from flask import session, current_app
from flask_wtf import FlaskForm
from wtforms import (StringField, BooleanField, SubmitField, DateField,
                     SelectField, FieldList, FormField, TextAreaField, URLField)
from wtforms.validators import DataRequired, Length, Optional, URL, ValidationError
from flask_wtf.file import FileField, FileAllowed, FileRequired
import json


def allowed_file(form, field):
    if field.data:
        filename = field.data.filename
        allowed_extensions = current_app.config.get('SUPPORTED_FILE_TYPES', [])
        if not ('.' in filename and filename.rsplit('.', 1)[1].lower() in allowed_extensions):
            raise ValidationError('Unsupported file type.')


def validate_json(form, field):
    if field.data:
        try:
            json.loads(field.data)
        except json.JSONDecodeError:
            raise ValidationError('Invalid JSON format')


class AddDocumentForm(FlaskForm):
    file = FileField('File', validators=[FileRequired(), allowed_file])
    name = StringField('Name', validators=[Length(max=100)])
    language = SelectField('Language', choices=[], validators=[Optional()])
    user_context = TextAreaField('User Context', validators=[Optional()])
    valid_from = DateField('Valid from', id='form-control datepicker', validators=[Optional()])
    user_metadata = TextAreaField('User Metadata', validators=[Optional(), validate_json])

    submit = SubmitField('Submit')

    def __init__(self):
        super().__init__()
        self.language.choices = [(language, language) for language in
                                 session.get('tenant').get('allowed_languages')]
        if not self.language.data:
            self.language.data = session.get('tenant').get('default_language')


class AddURLForm(FlaskForm):
    url = URLField('URL', validators=[DataRequired(), URL()])
    name = StringField('Name', validators=[Length(max=100)])
    language = SelectField('Language', choices=[], validators=[Optional()])
    user_context = TextAreaField('User Context', validators=[Optional()])
    valid_from = DateField('Valid from', id='form-control datepicker', validators=[Optional()])
    user_metadata = TextAreaField('User Metadata', validators=[Optional(), validate_json])

    submit = SubmitField('Submit')

    def __init__(self):
        super().__init__()
        self.language.choices = [(language, language) for language in
                                 session.get('tenant').get('allowed_languages')]
        if not self.language.data:
            self.language.data = session.get('tenant').get('default_language')


class AddURLsForm(FlaskForm):
    urls = TextAreaField('URL(s) (one per line)', validators=[DataRequired()])
    name = StringField('Name Prefix', validators=[Length(max=100)])
    language = SelectField('Language', choices=[], validators=[Optional()])
    user_context = TextAreaField('User Context', validators=[Optional()])
    valid_from = DateField('Valid from', id='form-control datepicker', validators=[Optional()])

    submit = SubmitField('Submit')

    def __init__(self):
        super().__init__()
        self.language.choices = [(language, language) for language in
                                 session.get('tenant').get('allowed_languages')]
        if not self.language.data:
            self.language.data = session.get('tenant').get('default_language')


class EditDocumentForm(FlaskForm):
    name = StringField('Name', validators=[Length(max=100)])
    valid_from = DateField('Valid from', id='form-control datepicker', validators=[Optional()])
    valid_to = DateField('Valid to', id='form-control datepicker', validators=[Optional()])

    submit = SubmitField('Submit')


class EditDocumentVersionForm(FlaskForm):
    language = StringField('Language')
    user_context = TextAreaField('User Context', validators=[Optional()])
    system_context = TextAreaField('System Context', validators=[Optional()])
    user_metadata = TextAreaField('User Metadata', validators=[Optional(), validate_json])
    system_metadata = TextAreaField('System Metadata', validators=[Optional(), validate_json])

    submit = SubmitField('Submit')