From 68a69505ac4e4abb9605990a61e5fc2944d01ad9 Mon Sep 17 00:00:00 2001
From: Greg Heartsfield <scsibug@imap.cc>
Date: Wed, 24 Nov 2021 12:25:38 -0600
Subject: [PATCH] Start of protocol module

---
 src/proto.rs | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 src/proto.rs

diff --git a/src/proto.rs b/src/proto.rs
new file mode 100644
index 0000000..cf40037
--- /dev/null
+++ b/src/proto.rs
@@ -0,0 +1,87 @@
+use crate::error::{Error, Result};
+use crate::event;
+use log::{debug, info};
+use uuid::Uuid;
+
+// A protocol handler/helper.  Use one per client.
+pub struct Proto {
+    client_id: Uuid,
+}
+
+impl Proto {
+    pub fn new() -> Self {
+        let p = Proto {
+            client_id: Uuid::new_v4(),
+        };
+        debug!("New client: {:?}", p.client_id);
+        p
+    }
+
+    pub fn process_message(self: &Self, cmd: String) {
+        info!(
+            "Processing message in proto for client: {:?}",
+            self.client_id
+        );
+        // check what kind of message
+        info!("Parse result: {:?}", parse_type(cmd));
+    }
+}
+
+// A raw message with the expected type
+#[derive(PartialEq, Debug)]
+pub enum NostrRawMessage {
+    Event(String),
+    Req(String),
+    Close(String),
+}
+
+// A fully parsed request
+#[derive(PartialEq, Debug)]
+pub enum NostrRequest {
+    Event(event::Event),
+}
+
+// Wrap the message in the expected request type
+fn msg_type_wrapper(msg: String) -> Result<NostrRawMessage> {
+    // check prefix.
+    if msg.starts_with(r#"["EVENT","#) {
+        Ok(NostrRawMessage::Event(msg))
+    } else if msg.starts_with(r#"["REQ","#) {
+        Ok(NostrRawMessage::Req(msg))
+    } else if msg.starts_with(r#"["CLOSE","#) {
+        Ok(NostrRawMessage::Close(msg))
+    } else {
+        Err(Error::CommandNotFound)
+    }
+}
+
+pub fn parse_type(msg: String) -> Result<NostrRequest> {
+    // turn this raw string into a parsed request
+    let typ = msg_type_wrapper(msg)?;
+    match typ {
+        NostrRawMessage::Event(_) => Err(Error::EventParseFailed),
+        NostrRawMessage::Req(_) => Err(Error::ReqParseFailed),
+        NostrRawMessage::Close(_) => Err(Error::CloseParseFailed),
+    }
+}
+
+// Parse the request into a fully deserialized type
+
+// The protocol-handling process looks something like:
+// Receive a message (bytes).
+// Determine the type.  We could do this with an untagged deserialization in serde.  Or we can peek at the prefix.
+// Wrap the message string in the client request type (either Event, Req, Close)
+// For Req/Close, we can fully parse these.
+
+// For Event, we want to be more cautious.
+// Before we admit an event, we should reject any duplicates.
+// duplicates in the datastore will have already been sent out to interested subscribers.
+// No point in verifying an event that we already have.
+
+// Event pipeline looks like:
+// Get message. (./)
+// Verify it is an event. (./)
+// Parse into string / number components from JSON.
+// Perform validation, re-serialize (or can we re-use the original?)
+// Publish to subscribers.
+// Push to datastore.