////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2009-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
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// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
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////////////////////////////////////////////////////////////////////////

#if ! defined (octave_text_engine_h)
#define octave_text_engine_h 1

#include "octave-config.h"

#include <memory>
#include <string>

#include "base-list.h"
#include "caseless-str.h"
#include "dMatrix.h"

namespace octave
{
  class text_element;
  class text_element_string;
  class text_element_symbol;
  class text_element_list;
  class text_element_subscript;
  class text_element_superscript;
  class text_element_combined;
  class text_element_fontname;
  class text_element_fontsize;
  class text_element_fontstyle;
  class text_element_color;

  class text_processor;

  class
  OCTINTERP_API
  text_element
  {
  public:
    text_element (void) { }

    virtual ~text_element (void) = default;

    virtual void accept (text_processor& p) = 0;

  private:
    text_element (const text_element&);
  };

  class
  OCTINTERP_API
  text_element_string : public text_element
  {
  public:
    text_element_string (const std::string& s = "")
      : text_element (), m_str (s) { }

    ~text_element_string (void) = default;

    std::string string_value (void) const { return m_str; }

    void accept (text_processor& p);

  private:
    text_element_string (const text_element_string &);

    //--------

    std::string m_str;
  };

  class
  OCTINTERP_API
  text_element_symbol : public text_element
  {
  public:
    enum { invalid_code = 0xFFFFFFFFU };

    text_element_symbol (int sym)
      : text_element (), m_symbol (sym) { }

    ~text_element_symbol (void) = default;

    int get_symbol (void) const { return m_symbol; }

    uint32_t get_symbol_code (void) const;

    void accept (text_processor& p);

  private:
    int m_symbol;
  };

  class
  OCTINTERP_API
  text_element_list
    : public text_element, public base_list<text_element *>
  {
  public:
    text_element_list (void)
      : text_element (), base_list<text_element*> () { }

    text_element_list (text_element *e)
      : text_element (), base_list<text_element*> ()
    {
      push_back (e);
    }

    ~text_element_list (void)
    {
      while (! empty ())
        {
          auto it = begin ();
          delete (*it);
          erase (it);
        }
    }

    void accept (text_processor& p);
  };

  class
  OCTINTERP_API
  text_element_subscript : public text_element
  {
  public:
    text_element_subscript (text_element *e)
      : text_element (), m_elem (e) { }

    text_element_subscript (char c)
      : text_element ()
    { m_elem = new text_element_string (std::string (1, c)); }

    ~text_element_subscript (void)
    { delete m_elem; }

    void accept (text_processor& p);

    text_element * get_element (void) { return m_elem; }

  private:
    text_element_subscript (void);
    
    //--------

    text_element *m_elem;

  };

  class
  OCTINTERP_API
  text_element_superscript : public text_element
  {
  public:
    text_element_superscript (text_element *e)
      : text_element (), m_elem (e) { }

    text_element_superscript (char c)
      : text_element ()
    { m_elem = new text_element_string (std::string (1, c)); }

    ~text_element_superscript (void)
    { delete m_elem; }

    void accept (text_processor& p);

    text_element * get_element (void) { return m_elem; }

  private:
    text_element_superscript (void);

    //--------

    text_element *m_elem;

  };

  class
  OCTINTERP_API
  text_element_combined : public text_element_list
  {
  public:
    text_element_combined (text_element *e)
      : text_element_list (e) { }

    text_element_combined (text_element *e1, text_element *e2)
      : text_element_list(e1)
    { push_back (e2); }

    void accept (text_processor& p);
  };

  class
  OCTINTERP_API
  text_element_fontstyle : public text_element
  {
  public:
    enum fontstyle
    {
      normal,
      bold,
      italic,
      oblique
    };

    text_element_fontstyle (fontstyle st)
      : text_element (), m_style (st) { }

    ~text_element_fontstyle (void) = default;

    fontstyle get_fontstyle (void) const { return m_style; }

    void accept (text_processor& p);

  private:
    text_element_fontstyle (void);

    //--------

    fontstyle m_style;

  };

  class
  OCTINTERP_API
  text_element_fontname : public text_element
  {
  public:
    text_element_fontname (const std::string& fname)
      : text_element (), m_name (fname) { }

    ~text_element_fontname (void) = default;

    const std::string& get_fontname (void) const { return m_name; }

    void accept (text_processor& p);

  private:
    text_element_fontname (void);

    //--------

    std::string m_name;

  };

  class
  OCTINTERP_API
  text_element_fontsize : public text_element
  {
  public:
    text_element_fontsize (double fsize)
      : text_element (), m_size (fsize) { }

    ~text_element_fontsize (void) = default;

    double get_fontsize (void) const { return m_size; }

    void accept (text_processor& p);

  private:
    text_element_fontsize (void);

    //--------

    double m_size;

