feat(whatsmeow-signal): implement whatsmeow's Signal protocol with libsignal

.github/workspace-dep-closures.json

@@ -13786,6 +13786,13 @@
       "crates/webhook_signature",
       "crates/workspace-hack"
     ],
+    "whatsapp_fake_server": [
+      "crates/whatsapp_fake_server",
+      "crates/whatsmeow",
+      "crates/whatsmeow_proto",
+      "crates/whatsmeow_signal",
+      "crates/workspace-hack"
+    ],
     "whatsmeow": [
       "crates/whatsmeow",
       "crates/whatsmeow_proto",
@@ -13795,6 +13802,12 @@
       "crates/whatsmeow_proto",
       "crates/workspace-hack"
     ],
+    "whatsmeow_signal": [
+      "crates/whatsmeow",
+      "crates/whatsmeow_proto",
+      "crates/whatsmeow_signal",
+      "crates/workspace-hack"
+    ],
     "work_feed": [
       "crates/activity",
       "crates/agent",

Cargo.toml

@@ -125,8 +125,10 @@ members = [
   "crates/unfurl",
   "crates/user_api_key",
   "crates/webhook_signature",
+  "crates/whatsapp_fake_server",
   "crates/whatsmeow",
   "crates/whatsmeow_proto",
+  "crates/whatsmeow_signal",
   "crates/work_feed",
   "crates/worker-rs-otel",
   "crates/workspace-hack",
@@ -286,6 +288,8 @@ jsonwebtoken = { git = "https://github.com/whutchinson98/jsonwebtoken", features
 lambda_runtime = "0.13.0"
 lazy-regex = "3.6.1"
 lazy_static = "1.5.0"
+# Signal's curve25519 keys and XEdDSA; see crates/whatsmeow_signal/AGENTS.md.
+libsignal-core = { git = "https://github.com/signalapp/libsignal", tag = "v0.105.2" }
 livekit-api = { version = "0.4.16", default-features = false, features = [
   "access-token",
   "rustls-tls-webpki-roots",

crates/whatsapp_fake_server/AGENTS.md

@@ -0,0 +1,52 @@
+# whatsapp_fake_server
+
+## What it is
+
+Test support for WhatsApp linked devices: a fake WhatsApp server that the real
+whatsmeow port (`crates/whatsmeow`) connects to over a local websocket, and fake
+phones (the other people) with real Signal sessions from `whatsmeow_signal`.
+Lets the session service and its tests run end to end without WhatsApp.
+
+## How it works
+
+- `FakeWhatsApp::start()` binds a websocket port (noise XX responder, binary XML)
+  and a plain-HTTP media port on `127.0.0.1`.
+- The server's noise certificate chain is signed by a test root key, not
+  WhatsApp's. Clients must use `test_signal()` (`TestSignal`): libsignal with
+  WhatsApp's root key swapped for the test root when verifying. Nothing else is
+  faked; prekey, pairing and message crypto are real.
+- `add_user` creates a user with a phone (device 0, a `FakePhone` in process)
+  that publishes prekeys. `FakePhone::scan_qr` approves a client's QR code; the
+  client signs, gets the 515 restart and logs in as device 1, 2, ….
+- Routing is LID-first like WhatsApp today: groups use `addressing_mode="lid"`,
+  usync returns LIDs, delivered stanzas carry `participant_pn` / `sender_pn`.
+- A message handed to a connection stays unacked until the device sends a
+  receipt or message ack; if the connection drops it goes back to the offline
+  queue and is delivered again on the next login, then `<ib><offline/>`.
+
+## Start here
+
+- `src/lib.rs`: the `FakeWhatsApp` API (users, groups, kick, drop connection,
+  delivery counters, waiters).
+- `src/state.rs`: routing, IQ handlers (encrypt, usync, w:g2, w:m), offline queues.
+- `src/phone.rs`: fake phones: send/receive with real Signal, QR approval.
+- `src/connection.rs`: handshake, login, `conflict replaced`, pairing.
+
+## Checks
+
+- `cargo test -p whatsapp_fake_server`
+
+## Gotchas
+
+- Never point it at real WhatsApp; it only listens on `127.0.0.1`.
+- Waiting is event driven (`Shared::wait_for` re-checks on every state change);
+  don't add sleep loops.
+- Media: clients set `ClientConfig::media_base_url` to `media_base_url()`
+  (plain HTTP); phones upload and download with whatsmeow's own media crypto.
+- Unhandled IQs get an empty `result`; add a handler in `State::handle_iq` when
+  the port starts parsing a response.
+
+## Related
+
+- `crates/whatsmeow/AGENTS.md`, `crates/whatsmeow_signal/AGENTS.md`,
+  `crates/whatsapp_e2e/AGENTS.md`

crates/whatsapp_fake_server/CLAUDE.md

@@ -0,0 +1 @@
+AGENTS.md

crates/whatsapp_fake_server/Cargo.toml

@@ -0,0 +1,32 @@
+[package]
+edition = "2024"
+name = "whatsapp_fake_server"
+publish = false
+version = "0.1.0"
+description = "Test support: a fake WhatsApp server and fake phones that speak the real protocol, for testing the whatsmeow port and the session service without WhatsApp."
+
+[dependencies]
+aes-gcm = { workspace = true }
+async-trait = { workspace = true }
+axum = { workspace = true }
+base64 = { workspace = true }
+chrono = { workspace = true }
+futures = { workspace = true }
+hmac = { workspace = true }
+nom = { workspace = true }
+prost = { workspace = true }
+rand = { workspace = true }
+reqwest = { workspace = true }
+serde_json = { workspace = true }
+sha2 = { workspace = true }
+thiserror = { workspace = true }
+tokio = { workspace = true, features = ["macros", "net", "rt", "sync", "time"] }
+tokio-tungstenite = { workspace = true }
+tokio-util = { workspace = true, features = ["rt"] }
+tracing = { workspace = true }
+whatsmeow = { path = "../whatsmeow", features = ["testing"] }
+whatsmeow_signal = { path = "../whatsmeow_signal" }
+workspace-hack = { version = "0.1", path = "../workspace-hack" }
+
+[dev-dependencies]
+tokio = { workspace = true, features = ["macros", "rt-multi-thread", "test-util"] }