#!/bin/sh

# Copyright (C) 2014-2015 Internet Systems Consortium, Inc. ("ISC")
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# This is kea-admin script that conducts administrative tasks on the Kea
# installation. Currently supported operations are:
#
# - lease database init
# - lease database version check
# - lease database version upgrade


# Get the location of the kea-admin scripts
prefix=/usr/local
SCRIPTS_DIR_DEFAULT=${prefix}/share/kea/scripts
scripts_dir=${SCRIPTS_DIR_DEFAULT}

# These are the default parameters. They will likely not work in any
# specific deployment.
db_user="keatest"
db_password="keatest"
db_name="keatest"

# lease dump parameters
dump_type=0
dump_file=""
dump_qry=""

# Include utilities. Use installed version if available and
# use build version if it isn't.
if [ -e ${prefix}/share/kea/scripts/admin-utils.sh ]; then
    . ${prefix}/share/kea/scripts/admin-utils.sh
else
    . /usr/obj/ports/kea-1.0.0/kea-1.0.0/src/bin/admin/admin-utils.sh
fi

# Prints out usage version.
usage() {
    printf "kea-admin 1.0.0\n"
    printf "\n"
    printf "This is a kea-admin script that conducts administrative tasks on\n"
    printf "the Kea installation.\n"
    printf "\n"
    printf "Usage: $0 COMMAND BACKEND [parameters]\n"
    printf "\n"
    printf "COMMAND: Currently supported operations are:\n"
    printf "\n"
    printf " - lease-init: Initalizes new lease database. Useful for first time installation.\n"
    printf " - lease-version: Checks version of the existing lease database scheme. Useful\n"
    printf " -                for checking lease DB version when preparing for an upgrade.\n"
    printf " - lease-upgrade: Upgrades your lease database scheme\n"
    printf " - lease-dump: Dump current leases to a CSV file\n"
    printf "\n"
    printf "BACKEND - one of the supported backends: memfile|mysql|pgsql\n"
    printf "\n"
    printf "PARAMETERS: Parameters are optional in general, but may be required\n"
    printf "            for specific operation.\n"
    printf " -u or --user name - specifies username when connecting to a database\n"
    printf " -p or --password pass - specifies a password when connecting to a database\n"
    printf " -n or --name database - specifies a database name to connect to\n"
    printf " -d or --directory - path to upgrade scripts (default: ${SCRIPTS_DIR_DEFAULT})\n"
    printf "\n"
    printf " Parameters specific to lease-dump:\n"
    printf "     -4 to dump IPv4 leases to file\n"
    printf "     -6 to dump IPv6 leases to file\n"
    printf "     -o or --output - name of file to which leases will be dumped\n"
}


### Logging functions ###

# Logs message at the error level.
# Takes one parameter that is printed as is.
log_error() {
    printf "ERROR/kea-admin: ${1}\n"
}

# Logs message at the warning level.
# Takes one parameter that is printed as is.
log_warning() {
    printf "WARNING/kea-admin: ${1}\n"
}

# Logs message at the info level.
# Takes one parameter that is printed as is.
log_info() {
    printf "INFO/kea-admin: ${1}\n"
}

### Convenience functions ###

# Checks if the value is in the list. An example usage of this function
# is to determine whether the kea-admin command belongs to the list of
# supported commands.
is_in_list() {
    local member=${1}  # Value to be checked
    local list="${2}"  # Comma separated list of items
    _inlist=0          # Return value: 0 if not in list, 1 otherwise.
    if [ -z ${member} ]; then
        log_error "missing ${class}"
    fi
    # Iterate over all items on the list and compare with the member.
    # If they match, return, otherwise log error and exit.
    for item in ${list}
    do
        if [ ${item} = ${member} ]; then
            _inlist=1
            return
        fi
    done
}


### Functions that implement database initialization commands

memfile_init() {
    # @todo Implement this as part of #3601
    log_error "NOT IMPLEMENTED"
    exit 1
}

# Initializes a new, empty MySQL database.
# It essentially calls scripts/mysql/dhcpdb_create.mysql script, with
# some extra sanity checks. It will refuse to use it if there are any
# existing tables. It's better safe than sorry.
mysql_init() {
    printf "Checking if there is a database initialized already. Please ignore errors.\n"

