Expand filtering to include complexity, categories and title

Author: solomonng2001

services/question-service/handlers/create.go

@@ -31,7 +31,7 @@ func (s *Service) CreateQuestion(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Map data
-	question.ID = docRef.ID
+	question.Ref = docRef.ID
 
 	w.Header().Set("Content-Type", "application/json")
 	json.NewEncoder(w).Encode(question)

services/question-service/handlers/list.go

@@ -1,17 +1,90 @@
 package handlers
 
 import (
+	"cloud.google.com/go/firestore"
 	"encoding/json"
+	"google.golang.org/api/iterator"
 	"net/http"
 	"question-service/models"
-
-	"google.golang.org/api/iterator"
+	"strconv"
+	"strings"
 )
 
-// TODO: add filters/pagination/sorter
 func (s *Service) ListQuestions(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
-	iter := s.Client.Collection("questions").Documents(ctx)
+
+	query := s.Client.Collection("questions").Query
+
+	// Filtering by title
+	titleParam := r.URL.Query().Get("title")
+	if titleParam != "" {
+		query = query.Where("Title", "==", titleParam)
+	}
+
+	// Filtering by complexity (multi-select)
+	complexityParam := r.URL.Query().Get("complexity")
+	if complexityParam != "" {
+		complexities := strings.Split(complexityParam, ",")
+		query = query.Where("Complexity", "in", complexities)
+	}
+
+	// Filtering by categories (multi-select)
+	categoriesParam := r.URL.Query().Get("categories")
+	if categoriesParam != "" {
+		categories := strings.Split(categoriesParam, ",")
+		query = query.Where("Categories", "array-contains-any", categories)
+	}
+
+	// Sorting
+	sortField := r.URL.Query().Get("sortField")
+	sortValue := r.URL.Query().Get("sortValue")
+	if sortField != "" {
+		order := firestore.Asc // Default ascending order
+		if sortValue == "desc" {
+			order = firestore.Desc
+		}
+		query = query.OrderBy(sortField, order)
+	}
+
+	// Count total documents matching the filter
+	totalIter, err := query.Documents(ctx).GetAll()
+	totalCount := len(totalIter)
+	if err != nil {
+		http.Error(w, "Failed to count questions: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// Pagination
+	currentPage := 1
+	limitParam := r.URL.Query().Get("limit")
+	limit, err := strconv.Atoi(limitParam) // convert limit to integer
+	if err != nil || limit <= 0 {
+		limit = 10 // Default to 10
+	}
+	startAfterParam := r.URL.Query().Get("startAfter")
+	if startAfterParam != "" {
+		// Calculate current page based on total documents before startAfter
+		beforeIter := query.EndAt(startAfterParam).Documents(ctx)
+		countBeforeStart := 0
+		for {
+			_, err := beforeIter.Next()
+			if err == iterator.Done {
+				break
+			}
+			if err != nil {
+				http.Error(w, "Failed to retrieve documents: "+err.Error(), http.StatusInternalServerError)
+				return
+			}
+			countBeforeStart++
+		}
+		currentPage = (countBeforeStart / limit) + 1
+
+		// start after previous page last question's document reference
+		query = query.StartAfter(startAfterParam)
+	}
+	query = query.Limit(limit)
+
+	iter := query.Documents(ctx)
 
 	var questions []models.Question
 	for {
@@ -21,20 +94,60 @@ func (s *Service) ListQuestions(w http.ResponseWriter, r *http.Request) {
 			break
 		}
 		if err != nil {
-			http.Error(w, "Failed to retrieve questions", http.StatusInternalServerError)
+			http.Error(w, "Failed to retrieve questions: "+err.Error(), http.StatusInternalServerError)
 			return
 		}
 
 		// Map data
 		var question models.Question
-		question.ID = doc.Ref.ID
 		if err := doc.DataTo(&question); err != nil {
-			http.Error(w, "Failed to parse question", http.StatusInternalServerError)
+			http.Error(w, "Failed to parse question: "+err.Error(), http.StatusInternalServerError)
 			return
 		}
+		question.Ref = doc.Ref.ID
 		questions = append(questions, question)
 	}
 
+	// Calculate pagination info
+	totalPages := (totalCount + limit - 1) / limit
+	hasNextPage := totalPages > currentPage
+
+	// Construct response
+	response := models.QuestionResponse{
+		TotalCount:  totalCount,
+		TotalPages:  totalPages,
+		CurrentPage: currentPage,
+		Limit:       limit,
+		HasNextPage: hasNextPage,
+		Questions:   questions,
+	}
+
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(questions)
+	json.NewEncoder(w).Encode(response)
 }
+
+//Manual test cases
+//
+//curl -X GET "http://localhost:8080/questions"
+//
+//curl -X GET "http://localhost:8080/questions?title=Reverse%20a%20String"
+//
+//curl -X GET "http://localhost:8080/questions?complexity=Easy,Medium"
+//
+//curl -X GET "http://localhost:8080/questions?categories=Algorithms,Data%20Structures"
+//
+//curl -X GET "http://localhost:8080/questions?sortField=title&sortValue=asc"
+//
+//curl -X GET "http://localhost:8080/questions?sortField=title&sortValue=desc"
+//
+//curl -X GET "http://localhost:8080/questions?sortField=complexity&sortValue=desc"
+//
+//curl -X GET "http://localhost:8080/questions?limit=5"
+//
+//curl -X GET "http://localhost:8080/questions?limit=5&startAfter=<last_question_document_ref>"
+//
+//curl -X GET "http://localhost:8080/questions?complexity=Easy,Medium&sortField=title&sortValue=asc&limit=5"
+//
+//curl -X GET "http://localhost:8080/questions?categories=Data%20Structures,Algorithms&complexity=Hard,Easy"
+//
+//curl -X GET "http://localhost:8080/questions?complexity=InvalidComplexity"

services/question-service/handlers/read.go

@@ -28,7 +28,7 @@ func (s *Service) ReadQuestion(w http.ResponseWriter, r *http.Request) {
 
 	// Map data
 	var question models.Question
-	question.ID = doc.Ref.ID
+	question.Ref = doc.Ref.ID
 	if err := doc.DataTo(&question); err != nil {
 		http.Error(w, "Failed to map question data", http.StatusInternalServerError)
 		return

services/question-service/handlers/update.go

@@ -51,7 +51,7 @@ func (s *Service) UpdateQuestion(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Map data
-	question.ID = id
+	question.Ref = id
 
 	w.Header().Set("Content-Type", "application/json")
 	json.NewEncoder(w).Encode(question)

services/question-service/models/pagination.go

@@ -0,0 +1,10 @@
+package models
+
+type QuestionResponse struct {
+	TotalCount  int        `json:"totalCount"`
+	TotalPages  int        `json:"totalPages"`
+	CurrentPage int        `json:"currentPage"`
+	Limit       int        `json:"limit"`
+	HasNextPage bool       `json:"hasNextPage"`
+	Questions   []Question `json:"questions"`
+}

services/question-service/models/question.go

@@ -2,7 +2,8 @@ package models
 
 // TODO: currently the Question model is a simplified model
 type Question struct {
-	ID          string   `json:"id"`
+	ID          int      `json:"id"`
+	Ref         string   `json:"ref"`
 	Title       string   `json:"title"`
 	Description string   `json:"description"`
 	Categories  []string `json:"categories"`