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, HttpResponse
from django.http.request import HttpRequest
from django.shortcuts import get_object_or_404, 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__)  # 初始化日志记录器


# ------------------------- 注册视图 -------------------------
class RegisterView(FormView):
    """用户注册视图"""
    form_class = RegisterForm
    template_name = 'account/registration_form.html'  # 注册页面模板路径

    @method_decorator(csrf_protect)  # 防止CSRF攻击
    def dispatch(self, *args, **kwargs):
        return super(RegisterView, self).dispatch(*args, **kwargs)

    def form_valid(self, form):
        """当表单验证通过时调用"""
        if form.is_valid():
            user = form.save(False)  # 保存用户但不提交数据库
            user.is_active = False   # 新注册用户默认未激活
            user.source = 'Register'  # 标记注册来源
            user.save(True)          # 保存到数据库

            site = get_current_site().domain  # 获取当前站点域名
            sign = get_sha256(get_sha256(settings.SECRET_KEY + str(user.id)))  # 生成验证签名

            if settings.DEBUG:  # 开发环境下替换站点域名
                site = '127.0.0.1:8000'

            # 生成邮箱验证链接
            path = reverse('account:result')
            url = "http://{site}{path}?type=validation&id={id}&sign={sign}".format(
                site=site, path=path, id=user.id, sign=sign)

            # 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
            )

            # 注册成功后跳转到结果页面
            url = reverse('accounts:result') + '?type=register&id=' + str(user.id)
            return HttpResponseRedirect(url)
        else:
            # 验证失败重新渲染表单
            return self.render_to_response({'form': form})


# ------------------------- 登出视图 -------------------------
class LogoutView(RedirectView):
    """用户登出视图"""
    url = '/login/'  # 登出后跳转页面

    @method_decorator(never_cache)  # 禁止页面缓存
    def dispatch(self, request, *args, **kwargs):
        return super(LogoutView, self).dispatch(request, *args, **kwargs)

    def get(self, request, *args, **kwargs):
        logout(request)  # 注销当前用户
        delete_sidebar_cache()  # 清理缓存
        return super(LogoutView, self).get(request, *args, **kwargs)


# ------------------------- 登录视图 -------------------------
class LoginView(FormView):
    """用户登录视图"""
    form_class = LoginForm
    template_name = 'account/login.html'
    success_url = '/'  # 登录成功默认跳转首页
    redirect_field_name = REDIRECT_FIELD_NAME
    login_ttl = 2626560  # “记住我”有效期（30天）

    @method_decorator(sensitive_post_parameters('password'))  # 标记敏感字段
    @method_decorator(csrf_protect)
    @method_decorator(never_cache)
    def dispatch(self, request, *args, **kwargs):
        return super(LoginView, self).dispatch(request, *args, **kwargs)

    def get_context_data(self, **kwargs):
        """为模板提供重定向参数"""
        redirect_to = self.request.GET.get(self.redirect_field_name)
        if redirect_to is None:
            redirect_to = '/'
        kwargs['redirect_to'] = redirect_to
        return super(LoginView, self).get_context_data(**kwargs)

    def form_valid(self, form):
        """登录逻辑"""
        form = AuthenticationForm(data=self.request.POST, request=self.request)
        if form.is_valid():
            delete_sidebar_cache()  # 清除缓存
            logger.info(self.redirect_field_name)

            auth.login(self.request, form.get_user())  # 登录用户
            if self.request.POST.get("remember"):  # 如果勾选“记住我”
                self.request.session.set_expiry(self.login_ttl)
            return super(LoginView, self).form_valid(form)
        else:
            # 登录失败，重新渲染页面
            return self.render_to_response({'form': form})

    def get_success_url(self):
        """登录成功后跳转路径校验"""
        redirect_to = self.request.POST.get(self.redirect_field_name)
        if not url_has_allowed_host_and_scheme(
            url=redirect_to, allowed_hosts=[self.request.get_host()]
        ):
            redirect_to = self.success_url
        return redirect_to


# ------------------------- 注册与验证结果视图 -------------------------
def account_result(request):
    """注册或邮箱验证结果页"""
    type = request.GET.get('type')
    id = request.GET.get('id')

    user = get_object_or_404(get_user_model(), id=id)  # 获取用户对象
    logger.info(type)

    if user.is_active:  # 若已激活，直接跳转首页
        return HttpResponseRedirect('/')

    if type and type in ['register', 'validation']:
        if type == 'register':
            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:
            # 验证签名
            c_sign = get_sha256(get_sha256(settings.SECRET_KEY + str(user.id)))
            sign = request.GET.get('sign')
            if sign != c_sign:
                return HttpResponseForbidden()  # 签名不符禁止访问

            user.is_active = True  # 激活账号
            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'

        # 渲染结果模板
        return render(request, 'account/result.html', {
            'title': title,
            'content': content
        })
    else:
        return HttpResponseRedirect('/')


# ------------------------- 忘记密码视图 -------------------------
class ForgetPasswordView(FormView):
    """忘记密码（直接重置密码）"""
    form_class = ForgetPasswordForm
    template_name = 'account/forget_password.html'

    def form_valid(self, form):
        if form.is_valid():
            # 通过邮箱查找用户
            blog_user = BlogUser.objects.filter(email=form.cleaned_data.get("email")).get()
            # 更新加密后的新密码
            blog_user.password = make_password(form.cleaned_data["new_password2"])
            blog_user.save()
            return HttpResponseRedirect('/login/')  # 修改成功后跳转登录页
        else:
            return self.render_to_response({'form': form})


# ------------------------- 发送邮箱验证码视图 -------------------------
class ForgetPasswordEmailCode(View):
    """用于发送找回密码邮箱验证码"""

    def post(self, request: HttpRequest):
        form = ForgetPasswordCodeForm(request.POST)
        if not form.is_valid():
            return HttpResponse("错误的邮箱")  # 邮箱格式错误

        to_email = form.cleaned_data["email"]
        code = generate_code()  # 生成随机验证码
        utils.send_verify_email(to_email, code)  # 发送验证码邮件
        utils.set_code(to_email, code)  # 将验证码写入缓存或数据库
        return HttpResponse("ok")  # 返回成功响应