package com.moandjiezana.toml;

import java.util.concurrent.atomic.AtomicInteger;

public class IdentifierConverter {
  
  static final IdentifierConverter IDENTIFIER_CONVERTER = new IdentifierConverter();

  Identifier convert(String s, AtomicInteger index, Context context) {
    boolean quoted = false;
    StringBuilder name = new StringBuilder();
    boolean terminated = false;
    boolean isKey = s.charAt(index.get()) != '[';
    boolean isTableArray = !isKey && s.length() > index.get() + 1 && s.charAt(index.get() + 1) == '[';
    boolean inComment = false;
    
    for (int i = index.get(); i < s.length(); i = index.incrementAndGet()) {
      char c = s.charAt(i);
      if (Keys.isQuote(c) && (i == 0 || s.charAt(i - 1) != '\\')) {
        quoted = !quoted;
        name.append(c);
      } else if (c == '\n') {
        index.decrementAndGet();
        break;
      } else if (quoted) {
        name.append(c);
      } else if (c == '=' && isKey) {
        terminated = true;
        break;
      } else if (c == ']' && !isKey) {
        if (!isTableArray || s.length() > index.get() + 1 && s.charAt(index.get() + 1) == ']') {
          terminated = true;
          name.append(']');
          if (isTableArray) {
            name.append(']');
          }
        }
      } else if (terminated && c == '#') {
        inComment = true;
      } else if (terminated && !Character.isWhitespace(c) && !inComment) {
        terminated = false;
        break;
      } else if (!terminated) {
        name.append(c);
      }
    }
    
    if (!terminated) {
      if (isKey) {
        context.errors.unterminatedKey(name.toString(), context.line.get());
      } else {
        context.errors.invalidKey(name.toString(), context.line.get());
      }
      
      return Identifier.INVALID;
    }
    
    return Identifier.from(name.toString(), context);
  }
  
  private IdentifierConverter() {}
}