/*

 * Copyright (c) Meta Platforms, Inc. and affiliates.

 *

 * This source code is licensed under the MIT license found in the

 * LICENSE file in the root directory of this source tree.

 */

#include "hermes/SourceMap/SourceMap.h"

namespace hermes {

/// Query source map text location for \p line and \p column.

/// In both the input and output of this function, line and column numbers

/// are 1-based.

llvh::Optional<SourceMapTextLocationFIndex>

SourceMap::getLocationForAddressFIndex(uint32_t line, uint32_t column) const {

  auto seg = this->getSegmentForAddress(line, column);

  // Unmapped location

  if (!seg.hasValue() || !seg->representedLocation.hasValue()) {

    return llvh::None;

  }

  // parseSegment() should have validated this.

  assert(

      (size_t)seg->representedLocation->sourceIndex < sources_.size() &&

      "SourceIndex is out-of-range.");

  return SourceMapTextLocationFIndex{

      (uint32_t)seg->representedLocation->sourceIndex,

      (uint32_t)seg->representedLocation->lineIndex + 1,

      (uint32_t)seg->representedLocation->columnIndex + 1};

}

llvh::Optional<SourceMapTextLocation> SourceMap::getLocationForAddress(

    uint32_t line,

    uint32_t column) const {

  auto loc = getLocationForAddressFIndex(line, column);

  if (!loc)

    return llvh::None;

  return SourceMapTextLocation{

      getSourceFullPath(loc->fileIndex), loc->line, loc->column};

}

llvh::Optional<SourceMap::Segment> SourceMap::getSegmentForAddress(

    uint32_t line,

    uint32_t column) const {

  if (line == 0 || line > lines_.size()) {

    return llvh::None;

  }

  // line is 1-based.

  uint32_t lineIndex = line - 1;

  auto &segments = lines_[lineIndex];

  if (segments.empty()) {

    return llvh::None;

  }

  assert(column >= 1 && "the column argument to this function is 1-based");

  uint32_t columnIndex = column - 1;

  // Algorithm: we wanted to locate the segment covering

  // the needle(`column`) -- segment.generatedColumn <= column.

  // We achieve it by binary searching the first sentinel

  // segment strictly greater than needle(`column`) and then move backward

  // one slot.

  auto segIter = std::upper_bound(

      segments.begin(),

      segments.end(),

      columnIndex,

      [](uint32_t column, const Segment &seg) {

        return column < (uint32_t)seg.generatedColumn;

      });

  // The found sentinel segment is the first one. No covering segment.

  if (segIter == segments.begin()) {

    return llvh::None;

  }

  // Move back one slot.

  const Segment &target =

      segIter == segments.end() ? segments.back() : *(--segIter);

  return target;

}

} // namespace hermes