import uvicorn, secrets, utils
import os, asyncio
from fastapi import FastAPI, HTTPException, Depends, APIRouter
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from jose import jwt
from passlib.context import CryptContext
from fastapi_socketio import SocketManager
from utils.sqlite import SQLite
from utils import API_VERSION, FIREGEX_PORT, JWT_ALGORITHM, get_interfaces, socketio_emit, DEBUG, SysctlManager
from utils.loader import frontend_deploy, load_routers
from utils.models import ChangePasswordModel, IpInterface, PasswordChangeForm, PasswordForm, ResetRequest, StatusModel, StatusMessageModel
from contextlib import asynccontextmanager
from fastapi.middleware.cors import CORSMiddleware

# DB init
db = SQLite('db/firegex.db')
sysctl = SysctlManager({
    "net.ipv4.conf.all.forwarding": True,
    "net.ipv6.conf.all.forwarding": True,
    "net.ipv4.conf.all.route_localnet": True,
    "net.ipv4.ip_forward": True
})

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/login", auto_error=False)
crypto = CryptContext(schemes=["bcrypt"], deprecated="auto")

@asynccontextmanager
async def lifespan(app):
    await startup_main()
    yield
    await shutdown_main()

app = FastAPI(debug=DEBUG, redoc_url=None, lifespan=lifespan)
utils.socketio = SocketManager(app, "/sock", socketio_path="")

if DEBUG:
    app.add_middleware(CORSMiddleware, allow_origins=["*"], allow_credentials=True, allow_methods=["*"], allow_headers=["*"])

def APP_STATUS(): return "init" if db.get("password") is None else "run"
def JWT_SECRET(): return db.get("secret")

def set_psw(psw: str):
    hash_psw = crypto.hash(psw)
    db.put("password",hash_psw)

@utils.socketio.on("update")
async def updater(): pass

def create_access_token(data: dict):
    to_encode = data.copy()
    encoded_jwt = jwt.encode(to_encode, JWT_SECRET(), algorithm=JWT_ALGORITHM)
    return encoded_jwt

async def refresh_frontend(additional:list[str]=[]):
    await socketio_emit([]+additional)

async def check_login(token: str = Depends(oauth2_scheme)):
    if not token:
        return False
    try:
        payload = jwt.decode(token, JWT_SECRET(), algorithms=[JWT_ALGORITHM])
        logged_in: bool = payload.get("logged_in")
    except Exception:
        return False
    return logged_in

async def is_loggined(auth: bool = Depends(check_login)):
    if not auth:
        raise HTTPException(
            status_code=401,
            detail="Could not validate credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    return True

api = APIRouter(prefix="/api", dependencies=[Depends(is_loggined)])

@app.get("/api/status", response_model=StatusModel)
async def get_app_status(auth: bool = Depends(check_login)):
    """Get the general status of firegex and your session with firegex"""
    return { 
        "status": APP_STATUS(),
        "loggined": auth,
        "version": API_VERSION
    }

@app.post("/api/login")
async def login_api(form: OAuth2PasswordRequestForm = Depends()):
    """Get a login token to use the firegex api"""
    if APP_STATUS() != "run": raise HTTPException(status_code=400)
    if form.password == "":
        return {"status":"Cannot insert an empty password!"}
    await asyncio.sleep(0.3) # No bruteforce :)
    if crypto.verify(form.password, db.get("password")):
        return {"access_token": create_access_token({"logged_in": True}), "token_type": "bearer"}
    raise HTTPException(406,"Wrong password!")

@app.post('/api/set-password', response_model=ChangePasswordModel)
async def set_password(form: PasswordForm):
    """Set the password of firegex"""
    if APP_STATUS() != "init": raise HTTPException(status_code=400)
    if form.password == "":
        return {"status":"Cannot insert an empty password!"}
    set_psw(form.password)
    await refresh_frontend()
    return {"status":"ok", "access_token": create_access_token({"logged_in": True})}

@api.post('/change-password', response_model=ChangePasswordModel)
async def change_password(form: PasswordChangeForm):
    """Change the password of firegex"""
    if APP_STATUS() != "run": raise HTTPException(status_code=400)

    if form.password == "":
        return {"status":"Cannot insert an empty password!"}
    if form.expire:
        db.put("secret", secrets.token_hex(32))
    
    set_psw(form.password)
    await refresh_frontend()
    return {"status":"ok", "access_token": create_access_token({"logged_in": True})}


@api.get('/interfaces', response_model=list[IpInterface])
async def get_ip_interfaces():
    """Get a list of ip and ip6 interfaces"""
    return get_interfaces()

#Routers Loader
reset, startup, shutdown = load_routers(api)

async def startup_main():
    db.init()
    if os.getenv("HEX_SET_PSW"):
        set_psw(bytes.fromhex(os.getenv("HEX_SET_PSW")).decode())
    sysctl.set()
    await startup()
    if not JWT_SECRET(): db.put("secret", secrets.token_hex(32))
    await refresh_frontend()

async def shutdown_main():
    await shutdown()
    sysctl.reset()
    db.disconnect()

@api.post('/reset', response_model=StatusMessageModel)
async def reset_firegex(form: ResetRequest):
    """Reset firegex nftables rules and optionally all the database"""
    if form.delete:
        db.delete()
        db.init()
        db.put("secret", secrets.token_hex(32))
    sysctl.set()
    await reset(form)
    await refresh_frontend()
    return {'status': 'ok'}

app.include_router(api)
frontend_deploy(app)

if __name__ == '__main__':
    # os.environ {PORT = Backend Port (Main Port), F_PORT = Frontend Port}
    os.chdir(os.path.dirname(os.path.realpath(__file__)))
    uvicorn.run(
        "app:app",
        host="::" if DEBUG else None,
        port=FIREGEX_PORT,
        reload=DEBUG,
        access_log=True,
        workers=1, # Multiple workers will cause a crash due to the creation
                  # of multiple processes with separated memory
    )