Refactoring file structure, not tested yet

app/services/url_service.py

@@ -0,0 +1,104 @@
+# app/services/url_service.py
+
+from sqlalchemy.orm import Session
+from sqlalchemy import select
+from datetime import datetime
+from typing import Optional
+
+from app.db.models import URL
+from app.utils.short_code import generate_short_code
+from app.core.config import settings
+
+
+SHORT_CODE_LENGTH = 6
+MAX_GENERATION_ATTEMPTS = 5
+
+
+def create_short_url(db: Session, original_url: str) -> str:
+    """
+    Create a shortened URL or return existing one if already present.
+    """
+
+    # 1️⃣ Check if URL already exists
+    existing = db.execute(
+        select(URL).where(URL.original_url == original_url)
+    ).scalar_one_or_none()
+
+    if existing:
+        return f"{settings.base_url}/{existing.short_code}"
+
+    # 2️⃣ Generate unique short code with collision handling
+    for _ in range(MAX_GENERATION_ATTEMPTS):
+        short_code = generate_short_code(SHORT_CODE_LENGTH)
+
+        collision = db.execute(
+            select(URL).where(URL.short_code == short_code)
+        ).scalar_one_or_none()
+
+        if not collision:
+            new_url = URL(
+                short_code=short_code,
+                original_url=original_url,
+            )
+            db.add(new_url)
+            db.commit()
+            db.refresh(new_url)
+
+            return f"{settings.base_url}/{new_url.short_code}"
+
+    # If we somehow fail multiple times
+    raise RuntimeError("Failed to generate unique short code")
+
+
+def get_original_url(db: Session, short_code: str) -> Optional[str]:
+    """
+    Retrieve original URL for redirection.
+    """
+
+    url_entry = db.execute(
+        select(URL).where(URL.short_code == short_code)
+    ).scalar_one_or_none()
+
+    if not url_entry:
+        return None
+
+    return url_entry.original_url
+
+
+def increment_clicks(db: Session, short_code: str) -> bool:
+    """
+    Increment click counter and update last_accessed timestamp.
+    """
+
+    url_entry = db.execute(
+        select(URL).where(URL.short_code == short_code)
+    ).scalar_one_or_none()
+
+    if not url_entry:
+        return False
+
+    url_entry.clicks += 1
+    url_entry.last_accessed = datetime.utcnow()
+
+    db.commit()
+    return True
+
+
+def get_stats(db: Session, short_code: str) -> Optional[dict]:
+    """
+    Return URL statistics.
+    """
+
+    url_entry = db.execute(
+        select(URL).where(URL.short_code == short_code)
+    ).scalar_one_or_none()
+
+    if not url_entry:
+        return None
+
+    return {
+        "original_url": url_entry.original_url,
+        "clicks": url_entry.clicks,
+        "created_at": url_entry.created_at,
+        "last_accessed": url_entry.last_accessed,
+    }