm::make_unique<GeneratorExpressionContent>(

    startToken->Content, contentLength);

  content->SetIdentifier(std::move(identifier));

  content->SetParameters(std::move(parameters));

  result.push_back(std::move(content));

}

void cmGeneratorExpressionParser::ParseContent(

  cmGeneratorExpressionEvaluatorVector& result)

{

  assert(this->it != this->Tokens.end());

  switch (this->it->TokenType) {

    case cmGeneratorExpressionToken::Text: {

      if (this->NestingLevel == 0) {

        if (!result.empty() &&

            (*(result.end() - 1))->GetType() ==

              cmGeneratorExpressionEvaluator::Text) {

          // A comma in 'plain text' could have split text that should

          // otherwise be continuous. Extend the last text content instead of

          // creating a new one.

          cm::static_reference_cast<TextContent>(*(result.end() - 1))

            .Extend(this->it->Length);

          assert(this->it != this->Tokens.end());

          ++this->it;

          return;

        }

      }

      auto n =

        cm::make_unique<TextContent>(this->it->Content, this->it->Length);

      result.push_back(std::move(n));

      assert(this->it != this->Tokens.end());

      ++this->it;

      return;

    }

    case cmGeneratorExpressionToken::BeginExpression:

      assert(this->it != this->Tokens.end());

      ++this->it;

      this->ParseGeneratorExpression(result);

      return;

    case cmGeneratorExpressionToken::EndExpression:

    case cmGeneratorExpressionToken::ColonSeparator:

    case cmGeneratorExpressionToken::CommaSeparator:

      if (this->NestingLevel == 0) {

        extendText(result, this->it);

      } else {

        CM_UNREACHABLE;

      }

      assert(this->it != this->Tokens.end());

      ++this->it;

      return;

  }

  CM_UNREACHABLE;

}