import json
from sqlite3 import IntegrityError
from typing import Literal

from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.encoders import jsonable_encoder
from fastapi.middleware.cors import CORSMiddleware

import queries
from auth import Hasher, create_access_token, get_current_user
from crypto import (deserialize_into_bytes, fernet_decrypt, fernet_encrypt,
                    generate_random_encryption_key, generate_user_passkey,
                    serialize_bytes)
from models import Key, Secret, User, UserLogin

app = FastAPI()


origins = [
    'http://localhost',
    'http://localhost:5173',
    "*"
]
app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,
    allow_credentials=True,
    allow_methods=['*'],
    allow_headers=['*']
)


@app.get("/")
async def root():
    return {"'message'": "Hello World"}


@app.post('/register')
async def register(user: User):
    """Registers a user"""

    plain_text_password = user.password
    user.password = Hasher.get_password_hash(plain_text_password)

    try:
        user = queries.CREATE_USER(user.model_dump())
        user_id = user['id']
    except IntegrityError as e:
        raise HTTPException(status_code=400, detail="Username already in use")

    encryption_key = generate_random_encryption_key()
    salt, master_key = generate_user_passkey(plain_text_password)

    key = Key(
        user_id=user_id,
        encryption_key=fernet_encrypt(encryption_key, master_key).decode('utf-8'),
        encryption_key_salt=serialize_bytes(salt)
    )

    try:
        queries.CREATE_KEY(key.model_dump())
    except Exception as e:
        print('failed to create key', e)

    return {'user_id': user_id}


@app.post('/login')
async def login(user: UserLogin):
    """logs in the user"""

    login_exception = HTTPException(
        status_code=status.HTTP_400_BAD_REQUEST,
        detail="username or password is incorrect"
    )

    cur_user = queries.GET_USER_WITH_KEY(user.model_dump())
    if cur_user is None:
        raise login_exception

    password_match = Hasher.verify_password(user.password, cur_user['password'])
    if not password_match:
        raise login_exception

    encrypted_encryption_key = cur_user['encryption_key'].encode()
    salt = deserialize_into_bytes(cur_user['encryption_key_salt'])
    _, master_key = generate_user_passkey(user.password, salt)
    encryption_key = fernet_decrypt(encrypted_encryption_key, master_key)
    access_token = create_access_token(subject=cur_user['id'], encryption_key=encryption_key)

    response = {
        'message': 'authenticated',
        'accessToken': access_token
    }

    return response


@app.post("/secret")
async def create_secret(secret: Secret, current_user: dict = Depends(get_current_user)):
    """
    Stores an encrypted secret for the user.
    """

    secret.user_id = current_user['id']
    encryption_key = current_user['encryption_key'].encode()

    encrypted_data = fernet_encrypt(secret.data.encode(), encryption_key)

    secret.data = encrypted_data.decode('utf-8')

    queries.CREATE_SECRET(secret.model_dump())

    return secret


@app.put("/secret")
async def update_secret(secret: Secret, current_user: dict = Depends(get_current_user)):
    """
    Updates an encrypted secret for the user.
    """

    data = []
    with open('database/secrets.json', 'r') as f:
        text = f.read()
        if text:
            data.extend(json.loads(text))

    if secret.id is None:
        raise HTTPException(status.HTTP_400_BAD_REQUEST, detail="Id must be passed for updating secret")

    secret.user_id = current_user['id']

    found_secrets = [(i, j) for i, j in enumerate(data) if j['user_id'] == secret.user_id and j['id']==secret.id]
    if not found_secrets:
        raise HTTPException(status.HTTP_400_BAD_REQUEST, deatil="Secret with this Id not found for this user")

    secret_pos = found_secrets[0][0]

    encryption_key = current_user['encryption_key'].encode()
    encrypted_data = fernet_encrypt(secret.data.encode(), encryption_key)

    secret.data = encrypted_data.decode('utf-8')
    data[secret_pos] = jsonable_encoder(secret)

    with open('database/secrets.json', 'w') as f:
        json.dump(data, f)
    return secret


@app.get('/secret')
async def list_secret(current_user: dict = Depends(get_current_user)):
    """Returns the encrypted secrets of the user."""

    user_secrets = queries.GET_SECRETS({'user_id': current_user['id']})
    encryption_key = current_user['encryption_key'].encode()

    for secret in user_secrets:
        cur_data = secret['data']
        decrypted_data = fernet_decrypt(cur_data, encryption_key)
        secret['data'] = decrypted_data

    return user_secrets


@app.get('/validate-token')
async def validate_token(current_user: dict = Depends(get_current_user)):
    user_id = current_user['id']
    if user_id is None:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED)

    return {'message': 'authenticated'}