From 9b69eb46b75e9022213f384052a356c92a3caec1 Mon Sep 17 00:00:00 2001
From: Yanislav Igonin <yanislavdabest@gmail.com>
Date: Fri, 10 Sep 2021 02:17:45 +0300
Subject: [PATCH] feat: add pagination

---
 controllers/threads_controller.go | 26 ++++++++++++++++++++++++--
 main.go                           | 11 +++++++++++
 repositories/posts_repository.go  | 23 +++++++++++++++++++++--
 repositories/structs.go           |  6 ++++++
 static/index.css                  |  3 +++
 templates/index.html              | 23 ++++++++++++++++++-----
 6 files changed, 83 insertions(+), 9 deletions(-)

diff --git a/controllers/threads_controller.go b/controllers/threads_controller.go
index 2688aec..b919417 100644
--- a/controllers/threads_controller.go
+++ b/controllers/threads_controller.go
@@ -2,6 +2,7 @@ package controlers
 
 import (
 	"log"
+	"math"
 	"net/http"
 	"strconv"
 
@@ -11,13 +12,34 @@ import (
 )
 
 func GetThreads(c *gin.Context) {
-	threads, err := Repositories.Posts.Get(10, 10)
+	pageString := c.Query("page")
+	page, err := strconv.Atoi(pageString)
 	if err != nil {
 		log.Println("error:", err)
 		c.HTML(http.StatusOK, "500.html", nil)
 		return
 	}
-	c.HTML(http.StatusOK, "index.html", threads)
+	limit := 10
+	offset := limit * (page - 1)
+	threads, err := Repositories.Posts.Get(limit, offset)
+	if err != nil {
+		log.Println("error:", err)
+		c.HTML(http.StatusOK, "500.html", nil)
+		return
+	}
+	count, err := Repositories.Posts.GetCount()
+	if err != nil {
+		log.Println("error:", err)
+		c.HTML(http.StatusOK, "500.html", nil)
+		return
+	}
+
+	data := Repositories.IndexPageData{
+		Threads:    threads,
+		PagesCount: int(math.Ceil(float64(count) / 10)),
+		Page:       page,
+	}
+	c.HTML(http.StatusOK, "index.html", data)
 }
 
 func GetThread(c *gin.Context) {
diff --git a/main.go b/main.go
index 0df9446..b5a03a4 100644
--- a/main.go
+++ b/main.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"html/template"
 	"log"
 	"strconv"
 	"time"
@@ -41,6 +42,16 @@ func main() {
 	middleware := mgin.NewMiddleware(instance)
 
 	router := gin.Default()
+	router.SetFuncMap(template.FuncMap{
+		"Iterate": func(count int) []int {
+			var i int
+			var Items []int
+			for i = 1; i < count; i++ {
+				Items = append(Items, i)
+			}
+			return Items
+		},
+	})
 	router.LoadHTMLGlob("templates/*.html")
 	router.ForwardedByClientIP = true
 	if Config.App.IsRateLimiterEnabled {
diff --git a/repositories/posts_repository.go b/repositories/posts_repository.go
index 013d584..254c4d9 100644
--- a/repositories/posts_repository.go
+++ b/repositories/posts_repository.go
@@ -19,10 +19,11 @@ func (r *PostsRepository) Get(limit, offset int) ([]Post, error) {
 			is_parent = true
 			AND is_deleted = false
 		ORDER BY updated_at DESC
-		LIMIT $1
+		OFFSET $1
+		LIMIT $2
 	`
 
-	rows, err := Db.Pool.Query(context.TODO(), sql, limit)
+	rows, err := Db.Pool.Query(context.TODO(), sql, offset, limit)
 	if err != nil {
 		return nil, err
 	}
@@ -58,6 +59,24 @@ func (r *PostsRepository) Get(limit, offset int) ([]Post, error) {
 	return posts, nil
 }
 
+func (r *PostsRepository) GetCount() (int, error) {
+	sql := `
+		SELECT COUNT(*)
+		FROM posts
+		WHERE 
+			is_parent = true
+			AND is_deleted = false
+	`
+
+	row := Db.Pool.QueryRow(context.TODO(), sql)
+	var count int
+	err := row.Scan(&count)
+	if err != nil {
+		return 0, err
+	}
+	return count, nil
+}
+
 func (r *PostsRepository) Create(p Post) (int, error) {
 	sql := `
 		INSERT INTO posts (is_parent, parent_id, title, text, is_sage)
diff --git a/repositories/structs.go b/repositories/structs.go
index f8d3106..e019585 100644
--- a/repositories/structs.go
+++ b/repositories/structs.go
@@ -23,3 +23,9 @@ type File struct {
 	Ext       string    `json:"-"`
 	Size      int       `json:"size"`
 }
+
+type IndexPageData struct {
+	Threads    []Post
+	PagesCount int
+	Page       int
+}
diff --git a/static/index.css b/static/index.css
index e69de29..00426ea 100644
--- a/static/index.css
+++ b/static/index.css
@@ -0,0 +1,3 @@
+#pagesList {
+  flex-wrap: wrap
+}
\ No newline at end of file
diff --git a/templates/index.html b/templates/index.html
index fffd9ad..1e7bc6b 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -15,19 +15,19 @@
   <div class="container">
     {{ template "post-form" }}
     
-    <div class="row row-cols-auto gy-4">
-      {{range $Post := .}}
+    <div id="" class="row row-cols-auto gy-4 mb-4">
+      {{ range $Post := .Threads }}
       <div class="col col-sm-6 col-md-4 col-lg-3">
         <div class="card">
 
           {{ $length := len $Post.Files }} {{ if gt $length 0 }}
-          {{$FirstFile := index $Post.Files 0}}
+          {{ $FirstFile := index $Post.Files 0 }}
           <img 
             src="{{$FirstFile.Name}}" 
             class="card-img-top"
             alt="Uploaded picture"
           >
-          {{end}}
+          {{ end }}
 
           <div class="card-body">
             <h5 class="card-title">{{$Post.Title}}</h5>
@@ -36,7 +36,20 @@
           </div>
         </div>
       </div>
-      {{end}}
+      {{ end }}
+    </div>
+
+    <div class="col col-12">
+      <nav aria-label="Page navigation">
+        <ul id="pagesList" class="pagination justify-content-center">
+          {{ $ActivePage := .Page }}
+          {{ range $i := Iterate .PagesCount }}
+            <li class="page-item {{ if (eq $i $ActivePage) }} active {{ end }}">
+              <a class="page-link" href="/?page={{ $i }}">{{ $i }}</a>
+            </li>
+          {{ end }}
+        </ul>
+      </nav>
     </div>
     
   </div>