import logging
from django.utils.translation import gettext_lazy as _
from django.conf import settings
from django.contrib import auth
from django.contrib.auth import REDIRECT_FIELD_NAME
from django.contrib.auth import get_user_model
from django.contrib.auth import logout
from django.contrib.auth.forms import AuthenticationForm
from django.contrib.auth.hashers import make_password
from django.http import HttpResponseRedirect, HttpResponseForbidden
from django.http.request import HttpRequest
from django.http.response import HttpResponse
from django.shortcuts import get_object_or_404
from django.shortcuts import render
from django.urls import reverse
from django.utils.decorators import method_decorator
from django.utils.http import url_has_allowed_host_and_scheme
from django.views import View
from django.views.decorators.cache import never_cache
from django.views.decorators.csrf import csrf_protect
from django.views.decorators.debug import sensitive_post_parameters
from django.views.generic import FormView, RedirectView

from djangoblog.utils import send_email, get_sha256, get_current_site, generate_code, delete_sidebar_cache
from . import utils
from .forms import RegisterForm, LoginForm, ForgetPasswordForm, ForgetPasswordCodeForm
from .models import BlogUser

logger = logging.getLogger(__name__)


class RegisterView(FormView):
    """
    用户注册视图
    处理用户注册流程，包括表单验证、用户创建和发送验证邮件
    """
    form_class = RegisterForm
    template_name = 'account/registration_form.html'

    @method_decorator(csrf_protect)
    def dispatch(self, *args, **kwargs):
        """确保视图受到CSRF保护"""
        return super(RegisterView, self).dispatch(*args, **kwargs)

    def form_valid(self, form):
        """
        处理有效的注册表单
        创建非活跃用户，发送邮箱验证邮件
        """
        if form.is_valid():
            # 创建用户但不立即保存到数据库
            user = form.save(False)
            user.is_active = False  # 邮箱验证前用户不可用
            user.source = 'Register'  # 标记用户来源
            user.save(True)  # 保存用户到数据库
            
            # 获取当前站点信息
            site = get_current_site().domain
            
            # 生成验证签名，用于验证链接的安全性
            sign = get_sha256(get_sha256(settings.SECRET_KEY + str(user.id)))

            # 调试模式下使用本地地址
            if settings.DEBUG:
                site = '127.0.0.1:8000'
                
            # 构建验证URL
            path = reverse('account:result')
            url = "http://{site}{path}?type=validation&id={id}&sign={sign}".format(
                site=site, path=path, id=user.id, sign=sign)

            # 构建邮件内容
            content = """
                            <p>请点击下面链接验证您的邮箱</p>

                            <a href="{url}" rel="bookmark">{url}</a>

                            再次感谢您！
                            <br />
                            如果上面链接无法打开，请将此链接复制至浏览器。
                            {url}
                            """.format(url=url)
                            
            # 发送验证邮件
            send_email(
                emailto=[
                    user.email,
                ],
                title='验证您的电子邮箱',
                content=content)

            # 重定向到结果页面
            url = reverse('accounts:result') + \
                  '?type=register&id=' + str(user.id)
            return HttpResponseRedirect(url)
        else:
            # 表单无效，重新渲染表单页面
            return self.render_to_response({
                'form': form
            })


class LogoutView(RedirectView):
    """
    用户登出视图
    处理用户登出操作并清理相关缓存
    """
    url = '/login/'  # 登出后重定向的URL

    @method_decorator(never_cache)
    def dispatch(self, request, *args, **kwargs):
        """确保登出页面不被缓存"""
        return super(LogoutView, self).dispatch(request, *args, **kwargs)

    def get(self, request, *args, **kwargs):
        """处理GET请求的登出操作"""
        logout(request)  # 执行登出操作
        delete_sidebar_cache()  # 清理侧边栏缓存
        return super(LogoutView, self).get(request, *args, **kwargs)


class LoginView(FormView):
    """
    用户登录视图
    处理用户认证和登录会话管理
    """
    form_class = LoginForm
    template_name = 'account/login.html'
    success_url = '/'  # 登录成功后默认重定向的URL
    redirect_field_name = REDIRECT_FIELD_NAME  # 重定向字段名
    login_ttl = 2626560  # 一个月的时间（秒），用于"记住我"功能

