kandev/docs/plans/plugins/host-data-api/task-02-session-loc-aggregation.md

id, title, status, wave, depends_on, plan, spec, adr

id	title	status	wave	depends_on	plan	spec	adr
02-session-loc-aggregation	Per-session LOC aggregation (committed + peak-pending)	done	1		plan.md	../../../specs/plugins/requirements/plugins.md	../../../decisions/0043-plugin-host-data-api.md

Task 02: Per-session LOC aggregation (committed + peak-pending)

Add the one net-new read-only query the Host data API needs: per-session code stats. No existing method computes this. internal/analytics/repository/sqlite/ stats.go aggregates git stats at workspace and per-repository granularity only, and the peak-pending snapshot aggregation exists nowhere in-tree.

Scope

Add a repository method (recommended home: internal/analytics/repository/sqlite/, alongside GetGitStats/GetRepositoryStats) returning, per session id:

• lines_added_committed = SUM(insertions) over task_session_commits.
• lines_deleted_committed = SUM(deletions).
• lines_added_peak_pending = MAX over each snapshot's SUM(json_extract(json_each(files).value,'$.additions')) from task_session_git_snapshots (peak, not latest — the latest is usually a clean tree).
• lines_deleted_peak_pending = the deletions equivalent.

Mirror the SQL in the agent-stats plugin (/home/jcfs/.kandev/tasks/tokens-per-task-loc_9tk/kandev-plugin-agent-stats/server/stats.go, sessionsQuery). Use internal/db/dialect helpers (JSONExtract, etc.) so the query is portable to Postgres. Support filtering by a session-id set and/or workspace, plus a limit/offset (or cursor bound) for pagination. Expose it via a service method so the Host handler (task-04) calls the service, not the repository.

Acceptance

• New repository + service method returns per-session committed sums and the peak-pending MAX semantics, filterable by session ids / workspace.
• Peak-pending uses the peak snapshot, not the latest, and does not double-count committed work (matches effectiveLines intent in the source plugin).
• Table-driven SQLite test with commits + multiple snapshots asserts both.

Verification

• cd apps/backend && go test ./internal/analytics/...

Files likely touched

• apps/backend/internal/analytics/repository/sqlite/stats.go
• apps/backend/internal/analytics/models/ (new SessionCodeStats model)
• analytics service file exposing the method
• apps/backend/internal/analytics/repository/sqlite/*_test.go

Inputs

• Source SQL: agent-stats server/stats.go sessionsQuery (committed sums + snapshot peak).
• Patterns: GetGitStats / buildRepositoryStatsQuery in internal/analytics/repository/sqlite/stats.go; dialect helpers.
• Spec: "Host data API" → ListSessionCodeStats row.

Dependencies

None. Independent of the proto task (pure Go/SQL).

Output contract

Summary, method signatures added, chosen home (analytics vs task repo), test result, portability notes (SQLite/Postgres), and status update here + in plan.md.