minstrel/internal/db/migrations/0057_songs_like_tuning.up.sql

-- 0057_songs_like_tuning.up.sql — a THIRD weight profile, for Songs-like.
--
-- Before: Songs-like shared the `daily_mix` profile with For-You. The two
-- surfaces want opposite things: For-You is a broad "what will they enjoy
-- today", Songs-like answers "what sounds like THIS" and should stay in one
-- neighbourhood of sound, and under one set of weights the broad answer wins.
--
-- Under the shared daily_mix weights, an UNRELATED track the user had liked
-- and not played recently scored 1.0 + 2.0 + 1.0 = 4.0 before taste, while a
-- PERFECT similarity match they had not liked scored 1.0 + 1.5 = 2.5. Liking
-- something outranked sounding like the seed. Splitting the profile is what
-- lets similarity dominate here without making For-You narrow.
--
-- Rows are seeded by the recsettings boot reconcile, not here, so shipped
-- defaults live in exactly one place (Go) — same as 0040.

-- Rule #36: a new value for a CHECK-gated column needs the constraint
-- rewritten in the SAME change, or the first row written under the new
-- profile fails at runtime rather than at migrate time.
ALTER TABLE recommendation_weight_profiles
    DROP CONSTRAINT recommendation_weight_profiles_profile_check;
ALTER TABLE recommendation_weight_profiles
    ADD CONSTRAINT recommendation_weight_profiles_profile_check
    CHECK (profile IN ('radio', 'daily_mix', 'songs_like'));

-- The audit table gates the same name on a separate constraint. Missing this
-- one would let the profile be seeded and then fail on the first knob turn —
-- green at boot, 500 on first use.
ALTER TABLE recommendation_tuning_audit
    DROP CONSTRAINT recommendation_tuning_audit_scope_check;
ALTER TABLE recommendation_tuning_audit
    ADD CONSTRAINT recommendation_tuning_audit_scope_check
    CHECK (scope IN ('radio', 'daily_mix', 'taste', 'discover', 'songs_like'));