#!/usr/bin/env ruby
# -*- ruby -*-
# Script to smartly chop off portions of the current working directory for
# use in the shell prompt

# Constants used to decide when to start chopping
DIRLIM = 5
DIR_L = 3
DIR_R = 2
PWDLEN = 14

def smartwd
    username = ENV['USER']
    homedir = ENV['HOME']
    pwd = ENV['PWD']

    path = pwd.split('/')

    # Ignore the root path
    if (path.length > 0)
        index = path.index(username)
        if index
            prefix = path.shift(index + 1)
            
            # We need to map additional paths in environments where the user
            # may have more than one available folder in his/her name.
            if prefix.join('/') == homedir
                path.unshift('~')
            else
                # The first entry in the prefix array is the empty string
                pre = prefix[1].split('').shift(4).join('') + '~'
                path.unshift(pre)
            end
        else
            # Replace the first two entries in the array with /<entry1>
            # (because the first entry is always empty string)
            prefix = path.shift(2).join('/')
            path.unshift(prefix)
        end

        # Check to make sure that both the DIRLIM and PWDLEN constraints
        # are met before splitting
        pwd = path.join('/')
        if path.length > DIRLIM and pwd.length > PWDLEN
            pwd_l = path.shift(DIR_L).join('/')
            pwd_r = path.pop(DIR_R).join('/')
            pwd = pwd_l + '/.../' + pwd_r
        end
    end

    print pwd
end

smartwd