use crate::AppConfig;
use rocket::request::Outcome;
use jsonwebtoken::decode;
use crate::schema::DbConn;
use jsonwebtoken::DecodingKey;
use jsonwebtoken::Validation;
use rocket::State;
use chrono::Utc;
use jsonwebtoken::{Header, EncodingKey};
use crate::schema;
use std::borrow::Cow;
use jsonwebtoken::encode;
use rocket::serde::json::{Json, json, Value};
use rocket::http::Status;
use rocket::request::{self, Request, FromRequest};
use rocket::outcome::Outcome::{Success, Failure};
use serde::{Serialize, Deserialize};

pub struct Referer(String);

#[derive(Debug)]
pub enum ReferrerError {
    Missing,
    MoreThanOne
}

#[derive(Debug, Responder)]
pub enum ApiResponseVariant {
    Status(Status),
//    Redirect(Redirect),
    Value(Value),
//    Flash(Flash<Redirect>)
}

#[rocket::async_trait]
impl<'r> FromRequest<'r> for Referer {
    type Error = ReferrerError;

    async fn from_request(req: &'r Request<'_>) -> request::Outcome<Self, Self::Error> {
        let referers : Vec<_> = req.headers().get("Referer").collect();
        match referers.len() {
            0 => Failure((Status::BadRequest, ReferrerError::Missing)),
            1 => Success(Referer(referers[0].to_string())),
            _ => Failure((Status::BadRequest, ReferrerError::MoreThanOne)),
        }
    }
}

#[derive(Serialize, Deserialize, Debug)]
struct ApiResponse {
    result: Cow<'static, str>,
    #[serde(skip_serializing_if = "Option::is_none")]
    message: Option::<Cow<'static, str>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    jwt: Option::<Cow<'static, str>>
}

impl ApiResponse {
    const SUCCES_RESULT: Cow<'static, str> = Cow::Borrowed("Ok");
    const FAILURE_RESULT: Cow<'static, str> = Cow::Borrowed("Failure");

    const SUCCES: Self = Self {
        result: Self::SUCCES_RESULT,
        message: None,
        jwt: None
    };

    fn error(message: String) -> Self {
        Self { 
            result: Self::FAILURE_RESULT,
            message: Some(Cow::Owned(message)),
            jwt: None
        }
    }

    fn login_response(jwt: String) -> Self {
        Self {
            result: Self::SUCCES_RESULT,
            message: None,
            jwt: Some(Cow::Owned(jwt))
        }
    }
}

#[derive(Debug)]
pub enum ApiError {
    RequestError(String),
}

const AUTH_HEADER: &str = "Authorization";
const BEARER: &str = "Bearer ";

#[rocket::async_trait]
impl<'r> FromRequest<'r> for schema::User {
    type Error = ApiError;

    async fn from_request(req: &'r Request<'_>) -> Outcome<Self, Self::Error> {
        let header = match req.headers().get_one(AUTH_HEADER) {
            Some(header) => header,
            None => return Outcome::Failure((Status::BadRequest, ApiError::RequestError("No authorization header found".to_string())))
        };

        if !header.starts_with(BEARER) {
            return Outcome::Failure((Status::BadRequest, ApiError::RequestError("Invalid Authorization header.".to_string())))
        };

        let app_config = req.guard::<&State<AppConfig>>().await.unwrap().inner();
        let jwt = header.trim_start_matches(BEARER).to_owned();
        let token = match decode::<Claims>(&jwt, &DecodingKey::from_secret(app_config.jwt_secret.as_bytes()), &Validation::default()) {
            Ok(token) => token,
            Err(error) => return Outcome::Failure((Status::BadRequest, ApiError::RequestError(error.to_string())))
        };
        let id = token.claims.uid;
        
        let conn = req.guard::<DbConn>().await.unwrap();
        return Outcome::Success(schema::get_user(conn, id).await)
    }
}

#[get("/gamenights")]
pub async fn gamenights(conn: DbConn, user: Option<schema::User>) -> ApiResponseVariant {
    if user.is_some() {
        let gamenights = schema::get_all_gamenights(conn).await;
        ApiResponseVariant::Value(json!(gamenights))
    } 
    else {
        ApiResponseVariant::Status(Status::Unauthorized)
    }
}

#[post("/gamenight", format = "application/json", data = "<gamenight_json>")]
pub async fn gamenight_post_json(conn: DbConn, user: Option<schema::User>, gamenight_json: Json<schema::GameNightNoId>) -> ApiResponseVariant  {
    if user.is_some() {
        schema::insert_gamenight(conn, gamenight_json.into_inner()).await;
        ApiResponseVariant::Value(json!(ApiResponse::SUCCES))
    } 
    else {
        ApiResponseVariant::Status(Status::Unauthorized)
    }
}

#[post("/register", format = "application/json", data = "<register_json>")]
pub async fn register_post_json(conn: DbConn, register_json: Json<schema::Register>) -> ApiResponseVariant  {
    match schema::insert_user(conn, register_json.into_inner()).await {
        Ok(_) => ApiResponseVariant::Value(json!(ApiResponse::SUCCES)),
        Err(err) => ApiResponseVariant::Value(json!(ApiResponse::error(err.to_string())))
    }
}

#[derive(Debug, Serialize, Deserialize)]
struct Claims {
    exp: i64,
    uid: i32,
    role: schema::Role,
}

#[post("/login", format = "application/json", data = "<login_json>")]
pub async fn login_post_json(conn: DbConn, config: &State<AppConfig>, login_json: Json<schema::Login>) -> ApiResponseVariant {

    match schema::login(conn, login_json.into_inner()).await {
        Err(err) => ApiResponseVariant::Value(json!(ApiResponse::error(err.to_string()))),
        Ok(login_result) => {
            
            let my_claims = Claims {
                exp: Utc::now().timestamp() + chrono::Duration::days(7).num_seconds(),
                uid: login_result.id.unwrap(),
                role: login_result.role.unwrap()
            };
            
            let secret = &config.inner().jwt_secret;
            match encode(&Header::default(), &my_claims, &EncodingKey::from_secret(secret.as_bytes())) 
            {
                Ok(token) => ApiResponseVariant::Value(json!(ApiResponse::login_response(token))),
                Err(error) => ApiResponseVariant::Value(json!(ApiResponse::error(error.to_string())))
            }
        }
    }
}