#include <fmt/core.h>
#include <string_view>
#include <charconv>
#include "dbc.hpp"
#include <SFML/Graphics.hpp>
#include "ansi_parser.hpp"

using namespace fmt;

%%{
  machine foo;
  alphtype int;

  action tstart {
    start = fpc;
  }

  action number {
    value = 0;
    size_t len = fpc - start;
    dbc::check(start[0] != '-', "negative numbers not supported");

    switch(len) {
      case 10:    value += (start[len-10] - '0') * 1000000000;
      case  9:    value += (start[len- 9] - '0') * 100000000;
      case  8:    value += (start[len- 8] - '0') * 10000000;
      case  7:    value += (start[len- 7] - '0') * 1000000;
      case  6:    value += (start[len- 6] - '0') * 100000;
      case  5:    value += (start[len- 5] - '0') * 10000;
      case  4:    value += (start[len- 4] - '0') * 1000;
      case  3:    value += (start[len- 3] - '0') * 100;
      case  2:    value += (start[len- 2] - '0') * 10;
      case  1:    value += (start[len- 1] - '0');
        break;
      default:
        dbc::sentinel("can't process > 10 digits");
    }
  }

  action color24b { }
  action is_fg {
    target = color;
  }
  action is_bg {
    target = bgcolor;
  }

  action out {
    write(bgcolor, color, fc);
  }

  action reset_fg { color = default_fg; }
  action reset_bg { bgcolor = default_bg; }

  action red { target.r = value; }
  action blue { target.g = value; }
  action green { target.b = value; }
  action start { value = 0; }
  action end { }

  ESC = 0x1B;
  start = ESC "[";
  fg = "38;" %is_fg;
  bg = "48;" %is_bg;
  reset = ("39" %reset_fg | "49" %reset_bg);
  num = digit+ >tstart %number;
  color256 = "5;";
  color24b = "2;";

  ansi = (
      start %start
      (
        reset |
        (fg|bg) color24b num %red ";" num %blue ";" num %green %color24b
      ) "m" %end
  );

  other = (any+ @out -- ESC)*;

  main := (other :> ansi)**;
}%%

%% write data;

bool parse_ansi(std::wstring_view codes, sf::Color default_fg, sf::Color default_bg, WriteCB write) {
  const wchar_t *start = NULL;
  int cs = 0;
  unsigned int value = 0;
  const wchar_t *p = codes.data();
  const wchar_t *pe = p + codes.size();
  const wchar_t *eof = pe;
  sf::Color bgcolor(default_bg);
  sf::Color color(default_fg);
  sf::Color &target = color;

  %% write init;
  %% write exec;

  return p - pe == 0;
}