/*
 * Copyright 2013 Guidewire Software, Inc.
 */

package gw.plugin.ij.actions;

import com.google.common.base.Strings;
import org.jetbrains.annotations.NotNull;

import javax.swing.*;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.PlainDocument;

public class IdentifierTextField extends JTextField {
  private final boolean _bAcceptDot;
  private final boolean _bAcceptUnderscore;

  public IdentifierTextField() {
    this(false, true);
  }

  public IdentifierTextField(boolean bAcceptDot) {
    this(bAcceptDot, true);
  }

  public IdentifierTextField(boolean bAcceptDot, boolean bAcceptUnderscore) {
    _bAcceptDot = bAcceptDot;
    _bAcceptUnderscore = bAcceptUnderscore;
  }

  @NotNull
  @Override
  protected Document createDefaultModel() {
    return new IdentifierDocument();
  }

  private class IdentifierDocument extends PlainDocument {
    @Override
    public void insertString(int iOffset, String str, AttributeSet a) throws BadLocationException {
      if (Strings.isNullOrEmpty(str)) {
        return;
      }

      String strText = IdentifierTextField.this.getText();
      StringBuilder strbText = new StringBuilder(Strings.nullToEmpty(strText));

      if (iOffset <= strbText.length()) {
        strbText.insert(iOffset, str);
      } else {
        strbText.append(str);
      }

      if (!isValidIdentifier(strbText, _bAcceptDot) || strbText.toString().contains("$")) {
        String validID = makeValidIdentifier(strbText.toString(), _bAcceptDot, _bAcceptUnderscore);
        if (!_bAcceptUnderscore) {
          validID = validID.replace("$", "");
        }
        str = validID.substring(iOffset, iOffset + (validID.length() - strText.length()));
      }

      super.insertString(iOffset, str, a);
    }
  }

  public static boolean isValidIdentifier(@NotNull CharSequence seqId, boolean acceptDot) {
    if (seqId.length() == 0 || !Character.isJavaIdentifierStart(seqId.charAt(0))) {
      return false;
    }
    for (int i = 1, iLen = seqId.length(); i < iLen; i++) {
      if (acceptDot && (seqId.charAt(i) == '.' || seqId.charAt(i) == '#')) {
        continue;
      }

      if (!Character.isJavaIdentifierPart(seqId.charAt(i))) {
        return false;
      }
    }
    return true;
  }

  public static String makeValidIdentifier(String str, boolean acceptDot, boolean bAcceptUnderscore) {
    StringBuilder rtn = new StringBuilder(str);
    while (rtn.length() > 0 && (!Character.isJavaIdentifierStart(rtn.charAt(0)) || (!bAcceptUnderscore && rtn.charAt(0) == '_'))) {
      rtn.deleteCharAt(0);
    }

    for (int i = 1; i < rtn.length(); ) {
      char c = rtn.charAt(i);
      if (acceptDot && (c == '.' || c == '#')) {
        i++;
        continue;
      }

      if (!Character.isJavaIdentifierPart(c) || (!bAcceptUnderscore && c == '_')) {
        rtn.deleteCharAt(i);
        continue;
      }

      i++;
    }
    return rtn.toString();
  }
}