from django import forms

class ContactForm(forms.Form):
    name = forms.CharField(max_length=100)
    email = forms.EmailField()
    age = forms.IntegerField(min_value=0)

# 在視圖中使用
def contact_view(request):
    if request.method == 'POST':
        form = ContactForm(request.POST)
        if form.is_valid():  # 必須先調(diào)用 is_valid()
            # 訪問(wèn)清理后的數(shù)據(jù)
            name = form.cleaned_data['name']
            email = form.cleaned_data['email']
            age = form.cleaned_data['age']  # 已經(jīng)是 int 類(lèi)型
            
            # 處理業(yè)務(wù)邏輯
            save_contact(name, email, age)
            return redirect('success')

if form.is_valid():
    required_field = form.cleaned_data['required_field']
    optional_field = form.cleaned_data.get('optional_field', '默認(rèn)值')

def clean_字段名(self):
    # 獲取該字段已清理的數(shù)據(jù)
    field_data = self.cleaned_data['字段名']
    # 自定義驗(yàn)證邏輯
    # 返回處理后的數(shù)據(jù)或拋出 ValidationError
    return field_data

from django.core.exceptions import ValidationError

class UserRegistrationForm(forms.Form):
    username = forms.CharField(max_length=30)
    email = forms.EmailField()
    
    def clean_username(self):
        username = self.cleaned_data['username']
        
        # 驗(yàn)證用戶(hù)名唯一性
        if User.objects.filter(username=username).exists():
            raise ValidationError("該用戶(hù)名已被注冊(cè)")
        
        # 驗(yàn)證用戶(hù)名格式
        if not username.isalnum():
            raise ValidationError("用戶(hù)名只能包含字母和數(shù)字")
        
        # 返回標(biāo)準(zhǔn)化數(shù)據(jù)
        return username.lower()
    
    def clean_email(self):
        email = self.cleaned_data['email'].strip().lower()
        
        # 驗(yàn)證郵箱唯一性
        if User.objects.filter(email=email).exists():
            raise ValidationError("該郵箱已被注冊(cè)")
        
        return email

def clean(self):
    # 必須調(diào)用父類(lèi)方法
    cleaned_data = super().clean()
    
    # 獲取字段數(shù)據(jù)
    field1 = cleaned_data.get('field1')
    field2 = cleaned_data.get('field2')
    
    # 多字段驗(yàn)證邏輯
    if 驗(yàn)證條件:
        raise ValidationError("錯(cuò)誤信息")
    
    # 必須返回 cleaned_data
    return cleaned_data

class EventForm(forms.Form):
    start_date = forms.DateField()
    end_date = forms.DateField()
    participants = forms.IntegerField(min_value=1)
    capacity = forms.IntegerField(min_value=1)
    
    def clean(self):
        cleaned_data = super().clean()
        
        start_date = cleaned_data.get('start_date')
        end_date = cleaned_data.get('end_date')
        participants = cleaned_data.get('participants')
        capacity = cleaned_data.get('capacity')
        
        # 驗(yàn)證日期邏輯
        if start_date and end_date and end_date < start_date:
            raise ValidationError({
                'end_date': "結(jié)束日期不能早于開(kāi)始日期"
            })
        
        # 驗(yàn)證人數(shù)邏輯
        if participants and capacity and participants > capacity:
            raise ValidationError("參與人數(shù)不能超過(guò)場(chǎng)地容量")
        
        # 驗(yàn)證業(yè)務(wù)邏輯：活動(dòng)至少需要2天
        if start_date and end_date and (end_date - start_date).days < 1:
            raise ValidationError("活動(dòng)至少需要持續(xù)2天")
        
        return cleaned_data

raise ValidationError({
    'end_date': "結(jié)束日期無(wú)效",
    'start_date': "開(kāi)始日期需要調(diào)整"
})

raise ValidationError("日期和人數(shù)組合無(wú)效")

class PasswordChangeForm(forms.Form):
    current_password = forms.CharField(widget=forms.PasswordInput)
    new_password = forms.CharField(
        widget=forms.PasswordInput,
        min_length=8
    )
    confirm_password = forms.CharField(widget=forms.PasswordInput)
    
    def __init__(self, user, *args, **kwargs):
        self.user = user
        super().__init__(*args, **kwargs)
    
    def clean_current_password(self):
        current_password = self.cleaned_data['current_password']
        
        if not self.user.check_password(current_password):
            raise ValidationError("當(dāng)前密碼不正確")
        
        return current_password
    
    def clean_new_password(self):
        new_password = self.cleaned_data['new_password']
        
        # 密碼強(qiáng)度驗(yàn)證
        if len(new_password) < 8:
            raise ValidationError("密碼至少需要8個(gè)字符")
        
        if not any(char.isdigit() for char in new_password):
            raise ValidationError("密碼必須包含至少一個(gè)數(shù)字")
        
        if not any(char.isupper() for char in new_password):
            raise ValidationError("密碼必須包含至少一個(gè)大寫(xiě)字母")
        
        return new_password
    
    def clean(self):
        cleaned_data = super().clean()
        
        new_password = cleaned_data.get('new_password')
        confirm_password = cleaned_data.get('confirm_password')
        current_password = cleaned_data.get('current_password')
        
        # 驗(yàn)證密碼確認(rèn)
        if new_password and confirm_password and new_password != confirm_password:
            raise ValidationError({
                'confirm_password': "兩次輸入的密碼不一致"
            })
        
        # 驗(yàn)證新密碼不能與舊密碼相同
        if new_password and current_password and new_password == current_password:
            raise ValidationError("新密碼不能與當(dāng)前密碼相同")
        
        return cleaned_data

def change_password(request):
    if request.method == 'POST':
        form = PasswordChangeForm(request.user, data=request.POST)
        if form.is_valid():
            # 所有驗(yàn)證通過(guò)，使用 cleaned_data
            new_password = form.cleaned_data['new_password']
            request.user.set_password(new_password)
            request.user.save()
            messages.success(request, "密碼修改成功！")
            return redirect('profile')
    else:
        form = PasswordChangeForm(request.user)
    
    return render(request, 'change_password.html', {'form': form})

class ExampleForm(forms.Form):
    field1 = forms.CharField()
    field2 = forms.CharField()
    
    def clean_field1(self):
        print("執(zhí)行 clean_field1")
        return self.cleaned_data['field1']
    
    def clean_field2(self):
        print("執(zhí)行 clean_field2")
        return self.cleaned_data['field2']
    
    def clean(self):
        print("執(zhí)行 clean()")
        return super().clean()

# 執(zhí)行順序：
# 1. clean_field1()
# 2. clean_field2()  
# 3. clean()

form = MyForm(request.POST)
if form.is_valid():
    data = form.cleaned_data
else:
    print(form.errors)

class MyForm(forms.Form):
    password = forms.CharField()
    confirm_password = forms.CharField()

    def clean(self):
        cleaned_data = super().clean()
        pwd = cleaned_data.get('password')
        confirm = cleaned_data.get('confirm_password')
        if pwd and confirm and pwd != confirm:
            raise forms.ValidationError("Passwords do not match.")
        return cleaned_data