//! Used to determine which post belongs to who.
//!
//! Mostly for determining if a poster owns a post.
use super::*;

use std::{
    net::SocketAddr,
};
use cryptohelpers::sha256;

/// A user's unique ID.
///
/// This is composed by the user's address and their session ID.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
pub struct UserID(SocketAddr, session::SessionID);

static COUNTER: GlobalCounter = GlobalCounter::new();

impl UserID
{
    /// Generate a token from this instance.
    ///
    /// User tokens are deterministically generated and can be deterministically verified.
    pub fn generate_token(&self) -> u64
    {
	let cnt = COUNTER.get();
	let mut trunc = [0u8; std::mem::size_of::<u64>()];
	
	let hash = GloballySalted::new(self).compute_sha256_hash();
	bytes::move_slice(&mut trunc[..], hash.as_ref());

	u64::from_le_bytes(trunc) ^ cnt
    }

    /// Validate a token for this instance created with `generate_token`.
    pub fn validate_token(&self, val: u64) -> bool
    {
	let mut trunc = [0u8; std::mem::size_of::<u64>()];
	
	let hash = GloballySalted::new(self).compute_sha256_hash();
	bytes::move_slice(&mut trunc[..], hash.as_ref());

	COUNTER.valid(u64::from_le_bytes(trunc) ^ val)
    }
}

/// A user not bound to a session.
#[derive(Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
pub struct User
{
    addr: SocketAddr,
}

impl User
{
    /// Get the user ID for this session.
    pub fn id_for_session(&self, session: &session::Session) -> UserID
    {
	UserID(self.addr, session.session_id().clone())
    }
}