-- Plex's addedAt tracks the FILE, not the library entry. Replacing or
-- re-encoding a file resets Date Added while the item and its watch history
-- survive, so 19% of the live library (22% of TV Show Archive) reports a
-- lastViewedAt EARLIER than its addedAt — watched before it was "added".
--
-- That matters beyond cosmetics: pre_history is derived from added_at, so an
-- old item whose file was replaced looks post-coverage and lands in the
-- CONFIDENT reclaim pool when it belongs in the uncertain one.
--
-- Keep Plex's raw value for reference, and let added_at hold the best estimate
-- (see ingest._correct_added_at). Also record when MediaShelf itself first saw
-- a row, which is authoritative from now on regardless of what Plex does.

ALTER TABLE media_item ADD COLUMN provider_added_at INTEGER;
ALTER TABLE media_item ADD COLUMN added_at_source TEXT;
ALTER TABLE media_item ADD COLUMN first_seen_at INTEGER;

ALTER TABLE episode ADD COLUMN provider_added_at INTEGER;
ALTER TABLE episode ADD COLUMN first_watched_at INTEGER;
ALTER TABLE episode ADD COLUMN first_seen_at INTEGER;

-- Backfill: existing rows carry Plex's value in added_at.
UPDATE media_item SET provider_added_at = added_at WHERE provider_added_at IS NULL;
UPDATE episode SET provider_added_at = added_at WHERE provider_added_at IS NULL;

CREATE INDEX ix_item_first_seen ON media_item(first_seen_at);