Add legends using conditionals - ggplot2

[avelar.a.o]

Hello,

I'm writing a function and inside this function I need to generate a plot, using ggplot2. The user has the option to highlight specific points of this plot, e.g the top or bottom 10% and also some specific points (controls).
I'm struggling to add a legend to this plot, since it is conditional to the parameters specified by the users. I would like a legend that specifie: top = green, bottom = red and controls = blue.
Do you have any idea about it?
Please, see a sample of my codes and data bellow.

Thanks in advance.

res <- data.frame(genotype = c("a","c","b","d"), superiority = c(1.35,2.45,5.73,7.14),mean =  c(7.33,7.24,7.28,7.54))
plot = TRUE
top = TRUE
bottom =TRUE
controls = "c"
percentage = 10


if(plot == TRUE){
  (p <- ggplot(res, aes(x=mean, y=superiority), label = genotype) +
     geom_point(colour ="black") )
  if(top == TRUE){
    p <- p + geom_point(data = head(res, ceiling((percentage*nrow(res))/100)), aes(x=mean, y=superiority),
                        colour = "green") + 
      geom_label_repel(data = head(res, ceiling((percentage*nrow(res))/100)),
                       aes(label = head(res, ceiling((10*nrow(res))/100))$genotype))
    }
  if(bottom == TRUE){
    p <- p + geom_point(data =  tail(res, ceiling((percentage*nrow(res))/100)), aes(x=mean, y=superiority),
                        colour = "red") + 
      geom_label_repel(data = tail(res, ceiling((percentage*nrow(res))/100)), 
                       aes(label = tail(res, ceiling((10*nrow(res))/100))$genotype))
    }
  if(!is.null(controls)){   
    p <- p + geom_point(data = res[res$genotype== controls,],aes(x=mean, y=superiority), 
                        colour = "blue")  +
      geom_label_repel(data = res[res$genotype== controls,], 
                       aes(label = res$genotype[res$genotype== controls]))
    }
  p <- p + labs(y = "Superiority")
}
p

[nirgrahamuk]

I think to be in a legend the colour has to be an aes/aesthetic
then a scale manual at the end sets the colour rules

  (p <- ggplot(res, aes(x=mean, y=superiority), label = genotype) +
     geom_point(colour ="black") )
  if(top == TRUE){
    p <- p + geom_point(data = head(res, ceiling((percentage*nrow(res))/100)), 
                        aes(x=mean, y=superiority, colour = "top")) + 
      geom_label_repel(data = head(res, ceiling((percentage*nrow(res))/100)),
                       aes(label = head(res, ceiling((10*nrow(res))/100))$genotype))
  }
  if(bottom == TRUE){
    p <- p + geom_point(data =  tail(res, ceiling((percentage*nrow(res))/100)),
                        aes(x=mean, y=superiority,colour="bottom")) + 
      geom_label_repel(data = tail(res, ceiling((percentage*nrow(res))/100)), 
                       aes(label = tail(res, ceiling((10*nrow(res))/100))$genotype))
  }
  if(!is.null(controls)){   
    p <- p + geom_point(data = res[res$genotype== controls,],
                        aes(x=mean, y=superiority, colour="controls" 
                       ))  
      geom_label_repel(data = res[res$genotype== controls,], 
                       aes(label = res$genotype[res$genotype== controls]))
  }
  p <- p + labs(y = "Superiority") +
    scale_color_manual(values=c("top"="green","bottom"="red","controls"="blue"))