refactor api package comments

* use encoding/json for comment parsing

* refactor by moving loop code to an UnmarshalJSON

* use a preallocated array and indices to maintain order while using
  goroutines again, this was removed a while ago

* use new struct in comment.hbs and contextComment.hbs

* rewriteUrl partial to reduce rimgo-specific code in api

* move RenderError into pages package to avoid import cycle between render and utils

utils/request.go

@@ -1,6 +1,7 @@
 package utils
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"net/http"
@@ -9,6 +10,42 @@ import (
 	"github.com/tidwall/gjson"
 )
 
+func GetJSONNew(url string) (json.RawMessage, error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return json.RawMessage{}, err
+	}
+
+	SetReqHeaders(req)
+
+	client := http.Client{}
+	res, err := client.Do(req)
+	if err != nil {
+		return json.RawMessage{}, err
+	}
+	rateLimitRemaining := res.Header.Get("X-RateLimit-UserRemaining")
+	if rateLimitRemaining != "" {
+		ratelimit, _ := strconv.Atoi(rateLimitRemaining)
+		if ratelimit <= 0 {
+			return json.RawMessage{}, fmt.Errorf("ratelimited by imgur")
+		}
+	}
+
+	body, err := io.ReadAll(res.Body)
+	if err != nil {
+		return json.RawMessage{}, err
+	}
+
+	switch res.StatusCode {
+	case 200:
+		return body, nil
+	case 429:
+		return json.RawMessage{}, fmt.Errorf("ratelimited by imgur")
+	default:
+		return json.RawMessage{}, fmt.Errorf("received status %s, expected 200 OK.\n%s", res.Status, string(body))
+	}
+}
+
 func GetJSON(url string) (gjson.Result, error) {
 	req, err := http.NewRequest("GET", url, nil)
 	if err != nil {