  };

  class
  OCTINTERP_API
  text_element_color : public text_element
  {
  public:
    text_element_color (double r, double g, double b)
      : text_element (), m_rgb (1, 3, 0.0)
    {
      m_rgb(0) = r;
      m_rgb(1) = g;
      m_rgb(2) = b;
    }

    text_element_color (const std::string& cname)
      : text_element (), m_rgb (1, 3, 0.0)
    {
#define ASSIGN_COLOR(r,g,b) { m_rgb(0) = r; m_rgb(1) = g; m_rgb(2) = b; }
      if (cname == "red") ASSIGN_COLOR(1, 0, 0)
      else if (cname == "green") ASSIGN_COLOR(0, 1, 0)
      else if (cname == "yellow") ASSIGN_COLOR(1, 1, 0)
      else if (cname == "magenta") ASSIGN_COLOR(1, 0, 1)
      else if (cname == "blue") ASSIGN_COLOR(0, 0, 1)
      else if (cname == "black") ASSIGN_COLOR(0, 0, 0)
      else if (cname == "white") ASSIGN_COLOR(1, 1, 1)
      else if (cname == "gray") ASSIGN_COLOR(.5, .5, .5)
      else if (cname == "darkGreen") ASSIGN_COLOR(0, .5, 0)
      else if (cname == "orange") ASSIGN_COLOR(1, .65, 0)
      else if (cname == "lightBlue") ASSIGN_COLOR(0.68, .85, .9)
#undef ASSIGN_COLOR
    }

    ~text_element_color (void) = default;

    Matrix get_color (void) { return m_rgb; }

    void accept (text_processor& p);

  private:
    Matrix m_rgb;
  };

  class
  OCTINTERP_API
  text_processor
  {
  public:
    virtual void visit (text_element_string&) { }

    virtual void visit (text_element_symbol&) { }

    virtual void visit (text_element_list& e)
    {
      for (auto& el_p : e)
        {
          el_p->accept (*this);
        }
    }

    virtual void visit (text_element_subscript& e)
    { e.get_element ()->accept (*this); }

    virtual void visit (text_element_superscript& e)
    { e.get_element ()->accept (*this); }

    virtual void visit (text_element_combined&) { }

    virtual void visit (text_element_fontstyle&) { }

    virtual void visit (text_element_fontname&) { }

    virtual void visit (text_element_fontsize&) { }

    virtual void visit (text_element_color&) { }

    virtual void reset (void) { }

  protected:
    text_processor (void) { }

    virtual ~text_processor (void) = default;
  };

#define TEXT_ELEMENT_ACCEPT(cls)                \
  inline void                                   \
  cls::accept (text_processor& p)               \
  {                                             \
    p.visit (*this);                            \
  }

  TEXT_ELEMENT_ACCEPT(text_element_string)
  TEXT_ELEMENT_ACCEPT(text_element_symbol)
  TEXT_ELEMENT_ACCEPT(text_element_list)
  TEXT_ELEMENT_ACCEPT(text_element_subscript)
  TEXT_ELEMENT_ACCEPT(text_element_superscript)
  TEXT_ELEMENT_ACCEPT(text_element_combined)
  TEXT_ELEMENT_ACCEPT(text_element_fontstyle)
  TEXT_ELEMENT_ACCEPT(text_element_fontname)
  TEXT_ELEMENT_ACCEPT(text_element_fontsize)
  TEXT_ELEMENT_ACCEPT(text_element_color)

  class
  OCTINTERP_API
  text_parser
  {
  public:
    text_parser (void) { }

    virtual ~text_parser (void) = default;

    virtual text_element * parse (const std::string& s) = 0;

  public:
    static text_element * parse (const std::string& s,
                                 const caseless_str& interpreter);
  };

  class
  OCTINTERP_API
  text_parser_none : public text_parser
  {
  public:
    text_parser_none (void) : text_parser () { }

    ~text_parser_none (void) = default;

    // FIXME: is it possible to use reference counting to manage the
    // memory for the object returned by the text parser?  That would be
    // preferable to having to know when and where to delete the object it
    // creates...

    text_element * parse (const std::string& s)
    {
      return new text_element_string (s);
    }
  };

  class
  OCTINTERP_API
  text_parser_tex : public text_parser
  {
  public:
    text_parser_tex (void)
      : text_parser (), m_scanner (nullptr), m_buffer_state (nullptr),
        m_result (nullptr)
    { }

    ~text_parser_tex (void)
    { destroy_lexer (); }

    text_element * parse (const std::string& s);

    void * get_scanner (void) { return m_scanner; }

    void set_parse_result (text_element *e) { m_result = e; }

    text_element * get_parse_result (void) { return m_result; }

  private:
    bool init_lexer (const std::string& s);

    void destroy_lexer (void);

    //--------

    void *m_scanner;

    void *m_buffer_state;

    text_element *m_result;
  };

  inline text_element*
  text_parser::parse (const std::string& s, const caseless_str& interpreter)
  {
    std::unique_ptr<text_parser> parser;

    if (interpreter.compare ("tex"))
      parser.reset (new text_parser_tex ());
    else
      parser.reset (new text_parser_none ());

    return parser->parse (s);
  }
}

#endif