From 175c78624b4ecdfe0fd83edb63808df76f2b5232 Mon Sep 17 00:00:00 2001
From: Jan-Lukas Else <mail@jlelse.de>
Date: Wed, 17 Feb 2021 16:07:42 +0100
Subject: [PATCH] Comments Admin pagination

---
 comments.go                    |  42 ++++++-------
 commentsAdmin.go               |  98 +++++++++++++++++++++++++++++
 go.mod                         |   2 +-
 go.sum                         |   4 +-
 http.go                        |   4 +-
 posts.go                       |   4 --
 templates/commentsadmin.gohtml |   8 ++-
 webmention.go                  | 107 --------------------------------
 webmentionAdmin.go             | 109 +++++++++++++++++++++++++++++++++
 9 files changed, 241 insertions(+), 137 deletions(-)
 create mode 100644 commentsAdmin.go
 create mode 100644 webmentionAdmin.go

diff --git a/comments.go b/comments.go
index fdc80e4..1670de8 100644
--- a/comments.go
+++ b/comments.go
@@ -104,20 +104,24 @@ func checkCommentTarget(w http.ResponseWriter, r *http.Request) string {
 	return targetURL.Path
 }
 
-func commentsAdmin(w http.ResponseWriter, r *http.Request) {
-	comments, err := getComments()
-	if err != nil {
-		serveError(w, r, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	render(w, templateCommentsAdmin, &renderData{
-		Data: comments,
-	})
+type commentsRequestConfig struct {
+	offset, limit int
 }
 
-func getComments() ([]*comment, error) {
+func buildCommentsQuery(config *commentsRequestConfig) (query string, args []interface{}) {
+	args = []interface{}{}
+	query = "select id, target, name, website, comment from comments order by id desc"
+	if config.limit != 0 || config.offset != 0 {
+		query += " limit @limit offset @offset"
+		args = append(args, sql.Named("limit", config.limit), sql.Named("offset", config.offset))
+	}
+	return
+}
+
+func getComments(config *commentsRequestConfig) ([]*comment, error) {
 	comments := []*comment{}
-	rows, err := appDbQuery("select id, target, name, website, comment from comments order by id desc")
+	query, args := buildCommentsQuery(config)
+	rows, err := appDbQuery(query, args...)
 	if err != nil {
 		return nil, err
 	}
@@ -132,19 +136,15 @@ func getComments() ([]*comment, error) {
 	return comments, nil
 }
 
-func commentsAdminDelete(w http.ResponseWriter, r *http.Request) {
-	id, err := strconv.Atoi(r.FormValue("commentid"))
+func countComments(config *commentsRequestConfig) (count int, err error) {
+	query, params := buildCommentsQuery(config)
+	query = "select count(*) from (" + query + ")"
+	row, err := appDbQueryRow(query, params...)
 	if err != nil {
-		serveError(w, r, err.Error(), http.StatusBadRequest)
 		return
 	}
-	err = deleteComment(id)
-	if err != nil {
-		serveError(w, r, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	purgeCache()
-	http.Redirect(w, r, ".", http.StatusFound)
+	err = row.Scan(&count)
+	return
 }
 
