#!/usr/bin/env -S bash

API_BASE_URL=https://labmanager-api.edu-al.unipmn.it/api/1.0
MAX_RETRY=5
RETRY_DELAY=5
NORMAL_CONFIG_NAME=normale
DEBUG=0

# Sysadmin can override local vars here:
CONFFILE=/etc/default/labmanager

#  Load configuration override if present:
if [ -e ${CONFFILE} ]; then
    . ${CONFFILE}
fi

if [[ "-d" == "$2" ]]; then
    DEBUG=1
fi

# execute a task and on fail execute it again MAX_RETRY times every RETRY_DELAY seconds
retry() {
    local n=1
    local max=$MAX_RETRY
    local delay=$RETRY_DELAY
    while true; do
        "$@"
        ret=$?
        if [[ $ret == 0 ]]; then
            return $ret
        else
            if [[ $n -lt $max ]]; then
                ((n++))
                echo "Failed. Attempt $n/$max..." >&2
                sleep $delay;
            else
                echo "Command failed after $n attempts." >&2
                return $ret
            fi
        fi
    done
}

debug() {
    if [[ "${DEBUG}" == 1 ]]; then
        echo >&2 "$@"
    fi
}

# authenticate and get the token
getTokenJSON() {
    # store the whole response with the status at the end
    HTTP_RESPONSE=$(curl -s -k -w "HTTPSTATUS:%{http_code}" --max-time 10 -X POST -H "Content-Type: application/json" -d "{\"login\":\"guest\",\"pwd\":\"\"}" ${API_BASE_URL}/login)
    ret=$?

    if [[ $ret -ne 0 ]]; then
        return $ret
    fi

    # extract the status
    HTTP_STATUS=$(echo "$HTTP_RESPONSE" | tr -d '\n' | sed -e 's/.*HTTPSTATUS://')

    # check the status
    if [[ $HTTP_STATUS -ne 200  ]]; then
        return 1
    else
        # extract the body
        HTTP_BODY=$(echo "$HTTP_RESPONSE" | sed -e 's/HTTPSTATUS\:.*//g')
        echo $HTTP_BODY
    fi
}


# extract a value from a JSON structure
jsonValue() {
    KEY=$1
    num=$2
    awk -F"[,:}]" '{for(i=1;i<=NF;i++){if($i~/\042'$KEY'\042/){print $(i+1)}}}' | tr -d '"' | sed -n ${num}p
}


stop() {
    if [[ "$1" == "bootstop" ]]; then
        echo "STOP esame-get-config-boot"
    else
        echo "STOP esame-get-config"
    fi
}


# get configuration from WS
getConfigVars() {
    echo "Authenticating to WS..."
    TOKEN_JSON=`retry getTokenJSON`
    if [[ "$TOKEN_JSON" == "" ]]; then
        echo "Authentication failed!"
        return 2
    fi
    TOKEN=`echo ${TOKEN_JSON} | jsonValue token 1`
    MACHINE_NAME=`hostname`
    echo "Getting machine configuration..."
    MACHINE_JSON=`retry /usr/bin/curl -s -k --max-time 10 -H "Authorization: Bearer ${TOKEN}" -X GET ${API_BASE_URL}/machines/name/${MACHINE_NAME}`
    MACHINE_ID=`echo $MACHINE_JSON | jsonValue id 1`
    MACHINE_CONFIGS_ID=`echo $MACHINE_JSON | jsonValue configs_id 1`
    CONFIG_NAME=`echo $MACHINE_JSON | jsonValue name 2`
    EXAM_ID=`echo $MACHINE_JSON | jsonValue examid 1`

    # web service returns "null" if there is no exam
    # just set an empty string as value
    if [[ "${EXAM_ID}" == "null" ]]; then
        EXAM_ID=""
    fi

    if [[ "${CONFIG_NAME}" == "" ]]; then
        echo "Error fetching machine configuration!"
        return 1
    fi

