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

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

#[derive(Debug, Serialize, Deserialize)]
pub struct UserWithToken {
    #[serde(flatten)]
    pub user: schema::User,
    pub jwt: String,
}

#[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")]
    user: Option<UserWithToken>,
    #[serde(skip_serializing_if = "Option::is_none")]
    gamenights: Option<Vec<schema::GameNight>>,
}

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,
        user: None,
        gamenights: None,
    };

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

    fn login_response(user: schema::User, jwt: String) -> Self {
        Self {
            result: Self::SUCCES_RESULT,
            message: None,
            user: Some(UserWithToken {
                user: user,
                jwt: jwt
            }),
            gamenights: None,
        }
    }

    fn gamenight_response(gamenights: Vec<schema::GameNight>) -> Self {
        Self {
            result: Self::SUCCES_RESULT,
            message: None,
            user: None,
            gamenights: Some(gamenights),
        }
    }
}

#[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::Forward(())
            }
        };

        if !header.starts_with(BEARER) {
            return Outcome::Forward(());
        };

        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(_) => {
                return Outcome::Forward(())
            }
        };
        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: schema::User) -> ApiResponseVariant {
    let gamenights = schema::get_all_gamenights(conn).await;
    ApiResponseVariant::Value(json!(ApiResponse::gamenight_response(gamenights)))
}

#[get("/gamenights", rank = 2)]
pub async fn gamenights_unauthorized() -> ApiResponseVariant {
    ApiResponseVariant::Status(Status::Unauthorized)
}

#[post("/gamenight", format = "application/json", data = "<gamenight_json>")]
pub async fn gamenight_post_json(
    conn: DbConn,
    _user: schema::User,
    gamenight_json: Json<schema::GameNightNoId>,
) -> ApiResponseVariant {
    match schema::insert_gamenight(conn, gamenight_json.into_inner()).await {
        Ok(_) => ApiResponseVariant::Value(json!(ApiResponse::SUCCES)),
        Err(err) => ApiResponseVariant::Value(json!(ApiResponse::error(err.to_string()))),
    }
}

#[post("/gamenight", rank = 2)]
pub async fn gamenight_post_json_unauthorized() -> ApiResponseVariant {
    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 {
    let register = register_json.into_inner();
    let register_clone = register.clone();
    match conn
        .run(move |c| register_clone.validate_args((c, c)))
        .await
    {
        Ok(()) => (),
        Err(error) => {
            return ApiResponseVariant::Value(json!(ApiResponse::error(error.to_string())))
        }
    }

    match schema::insert_user(conn, register).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) => {
            if !login_result.result {
                return ApiResponseVariant::Value(json!(ApiResponse::error(String::from(
                    "username and password didn't match"
                ))));
            }

            let user = login_result.user.unwrap();
            let my_claims = Claims {
                exp: Utc::now().timestamp() + chrono::Duration::days(7).num_seconds(),
                uid: user.id,
                role: user.role,
            };

            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(user, token))),
                Err(error) => {
                    ApiResponseVariant::Value(json!(ApiResponse::error(error.to_string())))
                }
            }
        }
    }
}