 func deleteComment(id int) error {
diff --git a/commentsAdmin.go b/commentsAdmin.go
new file mode 100644
index 0000000..8384273
--- /dev/null
+++ b/commentsAdmin.go
@@ -0,0 +1,98 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"reflect"
+	"strconv"
+
+	"github.com/go-chi/chi"
+	"github.com/vcraescu/go-paginator"
+)
+
+type commentsPaginationAdapter struct {
+	config *commentsRequestConfig
+	nums   int64
+}
+
+func (p *commentsPaginationAdapter) Nums() (int64, error) {
+	if p.nums == 0 {
+		nums, _ := countComments(p.config)
+		p.nums = int64(nums)
+	}
+	return p.nums, nil
+}
+
+func (p *commentsPaginationAdapter) Slice(offset, length int, data interface{}) error {
+	modifiedConfig := *p.config
+	modifiedConfig.offset = offset
+	modifiedConfig.limit = length
+
+	comments, err := getComments(&modifiedConfig)
+	reflect.ValueOf(data).Elem().Set(reflect.ValueOf(&comments).Elem())
+	return err
+}
+
+func commentsAdmin(blog, commentPath string) func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		// Adapter
+		pageNoString := chi.URLParam(r, "page")
+		pageNo, _ := strconv.Atoi(pageNoString)
+		p := paginator.New(&commentsPaginationAdapter{config: &commentsRequestConfig{}}, 5)
+		p.SetPage(pageNo)
+		var comments []*comment
+		err := p.Results(&comments)
+		if err != nil {
+			serveError(w, r, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		// Navigation
+		var hasPrev, hasNext bool
+		var prevPage, nextPage int
+		var prevPath, nextPath string
+		hasPrev, _ = p.HasPrev()
+		if hasPrev {
+			prevPage, _ = p.PrevPage()
+		} else {
+			prevPage, _ = p.Page()
+		}
+		if prevPage < 2 {
+			prevPath = commentPath
+		} else {
+			prevPath = fmt.Sprintf("%s/page/%d", commentPath, prevPage)
+		}
+		hasNext, _ = p.HasNext()
+		if hasNext {
+			nextPage, _ = p.NextPage()
+		} else {
+			nextPage, _ = p.Page()
+		}
+		nextPath = fmt.Sprintf("%s/page/%d", commentPath, nextPage)
+		// Render
+		render(w, templateCommentsAdmin, &renderData{
+			BlogString: blog,
+			Data: map[string]interface{}{
+				"Comments": comments,
+				"HasPrev":  hasPrev,
+				"HasNext":  hasNext,
+				"Prev":     slashIfEmpty(prevPath),
+				"Next":     slashIfEmpty(nextPath),
+			},
+		})
+	}
+}
+
+func commentsAdminDelete(w http.ResponseWriter, r *http.Request) {
+	id, err := strconv.Atoi(r.FormValue("commentid"))
+	if err != nil {
+		serveError(w, r, err.Error(), http.StatusBadRequest)
+		return
+	}
+	err = deleteComment(id)
+	if err != nil {
+		serveError(w, r, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	purgeCache()
+	http.Redirect(w, r, ".", http.StatusFound)
+}
diff --git a/go.mod b/go.mod
index 85b07b7..1283dfc 100644
--- a/go.mod
+++ b/go.mod
@@ -54,7 +54,7 @@ require (
 	golang.org/x/mod v0.4.1 // indirect
 	golang.org/x/net v0.0.0-20210119194325-5f4716e94777 // indirect
 	golang.org/x/sync v0.0.0-20201207232520-09787c993a3a
-	golang.org/x/sys v0.0.0-20210216224549-f992740a1bac // indirect
+	golang.org/x/sys v0.0.0-20210217105451-b926d437f341 // indirect
 	golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf // indirect
 	golang.org/x/text v0.3.5 // indirect
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
diff --git a/go.sum b/go.sum
index 299b167..6313862 100644
--- a/go.sum
+++ b/go.sum
@@ -404,8 +404,8 @@ golang.org/x/sys v0.0.0-20200724161237-0e2f3a69832c/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210119212857-b64e53b001e4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210216224549-f992740a1bac h1:9glrpwtNjBYgRpb67AZJKHfzj1stG/8BL5H7In2oTC4=
-golang.org/x/sys v0.0.0-20210216224549-f992740a1bac/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210217105451-b926d437f341 h1:2/QtM1mL37YmcsT8HaDNHDgTqqFVw+zr8UzMiBVLzYU=
+golang.org/x/sys v0.0.0-20210217105451-b926d437f341/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf h1:MZ2shdL+ZM/XzY3ZGOnh4Nlpnxz5GSOhOmtHo3iPU6M=
diff --git a/http.go b/http.go
index b8572e9..60a21f2 100644
--- a/http.go
+++ b/http.go
@@ -366,7 +366,9 @@ func buildHandler() (http.Handler, error) {
 				// Admin
 				cr.Group(func(r chi.Router) {
 					r.Use(authMiddleware)
-					r.Get("/", commentsAdmin)
+					handler := commentsAdmin(blog, commentsPath)
+					r.Get("/", handler)
+					r.Get(paginationPath, handler)
 					r.Post("/delete", commentsAdminDelete)
 				})
 			})
diff --git a/posts.go b/posts.go
index 6cb99fd..5c70c46 100644
--- a/posts.go
+++ b/posts.go
@@ -98,10 +98,6 @@ func (p *postPaginationAdapter) Nums() (int64, error) {
 }
 
