from fastapi.security import OAuth2PasswordBearer
from fastapi import FastAPI, Cookie, Response, Form
from fastapi.templating import Jinja2Templates
from fastapi.responses import RedirectResponse, HTMLResponse
from datetime import timedelta, datetime
from contextlib import asynccontextmanager
from . import db
from . import email as email_sys
from . import reg
import hashlib
import uuid
from typing import Annotated
import re
import asyncio
import uvicorn
from .cfg import config


ALGORITHM = config["common"]["algorithm"]
ACCESS_TOKEN_EXPIRE_MINUTES = config["common"]["access_token_expire_minutes"]
ACCESS_EMAIL_EXPIRE_MINUTES = config["common"]["access_email_expire_minutes"]
ROOT = config["common"]["root"]
CLEAN_TIMEOUT = config["common"]["clean_timeout"]
MANAGE_KEY = config["common"]["manage_key"]
REDIRECT_URL_WHITELIST = config["common"]["redirect_url_whitelist"]


tokens = {}
apikeys = {}
emails = {}
email_send_lst = []


async def clean_sys():
    while 1:
        await asyncio.sleep(CLEAN_TIMEOUT)
        for k in list(tokens.keys()):
            if (tokens[k][1] < datetime.now()):
                del tokens[k]
        for k in list(apikeys.keys()):
            if (apikeys[k][1] < datetime.now()):
                del apikeys[k]
        for k in list(emails.keys()):
            if (emails[k][2] < datetime.now()):
                del emails[k]


async def send_email():
    while 1:
        if (len(email_send_lst) > 0):
            infos = email_send_lst.pop(0)
            asyncio.create_task(email_sys.sendemail(infos[0], infos[1]))
            await asyncio.sleep(0.1)
        else:
            await asyncio.sleep(5)


@asynccontextmanager
async def lifespan(app: FastAPI):
    await db.connect_db()
    asyncio.create_task(clean_sys())
    asyncio.create_task(send_email())
    yield

app = FastAPI(lifespan=lifespan)

templates = Jinja2Templates(directory="src")

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


def check_passwd(passwd: str):
    if (len(passwd) < 8):
        return 1
    pattern = r'^(?![a-zA-Z]+$)(?!\d+$)(?![^\da-zA-Z\s]+$).{8,40}$'

    if re.match(pattern, passwd):
        return 0
    else:
        return 1


async def authenticate_user(username: str, password: str):
    hashed_password = await db.get_user(username)
    if not hashed_password:
        return False
    return hashed_password == hashlib.sha256(
        password.encode("utf-8")).hexdigest()


async def create_token(username: str):
    tkn = uuid.uuid4().hex
    tokens[tkn] = (username, datetime.now() +
                   timedelta(minutes=float(ACCESS_TOKEN_EXPIRE_MINUTES)))
    return tkn


async def check_token(tkn: str):
    res = tokens.get(tkn, None)
    if (res is None):
        return ""
    if (res[1] < datetime.now()):
        del tokens[tkn]
        return ""
    return res[0]


async def check_apikey(tkn: str):
    res = apikeys.get(tkn, None)
    if (res is None):
        return ""
    if (res[1] < datetime.now()):
        del apikeys[tkn]
        return ""
    return res[0]


@app.post("/api/login")
async def login_callback(response: Response, username: str = Form(), password: str = Form()):
    if (await authenticate_user(username, password)):
        tokennow = await create_token(username)
        tkn = uuid.uuid4().hex
        apikeys[tkn] = tokens[tokennow]
        response.set_cookie("session", tokennow)
        return {"msg": "", "key": tkn}
    else:
        return {"msg": "用户名或密码错误", "key": ""}


regex = re.compile(
    r'([A-Za-z0-9]+[.-_])*[A-Za-z0-9]+@[A-Za-z0-9-]+(\.[A-Z|a-z]{2,})+')


@app.post("/api/signup")
async def login_callback(username: str = Form(), password: str = Form(), email: str = Form()):
    if (check_passwd(password)):
        return {"msg": "密码强度弱，请至少包含一个大小写字符与数字且长度>8", "code": 1}
    if (not re.fullmatch(regex, email)):
        return {"msg": "邮箱不合法", "code": 1}
    if not (await db.check_user(username)):
        tkn = uuid.uuid4().hex
        emails[tkn] = (username, hashlib.sha256(
            password.encode("utf-8")).hexdigest(), datetime.now() +
            timedelta(minutes=float(ACCESS_EMAIL_EXPIRE_MINUTES)), email)

        email_send_lst.append((email, ROOT+"/api/checkemail?uid="+tkn))
        return {"msg": "验证邮件已发送到邮箱，请在10分钟内完成验证", "code": 0}
    else:
        return {"msg": "用户名重复", "code": 1}


