lb-rs 26.10.22

use crate::Lb;
use crate::model::api::GetPublicKeyRequest;
use crate::model::errors::{LbErr, LbErrKind, LbResult};
use crate::model::file::{File, ShareMode};
use crate::model::file_like::FileLike;
use crate::model::file_metadata::Owner;
use crate::model::tree_like::TreeLike;
use crate::service::events::Actor;
use libsecp256k1::PublicKey;
use serde::{Deserialize, Serialize};
use std::collections::{HashMap, HashSet};
use uuid::Uuid;

/// Account-wide sharing relationships, based on the current local metadata snapshot.
/// Counts documents, not folders or link placeholders, including pending incoming shares.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct SharingContact {
    pub username: String,
    pub outgoing_file_count: u64,
    pub incoming_file_count: u64,
    /// Distinct documents shared in either direction.
    pub total_file_count: u64,
}

impl Lb {
    /// Ranked contacts for the signed-in account. This is a local, read-only query;
    /// callers should run it off their UI thread.
    /// Inheritance follows real metadata parents, never the local placement of a link.
    #[instrument(level = "debug", skip(self))]
    pub async fn get_sharing_contacts(&self) -> LbResult<Vec<SharingContact>> {
        let me = self.keychain.get_pk()?;
        let tx = self.ro_tx().await;
        let db = tx.db();
        let mut tree = (&db.base_metadata).to_staged(&db.local_metadata).to_lazy();
        let mut counts: HashMap<Owner, (u64, u64, u64)> = HashMap::new();
        let root = db.root.as_ref().ok_or(LbErrKind::RootNonexistent)?;
        // A document can be reachable through an accepted link and a pending share.
        // Count each metadata ID only once, regardless of how it was reached.
        let mut document_ids = tree.descendants_using_links(root)?;
        document_ids.extend(tree.non_deleted_pending_files(&self.keychain)?);
        for id in document_ids {
            if !tree.find(&id)?.is_document() {
                continue;
            }
            let mut outgoing = HashSet::new();
            let mut incoming = HashSet::new();
            let mut visited = HashSet::new();
            let mut current = id;
            let mut deleted = false;
            while visited.insert(current) {
                let Some(file) = tree.maybe_find(&current) else { break };
                if file.explicitly_deleted() {
                    deleted = true;
                    break;
                }
                for access in file.user_access_keys() {
                    if access.deleted || access.encrypted_by == access.encrypted_for {
                        continue;
                    }
                    if access.encrypted_by == me {
                        outgoing.insert(Owner(access.encrypted_for));
                    } else if access.encrypted_for == me {
                        incoming.insert(Owner(access.encrypted_by));
                    }
                }
                if file.is_root() {
                    break;
                }
                current = *file.parent();
            }
            if deleted {
                continue;
            }
            for user in outgoing.union(&incoming) {
                let count = counts.entry(*user).or_default();
                count.0 += u64::from(outgoing.contains(user));
                count.1 += u64::from(incoming.contains(user));
                count.2 += 1;
            }
        }
        let mut contacts: Vec<_> = counts
            .into_iter()
            .filter_map(|(owner, (outgoing, incoming, total))| {
                let username = db.pub_key_lookup.get(&owner)?.clone();
                let trimmed = username.trim();
                if trimmed.is_empty() || trimmed.eq_ignore_ascii_case("<unknown>") {
                    return None;
                }
                Some(SharingContact {
                    username,
                    outgoing_file_count: outgoing,
                    incoming_file_count: incoming,
                    total_file_count: total,
                })
            })
            .collect();
        contacts.sort_by(|a, b| {
            b.total_file_count
                .cmp(&a.total_file_count)
                .then_with(|| a.username.cmp(&b.username))
        });
        Ok(contacts)
    }

    // todo: this can check whether the username is known already
    #[instrument(level = "debug", skip(self))]
    pub async fn share_file(&self, id: Uuid, username: &str, mode: ShareMode) -> LbResult<()> {
        let account = self.get_account()?;
        let username = username.to_lowercase();

        let sharee = Owner(
            self.client
                .request(account, GetPublicKeyRequest { username: username.clone() })
                .await
                .map_err(LbErr::from)?
                .key,
        );

        let mut tx = self.begin_tx().await;
        let db = tx.db();

        let mut tree = (&db.base_metadata)
            .to_staged(&mut db.local_metadata)
            .to_lazy();
        db.pub_key_lookup.insert(sharee, username)?;

        tree.add_share(id, sharee, mode, &self.keychain)?;

        tx.end();

        self.events.meta_changed(Actor::User(None));

