import json

from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.encoders import jsonable_encoder
from fastapi.middleware.cors import CORSMiddleware
from fastapi.security import OAuth2PasswordBearer

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 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"""

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

    if user.id is not None:
        raise HTTPException(
            status_code=400,
            detail="User id shall be auto generated, cannot be provided in request"
        )
    if not users:
        user.id = 0
    else:
        max_user_id = max([i['id'] for i in users])
        user.id = max_user_id + 1

    user_exists = [i for i in users if i['username'] == user.username]
    if user_exists:
        raise HTTPException(status_code=400, detail="Username already in use")

    encryption_key = generate_random_encryption_key()

    salt, master_key = generate_user_passkey(user.password)
    encrypted_encryption_key = fernet_encrypt(encryption_key, master_key)

    user.password = Hasher.get_password_hash(user.password)
    user.encryption_key = encrypted_encryption_key.decode('utf-8')
    user.salt = serialize_bytes(salt)

    users.append(jsonable_encoder(user))
    # print(f"{salt=}\n{user.salt=}\n{encrypted_encryption_key=}\n{user.encryption_key=}\n{master_key=}")
    with open('database/users.json', 'w') as f:
        json.dump(users, f)

    return {'user_id': user.id}


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

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

    cur_user = [i for i in users if i['username']==user.username]
    if not cur_user:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="username or password is incorrect"
        )
    else:
        cur_user = cur_user[0]

    password_match = Hasher.verify_password(user.password, cur_user['password'])
    if not password_match:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="username or password is incorrect"
        )

    encrypted_encryption_key = cur_user['encryption_key'].encode()
    salt = deserialize_into_bytes(cur_user['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.
    """

    data = []
    with open('database/secrets.json', 'r') as f:
        text = f.read()
        if text:
            data.extend(json.loads(text))
    secret_id = max(i['id'] for i in data) + 1
    secret.id = secret_id
    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')
    data.append(jsonable_encoder(secret))

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

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

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

    user_secrets = [i for i in data if i['user_id']==user_id and i['active']]
    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']
    print("user_id: ", user_id)
    if user_id is not None:
        return {'message': 'authenticated'}

    raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED)