#!/bin/sh

set -e

. /usr/share/debconf/confmodule

hasEc2Md() {
    local d=/var/lib/cloud i=/var/lib/cloud/instance/ f=""
    local flist="${i}/datasource ${i}/obj.pkl ${d}/cache/obj.pkl"
    # search current instance data source information
    for f in ${flist}; do
        [ -f "${f}" ] || continue
        grep -q DataSourceEc2 "${f}" 2>/dev/null && return 0
    done


    # there was no data above found that would have been indicated
    # by a upgrade. lets just see if we can't find the metadata
    # service.  if wget is not present (it is not 'essential')
    # then we will quietly return 1
    local url="http://169.254.169.254/2009-04-04/meta-data/instance-id"
    i=""
    if command -v wget >/dev/null 2>&1; then
        local tout="--connect-timeout 5 --read-timeout 5 --tries 1"
        i=$(wget "${url}" ${tout} -O - 2>/dev/null) || :
    elif command -v curl >/dev/null 2>&1; then
        i=$(curl "${url}" --max-time 1) || :
    fi
    # if instance-id starts with 'i-' then in all likelyhood its good
    [ "${i#i-}" != "${i}" ] && return 0
    return 1
}

get_yaml_list() {
    # get_yaml_list(file, key, def): return a comma delimited list with the value
    # for the yaml array defined in 'key' from 'file'. if not found , return 'def'
    # only really supports 'key: [ en1, en2 ]' or 'key: [en1, en2]' formats.
    local file="$1" key="$2" default="$3"
    [ -f "$file" ] || return 1
    # strip all whitespace, delete lines not matching key:,
    # strip key: and [] and replace ',' with ', '
    RET="$(sed -e "s/\s//g" -e "/^$key:/"'!'d \
               -e "s/$key:\[//" -e "s/]//" -e "s/,/, /g" "$file")"
    [ -n "$RET" ] || RET="$default"
}

# old_dpkg_cfg is very old file that is no longer read by cloud-init.
# it gets re-named to cloud.cfg.d/90_dpkg.cfg in the preinst.
dpkg_cfg="/etc/cloud/cloud.cfg.d/90_dpkg.cfg"
old_dpkg_cfg="/etc/cloud/distro.cfg"
if [ -f "${old_dpkg_cfg}" -a ! -f "$dpkg_cfg" ]; then
    dpkg_cfg="${old_dpkg_cfg}"
   echo "WARN: reading value from ${old_dpkg_cfg}" 1>&2
fi
if [ -f "$dpkg_cfg" ]; then
    if get_yaml_list "$dpkg_cfg" datasource_list NOTFOUND &&
        val="$RET" && [ "$val" != "NOTFOUND" ]; then
        db_set cloud-init/datasources $val
    else
        echo "WARN: failed to read datasource_list from $dpkg_cfg" 1>&2
    fi
elif { db_fget cloud-init/datasources seen || : ; } &&
        [ "${RET}" = "false" ]; then
    # this is the first time this we've run (installation or re-install after
    # purge). try to determine if the Ec2 datasource is there.
    # if it is, and Ec2 was not in the default list, then add it.
    db_get cloud-init/datasources
    def="${RET}"
    case " ${def}," in
        *\ Ec2,*) :;;
        *) hasEc2Md &&
            db_set cloud-init/datasources "${def:+${def}, }Ec2";;
    esac
fi

db_input low cloud-init/datasources || true
db_go

exit 0