text_editor.h

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#ifndef YAZE_APP_GUI_MODULES_TEXT_EDITOR_H
#define YAZE_APP_GUI_MODULES_TEXT_EDITOR_H
 
// Originally from ImGuiColorTextEdit/TextEditor.h
 
#include <array>
#include <map>
#include <memory>
#include <regex>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
 
#include "imgui/imgui.h"
 
class TextEditor {
 public:
  enum class PaletteIndex {
    Default,
    Keyword,
    Number,
    String,
    CharLiteral,
    Punctuation,
    Preprocessor,
    Identifier,
    KnownIdentifier,
    PreprocIdentifier,
    Comment,
    MultiLineComment,
    Background,
    Cursor,
    Selection,
    ErrorMarker,
    Breakpoint,
    LineNumber,
    CurrentLineFill,
    CurrentLineFillInactive,
    CurrentLineEdge,
    Max
  };
 
  enum class SelectionMode { Normal, Word, Line };
 
  struct Breakpoint {
    int mLine;
    bool mEnabled;
    std::string mCondition;
 
    Breakpoint() : mLine(-1), mEnabled(false) {}
  };
 
  // Represents a character coordinate from the user's point of view,
  // i. e. consider an uniform grid (assuming fixed-width font) on the
  // screen as it is rendered, and each cell has its own coordinate, starting
  // from 0. Tabs are counted as [1..mTabSize] count empty spaces, depending on
  // how many space is necessary to reach the next tab stop.
  // For example, coordinate (1, 5) represents the character 'B' in a line
  // "\tABC", when mTabSize = 4, because it is rendered as "    ABC" on the
  // screen.
  struct Coordinates {
    int mLine, mColumn;
    Coordinates() : mLine(0), mColumn(0) {}
    Coordinates(int aLine, int aColumn) : mLine(aLine), mColumn(aColumn) {
      assert(aLine >= 0);
      assert(aColumn >= 0);
    }
    static Coordinates Invalid() {
      static Coordinates invalid(-1, -1);
      return invalid;
    }
 
    bool operator==(const Coordinates& o) const {
      return mLine == o.mLine && mColumn == o.mColumn;
    }
 
    bool operator!=(const Coordinates& o) const {
      return mLine != o.mLine || mColumn != o.mColumn;
    }
 
    bool operator<(const Coordinates& o) const {
      if (mLine != o.mLine)
        return mLine < o.mLine;
      return mColumn < o.mColumn;
    }
 
    bool operator>(const Coordinates& o) const {
      if (mLine != o.mLine)
        return mLine > o.mLine;
      return mColumn > o.mColumn;
    }
 
    bool operator<=(const Coordinates& o) const {
      if (mLine != o.mLine)
        return mLine < o.mLine;
      return mColumn <= o.mColumn;
    }
 
    bool operator>=(const Coordinates& o) const {
      if (mLine != o.mLine)
        return mLine > o.mLine;
      return mColumn >= o.mColumn;
    }
  };
 
  struct Identifier {
    Coordinates mLocation;
    std::string mDeclaration;
  };
 
  typedef std::string String;
  typedef std::unordered_map<std::string, Identifier> Identifiers;
  typedef std::unordered_set<std::string> Keywords;
  typedef std::map<int, std::string> ErrorMarkers;
  typedef std::unordered_set<int> Breakpoints;
  typedef std::array<ImU32, (unsigned)PaletteIndex::Max> Palette;
  typedef uint8_t Char;
 
  struct Glyph {
    Char mChar;
    PaletteIndex mColorIndex = PaletteIndex::Default;
    bool mComment : 1;
    bool mMultiLineComment : 1;
    bool mPreprocessor : 1;
 
    Glyph(Char aChar, PaletteIndex aColorIndex)
        : mChar(aChar),
          mColorIndex(aColorIndex),
          mComment(false),
          mMultiLineComment(false),
          mPreprocessor(false) {}
  };
 
  typedef std::vector<Glyph> Line;
  typedef std::vector<Line> Lines;
 
  struct LanguageDefinition {
    typedef std::pair<std::string, PaletteIndex> TokenRegexString;
    typedef std::vector<TokenRegexString> TokenRegexStrings;
    typedef bool (*TokenizeCallback)(const char* in_begin, const char* in_end,
                                     const char*& out_begin,
                                     const char*& out_end,
                                     PaletteIndex& paletteIndex);
 
    std::string mName;
    Keywords mKeywords;
    Identifiers mIdentifiers;
    Identifiers mPreprocIdentifiers;
    std::string mCommentStart, mCommentEnd, mSingleLineComment;
    char mPreprocChar;
    bool mAutoIndentation;
 