    MACHINE_CONFIGS_ID_PREV=''
    CONFIG_NAME_PREV=''
    if [[ -e /local/config_name ]]
    then
        CONFIG_NAME_PREV=`cat /local/config_name`
    fi
}


getConfigFile() {
    echo "Downloading machine config file..."
    # get configuration file
    if [[ "${MACHINE_ID}" == "" ]]; then
        echo "Error downloading config file (machine_id empty, maybe it is not in LabManager's DB)"
        return 1
    fi
    retry /usr/bin/curl -s -k -o /local/esame-machine.conf --max-time 10 --header "Authorization: Bearer ${TOKEN}" -X GET ${API_BASE_URL}/machines/${MACHINE_ID}/configfile
    ret=$?
    if [[ $ret -ne 0 ]]; then
        echo "Error downloading config file (ret=$ret)"
        return 1
    else
        echo "Downloaded config file (ret=$ret)"
    fi
}


getIpConfigFile() {
    echo "Downloading machine iptables config file..."
    # get ipconfig file
    retry /usr/bin/curl -s -k -o /local/iptables --max-time 10 --header "Authorization: Bearer ${TOKEN}" -X GET ${API_BASE_URL}/machines/${MACHINE_ID}/ipconfigfile
    ret=$?
    if [[ $ret -ne 0 ]]; then
        echo "Error downloading iptables config file (ret=$ret)"
        return 1
    else
        echo "Downloaded iptables config file (ret=$ret)"
    fi
}


updateCurrentConfigId() {
    # Update this machine's current config id
    HTTP_STATUS=`/usr/bin/curl -s -k -w "%{http_code}" -o /dev/null --max-time 10 -H "Content-Type: application/json" -H "Authorization: Bearer ${TOKEN}" \
        -X PUT -d "{\"current_configs_id\":\"$MACHINE_CONFIGS_ID\"}" ${API_BASE_URL}/machines/${MACHINE_ID}/currentconfig`

    if [[ $HTTP_STATUS -ne 200 ]]
    then
        echo "Error updating current config (http_status=$HTTP_STATUS)"
        exit 1
    else
        echo "Updated current config (http_status=$HTTP_STATUS)"
    fi
}

getConfig() {
    getConfigVars
    while [[ $? != 0 ]]; do
        echo "Error fetching machine info!"
        echo "If this is a new machine, did you add it into labmanager-admin?"
        # to repeat until successful, just comment next line
        return 1
        sleep 30
        getConfigVars
    done

    # back config files up
    cp -f /local/esame-machine.conf /local/esame-machine.conf.prev >/dev/null 2>&1
    cp -f /local/iptables /local/iptables.prev >/dev/null 2>&1

    getConfigFile
    if [[ $? != 0 ]]; then
        echo "Error fetching machine config file!"
        return 1
    fi

    getIpConfigFile
    if [[ $? != 0 ]]; then
        echo "Error fetching machine iptables file!"
        return 1
    fi
    return 0
}

start() {
    if [[ "$1" == "boot" ]]; then
        echo "START esame-get-config-boot"
    else
        echo "START esame-get-config"
    fi

    getConfig
    RESULT=$?

    #echo "TOKEN_JSON: $TOKEN_JSON"
    #echo "TOKEN: $TOKEN"
    #echo "MACHINE_NAME: $MACHINE_NAME"
    #echo "MACHINE_JSON: $MACHINE_JSON"
    #echo "MACHINE_ID: $MACHINE_ID"
    #echo "Exam ID: $EXAM_ID"
    #echo "MACHINE_CONFIGS_ID: $MACHINE_CONFIGS_ID"
    #echo "MACHINE_CONFIGS_ID_PREV: $MACHINE_CONFIGS_ID_PREV"

