// Copyright 2010-2013, Google 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:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * 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.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "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 THE COPYRIGHT
// OWNER 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 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef MOZC_UNIX_FCITX_SURROUNDING_TEXT_URIL_H_
#define MOZC_UNIX_FCITX_SURROUNDING_TEXT_URIL_H_

#include <fcitx/inputcontext.h>

#include <string>

#include "base/port.h"

namespace fcitx {

class AddonInstance;

struct SurroundingTextInfo {
  SurroundingTextInfo() : relative_selected_length(0) {}

  int32 relative_selected_length;
  std::string preceding_text;
  std::string selection_text;
  std::string following_text;
};

class SurroundingTextUtil {
 public:
  // Calculates |from| - |to| and stores the result into |delta| with
  // checking integer overflow.
  // Returns true when neither |abs(delta)| nor |-delta| does not cause
  // integer overflow, that is, |delta| is in a safe range.
  // Returns false otherwise.
  static bool GetSafeDelta(uint from, uint to, int32 *delta);

  // Returns true if
  // 1. |surrounding_text| contains |selected_text|
  //    from |cursor_pos| to |*anchor_pos|.
  // or,
  // 2. |surrounding_text| contains |selected_text|
  //    from |*anchor_pos| to |cursor_pos|.
  // with calculating |*anchor_pos|,
  // where |cursor_pos| and |*anchor_pos| are counts of Unicode characters.
  // When both 1) and 2) are satisfied, this function calculates
  // |*anchor_pos| for case 1).
  // Otherwise returns false.
  static bool GetAnchorPosFromSelection(const std::string &surrounding_text,
                                        const std::string &selected_text,
                                        uint cursor_pos, uint *anchor_pos);

 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(SurroundingTextUtil);
};

bool GetSurroundingText(InputContext *ic, SurroundingTextInfo *info,
                        AddonInstance *clipboard);

}  // namespace fcitx

#endif  // MOZC_UNIX_FCITX_SURROUNDING_TEXT_URIL_H_
