from django.db import models


class Article(models.Model):
    title = models.CharField(max_length=50, verbose_name='標題')
    content = models.TextField(verbose_name='內容')
    create_date = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.title

from django.forms import ModelForm
from django import forms
from . models import Article
from django.core.exceptions import ValidationError

class ArticleForm(ModelForm):
    class Meta:
        model = Article
        exclude = ['id']
    
    def clean(self):
        cleaned_data = super().clean()
        title = cleaned_data.get('title')
        if 'My' not in title:
            raise ValidationError('標題中必須包含My字樣', code='title')

def add(request):
    if request.method == 'GET':
        return render(request, 'add.html')
    else:
        form = ArticleForm(request.POST)
        # 主要了解的是表單的驗證
        if form.is_valid():
            form.save()
            return HttpResponseRedirect('/show/')
        else:
            form.errors.as_data()            # {'__all__': [ValidationError(['標題中必須包含My字樣'])]}
            form.errors.get_context()        # {'errors': dict_items([('__all__', ['標題中必須包含My字樣'])]), 'error_class': 'errorlist'}
            d = form.errors.get_json_data()  # {'__all__': [{'message': '標題中必須包含My字樣', 'code': 'title'}]}
            return HttpResponse(d.get('__all__'))

class ErrorDict(dict, RenderableErrorMixin):
    """
    A collection of errors that knows how to display itself in various formats.

    The dictionary keys are the field names, and the values are the errors.
    """

    template_name = "django/forms/errors/dict/default.html"
    template_name_text = "django/forms/errors/dict/text.txt"
    template_name_ul = "django/forms/errors/dict/ul.html"

    def __init__(self, *args, renderer=None, **kwargs):
        super().__init__(*args, **kwargs)
        self.renderer = renderer or get_default_renderer()

    def as_data(self):
        return {f: e.as_data() for f, e in self.items()}

    def get_json_data(self, escape_html=False):
        return {f: e.get_json_data(escape_html) for f, e in self.items()}

    def get_context(self):
        return {
            "errors": self.items(),
            "error_class": "errorlist",
        }