-- Migration 002 — Phase 3. Telemetry reports arrive over MQTT and repeat.
--
-- A device reports a rolling daily total ("Spotify: 600 s today"), not a delta,
-- so one row per (device, day, app, domain) is the correct shape: a repeat
-- report replaces the previous total instead of adding to it. Devices may omit
-- the app or the domain, so both default to '' — SQLite treats NULLs in a
-- UNIQUE index as distinct, which would defeat the upsert.

UPDATE telemetry SET app = '' WHERE app IS NULL;
UPDATE telemetry SET domain = '' WHERE domain IS NULL;

CREATE UNIQUE INDEX IF NOT EXISTS idx_telemetry_daily
    ON telemetry(device_id, day, app, domain);