    # Let's try to count the number of tables. Anything above 0 means that there
    # is some database in place. If there is anything, we abort. Note that
    # mysql may spit out connection or access errors to stderr, we ignore those.
    # We should not hide them as they may give hints to user what is wrong with
    # his setup.
    #
    RESULT=`mysql_execute "SHOW TABLES;"`
    ERRCODE=$?
    if [ $ERRCODE -ne  0 ]
    then
        log_error "mysql_init table query failed, mysql status = $ERRCODE"
        exit 1
    fi

    COUNT=`echo $RESULT | wc -w`
    if [ $COUNT -gt 0 ]; then
        # Let't start with a new line. mysql could have printed something out.
        printf "\n"
        log_error "Expected empty database $db_name, but there are $COUNT tables: \n$_RESULT. Aborting."
        exit 1
    fi

    printf "Initializing database using script %s\n" $scripts_dir/mysql/dhcpdb_create.mysql
    mysql -B --user=$db_user --password=$db_password $db_name < $scripts_dir/mysql/dhcpdb_create.mysql
    ERRCODE=$?

    printf "mysql returned status code $ERRCODE\n"

    if [ "$ERRCODE" -eq 0 ]; then
        printf "Lease DB version reported after initialization: "
        mysql_version
        printf "\n"
    fi

    exit $ERRCODE
}

pgsql_init() {
    printf "Checking if there is a database initialized already. Please ignore errors.\n"

    # Let's try to count the number of tables. Anything above 0 means that there
    # is some database in place. If there is anything, we abort.
    RESULT=`pgsql_execute "\d"`
    ERRCODE=$?
    if [ "$ERRCODE" -ne 0 ]; then
        log_error "pgsql_init: table query failed, status code: $ERRCODE?"
        exit 1
    fi

    COUNT=`echo "$RESULT" | wc -w`
    if [ $COUNT -gt 0 ]; then
        printf "\n"
        log_error "Expected empty database $db_name, but the following tables are present \n$RESULT. Aborting."
        exit 2
    fi

    init_script="$scripts_dir/pgsql/dhcpdb_create.pgsql"
    printf "Initializing database using script %s\n" $init_script
    RESULT=`pgsql_execute_script $init_script`
    ERRCODE=$?
    if [ "$ERRCODE" -ne 0 ]; then
        log_error "Database initialization failed, status code: $ERRCODE?"
        exit 1
    fi

    version=`pgsql_version`
    printf "Lease DB version reported after initialization: $version\n"
    exit 0
}

### Functions that implement database version checking commands
memfile_version() {
    # @todo Implement this as part of #3601
    log_error "NOT IMPLEMENTED"
    exit 1
}

### Functions used for upgrade
memfile_upgrade() {
    # @todo Implement this as part of #3601
    log_error "NOT IMPLEMENTED"
    exit 1
}

# Upgrades existing MySQL database installation. The idea is that
# it will go over all upgrade scripts from (prefix)/share/kea/scripts/mysql
# and run them one by one. They will be named properly, so they will
# be run in order.
#
# This function prints version before and after upgrade.
mysql_upgrade() {

    printf "Lease DB version reported before upgrade: "
    mysql_version
    printf "\n"

    # Check if the scripts directory exists at all.
    if [ ! -d ${scripts_dir}/mysql ]; then
        log_error "Invalid scripts directory: ${scripts_dir}/mysql"
        exit 1
    fi

    # Check if there are any files in it
    num_files=$(find ${scripts_dir}/mysql/upgrade*.sh -type f | wc -l)
    if [ $num_files -eq 0 ]; then
        log_error "No scripts in ${scripts_dir}/mysql or the directory is not readable or does not have any upgrade* scripts."
        exit 1
    fi

    for script in ${scripts_dir}/mysql/upgrade*.sh
    do
        echo "Processing $script file..."
        sh ${script} --user=${db_user} --password=${db_password} ${db_name}
    done

    printf "Lease DB version reported after upgrade: "
    mysql_version
    printf "\n"
}

pgsql_upgrade() {
    version=`pgsql_version`
    printf "Lease DB version reported before upgrade: $version\n"

    # Check if the scripts directory exists at all.
    if [ ! -d ${scripts_dir}/pgsql ]; then
        log_error "Invalid scripts directory: ${scripts_dir}/pgsql"
        exit 1
    fi

    # Check if there are any files in it
    num_files=$(find ${scripts_dir}/pgsql/upgrade*.sh -type f | wc -l)
    if [ $num_files -eq 0 ]; then
        log_error "No scripts in ${scripts_dir}/pgsql or the directory is not readable or does not have any upgrade* scripts."
        exit 1
    fi

