use axum::{
    extract::FromRequestParts,
    http::{
        request::Parts,
        StatusCode,
    },
    Json, RequestPartsExt,
    response::{IntoResponse, Response},
};
use axum_extra::{
    headers::{authorization::Bearer, Authorization},
    TypedHeader,
};
use serde::{Deserialize, Serialize};
use serde_json::json;
use jsonwebtoken::{decode,encode, DecodingKey, EncodingKey, Header, Validation};
use std::fmt::Display;
use once_cell::sync::Lazy;
use crate::util;

#[derive(Debug, Serialize, Deserialize)]
pub struct Claims {
    sub: String,
    // company: String,
    exp: usize,
    pub uid: i64,
}

#[derive(Debug, Serialize)]
struct AuthBody {
    access_token: String,
    token_type: String,
}

#[derive(Debug, Deserialize)]
struct AuthPayload {
    client_id: String,
    client_secret: String,
}

#[derive(Debug)]
pub enum AuthError {
    WrongCredentials,
    MissingCredentials,
    TokenCreation,
    InvalidToken,
}

static KEYS: Lazy<Keys> = Lazy::new(|| {
    let secret = std::env::var("JWT_SECRET").expect("JWT_SECRET must be set");
    Keys::new(secret.as_bytes())
});

struct Keys {
    encoding: EncodingKey,
    decoding: DecodingKey,
}

impl Keys {
    fn new(secret: &[u8]) -> Self {
        Self {
            encoding: EncodingKey::from_secret(secret),
            decoding: DecodingKey::from_secret(secret),
        }
    }
}

impl Display for Claims {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "Email: {}", self.sub)
    }
}

impl AuthBody {
    fn new(access_token: String) -> Self {
        Self {
            access_token,
            token_type: "Bearer".to_string(),
        }
    }
}

impl<S> FromRequestParts<S> for Claims
where
    S: Send + Sync,
{
    type Rejection = AuthError;

    async fn from_request_parts(parts: &mut Parts, _state: &S) -> Result<Self, Self::Rejection> {
        // Extract the token from the authorization header
        let TypedHeader(Authorization(bearer)) = parts
            .extract::<TypedHeader<Authorization<Bearer>>>()
            .await
            .map_err(|_| AuthError::InvalidToken)?;
        // Decode the user data
        let token_data = decode::<Claims>(bearer.token(), &KEYS.decoding, &Validation::default())
            .map_err(|_| AuthError::InvalidToken)?;

        Ok(token_data.claims)
    }
}
impl IntoResponse for AuthError {
    fn into_response(self) -> Response {
        let (status, error_message) = match self {
            AuthError::WrongCredentials => (StatusCode::UNAUTHORIZED, "Wrong credentials"),
            AuthError::MissingCredentials => (StatusCode::BAD_REQUEST, "Missing credentials"),
            AuthError::TokenCreation => (StatusCode::INTERNAL_SERVER_ERROR, "Token creation error"),
            AuthError::InvalidToken => (StatusCode::BAD_REQUEST, "Invalid token"),
        };
        let body = Json(json!({
            "error": error_message,
        }));
        (status, body).into_response()
    }
}