As far as you know your partner has only 4 hearts, you do not have a fit, and you cannot bid spades. You only have 12 HCPs so 1NT.
You could bid 2D as you have 6 of them but you have 19 HCPs and 2D is a limiting bid. You want to continue bidding so 'lie in a minor' and bid 2C.
Your partner has jumped and repeated the suit so has 6 clubs and 16+ HCPs, but cannot support your hearts and has denied having spades. You cannot support clubs, but you have the other 3 suits so bid 3NT