use owl::{db::model::file::File, get, prelude::*, query, save, update};
use rocket::{Request, http::Status, outcome::Outcome, request::FromRequest};
use serde::{Deserialize, Serialize};
use serde_json::json;

use super::Sessions;
use crate::request::api::ToAPI;

// TODO : 2FA

/// User
///
/// # Example:
///
/// ```ignore
///
/// // Needs login
/// #[get("/myaccount")]
/// pub async fn account_page(ctx: RequestContext, user: User) -> StringResponse {
///     ...
/// }
/// ```
#[derive(Debug, Clone)]
#[model]
pub struct User {
    /// The username chosen by the user
    pub id: Id,
    /// The hashed password for the user
    pub password: String,
    /// The role of the user
    pub user_role: UserRole,
    #[serde(skip)]
    pub session: String,
    pub profile_picture: Option<IdRef<File>>,
}

#[derive(Debug, Clone, Serialize, Deserialize, sqlx::Type)]
#[sqlx(type_name = "user_role", rename_all = "lowercase")]
pub enum UserRole {
    /// A regular user with limited permissions
    Regular,
    /// An admin user with full system privileges
    Admin,
}

impl User {
    /// Find a user by their username
    pub async fn find(username: &str) -> Option<Model<Self>> {
        get!(username)
    }

    /// Create a new user with the given details
    ///
    /// Returns an Option containing the created user, or None if a user already exists with the same username
    pub async fn create(username: String, password: &str, role: UserRole) -> Option<Model<Self>> {
        // Check if a user already exists with the same username
        if Self::find(&username).await.is_some() {
            return None;
        }

        let u = Self {
            id: Id::String(username),
            password: bcrypt::hash(password, bcrypt::DEFAULT_COST).unwrap(),
            user_role: role,
            profile_picture: None,
            session: String::new(),
        };

        Some(save!(u))
    }

    /// Change the password of a User
    ///
    /// Returns a Result indicating whether the password change was successful or not
    pub async fn passwd(&self, old: &str, new: &str) -> Result<(), ()> {
        if self.verify_pw(old) {
            let mut target = vec![get!(self.id.clone()).unwrap()];
            update!(&mut target, |u: &mut User| {
                u.password = bcrypt::hash(new, bcrypt::DEFAULT_COST).unwrap();
            });

            return Ok(());
        }

        Err(())
    }

    /// Find all users in the system
    #[must_use]
    pub async fn find_all() -> Vec<Model<Self>> {
        query!(|_| true)
    }

    /// Check if the user is an admin
    #[must_use]
    pub const fn is_admin(&self) -> bool {
        matches!(self.user_role, UserRole::Admin)
    }

    /// Verify that a provided password matches the hashed password for the user
    ///
    /// Returns a boolean indicating whether the passwords match or not
    #[must_use]
    pub fn verify_pw(&self, password: &str) -> bool {
        bcrypt::verify(password, &self.password).unwrap()
    }
}

impl ToAPI for User {
    async fn api(&self) -> serde_json::Value {
        json!({
            "username": self.id.to_string(),
            "role": self.user_role
        })
    }
}

/// extracts a user from a request with `session` cookie
async fn extract_user(request: &Request<'_>) -> Option<Model<User>> {
    if let Some(session_id) = request.cookies().get("session") {
        if let Some(user) = User::from_session(session_id.value().to_string()).await {
            return Some(user);
        }
        return None;
    }

    None
}

pub struct UserAuth(pub Model<User>);

#[rocket::async_trait]
impl<'r> FromRequest<'r> for UserAuth {
    type Error = ();

    async fn from_request(request: &'r Request<'_>) -> rocket::request::Outcome<Self, Self::Error> {
        if let Some(user) = extract_user(request).await {
            return Outcome::Success(UserAuth(user));
        }
        Outcome::Error((Status::Unauthorized, ()))
    }
}

/// Struct which extracts a user with session from `Token` HTTP Header.
pub struct APIUser(pub Model<User>);

#[rocket::async_trait]
impl<'r> FromRequest<'r> for APIUser {
    type Error = ();

    async fn from_request(request: &'r Request<'_>) -> rocket::request::Outcome<Self, Self::Error> {
        match request.headers().get_one("token") {
            Some(key) => {
                if let Some(user) = User::from_session(key.to_string()).await {
                    return Outcome::Success(APIUser(user));
                }
                return Outcome::Error((Status::Unauthorized, ()));
            }
            None => Outcome::Error((Status::Unauthorized, ())),
        }
    }
}

/// Maybe User?
///
/// This struct extracts a user if possible, but also allows anybody.
///
/// # Example:
///
/// ```ignore
///
/// // Publicly accessable
/// #[get("/")]
/// pub async fn index(ctx: RequestContext, user: MaybeUser) -> StringResponse {
///     match user {
///         MaybeUser::User(user) => println!("You are {}", user.username),
///         MaybeUser::Anonymous => println!("Who are you?")
///     }
/// }
/// ```
pub enum MaybeUser {
    User(Model<User>),
    Anonymous,
}

#[rocket::async_trait]
impl<'r> FromRequest<'r> for MaybeUser {
    type Error = ();

    async fn from_request(request: &'r Request<'_>) -> rocket::request::Outcome<Self, Self::Error> {
        if let Some(user) = extract_user(request).await {
            return Outcome::Success(MaybeUser::User(user));
        }

        Outcome::Success(MaybeUser::Anonymous)
    }
}

impl From<MaybeUser> for Option<Model<User>> {
    fn from(value: MaybeUser) -> Self {
        value.take_user()
    }
}

impl MaybeUser {
    #[must_use]
    pub const fn user(&self) -> Option<&Model<User>> {
        match self {
            MaybeUser::User(user) => Some(user),
            MaybeUser::Anonymous => None,
        }
    }

    #[must_use]
    pub fn take_user(self) -> Option<Model<User>> {
        match self {
            MaybeUser::User(user) => Some(user),
            MaybeUser::Anonymous => None,
        }
    }
}

/// Admin User
///
/// This struct expects an Admin User and returns `Forbidden` otherwise.
///
/// # Example:
///
/// ```ignore
///
/// // Only admin users can access this route
/// #[get("/admin")]
/// pub async fn admin_panel(ctx: RequestContext, user: AdminUser) -> StringResponse {
///     ...
/// }
/// ```
pub struct AdminUser(pub Model<User>);

#[rocket::async_trait]
impl<'r> FromRequest<'r> for AdminUser {
    type Error = ();

    async fn from_request(request: &'r Request<'_>) -> rocket::request::Outcome<Self, Self::Error> {
        if let Some(user) = extract_user(request).await {
            if user.read().is_admin() {
                return Outcome::Success(AdminUser(user));
            }
        }

        Outcome::Error((Status::Unauthorized, ()))
    }
}