    @method_decorator(sensitive_post_parameters('password'))  # 保护密码参数
    @method_decorator(csrf_protect)  # CSRF保护
    @method_decorator(never_cache)  # 禁止缓存
    def dispatch(self, request, *args, **kwargs):
        """应用装饰器到视图分发方法"""
        return super(LoginView, self).dispatch(request, *args, **kwargs)

    def get_context_data(self, **kwargs):
        """向模板上下文添加重定向URL"""
        redirect_to = self.request.GET.get(self.redirect_field_name)
        if redirect_to is None:
            redirect_to = '/'  # 默认重定向到首页
        kwargs['redirect_to'] = redirect_to

        return super(LoginView, self).get_context_data(**kwargs)

    def form_valid(self, form):
        """处理有效的登录表单"""
        # 使用Django的AuthenticationForm进行认证
        form = AuthenticationForm(data=self.request.POST, request=self.request)

        if form.is_valid():
            # 认证成功，清理缓存并记录日志
            delete_sidebar_cache()
            logger.info(self.redirect_field_name)

            # 登录用户
            auth.login(self.request, form.get_user())
            
            # 处理"记住我"功能
            if self.request.POST.get("remember"):
                self.request.session.set_expiry(self.login_ttl)
                
            return super(LoginView, self).form_valid(form)
        else:
            # 认证失败，重新显示表单
            return self.render_to_response({
                'form': form
            })

    def get_success_url(self):
        """获取登录成功后重定向的URL"""
        redirect_to = self.request.POST.get(self.redirect_field_name)
        
        # 验证重定向URL的安全性
        if not url_has_allowed_host_and_scheme(
                url=redirect_to, allowed_hosts=[
                    self.request.get_host()]):
            redirect_to = self.success_url  # 不安全的URL使用默认URL
            
        return redirect_to


def account_result(request):
    """
    账户操作结果页面
    处理注册结果和邮箱验证
    """
    type = request.GET.get('type')  # 操作类型：register或validation
    id = request.GET.get('id')  # 用户ID

    # 获取用户对象，如果不存在返回404
    user = get_object_or_404(get_user_model(), id=id)
    logger.info(type)
    
    # 如果用户已激活，直接重定向到首页
    if user.is_active:
        return HttpResponseRedirect('/')
        
    # 处理注册和验证操作
    if type and type in ['register', 'validation']:
        if type == 'register':
            # 注册成功页面
            content = '''
    恭喜您注册成功，一封验证邮件已经发送到您的邮箱，请验证您的邮箱后登录本站。
    '''
            title = '注册成功'
        else:
            # 邮箱验证处理
            c_sign = get_sha256(get_sha256(settings.SECRET_KEY + str(user.id)))
            sign = request.GET.get('sign')
            
            # 验证签名安全性
            if sign != c_sign:
                return HttpResponseForbidden()  # 签名不匹配，禁止访问
                
            # 激活用户账户
            user.is_active = True
            user.save()
            
            content = '''
            恭喜您已经成功的完成邮箱验证，您现在可以使用您的账号来登录本站。
            '''
            title = '验证成功'
            
        # 渲染结果页面
        return render(request, 'account/result.html', {
            'title': title,
            'content': content
        })
    else:
        # 无效的操作类型，重定向到首页
        return HttpResponseRedirect('/')


class ForgetPasswordView(FormView):
    """
    忘记密码视图
    处理密码重置请求
    """
    form_class = ForgetPasswordForm
    template_name = 'account/forget_password.html'

    def form_valid(self, form):
        """处理有效的密码重置表单"""
        if form.is_valid():
            # 根据邮箱查找用户
            blog_user = BlogUser.objects.filter(email=form.cleaned_data.get("email")).get()
            # 使用Django的密码哈希器设置新密码
            blog_user.password = make_password(form.cleaned_data["new_password2"])
            blog_user.save()  # 保存新密码
            
            # 重定向到登录页面
            return HttpResponseRedirect('/login/')
        else:
            # 表单无效，重新显示表单
            return self.render_to_response({'form': form})


class ForgetPasswordEmailCode(View):
    """
    发送忘记密码验证码视图
    处理密码重置验证码的发送
    """

    def post(self, request: HttpRequest):
        """处理POST请求，发送密码重置验证码"""
        form = ForgetPasswordCodeForm(request.POST)
        
        # 验证表单数据
        if not form.is_valid():
            return HttpResponse("错误的邮箱")
            
        to_email = form.cleaned_data["email"]

        # 生成并发送验证码
        code = generate_code()
        utils.send_verify_email(to_email, code)  # 发送验证邮件
        utils.set_code(to_email, code)  # 存储验证码（通常在缓存中）

        return HttpResponse("ok")  # 返回成功响应