compute gower distance without using method = "gower", given a dataset of mixed data

gower_dist <- function(data) {
     
     # gower_dist <- function() {
        df <- data
        num_rows <- nrow(df)
        num_cols <- ncol(df)
        dist <- matrix(0, nrow=num_rows, ncol=num_rows)
        for (i in 1:num_cols) {
            if (is.numeric(df[,i])) {
                dist <- dist + ((df[,i]-t(df[,i]))^2)/var(df[,i])
            } else if (is.ordered(df[,i]) || is.factor(df[,i])) {
                dist <- dist + (abs(df[,i]-t(df[,i])))/(max(df[,i],na.rm = TRUE)-min(df[,i],na.rm = TRUE))
            } else {
                dist <- dist + (df[,i] != t(df[,i]))
            }
        }
        return (dist)