feat(affiliate): add program CRUD functions + build_affiliate_url()

Adds get_all_programs(), get_program(), get_program_by_slug() for admin
CRUD. Adds build_affiliate_url() that assembles URLs from program template
+ product identifier, with fallback to baked affiliate_url for legacy
products. Updates get_product() to JOIN affiliate_programs so _program
dict is available at redirect time. _parse_product() extracts program
fields into nested _program key.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/padelnomics/affiliate.py

@@ -21,6 +21,7 @@ logger = logging.getLogger(__name__)
 
 VALID_CATEGORIES = ("racket", "ball", "shoe", "bag", "grip", "eyewear", "accessory")
 VALID_STATUSES = ("draft", "active", "archived")
+VALID_PROGRAM_STATUSES = ("active", "inactive")
 
 
 def hash_ip(ip_address: str) -> str:
@@ -32,20 +33,86 @@ def hash_ip(ip_address: str) -> str:
     return hashlib.sha256(raw.encode()).hexdigest()
 
 
-async def get_product(slug: str, language: str = "de") -> dict | None:
-    """Return active product by slug+language, falling back to any language."""
+async def get_all_programs(status: str | None = None) -> list[dict]:
+    """Return all affiliate programs, optionally filtered by status."""
+    if status:
+        assert status in VALID_PROGRAM_STATUSES, f"unknown program status: {status}"
+        rows = await fetch_all(
+            "SELECT ap.*, ("
+            "  SELECT COUNT(*) FROM affiliate_products WHERE program_id = ap.id"
+            ") AS product_count"
+            " FROM affiliate_programs ap WHERE ap.status = ?"
+            " ORDER BY ap.name ASC",
+            (status,),
+        )
+    else:
+        rows = await fetch_all(
+            "SELECT ap.*, ("
+            "  SELECT COUNT(*) FROM affiliate_products WHERE program_id = ap.id"
+            ") AS product_count"
+            " FROM affiliate_programs ap ORDER BY ap.name ASC"
+        )
+    return [dict(r) for r in rows]
+
+
+async def get_program(program_id: int) -> dict | None:
+    """Return a single affiliate program by id."""
+    assert program_id > 0, "program_id must be positive"
+    row = await fetch_one(
+        "SELECT * FROM affiliate_programs WHERE id = ?", (program_id,)
+    )
+    return dict(row) if row else None
+
+
+async def get_program_by_slug(slug: str) -> dict | None:
+    """Return a single affiliate program by slug."""
     assert slug, "slug must not be empty"
     row = await fetch_one(
-        "SELECT * FROM affiliate_products"
-        " WHERE slug = ? AND language = ? AND status = 'active'",
+        "SELECT * FROM affiliate_programs WHERE slug = ?", (slug,)
+    )
+    return dict(row) if row else None
+
+
+def build_affiliate_url(product: dict, program: dict | None = None) -> str:
+    """Assemble the final affiliate URL from program template + product identifier.
+
+    Falls back to the baked product["affiliate_url"] when no program is set,
+    preserving backward compatibility with products created before programs existed.
+    """
+    if not product.get("program_id") or not program:
+        return product["affiliate_url"]
+    return program["url_template"].format(
+        product_id=product["product_identifier"],
+        tag=program["tracking_tag"],
+    )
+
+
+async def get_product(slug: str, language: str = "de") -> dict | None:
+    """Return active product by slug+language, falling back to any language.
+
+    JOINs affiliate_programs so the returned dict includes program fields
+    (prefixed with _program_*) for use in build_affiliate_url().
+    """
+    assert slug, "slug must not be empty"
+    row = await fetch_one(
+        "SELECT p.*, pg.url_template AS _program_url_template,"
+        "       pg.tracking_tag AS _program_tracking_tag,"
+        "       pg.name AS _program_name"
+        " FROM affiliate_products p"
+        " LEFT JOIN affiliate_programs pg ON pg.id = p.program_id"
+        " WHERE p.slug = ? AND p.language = ? AND p.status = 'active'",
         (slug, language),
     )
     if row:
         return _parse_product(row)
     # Graceful fallback: show any language rather than nothing
     row = await fetch_one(
-        "SELECT * FROM affiliate_products"
-        " WHERE slug = ? AND status = 'active' LIMIT 1",
+        "SELECT p.*, pg.url_template AS _program_url_template,"
+        "       pg.tracking_tag AS _program_tracking_tag,"
+        "       pg.name AS _program_name"
+        " FROM affiliate_products p"
+        " LEFT JOIN affiliate_programs pg ON pg.id = p.program_id"
+        " WHERE p.slug = ? AND p.status = 'active' LIMIT 1",
         (slug,),
     )
     return _parse_product(row) if row else None
@@ -217,8 +284,24 @@ async def get_distinct_retailers() -> list[str]:
 
 
 def _parse_product(row) -> dict:
-    """Convert aiosqlite Row to plain dict, parsing JSON pros/cons arrays."""
+    """Convert aiosqlite Row to plain dict, parsing JSON pros/cons arrays.
+
+    If the row includes _program_* columns (from a JOIN), extracts them into
+    a nested "_program" dict so build_affiliate_url() can use them directly.
+    """
     d = dict(row)
     d["pros"] = json.loads(d.get("pros") or "[]")
     d["cons"] = json.loads(d.get("cons") or "[]")
+    # Extract program fields added by get_product()'s JOIN
+    if "_program_url_template" in d:
+        if d.get("program_id") and d["_program_url_template"]:
+            d["_program"] = {
+                "url_template": d.pop("_program_url_template"),
+                "tracking_tag": d.pop("_program_tracking_tag", ""),
+                "name": d.pop("_program_name", ""),
+            }
+        else:
+            d.pop("_program_url_template", None)
+            d.pop("_program_tracking_tag", None)
+            d.pop("_program_name", None)
     return d