    TokenizeCallback mTokenize;
 
    TokenRegexStrings mTokenRegexStrings;
 
    bool mCaseSensitive;
 
    LanguageDefinition()
        : mPreprocChar('#'),
          mAutoIndentation(true),
          mTokenize(nullptr),
          mCaseSensitive(true) {}
 
    static const LanguageDefinition& CPlusPlus();
    static const LanguageDefinition& HLSL();
    static const LanguageDefinition& GLSL();
    static const LanguageDefinition& C();
    static const LanguageDefinition& SQL();
    static const LanguageDefinition& AngelScript();
    static const LanguageDefinition& Lua();
  };
 
  TextEditor();
  ~TextEditor();
 
  void SetLanguageDefinition(const LanguageDefinition& aLanguageDef);
  const LanguageDefinition& GetLanguageDefinition() const {
    return mLanguageDefinition;
  }
 
  const Palette& GetPalette() const { return mPaletteBase; }
  void SetPalette(const Palette& aValue);
 
  void SetErrorMarkers(const ErrorMarkers& aMarkers) {
    mErrorMarkers = aMarkers;
  }
  void SetBreakpoints(const Breakpoints& aMarkers) { mBreakpoints = aMarkers; }
 
  void Render(const char* aTitle, const ImVec2& aSize = ImVec2(),
              bool aBorder = false);
  void SetText(const std::string& aText);
  std::string GetText() const;
 
  void SetTextLines(const std::vector<std::string>& aLines);
  std::vector<std::string> GetTextLines() const;
 
  std::string GetSelectedText() const;
  std::string GetCurrentLineText() const;
 
  int GetTotalLines() const { return (int)mLines.size(); }
  bool IsOverwrite() const { return mOverwrite; }
 
  void SetReadOnly(bool aValue);
  bool IsReadOnly() const { return mReadOnly; }
  bool IsTextChanged() const { return mTextChanged; }
  bool IsCursorPositionChanged() const { return mCursorPositionChanged; }
 
  bool IsColorizerEnabled() const { return mColorizerEnabled; }
  void SetColorizerEnable(bool aValue);
 
  Coordinates GetCursorPosition() const { return GetActualCursorCoordinates(); }
  void SetCursorPosition(const Coordinates& aPosition);
 
  inline void SetHandleMouseInputs(bool aValue) { mHandleMouseInputs = aValue; }
  inline bool IsHandleMouseInputsEnabled() const {
    return mHandleKeyboardInputs;
  }
 
  inline void SetHandleKeyboardInputs(bool aValue) {
    mHandleKeyboardInputs = aValue;
  }
  inline bool IsHandleKeyboardInputsEnabled() const {
    return mHandleKeyboardInputs;
  }
 
  inline void SetImGuiChildIgnored(bool aValue) { mIgnoreImGuiChild = aValue; }
  inline bool IsImGuiChildIgnored() const { return mIgnoreImGuiChild; }
 
  inline void SetShowWhitespaces(bool aValue) { mShowWhitespaces = aValue; }
  inline bool IsShowingWhitespaces() const { return mShowWhitespaces; }
 
  void SetTabSize(int aValue);
  inline int GetTabSize() const { return mTabSize; }
 
  void InsertText(const std::string& aValue);
  void InsertText(const char* aValue);
 
  void MoveUp(int aAmount = 1, bool aSelect = false);
  void MoveDown(int aAmount = 1, bool aSelect = false);
  void MoveLeft(int aAmount = 1, bool aSelect = false, bool aWordMode = false);
  void MoveRight(int aAmount = 1, bool aSelect = false, bool aWordMode = false);
  void MoveTop(bool aSelect = false);
  void MoveBottom(bool aSelect = false);
  void MoveHome(bool aSelect = false);
  void MoveEnd(bool aSelect = false);
 
  void SetSelectionStart(const Coordinates& aPosition);
  void SetSelectionEnd(const Coordinates& aPosition);
  void SetSelection(const Coordinates& aStart, const Coordinates& aEnd,
                    SelectionMode aMode = SelectionMode::Normal);
  void SelectWordUnderCursor();
  void SelectAll();
  bool HasSelection() const;
 
  void Copy();
  void Cut();
  void Paste();
  void Delete();
 
  bool CanUndo() const;
  bool CanRedo() const;
  void Undo(int aSteps = 1);
  void Redo(int aSteps = 1);
 
  static const Palette& GetDarkPalette();
  static const Palette& GetLightPalette();
  static const Palette& GetRetroBluePalette();
 
