how can get the value of a multi value field and add some thing to it in script runner

[sahere]

hi all,

I am using scriptrunner to send sms, i have a multi value filed as following which can select multiple values:

for each value of the field 1 there is another multi value field as following:

for example if c1 and c2 have been selected; and in c1, A1 and A3 selected; and in c2, B2 and B3 selected; I want to send the value of the selected fields as following in the "fields" part of SMS message:

c1:A1,A3-c2:B2,B3

how can i do this in following script:

import groovyx.net.http.RESTClient
import groovyx.net.http.HTTPBuilder
import static groovyx.net.http.Method.*
import static groovyx.net.http.ContentType.*
import groovyx.net.http.ContentType
import org.apache.http.HttpRequest
import groovy.json.JsonBuilder
import org.apache.http.HttpRequestInterceptor
import org.apache.http.protocol.HttpContext
import com.atlassian.jira.issue.MutableIssue
import com.atlassian.jira.component.ComponentAccessor;
import com.atlassian.jira.ComponentManager;
import com.atlassian.jira.issue.CustomFieldManager;
import com.atlassian.jira.issue.fields.CustomField;
import com.atlassian.jira.issue.IssueManager;
import com.atlassian.jira.issue.Issue
import groovy.json.JsonSlurper

MutableIssue issue = issue as MutableIssue

def s1=(issue.summary)?.replaceAll(' ','%20')

def s4=(issue.description)?.replaceAll(' ','%20')

def bvField =ComponentAccessor.getCustomFieldManager().getCustomFieldObjectByName("Field 1")
def s2 = ((String)(issue.getCustomFieldValue(bvField)))?.replaceAll(' ','%20')

def http = new HTTPBuilder("...&message=subject:${s1}+fields:${s2}+description:${s4}")
http.request( groovyx.net.http.Method.POST) {
}

any advice will be so appreciated