text: from flask_wtf import FlaskForm
  from wtforms import StringField, TextAreaField, BooleanField, SelectField,\
      SubmitField
  from wtforms.validators import DataRequired, Length, Email, Regexp
  from wtforms import ValidationError
  from flask_pagedown.fields import PageDownField
  from ..models import Role, User
  
  
  class NameForm(FlaskForm):
      name = StringField('姓名', validators=[DataRequired()])
      submit = SubmitField('提交')
  
  
  class EditProfileForm(FlaskForm):
      name = StringField('真名', validators=[Length(0, 64)])
      location = StringField('地址', validators=[Length(0, 64)])
      about_me = TextAreaField('个人说明')
      submit = SubmitField('保存')
  
  
  class EditProfileAdminForm(FlaskForm):
      email = StringField('电子邮件', validators=[DataRequired(), Length(1, 64), Email()])
      username = StringField('用户名', validators=[
          DataRequired(), Length(1, 64), Regexp('^[A-Za-z][A-Za-z0-9_]*$', 0,'只能输入字母数字或下划线')])
      confirmed = BooleanField('确认')
      role = SelectField('角色', coerce=int)
      name = StringField('真实姓名', validators=[Length(0, 64)])
      location = StringField('地址', validators=[Length(0, 64)])
      about_me = TextAreaField('个人说明')
      submit = SubmitField('保存')
  
      def __init__(self, user, *args, **kwargs):
          super(EditProfileAdminForm, self).__init__(*args, **kwargs)
          self.role.choices = [(role.id, role.name)
                               for role in Role.query.order_by(Role.name).all()]
          self.user = user
  
      def validate_email(self, field):
          if field.data != self.user.email and \
                  User.query.filter_by(email=field.data).first():
              raise ValidationError('邮件已经被占用。')
  
      def validate_username(self, field):
          if field.data != self.user.username and \
                  User.query.filter_by(username=field.data).first():
              raise ValidationError('用户名已经被占用。')
  
  
  class PostForm(FlaskForm):
      body = PageDownField("写点啥？", validators=[DataRequired()])
      submit = SubmitField('发布')
  
  
  class CommentForm(FlaskForm):
      body = StringField('写评论', validators=[DataRequired()])
      submit = SubmitField('发布')
  