 func (p *postPaginationAdapter) Slice(offset, length int, data interface{}) error {
-	if reflect.TypeOf(data).Kind() != reflect.Ptr {
-		panic("data has to be a pointer")
-	}
-
 	modifiedConfig := *p.config
 	modifiedConfig.offset = offset
 	modifiedConfig.limit = length
diff --git a/templates/commentsadmin.gohtml b/templates/commentsadmin.gohtml
index 5673cdf..101f0d6 100644
--- a/templates/commentsadmin.gohtml
+++ b/templates/commentsadmin.gohtml
@@ -6,7 +6,7 @@
   <main>
     <h1>{{ string .Blog.Lang "comments" }}</h1>
     {{ $blog := .Blog }}
-    {{ range $i, $comment := .Data }}
+    {{ range $i, $comment := .Data.Comments }}
       <div class="p">
         <p>
           Target: <a href="{{ $comment.Target }}" target="_blank">{{ $comment.Target }}</a><br/>
@@ -20,6 +20,12 @@
         </form>
       </div>
     {{ end }}
+    {{ if .Data.HasPrev }}
+      <p><a href="{{ .Data.Prev }}">{{ string .Blog.Lang "prev" }}</a></p>
+    {{ end }}
+    {{ if .Data.HasNext }}
+      <p><a href="{{ .Data.Next }}">{{ string .Blog.Lang "next" }}</a></p>
+    {{ end }}
   </main>
 {{ end }}
 
diff --git a/webmention.go b/webmention.go
index cd665b1..b222b12 100644
--- a/webmention.go
+++ b/webmention.go
@@ -6,13 +6,8 @@ import (
 	"fmt"
 	"net/http"
 	"net/http/httptest"
-	"reflect"
-	"strconv"
 	"strings"
 	"time"
-
-	"github.com/go-chi/chi"
-	"github.com/vcraescu/go-paginator"
 )
 
 type webmentionStatus string
@@ -87,81 +82,6 @@ func extractMention(r *http.Request) (*mention, error) {
 	}, nil
 }
 
-func webmentionAdmin(w http.ResponseWriter, r *http.Request) {
-	pageNoString := chi.URLParam(r, "page")
-	pageNo, _ := strconv.Atoi(pageNoString)
-	p := paginator.New(&webmentionPaginationAdapter{config: &webmentionsRequestConfig{}}, 10)
-	p.SetPage(pageNo)
-	var mentions []*mention
-	err := p.Results(&mentions)
-	if err != nil {
-		serveError(w, r, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	// Navigation
-	var hasPrev, hasNext bool
-	var prevPage, nextPage int
-	var prevPath, nextPath string
-	hasPrev, _ = p.HasPrev()
-	if hasPrev {
-		prevPage, _ = p.PrevPage()
-	} else {
-		prevPage, _ = p.Page()
-	}
-	if prevPage < 2 {
-		prevPath = webmentionPath
-	} else {
-		prevPath = fmt.Sprintf("%s/page/%d", webmentionPath, prevPage)
-	}
-	hasNext, _ = p.HasNext()
-	if hasNext {
-		nextPage, _ = p.NextPage()
-	} else {
-		nextPage, _ = p.Page()
-	}
-	nextPath = fmt.Sprintf("%s/page/%d", webmentionPath, nextPage)
-	// Render
-	render(w, "webmentionadmin", &renderData{
-		Data: map[string]interface{}{
-			"Mentions": mentions,
-			"HasPrev":  hasPrev,
-			"HasNext":  hasNext,
-			"Prev":     slashIfEmpty(prevPath),
-			"Next":     slashIfEmpty(nextPath),
-		},
-	})
-}
-
-func webmentionAdminDelete(w http.ResponseWriter, r *http.Request) {
-	id, err := strconv.Atoi(r.FormValue("mentionid"))
-	if err != nil {
-		serveError(w, r, err.Error(), http.StatusBadRequest)
-		return
-	}
-	err = deleteWebmention(id)
-	if err != nil {
-		serveError(w, r, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	purgeCache()
-	http.Redirect(w, r, ".", http.StatusFound)
-}
-
-func webmentionAdminApprove(w http.ResponseWriter, r *http.Request) {
-	id, err := strconv.Atoi(r.FormValue("mentionid"))
-	if err != nil {
-		serveError(w, r, err.Error(), http.StatusBadRequest)
-		return
-	}
-	err = approveWebmention(id)
-	if err != nil {
-		serveError(w, r, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	purgeCache()
-	http.Redirect(w, r, ".", http.StatusFound)
-}
-
 func webmentionExists(source, target string) bool {
 	result := 0
 	row, err := appDbQueryRow("select exists(select 1 from webmentions where source = ? and target = ?)", source, target)
@@ -199,33 +119,6 @@ type webmentionsRequestConfig struct {
 	offset, limit int
 }
 
