Question: How to draw phase portrait of an ODE?

How to draw a phase portrait of (2) same as in the attached figure? I tried it by using dsolve, but couldn't redraw it.  

> 

restart

> 

with(DEtools); with(plots)

> 

alias(phi = phi(xi))

phi

(1)
> 

eq := (1/2)*m*(diff(phi, xi))^2+`Φ__∓` = h

(1/2)*m*(diff(phi, xi))^2+`Φ__∓` = h

(2)
> 

NULL

> 

`Φ__∓` = `&-+`(1-cos(phi))

`Φ__∓` = `&-+`(1-cos(phi))

(3)

``

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