How can I extract the angle from a function that determines if a circle is colliding with a line? - math

Question

So I have the following code that works fine
I've taken it from https://codereview.stackexchange.com/questions/192477/circle-line-segment-collision
I am now trying to figure out where along this function I can determine the angle in which the circle is hitting the line. Instead of returning true I'd like it to return the angle, since I didn't write the function myself going through it to try and figure this out myself has been a bit of a struggle. Wondering if someone excellent at math can help me figure this out at first glance. Thank you!
// Function to check intercept of line seg and circle
// A,B end points of line segment
// C center of circle
// radius of circle
// returns true if touching or crossing else false
function doesLineInterceptCircle(A, B, C, radius) {
var dist;
const v1x = B.x - A.x;
const v1y = B.y - A.y;
const v2x = C.x - A.x;
const v2y = C.y - A.y;
// get the unit distance along the line of the closest point to
// circle center
const u = (v2x * v1x + v2y * v1y) / (v1y * v1y + v1x * v1x);
// if the point is on the line segment get the distance squared
// from that point to the circle center
if(u >= 0 && u <= 1){
dist = (A.x + v1x * u - C.x) ** 2 + (A.y + v1y * u - C.y) ** 2;
} else {
// if closest point not on the line segment
// use the unit distance to determine which end is closest
// and get dist square to circle
dist = u < 0 ?
(A.x - C.x) ** 2 + (A.y - C.y) ** 2 :
(B.x - C.x) ** 2 + (B.y - C.y) ** 2;
}
return dist < radius * radius;
}