-type webmentionPaginationAdapter struct {
-	config *webmentionsRequestConfig
-	nums   int64
-}
-
-func (p *webmentionPaginationAdapter) Nums() (int64, error) {
-	if p.nums == 0 {
-		nums, _ := countWebmentions(p.config)
-		p.nums = int64(nums)
-	}
-	return p.nums, nil
-}
-
-func (p *webmentionPaginationAdapter) Slice(offset, length int, data interface{}) error {
-	if reflect.TypeOf(data).Kind() != reflect.Ptr {
-		panic("data has to be a pointer")
-	}
-
-	modifiedConfig := *p.config
-	modifiedConfig.offset = offset
-	modifiedConfig.limit = length
-
-	wms, err := getWebmentions(&modifiedConfig)
-	reflect.ValueOf(data).Elem().Set(reflect.ValueOf(&wms).Elem())
-	return err
-}
-
 func buildWebmentionsQuery(config *webmentionsRequestConfig) (query string, args []interface{}) {
 	args = []interface{}{}
 	filter := ""
diff --git a/webmentionAdmin.go b/webmentionAdmin.go
new file mode 100644
index 0000000..451d6b3
--- /dev/null
+++ b/webmentionAdmin.go
@@ -0,0 +1,109 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"reflect"
+	"strconv"
+
+	"github.com/go-chi/chi"
+	"github.com/vcraescu/go-paginator"
+)
+
+type webmentionPaginationAdapter struct {
+	config *webmentionsRequestConfig
+	nums   int64
+}
+
+func (p *webmentionPaginationAdapter) Nums() (int64, error) {
+	if p.nums == 0 {
+		nums, _ := countWebmentions(p.config)
+		p.nums = int64(nums)
+	}
+	return p.nums, nil
+}
+
+func (p *webmentionPaginationAdapter) Slice(offset, length int, data interface{}) error {
+	modifiedConfig := *p.config
+	modifiedConfig.offset = offset
+	modifiedConfig.limit = length
+
+	wms, err := getWebmentions(&modifiedConfig)
+	reflect.ValueOf(data).Elem().Set(reflect.ValueOf(&wms).Elem())
+	return err
+}
+
+func webmentionAdmin(w http.ResponseWriter, r *http.Request) {
+	pageNoString := chi.URLParam(r, "page")
+	pageNo, _ := strconv.Atoi(pageNoString)
+	p := paginator.New(&webmentionPaginationAdapter{config: &webmentionsRequestConfig{}}, 10)
+	p.SetPage(pageNo)
+	var mentions []*mention
+	err := p.Results(&mentions)
+	if err != nil {
+		serveError(w, r, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	// Navigation
+	var hasPrev, hasNext bool
+	var prevPage, nextPage int
+	var prevPath, nextPath string
+	hasPrev, _ = p.HasPrev()
+	if hasPrev {
+		prevPage, _ = p.PrevPage()
+	} else {
+		prevPage, _ = p.Page()
+	}
+	if prevPage < 2 {
+		prevPath = webmentionPath
+	} else {
+		prevPath = fmt.Sprintf("%s/page/%d", webmentionPath, prevPage)
+	}
+	hasNext, _ = p.HasNext()
+	if hasNext {
+		nextPage, _ = p.NextPage()
+	} else {
+		nextPage, _ = p.Page()
+	}
+	nextPath = fmt.Sprintf("%s/page/%d", webmentionPath, nextPage)
+	// Render
+	render(w, "webmentionadmin", &renderData{
+		Data: map[string]interface{}{
+			"Mentions": mentions,
+			"HasPrev":  hasPrev,
+			"HasNext":  hasNext,
+			"Prev":     slashIfEmpty(prevPath),
+			"Next":     slashIfEmpty(nextPath),
+		},
+	})
+}
+
+func webmentionAdminDelete(w http.ResponseWriter, r *http.Request) {
+	id, err := strconv.Atoi(r.FormValue("mentionid"))
+	if err != nil {
+		serveError(w, r, err.Error(), http.StatusBadRequest)
+		return
+	}
+	err = deleteWebmention(id)
+	if err != nil {
+		serveError(w, r, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	purgeCache()
+	http.Redirect(w, r, ".", http.StatusFound)
+}
+
+func webmentionAdminApprove(w http.ResponseWriter, r *http.Request) {
+	id, err := strconv.Atoi(r.FormValue("mentionid"))
+	if err != nil {
+		serveError(w, r, err.Error(), http.StatusBadRequest)
+		return
+	}
+	err = approveWebmention(id)
+	if err != nil {
+		serveError(w, r, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	purgeCache()
+	http.Redirect(w, r, ".", http.StatusFound)
+}