feat: articles pagination

api/handlers/article/articleHandler.go

@@ -11,7 +11,9 @@ import (
 	"fmt"
 	"log"
 	"net/http"
+	"net/url"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/go-chi/chi/v5"
@@ -268,26 +270,89 @@ func (h *Handler) callerIsVerified(r *http.Request) bool {
 	return currentUser.IsVerified
 }
 
+const (
+	defaultListPage = 1
+	defaultListSize = 25
+)
+
+type listQuery struct {
+	Page   int    `validate:"gte=1"`
+	Size   int    `validate:"oneof=5 25 50 100"`
+	Q      string `validate:"max=200"`
+	Status string `validate:"omitempty,oneof=online draft"`
+	Sort   string `validate:"oneof=title:asc title:desc status:asc status:desc created_at:asc created_at:desc updated_at:asc updated_at:desc"`
+}
+
+const defaultListSort = "updated_at:desc"
+
+func parseSort(value string) domain.Sort {
+	field, direction, _ := strings.Cut(value, ":")
+	return domain.Sort{Field: domain.SortField(field), Direction: domain.SortDirection(direction)}
+}
+
+type listResponse struct {
+	Items  []articleResponse `json:"items"`
+	Total  int               `json:"total"`
+	Page   int               `json:"page"`
+	Size   int               `json:"size"`
+	Counts domain.Counts     `json:"counts"`
+}
+
+func intQueryParam(values url.Values, name string, fallback int) (int, error) {
+	if !values.Has(name) {
+		return fallback, nil
+	}
+	return strconv.Atoi(values.Get(name))
+}
+
+func readListQuery(values url.Values) (listQuery, error) {
+	page, err := intQueryParam(values, "page", defaultListPage)
+	if err != nil {
+		return listQuery{}, err
+	}
+	size, err := intQueryParam(values, "size", defaultListSize)
+	if err != nil {
+		return listQuery{}, err
+	}
+	status := values.Get("status")
+	if values.Has("status") && status == "" {
+		return listQuery{}, errors.New("empty status")
+	}
+	sortValue := defaultListSort
+	if values.Has("sort") {
+		sortValue = values.Get("sort")
+	}
+	return listQuery{Page: page, Size: size, Q: values.Get("q"), Status: status, Sort: sortValue}, nil
+}
+
 func (h *Handler) ListArticles(w http.ResponseWriter, r *http.Request) {
 	format, ok := parseBodyFormat(w, r)
 	if !ok {
 		return
 	}
 
-	var articles []domain.Article
-	var err error
-	if h.callerIsVerified(r) {
-		articles, err = h.ListUseCase.ListAllArticles(format)
-	} else {
-		articles, err = h.ListUseCase.ListOnlineArticles(format)
+	query, err := readListQuery(r.URL.Query())
+	if err != nil || validator.Validate.Struct(query) != nil {
+		http.Error(w, apperr.BodyErrorMessage, http.StatusBadRequest)
+		return
 	}
+
+	page, err := h.ListUseCase.ListArticlesPage(useCases.ListArticlesCommand{
+		Format:   format,
+		Verified: h.callerIsVerified(r),
+		Page:     query.Page,
+		Size:     query.Size,
+		Q:        query.Q,
+		Status:   query.Status,
+		Sort:     parseSort(query.Sort),
+	})
 	if err != nil {
 		http.Error(w, "Failed to retrieve articles", http.StatusInternalServerError)
 		return
 	}
 
-	responses := make([]articleResponse, 0, len(articles))
-	for _, article := range articles {
+	responses := make([]articleResponse, 0, len(page.Items))
+	for _, article := range page.Items {
 		response, err := toArticleResponse(article, format)
 		if err != nil {
 			http.Error(w, "Failed to encode response", http.StatusInternalServerError)
@@ -296,7 +361,7 @@ func (h *Handler) ListArticles(w http.ResponseWriter, r *http.Request) {
 		responses = append(responses, response)
 	}
 
-	articlesJson, err := json.Marshal(responses)
+	articlesJson, err := json.Marshal(listResponse{Items: responses, Total: page.Total, Page: page.Page, Size: page.Size, Counts: page.Counts})
 	if err != nil {
 		http.Error(w, "Failed to encode response", http.StatusInternalServerError)
 		return