        Ok(())
    }

    /// returns pending shares -- files shared with us that we haven't accepted or rejected
    /// this function just returns the actual files that were shared -- or the roots of shared
    /// trees. For the full set of shares see [Self::get_pending_share_files]
    #[instrument(level = "debug", skip(self))]
    pub async fn get_pending_shares(&self) -> LbResult<Vec<File>> {
        let tx = self.ro_tx().await;
        let db = tx.db();

        let mut tree = (&db.base_metadata).to_staged(&db.local_metadata).to_lazy();
        let pending_roots = tree.pending_roots(&self.keychain)?.into_iter();

        tree.decrypt_all(&self.keychain, pending_roots, &db.pub_key_lookup, false)
    }

    /// returns *all* the files associated with any pending shares (the share as well as it's
    /// descendants).
    #[instrument(level = "debug", skip(self))]
    pub async fn get_pending_share_files(&self) -> LbResult<Vec<File>> {
        let tx = self.ro_tx().await;
        let db = tx.db();

        let mut tree = (&db.base_metadata).to_staged(&db.local_metadata).to_lazy();
        let pending_files = tree.non_deleted_pending_files(&self.keychain)?.into_iter();

        tree.decrypt_all(&self.keychain, pending_files, &db.pub_key_lookup, false)
    }

    #[instrument(level = "debug", skip(self))]
    async fn delete_share(
        &self, id: &Uuid, maybe_encrypted_for: Option<PublicKey>,
    ) -> LbResult<()> {
        let mut tx = self.begin_tx().await;
        let db = tx.db();

        let mut tree = (&db.base_metadata)
            .to_staged(&mut db.local_metadata)
            .to_lazy();

        tree.delete_share(id, maybe_encrypted_for, &self.keychain)?;

        tx.end();
        self.events.meta_changed(Actor::User(None));

        Ok(())
    }

    #[instrument(level = "debug", skip(self))]
    pub async fn known_usernames(&self) -> LbResult<Vec<String>> {
        let db = self.ro_tx().await;
        let db = db.db();

        Ok(db
            .pub_key_lookup
            .iter()
            .map(|(_, value)| value)
            .cloned()
            .collect())
    }

    /// Whether `username` is a known Lockbook account (local cache, then server).
    ///
    /// Server lookup uses [`GetPublicKeyRequest`]. Auth is only a signed envelope —
    /// when signed out we probe with an ephemeral key so onboard can check
    /// availability without an account. `UserNotFound` maps to `false`.
    #[instrument(level = "debug", skip(self))]
    pub async fn username_exists(&self, username: &str) -> LbResult<bool> {
        use crate::DEFAULT_API_LOCATION;
        use crate::model::account::Account;
        use crate::model::errors::LbErrKind;

        let username = username.trim().to_lowercase();
        if username.is_empty() {
            return Ok(false);
        }
        // Signed-in only: local roster can short-circuit a hit. Empty when signed out.
        if let Ok(known) = self.known_usernames().await {
            if known.iter().any(|u| u.eq_ignore_ascii_case(&username)) {
                return Ok(true);
            }
        }

        // Prefer real account for api_url; else ephemeral signer + API_URL / default.
        let owned;
        let account = match self.get_account() {
            Ok(a) => a,
            Err(_) => {
                let api =
                    std::env::var("API_URL").unwrap_or_else(|_| DEFAULT_API_LOCATION.to_string());
                owned = Account::new(String::new(), api);
                &owned
            }
        };

        match self
            .client
            .request(account, GetPublicKeyRequest { username })
            .await
        {
            Ok(_) => Ok(true),
            Err(e) => {
                let err = LbErr::from(e);
                match err.kind {
                    // GetPublicKey UserNotFound → AccountNonexistent in LbErr map.
                    LbErrKind::AccountNonexistent | LbErrKind::UsernameNotFound => Ok(false),
                    _ => Err(err),
                }
            }
        }
    }

    #[instrument(level = "debug", skip(self))]
    pub async fn reject_share(&self, id: &Uuid) -> Result<(), LbErr> {
        let pk = self.keychain.get_pk()?;
        self.delete_share(id, Some(pk)).await
    }
}