css_reader.hpp

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#pragma once
#include "selector_dictionary.hpp"
#include "../../io/stream_reader.hpp"
#include "../../object.hpp"

namespace xtd {
  namespace web {
    namespace css {
      class css_reader : public object {
      public:
        
        css_reader(std::istream& stream) {parse_text(xtd::io::stream_reader(stream).read_to_end());}
        css_reader(xtd::io::text_reader& text_reader) {parse_text(text_reader.read_to_end());}
        css_reader(const xtd::string& text) {parse_text(text);}
        
        
        [[nodiscard]] auto selectors() const noexcept -> const xtd::web::css::selector_dictionary& {return selectors_;}
        
      private:
        auto parse_text(const xtd::string& text) -> void {
          enum class parse_status {
            selector,
            key,
            value
          };
          parse_status status = parse_status::selector;
          xtd::usize start_index = 0;
          xtd::web::css::selector current_selector;
          xtd::string current_selector_name;
          xtd::string current_key;
          for (xtd::usize index = 0; index < text.length(); index++) {
            if (text[index] == '/' && text[index + 1] == '*') {
              // Skip comments...
              index = text.index_of("*/", index + 2);
              if (index == text.npos) xtd::helpers::throw_helper::throws(xtd::helpers::exception_case::format, "expected end comment");
              index++;
              start_index = index + 1;
              continue;
            } else if (status == parse_status::selector && text[index] == '{') {
              current_selector_name = text.substring(start_index, index - start_index).trim();
              current_selector.name(text.substring(start_index, index - start_index).trim());
              start_index = index + 1;
              status = parse_status::key;
            } else if (status == parse_status::key && text[index] == '}') {
              selectors_[current_selector_name] = current_selector;
              current_selector = xtd::web::css::selector();
              start_index = index + 1;
              status = parse_status::selector;
            } else if (status == parse_status::key && text[index] == ':') {
              current_key = text.substring(start_index, index - start_index).trim().to_lower();
              if (xtd::string::is_empty(current_key)) xtd::helpers::throw_helper::throws(xtd::helpers::exception_case::format, "key cannot be empty");
              start_index = index + 1;
              status = parse_status::value;
            } else if (status == parse_status::value && text[index] == ';') {
              auto value = text.substring(start_index, index - start_index).trim();
              if (xtd::string::is_empty(value)) xtd::helpers::throw_helper::throws(xtd::helpers::exception_case::format, "value cannot be empty");
              start_index = index + 1;
              current_selector.properties()[current_key] = property(value);
              status = parse_status::key;
            }
          }
        }
        
        xtd::web::css::selector_dictionary selectors_;
      };
    }
  }
}