    # any error?
    if [[ $RESULT != 0 ]]; then
        if [[ "$1" == "boot" ]]; then
            echo "Fatal error(s): aborting esame and switching machine to normal state..."
            # reset and remove exam configuration files
            echo "$NORMAL_CONFIG_NAME" > /local/config_name
            echo "" > /local/examid
            #rm /local/esame-machine.conf >/dev/null 2>&1
            #rm /local/esame-machine.conf.prev >/dev/null 2>&1
            rm /local/iptables >/dev/null 2>&1
            rm /local/iptables.prev >/dev/null 2>&1
            rm /local/mk-homedir >/dev/null 2>&1
            /usr/bin/systemctl start graphical.target && exit 0
        fi
        echo "Fatal error(s): missing or wrong web service reply, abort."
        exit 1
    fi

    # extract systemd target name from configuration file
    # default target on error/empty target
    ESAME_TARGET="graphical"
    RES_TARGET=`awk -F= -v key="ESAME_TARGET" '$1==key {print $2}' /local/esame-machine.conf | sed "s/\"//g"`
    if [[ "${RES_TARGET}" != "" ]]; then
        ESAME_TARGET=${RES_TARGET}
    fi

    # extract ESAME_USBGUARD from configuration file
    ESAME_USB_GUARD=0
    RES_USB_GUARD=`awk -F= -v key="ESAME_USB_GUARD" '$1==key {print $2}' /local/esame-machine.conf | sed "s/\"//g"`
    if [[ "${RES_USB_GUARD}" != "" ]]; then
        ESAME_USB_GUARD=${RES_USB_GUARD}
    fi


    # extract ESAME_AMQP from configuration file
    ESAME_AMQP=0
    RES_AMQP=`awk -F= -v key="ESAME_AMQP" '$1==key {print $2}' /local/esame-machine.conf | sed "s/\"//g"`
    if [[ "${RES_AMQP}" != "" ]]; then
        ESAME_AMQP=${RES_AMQP}
    fi

    if [[ -n "${CONFIG_NAME}" ]]; then
        echo "Configuration: ${CONFIG_NAME}"
        if [ "${EXAM_ID}" != "" ]; then
            echo "Exam ID: ${EXAM_ID}"
        fi
        if [ "${ESAME_TARGET}" != "" ]; then
            echo "Systemd Target: ${ESAME_TARGET}"
        fi
    fi

    # the PC is already up and running
    if [[ "$1" != "boot" ]]; then
        # get current examid (if any)
        EXAM_ID_CURRENT=""
        if [[ -f /local/examid ]]; then
            EXAM_ID_CURRENT=`cat /local/examid`
        fi
        # different examid?
        if [[ "${EXAM_ID}" != "${EXAM_ID_CURRENT}" ]]; then
            # reboot => normal
            if [[ "${EXAM_ID}" == "" ]]; then
                echo "Reboot to Normal!"
            # reboot => exam
            else
                echo "Reboot to Exam (exam id: ${EXAM_ID})"
            fi
            /usr/bin/systemctl reboot
        fi
    else
        # at boot time
        # update config_name file
        echo "${CONFIG_NAME}" > /local/config_name

        # no exam
        # if [[ "$CONFIG_NAME" == "$NORMAL_CONFIG_NAME" ]]; then
        if [[ "${EXAM_ID}" == "" ]]; then
            # remove some files used by exam mode
            #rm /local/esame-machine.conf >/dev/null 2>&1
            #rm /local/esame-machine.conf.prev >/dev/null 2>&1
            rm /local/iptables >/dev/null 2>&1
            rm /local/iptables.prev >/dev/null 2>&1
            rm /local/mk-homedir >/dev/null 2>&1
            rm /local/usbguard >/dev/null 2>&1
            # this is just cleaned up
            echo "" > /local/examid
        else
            # if the examid of the session before the boot is different,
            # then clean the exam user home (if the profile requires it)
            EXAM_ID_PREV=""
            # if the exam is already started, get examid from file
            if [[ -f /local/examid ]]; then
                EXAM_ID_PREV=`cat /local/examid`
            fi

