OMA 2020 Problem 3

Let $ABC$ be a right isosceles triangle with right angle at $A$ . Let $E$ and $F$ be points on A $B$ and $AC$ respectively such that $\angle ECB = 30^o$ and $\angle FBC = 15^o$ . Lines $CE$ and $BF$ intersect at $P$ and line $AP$ intersects side $BC$ at $D$ . Calculate the measure of angle $\angle FDC$ .