feat: add books APIs

internal/repository/essay_repo.go

@@ -0,0 +1,64 @@
+package repository
+
+import (
+	"context"
+
+	"go.mongodb.org/mongo-driver/v2/bson"
+	"go.mongodb.org/mongo-driver/v2/mongo"
+	"go.mongodb.org/mongo-driver/v2/mongo/options"
+)
+
+type EssayRepo struct {
+	col *mongo.Collection
+}
+
+func NewEssayRepo(db *MongoDB) *EssayRepo {
+	return &EssayRepo{col: db.Collection("essays")}
+}
+
+type EssayDoc struct {
+	ID         bson.ObjectID `bson:"_id" json:"id"`
+	Slug       string        `bson:"slug" json:"slug"`
+	Title      string        `bson:"title" json:"title"`
+	Author     string        `bson:"author" json:"author"`
+	Year       *int          `bson:"year,omitempty" json:"year,omitempty"`
+	Group      *string       `bson:"group,omitempty" json:"group,omitempty"`
+	Order      int           `bson:"order" json:"order"`
+	Paragraphs []string      `bson:"paragraphs" json:"paragraphs"`
+}
+
+type EssaySummaryDoc struct {
+	ID    bson.ObjectID `bson:"_id" json:"id"`
+	Slug  string        `bson:"slug" json:"slug"`
+	Title string        `bson:"title" json:"title"`
+	Year  *int          `bson:"year,omitempty" json:"year,omitempty"`
+	Group *string       `bson:"group,omitempty" json:"group,omitempty"`
+}
+
+func (r *EssayRepo) GetAll(ctx context.Context) ([]EssaySummaryDoc, error) {
+	opts := options.Find().
+		SetSort(bson.M{"group": 1, "order": 1}).
+		SetProjection(bson.M{"slug": 1, "title": 1, "year": 1, "group": 1})
+	cursor, err := r.col.Find(ctx, bson.M{}, opts)
+	if err != nil {
+		return nil, err
+	}
+	defer cursor.Close(ctx)
+	var results []EssaySummaryDoc
+	if err := cursor.All(ctx, &results); err != nil {
+		return nil, err
+	}
+	return results, nil
+}
+
+func (r *EssayRepo) GetBySlug(ctx context.Context, slug string) (*EssayDoc, error) {
+	var doc EssayDoc
+	err := r.col.FindOne(ctx, bson.M{"slug": slug}).Decode(&doc)
+	if err != nil {
+		if err == mongo.ErrNoDocuments {
+			return nil, nil
+		}
+		return nil, err
+	}
+	return &doc, nil
+}