use std::convert::Infallible;

use argon2::Argon2;
use either::Either;
use password_hash::{PasswordHasher, SaltString, rand_core::OsRng};
use rocket::{
    FromForm, Request, Route, TypedError, async_trait,
    form::Form,
    get,
    outcome::{Outcome, try_outcome},
    post,
    request::FromRequest,
    response::Redirect,
    routes,
    serde::{Deserialize, Serialize},
    trace::info,
    uri,
};
use rocket_db_pools::Connection;
use rocket_dyn_templates::{Template, context};

use crate::{
    Db, SqlError,
    auth::{self, AdminUser, BasicAuth},
};

#[get("/", rank = 1)]
fn dash(auth: Option<BasicAuth>) -> Template {
    info!("user: {:?}", auth.as_ref().map(|a| a.username()));
    Template::render(
        "dash",
        context! {
            username: auth.as_ref().map(|a| a.username()),
            admin: auth.as_ref().map(|a| a.is_admin()).unwrap_or(false),
            mode: "dark",
        },
    )
}

#[get("/login")]
fn login(auth: Option<BasicAuth>) -> Either<Template, Redirect> {
    if auth.is_some() {
        Either::Right(Redirect::temporary(uri!(dash)))
    } else {
        Either::Left(Template::render(
            "login",
            context! {
                mode: "dark",
            },
        ))
    }
}

#[get("/account")]
fn account(auth: BasicAuth) -> Template {
    Template::render(
        "account",
        context! {
            username: auth.username(),
            admin: auth.is_admin(),
            mode: "dark",
        },
    )
}

#[get("/admin")]
async fn admin(auth: AdminUser, mut db: Connection<Db>) -> Result<Template, SqlError> {
    let users = sqlx::query!("SELECT * from users")
        .fetch_all(&mut **db)
        .await?;
    Ok(Template::render(
        "admin",
        context! {
            username: auth.username(),
            admin: auth.is_admin(),
            users: users.into_iter().filter(|r| r.name != auth.username()).map(|r| r.name).collect::<Vec<_>>(),
            mode: "dark",
        },
    ))
}

struct InitialSetup;
#[derive(Debug, TypedError)]
pub enum InitialSetupError {
    #[error(status = 500)]
    InternalError,
    #[error(status = 500)]
    DbError(#[error(source)] SqlError),
}
impl From<SqlError> for InitialSetupError {
    fn from(value: SqlError) -> Self {
        Self::DbError(value)
    }
}
impl From<sqlx::Error> for InitialSetupError {
    fn from(value: sqlx::Error) -> Self {
        Self::DbError(value.into())
    }
}
#[derive(Debug, TypedError)]
struct Empty;
impl From<Infallible> for Empty {
    fn from(value: Infallible) -> Self {
        match value {}
    }
}
#[async_trait]
impl<'r> FromRequest<'r> for InitialSetup {
    type Forward = Empty;
    type Error = InitialSetupError;
    async fn from_request(req: &'r Request<'_>) -> Outcome<Self, Self::Error, Self::Forward> {
        // TODO: cache result in managed state?
        let mut db = try_outcome!(
            req.guard::<Connection<Db>>()
                .await
                .map_error(|_| InitialSetupError::InternalError)
        );
        let user_count = match sqlx::query!("SELECT count(name) as count from users")
            .fetch_one(&mut **db)
            .await
        {
            Ok(v) => v,
            Err(e) => return Outcome::Error(e.into()),
        };
        if user_count.count == 0 {
            Outcome::Success(Self)
        } else {
            Outcome::Forward(Empty)
        }
    }
}

#[get("/")]
fn initial_setup(_initial: InitialSetup) -> Template {
    Template::render("initial_setup", context! {})
}

#[derive(Debug, Serialize, Deserialize, FromForm)]
#[serde(crate = "rocket::serde")]
pub struct InitialSetupOptions<'a> {
    admin_username: &'a str,
    admin_password: &'a str,
}

#[post("/initial_setup", data = "<opts>")]
async fn initial_complete(
    _initial: InitialSetup,
    opts: Form<InitialSetupOptions<'_>>,
    mut db: Connection<Db>,
) -> Result<Redirect, SqlError> {
    let salt = SaltString::generate(&mut OsRng);
    let pw_hash = Argon2::default()
        .hash_password(opts.admin_password.as_bytes(), salt.as_salt())
        .expect("Failed to hash password");
    sqlx::query("INSERT INTO users (name, role, password) VALUES (?1, \"admin\", ?2)")
        .bind(opts.admin_username)
        .bind(pw_hash.to_string())
        .execute(&mut **db)
        .await?;
    Ok(Redirect::to("/"))
}

pub fn routes() -> Vec<Route> {
    routes![
        dash,
        login,
        auth::login_form,
        auth::update_password,
        account,
        admin,
        initial_setup,
        initial_complete,
    ]
}