From 34fca3d564640514d0af9561dc807d12d8d25c5f Mon Sep 17 00:00:00 2001
From: saji <champ189@umn.edu>
Date: Sat, 24 Feb 2024 16:48:19 -0600
Subject: [PATCH] wip: work on http api

---
 http.go                | 81 +++++++++++++++++++++---------------------
 internal/db/getters.go | 63 ++++++++++++++++++++++++++++++--
 2 files changed, 101 insertions(+), 43 deletions(-)

diff --git a/http.go b/http.go
index bb044d9..cbd80c6 100644
--- a/http.go
+++ b/http.go
@@ -31,13 +31,6 @@ func TelemRouter(log *slog.Logger, broker *Broker, db *db.TelemDb) http.Handler
 	r.Use(middleware.Logger) // TODO: integrate with slog instead of go default logger.
 	r.Use(middleware.Recoverer)
 
-	r.Get("/schema", func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/json")
-		// return the spicy json response.
-		w.WriteHeader(http.StatusOK)
-		w.Write([]byte(skylab.SkylabDefinitions))
-	})
-
 	// heartbeat request.
 	r.Get("/ping", func(w http.ResponseWriter, r *http.Request) {
 		w.Write([]byte("pong"))
@@ -84,39 +77,7 @@ func apiV1(broker *Broker, db *db.TelemDb) chi.Router {
 		})
 
 		// this is to get a single field
-		r.Get("/{name:[a-z_]+}/{field:[a-z_]+}", func(w http.ResponseWriter, r *http.Request) {
-			var err error
-
-			// we need a start and end time. If none is provided,
-			// we use unix epoch as start, and now + 1 day as end.
-			start := time.Unix(0, 0)
-			startString := r.URL.Query().Get("start")
-			if startString != "" {
-				start, err = time.Parse(time.RFC3339, startString)
-				if err != nil {
-
-				}
-			}
-			end := time.Now().Add(1 * time.Hour)
-			endParam := r.URL.Query().Get("start")
-			if endParam != "" {
-				end, err = time.Parse(time.RFC3339, endParam)
-				if err != nil {
-				}
-			}
-			name := chi.URLParam(r, "name")
-			field := chi.URLParam(r, "field")
-			// TODO: add limit/pagination ?
-
-			res, err := db.GetValues(r.Context(), name, field, start, end)
-			if err != nil {
-				// 500 server error:
-				fmt.Print(err)
-			}
-			b, err := json.Marshal(res)
-			w.Write(b)
-
-		})
+		r.Get("/{name:[a-z_]+}/{field:[a-z_]+}")
 
 	})
 
@@ -190,6 +151,46 @@ func apiV1PacketSubscribe(broker *Broker, db *db.TelemDb) http.HandlerFunc {
 	}
 }
 
+// apiV1GetValues is a function that creates a handler for
+// getting the specific value from a packet.
+// this is useful for OpenMCT or other viewer APIs
+func apiV1GetValues(db *db.TelemDb) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		var err error
+
+		// we need a start and end time. If none is provided,
+		// we use unix epoch as start, and now + 1 day as end.
+		start := time.Unix(0, 0)
+		startString := r.URL.Query().Get("start")
+		if startString != "" {
+			start, err = time.Parse(time.RFC3339, startString)
+			if err != nil {
+
+			}
+		}
+		end := time.Now().Add(1 * time.Hour)
+		endParam := r.URL.Query().Get("start")
+		if endParam != "" {
+			end, err = time.Parse(time.RFC3339, endParam)
+			if err != nil {
+			}
+		}
+		name := chi.URLParam(r, "name")
+		field := chi.URLParam(r, "field")
+		
+		// TODO: add limit and pagination
+
+		res, err := db.GetValues(r.Context(), name, field, start, end)
+		if err != nil {
+			// 500 server error:
+			fmt.Print(err)
+		}
+		b, err := json.Marshal(res)
+		w.Write(b)
+	}
+
+}
+
 // TODO: rename. record is not a clear name. Runs? drives? segments?
 func apiV1GetRecords(db *db.TelemDb) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
diff --git a/internal/db/getters.go b/internal/db/getters.go
index 203de55..c1925c7 100644
--- a/internal/db/getters.go
+++ b/internal/db/getters.go
@@ -3,9 +3,66 @@ package db
 import (
 	"context"
 	"fmt"
+	"strings"
 	"time"
 )
 
+// Modifier augments SQL strings.
+type Modifier interface {
+	ModifyStatement(string) string
+}
+
+
+type LimitOffsetModifier struct {
+	Limit int
+	Offset int
+}
+
+// BusEventFilter is a filter for bus events.
+type BusEventFilter struct {
+	Names []string
+	TimerangeStart time.Time
+	TimerangeEnd time.Time
+}
+
+func (bef *BusEventFilter) String() string {
+	var sb []string = make([]string, 0, 2)
+	if len(bef.Names) > 0 {
+		names := strings.Join(bef.Names, ",")
+		sb = append(sb, fmt.Sprintf("name IN (%s)", names))
+	}
+	if !bef.TimerangeStart.IsZero() && !bef.TimerangeEnd.IsZero() {
+		sb = append(sb, fmt.Sprintf(""))
+	}
+	return ""
+}
+
+type BusEventElement interface {
+	Element() string
+}
+
+type NormalExtract struct {
+	Key string
+}
+
+type JSONExtract struct {
+	Key string
+}
+
+type BusEventQuery struct {
+	Elements []BusEventElement
+	Filter BusEventFilter
+	Limits LimitOffsetModifier
+}
+
+func (beq *BusEventQuery) String() string {
+	// select
+	return ""
+}
+
+
+// now we can optionally add a limit.
+
 // Datum is a single measurement - it is more granular than a packet.
 // the classic example is bms_measurement.current
 type Datum struct {
@@ -23,10 +80,10 @@ func (tdb *TelemDb) GetValues(ctx context.Context, packetName, field string, sta
 	SqlFrag := `
 	SELECT 
 	ts as timestamp,
-	json_extract(data, '$.current') as val
-	FROM bus_events WHERE name IS 'bms_measurement' 
+	json_extract(data, '$.' || ?) as val
+	FROM bus_events WHERE name IS ? 
 	`
-	rows, err := tdb.db.QueryxContext(ctx, SqlFrag)
+	rows, err := tdb.db.QueryxContext(ctx, SqlFrag, field, packetName)
 	if err != nil {
 		return nil, err
 	}