To generate csv from text inputs

filter.awk

#!/usr/bin/awk -f
    BEGIN{
        RS="\.\s* \[[0-9]+\]";
        FS="\n";
        OFS=",";
    }

    function find_next_field_until_regex(regex, i, result){
        result = "";
        for (; i < NF; i++){
            field = $i
            sub(/,/, "\,", field);
            sub(/^[ \t]*/, "", field);
            if (field ~ regex){
                break;
            }
            result = result field;
        }
        printf("%s%s", result, OFS);
        return i;
    }

    {
        if(NF>1){
            sub(/,/, "\,", $1);
            printf("%s%s", $1, OFS);
            i = 2;
            i = find_next_field_until_regex("^[0-9]+", i); #discription
            i = find_next_field_until_regex("^ph: ", i); #address
            i = find_next_field_until_regex("www\\.", i); #phone
            for (; i < NF; ++i){
                printf("%s", $i);
            }
        }
        printf("\n");
    }
skyscribe@skyscribe-ubuntu:~/study/awk$ 
skyscribe@skyscribe-ubuntu:~/study/awk$ vim filter.awk 
skyscribe@skyscribe-ubuntu:~/study/awk$ cat filter.awk 
#!/usr/bin/awk -f
BEGIN{
    RS="\.\s* \[[0-9]+\]";
    FS="\n";
    OFS=",";
}

function find_next_field_until_regex(regex, i, result){
    result = "";
    for (; i < NF; i++){
        field = $i
        sub(/,/, "\,", field);
        sub(/^[ \t]*/, "", field);
        if (field ~ regex){
            break;
        }
        result = result field;
    }
    printf("%s%s", result, OFS);
    return i;
}

{
    if(NF>1){
        sub(/,/, "\,", $1);
        printf("%s%s", $1, OFS);
        i = 2;
        i = find_next_field_until_regex("^[0-9]+", i); #discription
        i = find_next_field_until_regex("^ph: ", i); #address
        i = find_next_field_until_regex("www\\.", i); #phone
        for (; i < NF; ++i){
            printf("%s", $i);
        }
    }
    printf("\n");
}

test.txt

    . [135]Edwards Engineering Pty Ltd
       Quality Structural Steel. Specialising In Fabrication And Steel
       Stairs
       21- 23 Ada Ave, Brookvale NSW 2100
       ph: (02) 9938 5320

 . [269]Diavolo Steel Fabrication
       5 Humeside Drv, Campbellfield VIC 3061
       ph: (03) 9357 7947


       . [40]WH Williams Pty Ltd
       Your Partner For High Quality Custom-Made Metal Products
       Short lead times & unbeatable quality. Make us the first choice for
       your entire sheetmetal laser cutting,bending,welding & more.
       61- 77 Egerton St, Silverwater NSW 2128
       ph: (02) 9647 1277
            [41]www.whwilliams.com.au