Finish datasheet acquisition: more vendors, Mouser, browser download links.

Add Microchip/Murata/Silicon Labs URL tables, optional Mouser search, and suggested URLs on a miss so the wizard can open PDFs in the user's browser when the VPS is blocked.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/services/mouser.py

@@ -0,0 +1,143 @@
+"""Mouser Search API — optional fourth datasheet source (same MPN matching as DigiKey)."""
+
+from __future__ import annotations
+
+import logging
+
+import httpx
+
+from backend.config import settings
+from backend.services.datasheet_finder import (
+    _alnum,
+    _download_pdf,
+    mpn_catalog_match,
+    mpn_matches,
+    mpn_query_variants,
+)
+
+logger = logging.getLogger(__name__)
+
+_SEARCH_URL = "https://api.mouser.com/api/v1/search/partnumber"
+
+
+class MouserFetchResult:
+    def __init__(
+        self,
+        mpn: str,
+        pdf_bytes: bytes | None = None,
+        error: str | None = None,
+        url: str | None = None,
+        catalog_mpn: str | None = None,
+    ):
+        self.mpn = mpn
+        self.pdf_bytes = pdf_bytes
+        self.error = error
+        self.url = url
+        self.catalog_mpn = catalog_mpn
+
+    @property
+    def ok(self) -> bool:
+        return self.pdf_bytes is not None
+
+
+def _product_mpn(product: dict) -> str:
+    return (
+        product.get("ManufacturerPartNumber")
+        or product.get("MouserPartNumber")
+        or ""
+    )
+
+
+def _product_ds(product: dict) -> str:
+    url = product.get("DataSheetUrl") or product.get("DatasheetUrl") or ""
+    if url.startswith("//"):
+        url = "https:" + url
+    return url
+
+
+def _pick_product(mpn: str, products: list[dict]) -> dict | None:
+    exact: dict | None = None
+    loose: dict | None = None
+    family: dict | None = None
+    want = _alnum(mpn)
+    for product in products:
+        cand = _product_mpn(product)
+        if not cand:
+            continue
+        got = _alnum(cand)
+        if got == want:
+            exact = product
+            break
+        if loose is None and mpn_matches(mpn, cand):
+            loose = product
+        elif family is None and mpn_catalog_match(mpn, cand):
+            family = product
+    return exact or loose or family
+
+
+async def _keyword_search(mpn: str) -> list[dict]:
+    key = settings.mouser_api_key
+    payload = {
+        "SearchByPartRequest": {
+            "mouserPartNumber": mpn,
+            "partSearchOptions": "Exact",
+        }
+    }
+    async with httpx.AsyncClient(timeout=20) as client:
+        resp = await client.post(
+            _SEARCH_URL,
+            params={"apiKey": key},
+            json=payload,
+            headers={"Content-Type": "application/json", "Accept": "application/json"},
+        )
+        resp.raise_for_status()
+        data = resp.json()
+    result = data.get("SearchResults") or {}
+    return result.get("Parts") or []
+
+
+def pick_mouser_product(mpn: str, products: list[dict]) -> dict | None:
+    """Public for tests — same family/packing rules as DigiKey/LCSC."""
+    return _pick_product(mpn, products)
+
+
+async def fetch_datasheet(mpn: str) -> MouserFetchResult:
+    if not settings.use_mouser:
+        return MouserFetchResult(mpn, error="Mouser API not configured")
+
+    product: dict | None = None
+    last_err: str | None = None
+    for query in mpn_query_variants(mpn):
+        try:
+            products = await _keyword_search(query)
+        except httpx.HTTPStatusError as exc:
+            last_err = f"Mouser search failed ({exc.response.status_code})"
+            logger.info("Mouser search %s: %s", query, last_err)
+            continue
+        except Exception as exc:
+            last_err = f"Mouser search error: {exc}"
+            logger.info("Mouser search %s: %s", query, last_err)
+            continue
+        product = _pick_product(mpn, products)
+        if product:
+            break
+
+    if not product:
+        return MouserFetchResult(mpn, error=last_err or "No datasheet found on Mouser")
+
+    url = _product_ds(product)
+    catalog = _product_mpn(product) or None
+    if not url:
+        return MouserFetchResult(
+            mpn, error="No datasheet URL on Mouser", catalog_mpn=catalog,
+        )
+
+    try:
+        pdf = await _download_pdf(url, mpn=mpn)
+    except Exception as exc:
+        logger.info("Mouser PDF download failed for %s (%s): %s", mpn, url, exc)
+        return MouserFetchResult(
+            mpn, error=f"Mouser download failed: {exc}", url=url, catalog_mpn=catalog,
+        )
+    logger.info("Fetched datasheet for %s via Mouser (%d KB)", mpn, len(pdf) // 1024)
+    return MouserFetchResult(mpn, pdf_bytes=pdf, url=url, catalog_mpn=catalog)