From 0e8904ebecd7bc0ef99c07858fe2041990529438 Mon Sep 17 00:00:00 2001
From: saji <champ189@umn.edu>
Date: Tue, 27 Jun 2023 18:22:24 -0500
Subject: [PATCH] wip: http subscribe endpoint

---
 db.go   |  5 ++--
 go.mod  |  1 +
 go.sum  |  2 ++
 http.go | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 4 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/db.go b/db.go
index 1dfc43b..50af08d 100644
--- a/db.go
+++ b/db.go
@@ -49,6 +49,7 @@ CREATE TABLE IF NOT EXISTS "bus_events" (
 	"ts"	REAL NOT NULL, -- timestamp
 	"id"	INTEGER NOT NULL, -- can ID
 	"name"	TEXT NOT NULL, -- name of base packet
+	"index" INTEGER, -- index of the repeated packet (base_id = id - index)
 	"packet"	TEXT NOT NULL CHECK(json_valid(packet)) -- JSON object describing the data
 );
 
@@ -74,7 +75,7 @@ DROP INDEX "times";
 
 // sql expression to insert a bus event into the packets database.1
 const sqlInsertEvent = `
-INSERT INTO "bus_events" (time, can_id, name, packet) VALUES ($1, $2, $3, json($4));
+INSERT INTO "bus_events" (time, can_id, name, index, packet) VALUES ($1, $2, $3, json($4));
 `
 
 // AddEvent adds the bus event to the database.
@@ -157,7 +158,7 @@ type EventsQuery struct {
 
 	Names []QueryNameString
 
-	Limit uint //  asdf
+	Limit uint //  max number of results.
 }
 
 // GetEvents is the mechanism to request underlying event data.
diff --git a/go.mod b/go.mod
index 70007cd..f36a42e 100644
--- a/go.mod
+++ b/go.mod
@@ -4,6 +4,7 @@ go 1.20
 
 require (
 	github.com/go-chi/chi/v5 v5.0.8
+	github.com/google/uuid v1.3.0
 	github.com/jmoiron/sqlx v1.3.5
 	github.com/mattn/go-sqlite3 v1.14.16
 	github.com/tinylib/msgp v1.1.8
diff --git a/go.sum b/go.sum
index 12e2f96..1981130 100644
--- a/go.sum
+++ b/go.sum
@@ -32,6 +32,8 @@ github.com/golang/protobuf v1.3.5/go.mod h1:6O5/vntMXwX2lRkT1hjjk0nAC1IDOTvTlVgj
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.8 h1:e6P7q2lk1O+qJJb4BtCQXlK8vWEO8V1ZeuEdJNOqZyg=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gorilla/websocket v1.4.1 h1:q7AeDBpnBk8AogcD4DSag/Ukw/KV+YhzLj2bP5HvKCM=
 github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/jmoiron/sqlx v1.3.5 h1:vFFPA71p1o5gAeqtEAwLU4dnX2napprKtHr7PYIcN3g=
diff --git a/http.go b/http.go
index d7150c8..d8302d0 100644
--- a/http.go
+++ b/http.go
@@ -3,20 +3,24 @@ package gotelem
 // this file defines the HTTP handlers and routes.
 
 import (
+	"encoding/json"
+	"fmt"
 	"net/http"
 
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
+	"github.com/google/uuid"
 	"github.com/kschamplin/gotelem/skylab"
 	"golang.org/x/exp/slog"
 	"nhooyr.io/websocket"
 )
 
+
 type slogHttpLogger struct {
 	slog.Logger
 }
 
-func TelemRouter(log *slog.Logger, broker *JBroker) http.Handler {
+func TelemRouter(log *slog.Logger, broker *JBroker, db *TelemDb) http.Handler {
 	r := chi.NewRouter()
 
 	r.Use(middleware.Logger) // TODO: integrate with slog
@@ -34,7 +38,7 @@ func TelemRouter(log *slog.Logger, broker *JBroker) http.Handler {
 		w.Write([]byte("pong"))
 	})
 
-	r.Mount("/api/v1", apiV1(broker))
+	r.Mount("/api/v1", apiV1(broker, db))
 
 	// To future residents - you can add new API calls/systems in /api/v2
 	// Don't break anything in api v1! keep legacy code working!
@@ -45,7 +49,7 @@ func TelemRouter(log *slog.Logger, broker *JBroker) http.Handler {
 }
 
 // define API version 1 routes.
-func apiV1(broker *JBroker) chi.Router {
+func apiV1(broker *JBroker, db *TelemDb) chi.Router {
 	r := chi.NewRouter()
 	r.Get("/schema", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
@@ -62,6 +66,76 @@ func apiV1(broker *JBroker) chi.Router {
 		
 	})
 
+	r.Route("/packets", func(r chi.Router) {
+		r.Get("/subscribe", apiV1PacketSubscribe(broker, db))
+		r.Post("/", func(w http.ResponseWriter, r *http.Request) {
+			var pkgs []skylab.BusEvent
+			decoder := json.NewDecoder(r.Body)
+			if err := decoder.Decode(&pkgs); err != nil{
+				w.WriteHeader(http.StatusTeapot)
+				return
+			}
+			// we have a list of packets now. let's commit them.
+			db.AddEvents(pkgs...)
+			return 
+		})
+	})
+
+
+
 	return r
 }
 
+
+// apiV1Subscriber is a websocket session for the v1 api.
+type apiV1Subscriber struct {
+	idFilter []uint64 // list of Ids to subscribe to. If it's empty, subscribes to all.
+}
+
+func apiV1PacketSubscribe(broker *JBroker, db *TelemDb) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		conn_id := r.RemoteAddr + uuid.New().String()
+		sub, err := broker.Subscribe(conn_id)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprintf(w, "error subscribing: %s", err)
+			return
+		}
+		defer broker.Unsubscribe(conn_id)
+		// attempt to upgrade.
+		c, err := websocket.Accept(w, r, nil)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprintf(w, "error ws handshake: %s", err)
+			return
+		}
+
+		sess := &apiV1Subscriber{}
+
+		for {
+			select {
+			case <- r.Context().Done():
+				return
+			case msgIn := <-sub:
+				if len(sess.idFilter) == 0 {
+					// send it.
+					goto escapeFilter
+				}
+				for _, id := range sess.idFilter {
+					if id == msgIn.Id {
+						// send it
+					}
+				}
+				escapeFilter:
+				return
+
+			}
+
+
+		}
+		
+
+
+	}
+}
+