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use std::collections::{HashMap, BTreeMap};
use std::sync::{Arc, Weak};
use anyhow::{Result, bail};
use lazy_static::lazy_static;
use serde::{Serialize, Deserialize};
use k2v_client::{K2vClient, CausalityToken, K2vValue};
use crate::cryptoblob::{seal_serialize, open_deserialize};
use crate::login::{Credentials, StorageCredentials};
use crate::mail::mailbox::Mailbox;
use crate::mail::unique_ident::{UniqueIdent, gen_ident};
use crate::mail::uidindex::ImapUidvalidity;
use crate::time::now_msec;
const MAILBOX_HIERARCHY_DELIMITER: &str = "/";
/// INBOX is the only mailbox that must always exist.
/// It is created automatically when the account is created.
/// IMAP allows the user to rename INBOX to something else,
/// in this case all messages from INBOX are moved to a mailbox
/// with the new name and the INBOX mailbox still exists and is empty.
/// In our implementation, we indeed move the underlying mailbox
/// to the new name (i.e. the new name has the same id as the previous
/// INBOX), and we create a new empty mailbox for INBOX.
const INBOX: &str = "INBOX";
pub struct User {
pub username: String,
pub creds: Credentials,
pub k2v: K2vClient,
}
impl User {
pub fn new(username: String, creds: Credentials) -> Result<Self> {
let k2v = creds.k2v_client()?;
Ok(Self {
username,
creds,
k2v,
})
}
/// Lists user's available mailboxes
pub async fn list_mailboxes(&self) -> Result<Vec<String>> {
let (list, _ct) = self.load_mailbox_list().await?;
Ok(list.into_iter().map(|(k, _)| k).collect())
}
/// Opens an existing mailbox given its IMAP name.
pub async fn open_mailbox(&self, name: &str) -> Result<Option<Arc<Mailbox>>> {
let (list, _ct) = self.load_mailbox_list().await?;
match list.get(name) {
Some(MailboxListEntry { id_lww: (_, Some(mbid)), uidvalidity }) =>
self.open_mailbox_by_id(*mbid, *uidvalidity).await,
_ =>
bail!("Mailbox does not exist: {}", name),
}
}
/// Creates a new mailbox in the user's IMAP namespace.
pub fn create_mailbox(&self, _name: &str) -> Result<()> {
unimplemented!()
}
/// Deletes a mailbox in the user's IMAP namespace.
pub fn delete_mailbox(&self, _name: &str) -> Result<()> {
unimplemented!()
}
/// Renames a mailbox in the user's IMAP namespace.
pub fn rename_mailbox(&self, _old_name: &str, _new_name: &str) -> Result<()> {
unimplemented!()
}
// ---- Internal mailbox management ----
async fn open_mailbox_by_id(&self, id: UniqueIdent, min_uidvalidity: ImapUidvalidity) -> Result<Option<Arc<Mailbox>>> {
let cache_key = (self.creds.storage.clone(), id);
{
let cache = MAILBOX_CACHE.cache.lock().unwrap();
if let Some(mb) = cache.get(&cache_key).and_then(Weak::upgrade) {
return Ok(Some(mb));
}
}
let mb = Arc::new(Mailbox::open(&self.creds, id, min_uidvalidity).await?);
let mut cache = MAILBOX_CACHE.cache.lock().unwrap();
if let Some(concurrent_mb) = cache.get(&cache_key).and_then(Weak::upgrade) {
drop(mb); // we worked for nothing but at least we didn't starve someone else
Ok(Some(concurrent_mb))
} else {
cache.insert(cache_key, Arc::downgrade(&mb));
Ok(Some(mb))
}
}
// ---- Mailbox list management ----
async fn load_mailbox_list(&self) -> Result<(MailboxList, Option<CausalityToken>)> {
let cv = match self.k2v.read_item("mailboxes", "list").await {
Err(k2v_client::Error::NotFound) => return Ok((BTreeMap::new(), None)),
Err(e) => return Err(e.into()),
Ok(cv) => cv,
};
let mut list = BTreeMap::new();
for v in cv.value {
if let K2vValue::Value(vbytes) = v {
let list2 = open_deserialize::<MailboxList>(&vbytes, &self.creds.keys.master)?;
list = merge_mailbox_lists(list, list2);
}
}
// If INBOX doesn't exist, create a new mailbox with that name
// and save new mailbox list.
match list.get_mut(INBOX) {
None => {
list.insert(INBOX.into(), MailboxListEntry {
id_lww: (now_msec(), Some(gen_ident())),
uidvalidity: ImapUidvalidity::new(1).unwrap(),
});
self.save_mailbox_list(&list, Some(cv.causality.clone())).await?;
}
Some(MailboxListEntry { id_lww, uidvalidity }) if id_lww.1.is_none() => {
id_lww.0 = std::cmp::max(id_lww.0 + 1, now_msec());
id_lww.1 = Some(gen_ident());
*uidvalidity = ImapUidvalidity::new(uidvalidity.get() + 1).unwrap();
self.save_mailbox_list(&list, Some(cv.causality.clone())).await?;
}
_ => (),
}
Ok((list, Some(cv.causality)))
}
async fn save_mailbox_list(&self, list: &MailboxList, ct: Option<CausalityToken>) -> Result<()> {
let list_blob = seal_serialize(list, &self.creds.keys.master)?;
self.k2v.insert_item("mailboxes", "list", list_blob, ct).await?;
Ok(())
}
}
// ---- User's mailbox list (serialized in K2V) ----
type MailboxList = BTreeMap<String, MailboxListEntry>;
#[derive(Serialize, Deserialize, Clone, Copy)]
struct MailboxListEntry {
id_lww: (u64, Option<UniqueIdent>),
uidvalidity: ImapUidvalidity,
}
impl MailboxListEntry {
fn merge(&mut self, other: &Self) {
// Simple CRDT merge rule
if other.id_lww.0 > self.id_lww.0
|| (other.id_lww.0 == self.id_lww.0 && other.id_lww.1 > self.id_lww.1) {
self.id_lww = other.id_lww;
}
self.uidvalidity = std::cmp::max(self.uidvalidity, other.uidvalidity);
}
}
fn merge_mailbox_lists(mut list1: MailboxList, list2: MailboxList) -> MailboxList {
for (k, v) in list2.into_iter() {
if let Some(e) = list1.get_mut(&k) {
e.merge(&v);
} else {
list1.insert(k, v);
}
}
list1
}
// ---- Mailbox cache ----
struct MailboxCache {
cache: std::sync::Mutex<HashMap<(StorageCredentials, UniqueIdent), Weak<Mailbox>>>,
}
impl MailboxCache {
fn new() -> Self {
Self {
cache: std::sync::Mutex::new(HashMap::new()),
}
}
}
lazy_static! {
static ref MAILBOX_CACHE: MailboxCache = MailboxCache::new();
}
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