Upsilon/escher/include/escher/text_area.h

#ifndef ESCHER_TEXT_AREA_H
#define ESCHER_TEXT_AREA_H

#include <escher/text_input.h>
#include <escher/input_event_handler.h>
#include <escher/text_area_delegate.h>
#include <assert.h>
#include <string.h>

// See TODO in EditableField

class TextArea : public TextInput, public InputEventHandler {
public:
  static constexpr int k_indentationSpaces = 2;

  TextArea(Responder * parentResponder, View * contentView, const KDFont * font = KDFont::LargeFont);
  void setDelegates(InputEventHandlerDelegate * inputEventHandlerDelegate, TextAreaDelegate * delegate) { m_inputEventHandlerDelegate = inputEventHandlerDelegate; m_delegate = delegate; }
  bool handleEvent(Ion::Events::Event event) override;
  bool handleEventWithText(const char * text, bool indentation = false, bool forceCursorRightOfText = false) override;
  void setText(char * textBuffer, size_t textBufferSize);

protected:
  int indentationBeforeCursor() const;

  class Text {
  public:
    Text(char * buffer, size_t bufferSize) :
      m_buffer(buffer),
      m_bufferSize(bufferSize)
    {
    }
    void setText(char * buffer, size_t bufferSize) {
      m_buffer = buffer;
      m_bufferSize = bufferSize;
    }
    const char * text() const { return m_buffer; }

    class Line {
    public:
      Line(const char * text);
      const char * text() const { return m_text; }
      size_t charLength() const { return m_charLength; }
      KDCoordinate glyphWidth(const KDFont * const font) const;
      bool contains(const char * c) const;
    private:
      const char * m_text;
      size_t m_charLength;
    };

    class LineIterator {
    public:
      LineIterator(const char * text) : m_line(text) {}
      Line operator*() { return m_line; }
      LineIterator& operator++();
      bool operator!=(const LineIterator& it) const { return m_line.text() != it.m_line.text(); }
    private:
      Line m_line;
    };

    class Position {
    /* column and line correspond to the visual column and line. The glyph at
     * the kth column is not the the glyph of kth code point, because of
     * combining code points that do not fave a personal glyph. */
    public:
      Position(int column, int line) : m_column(column), m_line(line) {}
      int column() const { return m_column; }
      int line() const { return m_line; }
    private:
      int m_column;
      int m_line;
    };

    LineIterator begin() const { return LineIterator(m_buffer); };
    LineIterator end() const { return LineIterator(nullptr); };

    KDSize span(const KDFont * const font) const;

    Position positionAtPointer(const char * pointer) const;
    const char * pointerAtPosition(Position p);

    void insertText(const char * s, int textLength, char * location);
    void insertSpacesAtLocation(int numberOfSpaces, char * location);

    CodePoint removePreviousGlyph(char * * position);
    size_t removeText(const char * start, const char * end);
    size_t removeRemainingLine(const char * position, int direction);
    char operator[](size_t index) {
      assert(index < m_bufferSize);
      return m_buffer[index];
    }
    size_t bufferSize() const {
      return m_bufferSize;
    }
    size_t textLength() const {
      return strlen(m_buffer);
    }
    int textLineTotal() const {
      return positionAtPointer(m_buffer+textLength()).line();
    }
  private:
    char * m_buffer;
    size_t m_bufferSize;
  };

  class ContentView : public TextInput::ContentView {
  public:
    ContentView(const KDFont * font) :
      TextInput::ContentView(font),
      m_text(nullptr, 0)
    {
      m_cursorLocation = m_text.text();
    }
    void drawRect(KDContext * ctx, KDRect rect) const override;
    void drawStringAt(KDContext * ctx, int line, int column, const char * text, int length, KDColor textColor, KDColor backgroundColor, const char * selectionStart, const char * selectionEnd, KDColor backgroundHighlightColor, bool isItalic = false) const;
    virtual void drawLine(KDContext * ctx, int line, const char * text, size_t length, int fromColumn, int toColumn, const char * selectionStart, const char * selectionEnd) const = 0;
    virtual void clearRect(KDContext * ctx, KDRect rect) const = 0;
    KDSize minimalSizeForOptimalDisplay() const override;
    void setText(char * textBuffer, size_t textBufferSize);
    const char * text() const override { return m_text.text(); }
    const char * editedText() const override { return m_text.text(); }
    size_t editedTextLength() const override { return m_text.textLength(); }
    const Text * getText() const { return &m_text; }
    bool insertTextAtLocation(const char * text, char * location, int textLength = -1) override;
    void moveCursorGeo(int deltaX, int deltaY);
    bool removePreviousGlyph() override;
    bool removeEndOfLine() override;
    bool removeStartOfLine();
    size_t removeText(const char * start, const char * end);
    size_t deleteSelection() override;
  protected:
    KDRect glyphFrameAtPosition(const char * text, const char * position) const override;
    Text m_text;
  };

  ContentView * contentView() { return static_cast<ContentView *>(TextInput::contentView()); }
private:
  void selectUpDown(bool up, int step);
  TextAreaDelegate * m_delegate;
  // Due to rect size limitation, the editor cannot display more than 1800 lines
  constexpr static int k_maxLines = 999;
  constexpr static int k_maxLineChars = 3000;
};

#endif