 private:
  typedef std::vector<std::pair<std::regex, PaletteIndex>> RegexList;
 
  struct EditorState {
    Coordinates mSelectionStart;
    Coordinates mSelectionEnd;
    Coordinates mCursorPosition;
  };
 
  class UndoRecord {
   public:
    UndoRecord() {}
    ~UndoRecord() {}
 
    UndoRecord(const std::string& aAdded,
               const TextEditor::Coordinates aAddedStart,
               const TextEditor::Coordinates aAddedEnd,
 
               const std::string& aRemoved,
               const TextEditor::Coordinates aRemovedStart,
               const TextEditor::Coordinates aRemovedEnd,
 
               TextEditor::EditorState& aBefore,
               TextEditor::EditorState& aAfter);
 
    void Undo(TextEditor* aEditor);
    void Redo(TextEditor* aEditor);
 
    std::string mAdded;
    Coordinates mAddedStart;
    Coordinates mAddedEnd;
 
    std::string mRemoved;
    Coordinates mRemovedStart;
    Coordinates mRemovedEnd;
 
    EditorState mBefore;
    EditorState mAfter;
  };
 
  typedef std::vector<UndoRecord> UndoBuffer;
 
  void ProcessInputs();
  void Colorize(int aFromLine = 0, int aCount = -1);
  void ColorizeRange(int aFromLine = 0, int aToLine = 0);
  void ColorizeInternal();
  float TextDistanceToLineStart(const Coordinates& aFrom) const;
  void EnsureCursorVisible();
  int GetPageSize() const;
  std::string GetText(const Coordinates& aStart, const Coordinates& aEnd) const;
  Coordinates GetActualCursorCoordinates() const;
  Coordinates SanitizeCoordinates(const Coordinates& aValue) const;
  void Advance(Coordinates& aCoordinates) const;
  void DeleteRange(const Coordinates& aStart, const Coordinates& aEnd);
  int InsertTextAt(Coordinates& aWhere, const char* aValue);
  void AddUndo(UndoRecord& aValue);
  Coordinates ScreenPosToCoordinates(const ImVec2& aPosition) const;
  Coordinates FindWordStart(const Coordinates& aFrom) const;
  Coordinates FindWordEnd(const Coordinates& aFrom) const;
  Coordinates FindNextWord(const Coordinates& aFrom) const;
  int GetCharacterIndex(const Coordinates& aCoordinates) const;
  int GetCharacterColumn(int aLine, int aIndex) const;
  int GetLineCharacterCount(int aLine) const;
  int GetLineMaxColumn(int aLine) const;
  bool IsOnWordBoundary(const Coordinates& aAt) const;
  void RemoveLine(int aStart, int aEnd);
  void RemoveLine(int aIndex);
  Line& InsertLine(int aIndex);
  void EnterCharacter(ImWchar aChar, bool aShift);
  void Backspace();
  void DeleteSelection();
  std::string GetWordUnderCursor() const;
  std::string GetWordAt(const Coordinates& aCoords) const;
  ImU32 GetGlyphColor(const Glyph& aGlyph) const;
 
  void HandleKeyboardInputs();
  void HandleMouseInputs();
  void Render();
 
  float mLineSpacing;
  Lines mLines;
  EditorState mState;
  UndoBuffer mUndoBuffer;
  int mUndoIndex;
 
  int mTabSize;
  bool mOverwrite;
  bool mReadOnly;
  bool mWithinRender;
  bool mScrollToCursor;
  bool mScrollToTop;
  bool mTextChanged;
  bool mColorizerEnabled;
  float mTextStart;  // position (in pixels) where a code line starts relative
                     // to the left of the TextEditor.
  int mLeftMargin;
  bool mCursorPositionChanged;
  int mColorRangeMin, mColorRangeMax;
  SelectionMode mSelectionMode;
  bool mHandleKeyboardInputs;
  bool mHandleMouseInputs;
  bool mIgnoreImGuiChild;
  bool mShowWhitespaces;
 
  Palette mPaletteBase;
  Palette mPalette;
  LanguageDefinition mLanguageDefinition;
  RegexList mRegexList;
 
  bool mCheckComments;
  Breakpoints mBreakpoints;
  ErrorMarkers mErrorMarkers;
  ImVec2 mCharAdvance;
  Coordinates mInteractiveStart, mInteractiveEnd;
  std::string mLineBuffer;
  uint64_t mStartTime;
 
  float mLastClick;
};
 
#endif  // YAZE_APP_GUI_MODULES_TEXT_EDITOR_H