#!/bin/sh

set -e
set -x

AUTHORITY=certidude.@authority[0]

# TODO: iterate over all authorities

GATEWAY=$(uci get $AUTHORITY.gateway)
COMMON_NAME=$(uci get system.@system[0].hostname)

DIR=/etc/certidude/authority/$(uci get $AUTHORITY.hostname)
mkdir -p $DIR

AUTHORITY_PATH=$DIR/ca_cert.pem
CERTIFICATE_PATH=$DIR/host_cert.pem
REQUEST_PATH=$DIR/host_req.pem
KEY_PATH=$DIR/host_key.pem
KEY_TYPE=$(uci get $AUTHORITY.key_type)
KEY_LENGTH=$(uci get $AUTHORITY.key_length)
KEY_CURVE=$(uci get $AUTHORITY.key_curve)

NTP_SERVERS=$(uci get system.ntp.server)

logger -t certidude -s "Fetching time from NTP servers: $NTP_SERVERS"
ntpd -q -n -d -p $NTP_SERVERS

logger -t certidude -s "Time is now: $(date)"

# If certificate file is there assume everything's set up
if [ -f $CERTIFICATE_PATH ]; then
    SERIAL=$(openssl x509 -in $CERTIFICATE_PATH -noout -serial | cut -d "=" -f 2 | tr [A-F] [a-f])
    logger -t certidude -s "Certificate with serial $SERIAL already exists in $CERTIFICATE_PATH, attempting to bring up VPN tunnel..."
    exit 0
fi


#########################################
### Generate private key if necessary ###
#########################################

if [ ! -f $KEY_PATH ]; then
    case $KEY_TYPE in
        rsa)
            logger -t certidude -s "Generating $KEY_LENGTH-bit RSA key..."
            openssl genrsa -out $KEY_PATH.part $KEY_LENGTH
            openssl rsa -in $KEY_PATH.part -noout
            ;;
        ec)
            logger -t certidude -s "Generating $KEY_CURVE ECDSA key..."
            openssl ecparam -name $KEY_CURVE -genkey -noout -out $KEY_PATH.part
            ;;
        *)
            logger -t certidude -s "Unsupported key type $KEY_TYPE"
            exit 255
            ;;
    esac
    mv $KEY_PATH.part $KEY_PATH
fi


############################
### Fetch CA certificate ###
############################

if [ ! -f $AUTHORITY_PATH ]; then

    logger -t certidude -s "Fetching CA certificate from $URL/api/certificate/"
    curl -f -s http://$(uci get $AUTHORITY.hostname)/api/certificate/ -o $AUTHORITY_PATH.part
    if [ $? -ne 0 ]; then
        logger -t certidude -s "Failed to receive CA certificate, server responded: $(cat $AUTHORITY_PATH.part)"
        exit 10
    fi

    openssl x509 -in $AUTHORITY_PATH.part -noout
    if [ $? -ne 0 ]; then
        logger -t certidude -s "Received invalid CA certificate"
        exit 11
    fi

    mv $AUTHORITY_PATH.part $AUTHORITY_PATH
fi

logger -t certidude -s "CA certificate md5sum: $(md5sum -b $AUTHORITY_PATH)"


#####################################
### Generate request if necessary ###
#####################################

if [ ! -f $REQUEST_PATH ]; then
    openssl req -new -sha256 -key $KEY_PATH -out $REQUEST_PATH.part -subj "/CN=$COMMON_NAME"
    mv $REQUEST_PATH.part $REQUEST_PATH
fi

logger -t certidude -s "Request md5sum is $(md5sum -b $REQUEST_PATH)"

curl -f -L \
    -H "Content-Type: application/pkcs10" \
    --cacert $AUTHORITY_PATH \
    --data-binary @$REQUEST_PATH \
    https://$(uci get $AUTHORITY.hostname):8443/api/request/?autosign=true\&wait=yes -o $CERTIFICATE_PATH.part

# TODO: Loop until we get exitcode 0
# TODO: Use backoff time $((2\*X))

if [ $? -ne 0 ]; then
    echo "Failed to fetch certificate"
    exit 21
fi

# Verify certificate
openssl verify -CAfile $AUTHORITY_PATH $CERTIFICATE_PATH.part

if [ $? -ne 0 ]; then
    logger -t certidude -s "Received bogus certificate!"
    exit 22
fi

logger -t certidude -s "Certificate md5sum: $(md5sum -b $CERTIFICATE_PATH.part)"

uci commit

echo $AUTHORITY_PATH >> /etc/sysupgrade.conf
echo $CERTIFICATE_PATH >> /etc/sysupgrade.conf
echo $KEY_PATH >> /etc/sysupgrade.conf
echo $REQUEST_PATH >> /etc/sysupgrade.conf

mv $CERTIFICATE_PATH.part $CERTIFICATE_PATH

# Start services
logger -t certidude -s "Starting IPSec IKEv2 daemon..."
/etc/init.d/ipsec enable
/etc/init.d/ipsec restart
