add previous button

api/tag.go

@@ -72,7 +72,8 @@ func (client *Client) FetchTag(tag string, sort string, page string) (Tag, error
 		func(key, value gjson.Result) bool {
 			url, _ := url.Parse(strings.ReplaceAll(value.Get("url").String(), "https://imgur.com", ""))
 			q := url.Query()
-			q.Add("tag", tag+"."+sort+"."+page+"."+key.String())
+			ts := tag + "." + sort + "." + page + "." + key.String()
+			q.Add("tag", ts)
 			url.RawQuery = q.Encode()
 
 			posts = append(posts, Submission{
@@ -90,6 +91,8 @@ func (client *Client) FetchTag(tag string, sort string, page string) (Tag, error
 				Comments:  value.Get("comment_count").Int(),
 				Views:     value.Get("view_count").Int(),
 				IsAlbum:   value.Get("is_album").Bool(),
+
+				tagstring: ts,
 			})
 
 			return true

api/user.go

@@ -33,6 +33,8 @@ type Submission struct {
 	Comments  int64
 	Views     int64
 	IsAlbum   bool
+
+	tagstring string
 }
 
 func (client *Client) FetchUser(username string) (User, error) {

pages/post.go

@@ -11,6 +11,34 @@ import (
 	"github.com/gofiber/fiber/v2"
 )
 
+func prevInTag(client *api.Client, tagname, sort, page, I string) string {
+	i, err := strconv.Atoi(I)
+	if err != nil || i < 0 {
+		return ""
+	}
+	if i == 0 {
+		// Don't go before the first in tag
+		if page == "1" {
+			return ""
+		}
+		pagen, err := strconv.Atoi(page)
+		if err != nil || pagen < 0 {
+			return ""
+		}
+		pagen--
+		page = strconv.Itoa(pagen)
+	}
+
+	tag, err := client.FetchTag(tagname, sort, page)
+	if err != nil {
+		return ""
+	}
+	if i == 0 {
+		return tag.Posts[len(tag.Posts)-1].Link
+	}
+	return tag.Posts[i-1].Link
+}
+
 // Cursed function
 func nextInTag(client *api.Client, tagname, sort, page, I string) string {
 	i, err := strconv.Atoi(I)
@@ -78,15 +106,17 @@ func HandlePost(c *fiber.Ctx) error {
 	}
 	c.Set("Content-Security-Policy", csp)
 
-	var next string
+	var prev, next string
 	tagParam := strings.Split(c.Query("tag"), ".")
 	if len(tagParam) == 4 {
 		tag, sort, page, index := tagParam[0], tagParam[1], tagParam[2], tagParam[3]
+		prev = prevInTag(ApiClient, tag, sort, page, index)
 		next = nextInTag(ApiClient, tag, sort, page, index)
 	}
 
 	return c.Render("post", fiber.Map{
 		"post":     post,
+		"prev":     prev,
 		"next":     next,
 		"comments": comments,
 		"nonce":    nonce,

views/post.hbs

@@ -53,9 +53,16 @@
         </div>
       </div>
       {{#noteq next ""}}
-      <a href="{{next}}" class="self-end">
-        <button class="p-2 rounded-lg bg-slate-600">Next &gt;</button>
-      </a>
+      <div class="flex">
+        {{#noteq prev ""}}
+        <a href="{{prev}}">
+          <button title="Previous" class="px-3 py-2 rounded-l-lg bg-slate-600">&lt;</button>
+        </a>
+        {{/noteq}}
+        <a class="[&:only-child>button]:rounded-lg" href="{{next}}">
+          <button class="px-3 py-2 rounded-r-lg  bg-green-400 text-gray-800">Next &gt;</button>
+        </a>
+      </div>
       {{/noteq}}
     </div>