Add database query status (and improved response), photos, likes, comments, bans

service/database/db-photos.go

@@ -1,6 +1,12 @@
 package database
 
-import "time"
+import (
+	"database/sql"
+	"time"
+
+	"github.com/notherealmarco/WASAPhoto/service/database/db_errors"
+	"github.com/notherealmarco/WASAPhoto/service/structures"
+)
 
 type Photo struct {
 	ID       int64
@@ -16,17 +22,63 @@ type UserProfile struct {
 	Photos    []Photo
 }
 
+type QueryResult int // todo: move to a separate file
+
+const (
+	SUCCESS       = 0
+	ERR_NOT_FOUND = 1
+	ERR_EXISTS    = 2
+	ERR_INTERNAL  = 3
+)
+
+type dbtransaction struct {
+	c *sql.Tx
+}
+
+func (tx *dbtransaction) Commit() error {
+	return tx.c.Commit()
+}
+
+func (tx *dbtransaction) Rollback() error {
+	return tx.c.Rollback()
+}
+
 // Post a new photo
-func (db *appdbimpl) PostPhoto(uid string) (int64, error) {
-	res, err := db.c.Exec(`INSERT INTO "photos" ("user", "date") VALUES (?, ?)`, uid, time.Now().Format(time.RFC3339))
+func (db *appdbimpl) PostPhoto(uid string) (DBTransaction, int64, error) {
+	tx, err := db.c.Begin()
+
 	if err != nil {
-		return 0, err
+		return nil, 0, err
+	}
+
+	res, err := tx.Exec(`INSERT INTO "photos" ("user", "date") VALUES (?, ?)`, uid, time.Now().Format(time.RFC3339))
+	if err != nil {
+		tx.Rollback() // error ?
+		return nil, 0, err
 	}
 	id, err := res.LastInsertId()
+
 	if err != nil {
-		return 0, err
+		tx.Rollback() // error ?
+		return nil, 0, err
 	}
-	return id, nil
+
+	return &dbtransaction{
+		c: tx,
+	}, id, nil
+}
+
+// Delete a photo, returns true if the photo was deleted and false if it did not exist
+func (db *appdbimpl) DeletePhoto(uid string, photo int64) (bool, error) {
+	res, err := db.c.Exec(`DELETE FROM "photos" WHERE "id" = ? AND "user" = ?`, photo, uid)
+	if err != nil {
+		return false, err
+	}
+	rows, err := res.RowsAffected()
+	if err != nil {
+		return false, err
+	}
+	return rows > 0, nil
 }
 
 // Get user profile, including username, followers, following, and photos
@@ -58,7 +110,7 @@ func (db *appdbimpl) GetUserProfile(uid string) (*UserProfile, error) {
 		return nil, err
 	}
 
-	var photos []Photo
+	photos := make([]Photo, 0)
 	for rows.Next() {
 		var id int64
 		var date string
@@ -75,14 +127,105 @@ func (db *appdbimpl) GetUserProfile(uid string) (*UserProfile, error) {
 	return &UserProfile{uid, name, followers, following, photos}, nil
 }
 
+// Check if a given photo owned by a given user exists
+func (db *appdbimpl) photoExists(uid string, photo int64) (bool, error) {
+
+	var cnt int64
+	err := db.c.QueryRow(`SELECT COUNT(*) FROM "photos" WHERE "id" = ? AND "user" = ?`, photo, uid).Scan(&cnt)
+	if err != nil {
+		return false, err
+	}
+	return cnt > 0, nil
+}
+
+// Get the list of users who liked a photo
+func (db *appdbimpl) GetPhotoLikes(uid string, photo int64) (QueryResult, *[]structures.UIDName, error) {
+
+	// Check if the photo exists, as it could exist but have no likes
+	exists, err := db.photoExists(uid, photo)
+	if err != nil {
+		return ERR_INTERNAL, nil, err
+	}
+
+	if !exists {
+		return ERR_NOT_FOUND, nil, nil
+	}
+
+	rows, err := db.c.Query(`SELECT "users.uid", "users.name" FROM "likes", "users"
+								WHERE "likes.photo_id" = ?
+								AND "likes.user" = "users.uid"`, photo)
+	if err != nil {
+		return ERR_INTERNAL, nil, err
+	}
+
+	likes := make([]structures.UIDName, 0)
+	for rows.Next() {
+		var uid string
+		var name string
+		err = rows.Scan(&uid, &name)
+		if err != nil {
+			return ERR_INTERNAL, nil, err
+		}
+		likes = append(likes, structures.UIDName{UID: uid, Name: name})
+	}
+
+	return SUCCESS, &likes, nil
+}
+
 // Like a photo
-func (db *appdbimpl) LikePhoto(uid string, photo int64) error {
-	_, err := db.c.Exec(`INSERT INTO "likes" ("user", "photo_id") VALUES (?, ?)`, uid, photo)
-	return err
+func (db *appdbimpl) LikePhoto(uid string, photo int64, liker_uid string) (QueryResult, error) {
+
+	// Check if the photo exists, as API specification requires
+	// photos to be identified also by the user who posted them.
+	// But our DB implementation only requires the photo id.
+	exists, err := db.photoExists(uid, photo)
+	if err != nil || !exists {
+		return ERR_NOT_FOUND, err
+	}
+
+	_, err = db.c.Exec(`PRAGMA foreign_keys = ON;
+						INSERT INTO "likes" ("user", "photo_id") VALUES (?, ?)`, liker_uid, photo)
+
+	// The photo exists, but the user already liked it
+	if db_errors.UniqueViolation(err) {
+		return ERR_EXISTS, nil
+	}
+
+	if db_errors.ForeignKeyViolation(err) {
+		return ERR_NOT_FOUND, nil
+	}
+
+	if err != nil {
+		return ERR_INTERNAL, err
+	}
+	return SUCCESS, nil
 }
 
 // Unlike a photo
-func (db *appdbimpl) UnlikePhoto(uid string, photo int64) error {
-	_, err := db.c.Exec(`DELETE FROM "likes" WHERE "user" = ? AND "photo_id" = ?`, uid, photo)
-	return err
+func (db *appdbimpl) UnlikePhoto(uid string, photo int64, liker_uid string) (QueryResult, error) {
+
+	// Check if the photo exists, as API specification requires
+	// photos to be identified also by the user who posted them.
+	// But our DB implementation only requires the photo id.
+	exists, err := db.photoExists(uid, photo)
+	if err != nil || !exists {
+		return ERR_NOT_FOUND, err
+	}
+
+	res, err := db.c.Exec(`DELETE FROM "likes" WHERE "user" = ? AND "photo_id" = ?`, liker_uid, photo)
+
+	if err != nil {
+		return ERR_INTERNAL, err
+	}
+
+	rows, err := res.RowsAffected()
+
+	if err != nil {
+		return ERR_INTERNAL, err
+	}
+
+	if rows == 0 {
+		return ERR_NOT_FOUND, nil
+	}
+	return SUCCESS, nil
 }