            # different examid?
            if [[ "${EXAM_ID}" != "${EXAM_ID_PREV}" ]]; then
                # update the file with the current examid
                echo "${EXAM_ID}" > /local/examid
                # clean home dir if requested by the profile
                touch /local/mk-homedir
            fi

            if [[ ${ESAME_USB_GUARD} == 1 ]]; then
                touch /local/usbguard
            else
                rm /local/usbguard >/dev/null 2>&1
            fi
        fi

        # if we use AMQP server, just disable esame-get-config.timer
        if [[ ${ESAME_AMQP} == 1 ]]; then
            systemctl disable esame-get-config.timer
            systemctl stop esame-get-config.timer
        # otherwise, enable it
        else
            systemctl enable esame-get-config.timer
            systemctl start esame-get-config.timer
        fi

        # choose the correct target
        # we have just booted/rebooted, update the current configuration via web service
        updateCurrentConfigId

        systemctl start ${ESAME_TARGET}.target && exit 0

        # case "$CONFIG_NAME" in
        #     $NORMAL_CONFIG_NAME) # normal
        #         systemctl start graphical.target && exit 0
        #         ;;
        #     'kiosk-dir' | 'kiosk-dir-esami' | 'kiosk-escher' | 'kiosk-freebrowsing' | 'kiosk-teco') # kiosk mode
        #         systemctl start esamekiosk.target && exit 0
        #         ;;
        #     'show') # show mode, an exam mode with no limitations on USB ports and network
        #         systemctl start esameshow.target && exit 0
        #         ;;
        #     *) # all full desktop exams
        #         systemctl start esame.target && exit 0
        #         ;;
        # esac
    fi


    # Runtime parameters
    if [[ "$CONFIG_NAME" != "$NORMAL_CONFIG_NAME" ]]; then
        # check if parameters are changed
        cmp --silent /local/esame-machine.conf /local/esame-machine.conf.prev
        if [[ $? -ne 0 ]]; then
            /usr/bin/systemctl daemon-reload
            echo "Configuration parameters changed: restart some services... "
            # restart some exam services
            #echo -n "USB..."
            #/usr/bin/systemctl restart esame-usb
            #echo " done."
            KIOSK_URL_CHANGED=$(diff /local/esame-machine.conf /local/esame-machine.conf.prev  | grep ESAME_KIOSK_URL -c)
            if [[ $KIOSK_URL_CHANGED -ne 0 ]]; then
                echo -n "Firefox Home..."
                FIREFOX_PID=$(pgrep firefox)
                if [[ "${FIREFOX_PID}" != "" ]]; then
                    FIREFOX_USER=$(ps -o user= -p ${FIREFOX_PID})
                    rm -f /local/${FIREFOX_USER}/.mozilla/firefox/n3bac2sw.default-release/lock
                    pkill firefox
                    sleep 2
                    /usr/bin/systemctl restart esame-firefox-home
                    echo " done."
                    # no way to restart firefox, I must miss something :(
                    #echo -n "Restarting Firefox..."
                    #su - ${FIREFOX_USER} -c 'nohup /usr/bin/firefox --display=:0.0 &'
                    #echo " done."
                else
                    /usr/bin/systemctl restart esame-firefox-home
                    echo " done."
                fi
            fi

            # USBGuard
            if [[ ${ESAME_USB_GUARD} == 1 ]]; then
                touch /local/usbguard
                /usr/bin/systemctl restart usbguard
            else
                rm /local/usbguard >/dev/null 2>&1
                # this one will not work anyway, as it is applied by kernel,
                # so it needs a reboot
                /usr/bin/systemctl stop usbguard
            fi
            echo
            echo "All done."
        fi
    fi
}


args=("$@")

case "$1" in
'bootstart')
    start "boot"
    ;;
'bootstop')
    stop "boot"
    ;;
'start')
    start
    ;;
'stop')
    stop
    ;;
'restart')
    stop
    start
    ;;
*)
    echo "Usage: $0 { bootstart | bootstop | start | stop | restart }";
    exit 1;
    ;;
esac
exit 0