# Batch Report

**Batch**: 21
**Tasks**: AZ-374 (C21 — typed/named `HttpClient` for Google Maps in DI)
**Date**: 2026-05-11
**Run**: `03-code-quality-refactoring`
**Cycle**: 1

## Task Results

| Task | Status | Files Modified | Tests | AC Coverage | Issues |
|------|--------|----------------|-------|-------------|--------|
| AZ-374_refactor_typed_httpclient_googlemaps | Done | 3 src/test = 3 files | 175 unit + 5 smoke pass | 3/3 covered | None |

## Design note: registration location

The task spec recommended adding `AddHttpClient("GoogleMapsTiles", ...)` in `Program.cs`. I placed it inside `TileDownloaderServiceCollectionExtensions.AddTileDownloader()` instead. Rationale (per `coderule.mdc` SRP guidance):

- The named-client name, User-Agent, and timeout are all TileDownloader-internal concerns. Their owner is the component that resolves them — `GoogleMapsDownloaderV2`. The DI extension already encapsulates everything else TileDownloader needs (memory cache, `ISatelliteDownloader`, `ITileService`).
- Placing this in `Program.cs` would have spread component-internal knowledge into the application entry-point file. The extension was created precisely to avoid that.
- The bare `builder.Services.AddHttpClient()` call in `Program.cs:36` was kept untouched — it is now structurally redundant (the named-client registration also wires up `IHttpClientFactory`), but removing it is outside this task's scope.

The named-client name itself (`"GoogleMapsTiles"`), the `User-Agent` header value, and the 100-second default timeout are now `internal const`s on `GoogleMapsDownloaderV2` so the extension method and the downloader resolve from the same source of truth.

## Changes

### Modified production code

- `SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs`
  - Promoted `private const USER_AGENT` → `internal const UserAgent` (PascalCase; visibility to allow the extension method in the same assembly to reference it).
  - Added `internal const string GoogleMapsTilesClientName = "GoogleMapsTiles";`.
  - Added `internal const int DefaultHttpClientTimeoutSeconds = 100;` (matches `HttpClient`'s implicit default; preserves prior behavior).
  - Three `CreateClient()` call sites updated to `CreateClient(GoogleMapsTilesClientName)`:
    - `GetSessionToken` (session-token POST)
    - `DownloadSingleTileAsync` retry lambda (single-tile GET)
    - `PerformDownloadAsync` retry lambda (batch-tile GET)
  - Removed the two per-call `httpClient.DefaultRequestHeaders.UserAgent.ParseAdd(USER_AGENT);` lines — the header is now set once at registration.
- `SatelliteProvider.Services.TileDownloader/TileDownloaderServiceCollectionExtensions.cs`
  - Added `services.AddHttpClient(GoogleMapsDownloaderV2.GoogleMapsTilesClientName, c => { c.DefaultRequestHeaders.UserAgent.ParseAdd(GoogleMapsDownloaderV2.UserAgent); c.Timeout = TimeSpan.FromSeconds(GoogleMapsDownloaderV2.DefaultHttpClientTimeoutSeconds); });`.

### Unchanged (deliberate)

- `SatelliteProvider.Api/Program.cs` — `builder.Services.AddHttpClient();` kept. See "Design note" above; cleanup deferred.
- Per-call `User-Agent` setup is removed; the named client carries the header on every `CreateClient(...)` resolution.

### Modified tests

- `SatelliteProvider.Tests/TileServiceTests.cs`
  - Added `Microsoft.Extensions.DependencyInjection` using.
  - New `TileDownloaderRegistrationTests.AddTileDownloader_RegistersNamedGoogleMapsTilesHttpClient_AZ374_AC1` — builds a `ServiceCollection`, calls `AddTileDownloader()`, resolves `IHttpClientFactory`, asks for `"GoogleMapsTiles"`, asserts the returned client carries a `Mozilla/5.0...`-style User-Agent and a 100-second `Timeout`. Covers AC-1 directly and AC-2 transitively (the only consumer of `CreateClient(GoogleMapsTilesClientName)` is `GoogleMapsDownloaderV2`).

## AC Test Coverage

| AC | Covered by |
|----|------------|
| AC-1 (single registration with User-Agent + Timeout) | `AddTileDownloader_RegistersNamedGoogleMapsTilesHttpClient_AZ374_AC1` |
| AC-2 (downloader uses `CreateClient("GoogleMapsTiles")` everywhere) | Source-level: the only `CreateClient(` occurrences in `GoogleMapsDownloaderV2.cs` reference `GoogleMapsTilesClientName`. Behavioral: smoke tests `GetTileByLatLon` + region/route tile downloads succeed end-to-end against the real Google Maps API, exercising all three call sites (session token, single-tile, batch-tile). |
| AC-3 (tests stay green) | `scripts/run-tests.sh --smoke` reports 175 unit + 5 smoke. |

## Test Run

| Suite | Result | Count |
|-------|--------|-------|
| Unit (`SatelliteProvider.Tests`) | All passed | 175 (was 174; +1 new test for the DI registration) |
| Smoke integration (Docker) | All passed | 5 scenarios |

## Code Review Verdict: PASS

Inline review covered:

- **Architecture**: Named-client registration co-located with the consumer in `AddTileDownloader()`; no leakage into the WebApi entry point. SRP improvement over the task-spec recommendation, with rationale recorded above and verified against `coderule.mdc`.
- **Behavior preservation**: User-Agent value byte-identical (`Mozilla/5.0 (Windows NT 10.0; …)`); timeout preserved at `HttpClient`'s implicit default (100 s); retry/backoff unchanged; session-token / single-tile / batch-tile code paths all confirmed via the smoke tile-download scenarios.
- **AC coverage**: 3/3 with at least one running test per AC; AC-2 also relies on the structural fact that there is no other `CreateClient(` in `GoogleMapsDownloaderV2`.
- **Code quality**: SRP preserved; no narrative comments; consts named per C# conventions; A/A/A test pattern; no suppressed errors; argument validation unaffected.
- **Cross-batch consistency**: extends the AZ-371 (C18 magic-numbers-to-config) theme by adding a third configuration-style constant cluster; consistent with the AZ-364 collaborator-extraction pattern (small, well-named extension surfaces); AZ-370 enums (batch 19) and AZ-373 MapsVersion drop (batch 20) untouched.

**Findings**: None.

## Auto-Fix Attempts: 0
## Stuck Agents: None

## Cumulative review — K=3 trigger

Batches 19, 20, 21 have completed since the last cumulative review (`cumulative_review_batches_16-18_cycle1_report.md`). The K=3 trigger now fires. Cumulative review will be run as the next step (autodev sub_step `cumulative-review`), targeting the union of files changed in batches 19–21.

## Next Batch

After the cumulative review passes, Phase 4 continues with the remaining 7 tasks in `todo/`:

- `AZ-375` — C22 O(N) existing-tile lookup (2 SP, needs AZ-371 ✓)
- `AZ-376` — C23 delete unused `FindExistingTileAsync` (1 SP)
- `AZ-377` — C24 consolidate Earth-geometry constants (2 SP, needs AZ-371 ✓)
- `AZ-378` — C25 repo `_logger` fields (1 SP)
- `AZ-379` — C26 repo SELECT column-list constants (2 SP)
- `AZ-380` — C27 delete `CalculatePolygonDiagonalDistance` (1 SP)
- `AZ-372` — C19 dotnet format + analyzers + Coverlet (3 SP)
