feat(grid): fetch_grid_page datasource server-side AG Grid (#41)

src/utils/grid.py

@@ -0,0 +1,34 @@
+"""Datasource server-side pour AG Grid (infinite row model)."""
+
+from src.db import count_marches, query_marches, schema
+from src.utils.query_ast import ast_to_sql, filtermodel_to_ast, sort_model_to_sql
+from src.utils.table import postprocess_page
+
+
+def fetch_grid_page(
+    filter_model,
+    sort_model,
+    start_row: int,
+    end_row: int,
+    base_where_sql: str = "TRUE",
+    base_params: tuple = (),
+) -> tuple[list[dict], int]:
+    """Renvoie (row_data, total_count) pour un bloc [start_row, end_row)."""
+    ast = filtermodel_to_ast(filter_model, schema)
+    filter_sql, filter_params = ast_to_sql(ast, schema)
+    where_sql = f"({base_where_sql}) AND ({filter_sql})"
+    params = [*base_params, *filter_params]
+
+    order_by = sort_model_to_sql(sort_model, schema) or None
+    total = count_marches(where_sql, params)
+
+    limit = max(0, end_row - start_row)
+    page = query_marches(
+        where_sql=where_sql,
+        params=params,
+        order_by=order_by,
+        limit=limit,
+        offset=start_row,
+    )
+    page = postprocess_page(page)
+    return page.to_dicts(), total