@app.get("/api/checkemail")
async def checkemail(uid: str):
    if (uid not in emails):
        return templates.TemplateResponse("checkemail.html", {"request": {}, "msg": "不存在的注册id"})
    if (emails[uid][2] < datetime.now()):
        del emails[uid]
        return templates.TemplateResponse("checkemail.html", {"request": {}, "msg": "链接已过期"})
    if (emails[uid][1] == ""):
        return templates.TemplateResponse("checkemail.html", {"request": {}, "msg": "不存在的注册id"})
    if await db.create_user(emails[uid][0], emails[uid][1], emails[uid][3]) == 0:
        del emails[uid]
        return templates.TemplateResponse("checkemail.html", {"request": {}, "msg": "创建成功"})
    else:
        del emails[uid]
        return templates.TemplateResponse("checkemail.html", {"request": {}, "msg": "重复的用户名"})


@app.get("/api/resetpasswd", response_class=HTMLResponse)
async def resetpasswd(uid: str, response: Response):
    if (uid not in emails):
        return templates.TemplateResponse("checkemail.html", {"request": {}, "msg": "不存在的验证id"})
    if (emails[uid][2] < datetime.now()):
        del emails[uid]
        return templates.TemplateResponse("checkemail.html", {"request": {}, "msg": "链接已过期"})
    if (emails[uid][1] != ""):
        return templates.TemplateResponse("checkemail.html", {"request": {}, "msg": "不存在的注册id"})
    tokennow = await create_token(emails[uid][0])
    tkn = uuid.uuid4().hex
    apikeys[tkn] = tokens[tokennow]
    response.set_cookie("session", tokennow)
    return '<html><head><meta http-equiv="refresh" content="0;url=/user"><title>正在跳转</title></head><body>正在跳转</body></html>'


@app.post("/api/send_resetpasswd")
async def resetpasswd(username: str = Form()):
    if (await db.check_user(username)):
        email = await db.get_email(username)
        tkn = uuid.uuid4().hex
        emails[tkn] = (username, "", datetime.now() +
                       timedelta(minutes=float(ACCESS_EMAIL_EXPIRE_MINUTES)), email)

        email_send_lst.append((email, ROOT+"/api/resetpasswd?uid="+tkn))
        return {"msg": "验证邮件已发送到邮箱，请在10分钟内完成验证", "code": 0}
    else:
        return {"msg": "用户名不存在", "code": 1}


@app.get("/api/getinfo")
async def get_user_info(uid: str):
    username = await check_apikey(uid)
    if (username == ""):
        return {"code": 1, "msg": "token无效", "data": {}}
    return {"code": 0, "msg": "", "data": {"username": username, "email": await db.get_email(username)}}


@app.post("/api/changepasswd")
async def changepasswd(password: str = Form(), session: Annotated[str | None, Cookie()] = None):
    if (check_passwd(password)):
        return {"msg": "密码强度弱，请至少包含一个大小写字符与数字且长度>8"}
    if (session is not None):
        username = await check_token(session)
        if (username != ""):
            await db.update_passwd(username, hashlib.sha256(
                password.encode("utf-8")).hexdigest())
            del tokens[session]
            return {"msg": ""}
        else:
            return {"msg": "无效的登录token"}
    else:
        return {"msg": "无效的登录token"}


@app.get("/login")
async def login(state: str = "", client_id: str = "", redirect_url: str = "/user", session: Annotated[str | None, Cookie()] = None):
    now_redirect_url = redirect_url.replace(
        "https://", "").replace("http://", "").split("#")[0].rstrip("/")
    if (now_redirect_url not in REDIRECT_URL_WHITELIST):
        return templates.TemplateResponse("checkemail.html", {"request": {}, "msg": "无效的重定向URL"})
    if (session is not None):
        username = await check_token(session)
        if (username != ""):
            tkn = uuid.uuid4().hex
            apikeys[tkn] = tokens[session]
            return RedirectResponse(url=redirect_url+f"#access_token={tkn}&token_type=Bearer&state={state}")
    return templates.TemplateResponse("login.html", {"request": {}, "redirect_url": redirect_url, "state": state})


@app.get("/signup")
async def login(redirect_url: str):
    return templates.TemplateResponse("signup.html", {"request": {}, "redirect_url": redirect_url})


@app.get("/user")
async def login(session: Annotated[str | None, Cookie()] = None):

    if (session is not None):
        username = await check_token(session)
        if (username == ""):
            return RedirectResponse(url="/login?redirect_url=/user")
    return templates.TemplateResponse("manage.html", {"request": {}})


@app.get("/resetpasswd")
async def resetpasswd(response: Response):
    return templates.TemplateResponse("resetpasswd.html", {"request": {}})


@app.get("/manager/init")
async def init(key: str):
    if (key != MANAGE_KEY):
        return 1
    await db.create_db()
    return 0
reg.main(app, ROOT, apikeys)


def run():
    uvicorn.run(app, host="0.0.0.0", port=8000)