/*
 * Copyright (C) 2004 Apple Computer, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
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 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_VISIBLE_SELECTION_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_VISIBLE_SELECTION_H_

#include "base/dcheck_is_on.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/editing/editing_strategy.h"
#include "third_party/blink/renderer/core/editing/forward.h"
#include "third_party/blink/renderer/core/editing/position.h"
#include "third_party/blink/renderer/core/editing/selection_adjuster.h"
#include "third_party/blink/renderer/core/editing/text_affinity.h"
#include "third_party/blink/renderer/core/editing/text_granularity.h"
#include "third_party/blink/renderer/core/editing/visible_units.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"

namespace blink {

const TextAffinity kSelDefaultAffinity = TextAffinity::kDownstream;

template <typename Strategy>
class VisibleSelectionTemplate {
  DISALLOW_NEW();

 public:
  class Creator;

  VisibleSelectionTemplate();
  VisibleSelectionTemplate(const VisibleSelectionTemplate&);
  VisibleSelectionTemplate& operator=(const VisibleSelectionTemplate&);

  TextAffinity Affinity() const { return affinity_; }

  SelectionTemplate<Strategy> AsSelection() const;
  PositionTemplate<Strategy> Anchor() const { return anchor_; }
  PositionTemplate<Strategy> Focus() const { return focus_; }
  PositionTemplate<Strategy> Start() const;
  PositionTemplate<Strategy> End() const;

  VisiblePositionTemplate<Strategy> VisibleStart() const;
  VisiblePositionTemplate<Strategy> VisibleEnd() const;
  VisiblePositionTemplate<Strategy> VisibleAnchor() const;
  VisiblePositionTemplate<Strategy> VisibleFocus() const;

  bool operator==(const VisibleSelectionTemplate&) const;

  bool IsNone() const;
  bool IsCaret() const;
  bool IsRange() const;

  // True if Anchor() <= Focus().
  bool IsAnchorFirst() const { return anchor_is_first_; }

  // TODO(yosin) Most callers probably don't want these functions, but
  // are using them for historical reasons. |toNormalizedEphemeralRange()|
  // contracts the range around text, and moves the caret most backward
  // visually equivalent position before returning the range/positions.
  EphemeralRangeTemplate<Strategy> ToNormalizedEphemeralRange() const;

  Element* RootEditableElement() const;
  bool IsContentEditable() const;

  bool IsValidFor(const Document&) const;

  void Trace(Visitor*) const;

#if DCHECK_IS_ON()
  void ShowTreeForThis() const;
#endif
  static void PrintTo(const VisibleSelectionTemplate&, std::ostream*);

 private:
  explicit VisibleSelectionTemplate(const SelectionTemplate<Strategy>&);

  // We need to store these as Positions because VisibleSelection is
  // used to store values in editing commands for use when
  // undoing the command. We need to be able to create a selection that, while
  // currently invalid, will be valid once the changes are undone.

  // Where the first click happened
  PositionTemplate<Strategy> anchor_;
  // Where the end click happened
  PositionTemplate<Strategy> focus_;

  // The upstream/downstream affinity of the caret.
  TextAffinity affinity_ = TextAffinity::kDownstream;

  // these are cached, can be recalculated by validate()
  bool anchor_is_first_ : 1 = true;  // True if anchor is before the focus
};

extern template class CORE_EXTERN_TEMPLATE_EXPORT
    VisibleSelectionTemplate<EditingStrategy>;
extern template class CORE_EXTERN_TEMPLATE_EXPORT
    VisibleSelectionTemplate<EditingInFlatTreeStrategy>;

using VisibleSelection = VisibleSelectionTemplate<EditingStrategy>;
using VisibleSelectionInFlatTree =
    VisibleSelectionTemplate<EditingInFlatTreeStrategy>;

CORE_EXPORT VisibleSelection CreateVisibleSelection(const SelectionInDomTree&);
CORE_EXPORT VisibleSelectionInFlatTree
CreateVisibleSelection(const SelectionInFlatTree&);

CORE_EXPORT SelectionInDomTree
ExpandWithGranularity(const SelectionInDomTree&,
                      TextGranularity,
                      const WordInclusion& = WordInclusion::kDefault);

CORE_EXPORT SelectionInFlatTree
ExpandWithGranularity(const SelectionInFlatTree&,
                      TextGranularity,
                      const WordInclusion& = WordInclusion::kDefault);

// We don't yet support multi-range selections, so we only ever have one range
// to return.
CORE_EXPORT EphemeralRange FirstEphemeralRangeOf(const VisibleSelection&);
CORE_EXPORT EphemeralRange NormalizeRange(const SelectionInDomTree&);
CORE_EXPORT EphemeralRangeInFlatTree NormalizeRange(const SelectionInFlatTree&);

CORE_EXPORT std::ostream& operator<<(std::ostream&, const VisibleSelection&);
CORE_EXPORT std::ostream& operator<<(std::ostream&,
                                     const VisibleSelectionInFlatTree&);

PositionInFlatTree ComputeStartRespectingGranularity(
    const PositionInFlatTreeWithAffinity&,
    TextGranularity);

PositionInFlatTree ComputeEndRespectingGranularity(
    const PositionInFlatTree&,
    const PositionInFlatTreeWithAffinity&,
    TextGranularity);

}  // namespace blink

#if DCHECK_IS_ON()
// Outside the blink namespace for ease of invocation from gdb.
void ShowTree(const blink::VisibleSelection&);
void ShowTree(const blink::VisibleSelection*);
void ShowTree(const blink::VisibleSelectionInFlatTree&);
void ShowTree(const blink::VisibleSelectionInFlatTree*);
#endif

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_VISIBLE_SELECTION_H_