Adding top-level Scopes table

app/services/scope_guide.py

@@ -0,0 +1,114 @@
+"""Assemble the scope-centric fit guide.
+
+Builds the data for the top-level ``/scopes`` page: one row per augmented part
+of part type "Scope", one column per non-Scope part type, where each cell lists
+the parts of that type that fit the row's scope.
+"""
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.crud import augmented_part as augmented_part_crud
+from app.crud import fit as fit_crud
+from app.crud import part_type as part_type_crud
+from app.crud import scope_info as scope_info_crud
+from app.models.fit import FitLabel
+
+SCOPE_TYPE_NAME = "Scope"
+
+# "exact" outranks "possible" when the same part fits a scope via several fits.
+_LABEL_RANK = {FitLabel.EXACT.value: 2, FitLabel.POSSIBLE.value: 1}
+
+
+async def build(db: AsyncSession) -> dict:
+    """Return the context for ``scopes.html``.
+
+    Shape::
+
+        {
+            "column_types": [PartType, ...],   # non-Scope, ordered by name
+            "rows": [
+                {
+                    "scope": AugmentedPart,
+                    "info": ScopeInfo | None,
+                    "cells": {part_type_id: [{"part": AugmentedPart, "label": str}]},
+                },
+                ...,
+            ],
+        }
+    """
+    part_types = await part_type_crud.list_all(db, limit=1000)
+    scope_type = next(
+        (pt for pt in part_types if pt.name == SCOPE_TYPE_NAME), None
+    )
+    column_types = [
+        pt for pt in part_types if scope_type is None or pt.id != scope_type.id
+    ]
+
+    if scope_type is None:
+        return {"column_types": column_types, "rows": []}
+
+    scopes = await augmented_part_crud.list_by_part_type(db, scope_type.id)
+    scope_ids = {s.id for s in scopes}
+    if not scope_ids:
+        return {"column_types": column_types, "rows": []}
+
+    fits = await fit_crud.list_for_parts(
+        db, list(scope_ids), exclude_label=FitLabel.NONE
+    )
+
+    # Resolve the "other" (non-scope) part on each fit in a single batched query.
+    other_ids: set[int] = set()
+    for fit in fits:
+        scope_id, other_id = _scope_and_other(fit, scope_ids)
+        if scope_id is not None and other_id not in scope_ids:
+            other_ids.add(other_id)
+    other_parts = {
+        p.id: p for p in await augmented_part_crud.get_many(db, list(other_ids))
+    }
+
+    infos = {
+        info.augmented_part_id: info
+        for info in await scope_info_crud.list_by_augmented_parts(db, list(scope_ids))
+    }
+
+    # cell_map[scope_id][type_id][other_part_id] -> {"part", "label"}, dedup'd so a
+    # part appears once per cell, keeping its strongest fit label.
+    cell_map: dict[int, dict[int, dict[int, dict]]] = {
+        sid: {} for sid in scope_ids
+    }
+    for fit in fits:
+        scope_id, other_id = _scope_and_other(fit, scope_ids)
+        if scope_id is None:
+            continue
+        other = other_parts.get(other_id)
+        if other is None or other.part_type_id == scope_type.id:
+            continue  # scope-to-scope fits have no column
+        by_type = cell_map[scope_id].setdefault(other.part_type_id, {})
+        existing = by_type.get(other.id)
+        label = fit.label.value
+        if existing is None or _LABEL_RANK[label] > _LABEL_RANK[existing["label"]]:
+            by_type[other.id] = {"part": other, "label": label}
+
+    rows = []
+    for scope in scopes:
+        cells = {
+            type_id: sorted(
+                entries.values(), key=lambda e: e["part"].description.lower()
+            )
+            for type_id, entries in cell_map[scope.id].items()
+        }
+        rows.append(
+            {"scope": scope, "info": infos.get(scope.id), "cells": cells}
+        )
+
+    return {"column_types": column_types, "rows": rows}
+
+
+def _scope_and_other(fit, scope_ids: set[int]) -> tuple[int | None, int]:
+    """Return (scope_part_id, other_part_id) for a fit, or (None, _) if neither
+    side is a scope. When both sides are scopes, side A is treated as the scope."""
+    if fit.augmented_part_a_id in scope_ids:
+        return fit.augmented_part_a_id, fit.augmented_part_b_id
+    if fit.augmented_part_b_id in scope_ids:
+        return fit.augmented_part_b_id, fit.augmented_part_a_id
+    return None, fit.augmented_part_b_id