    # Postgres psql does not accept pw on command line, but can do it
    # thru an env
    export PGPASSWORD=$db_password

    for script in ${scripts_dir}/pgsql/upgrade*.sh
    do
        echo "Processing $script file..."
        sh ${script} -U ${db_user} -d ${db_name}
    done

    version=`pgsql_version`
    printf "Lease DB version reported after upgrade: $version\n"
    exit 0
}

# Utility function which tests if the given file exists and
# if so notifies the user and provides them the opportunity
# to abort the current command.
check_file_overwrite () {
    local file=$1
    if [ -e ${file} ]
    then
        echo "Output file, $file, exists and will be overwritten."
        echo "Do you wish to continue? (y/n)"
        read ans
        if [ ${ans} != "y" ]
        then
            echo "$command aborted by user."
            exit 1
        fi
    fi
}

### Functions used for dump

# Sets the global variable, dump_qry, to the schema-version specific
# SQL text needed to dump the lease data for the current backend
# and protocol
get_dump_query() {
    local version=$1

    case ${backend} in
    mysql)
        invoke="call"
        ;;
    pgsql)
        invoke="select * from"
        ;;
    *)
        log_error "unsupported backend ${backend}"
        usage
        exit 1
        ;;
    esac

    dump_qry="${invoke} lease${dump_type}DumpHeader();${invoke} lease${dump_type}DumpData();";
}

memfile_dump() {
    log_error "lease-dump is not supported for memfile"
    exit 1
}

mysql_dump() {

    # get the correct dump query
    version=`mysql_version`
    retcode=$?
    if [ $retcode -ne 0 ]
    then
        log_error "lease-dump: mysql_version failed, exit code $retcode"
        exit 1;
    fi

    # Fetch the correct SQL text. Note this function will exit
    # if it fails.
    get_dump_query $version

    # Make sure they specified a file
    if [ "$dump_file" = "" ]; then
        log_error "you must specify an output file for lease-dump"
        usage
        exit 1

    fi

    # If output file exists, notify user, allow them a chance to bail
    check_file_overwrite $dump_file

    # Check the temp file too
    tmp_file="$dump_file.tmp"
    check_file_overwrite $tmp_file

    # Run the sql to output tab-delimited lease data to a temp file.
    # By using a temp file we can check for MySQL errors before using
    # 'tr' to translate tabs to commas.  We do not use MySQL's output
    # to file as that requires linux superuser privileges to execute
    # the select.
    mysql_execute "${dump_qry}" > $tmp_file
    retcode=$?
    if [ $retcode -ne 0 ]; then
        log_error "lease-dump: mysql_execute failed, exit code $retcode";
        exit 1
    fi

    # Now translate tabs to commas.
    cat $tmp_file | tr '\t' ',' >$dump_file
    if [ $? -ne 0 ]; then
        log_error "lease-dump: reformatting failed";
        exit 1
    fi

    # delete the tmp file on success
    rm $tmp_file
    echo lease$dump_type successfully dumped to $dump_file
    exit 0
}

### Functions used for dump
pgsql_dump() {
    version=`pgsql_version`
    get_dump_query $version

    # Make sure they specified a file
    if [ "$dump_file" = "" ]; then
        log_error "you must specify an output file for lease-dump"
        usage
        exit 1

    fi

    # If output file exists, notify user, allow them a chance to bail
    check_file_overwrite $dump_file

    # psql does not accept password as a parameter but will look in the environment
    export PGPASSWORD=$db_password

    # Call psql and redirect output to the dump file. We don't use psql "to csv"
    # as it can only be run as db superuser.
    echo "$dump_qry" | psql --set ON_ERROR_STOP=1 -t -q --user=$db_user --dbname=$db_name -w --no-align --field-separator=',' >$dump_file
    retcode=$?

    # Check for errors.
    if [ $retcode -ne 0 ]; then
        log_error "lease-dump: psql call failed, exit code: $retcode";
        exit 1
    fi

    echo lease$dump_type successfully dumped to $dump_file
    exit 0
}

### Script starts here ###

# First, find what the command is
command=${1}
if [ -z ${command} ]; then
    log_error "missing command"
    usage
    exit 1
fi
is_in_list "${command}" "lease-init lease-version lease-upgrade lease-dump"
if [ ${_inlist} -eq 0 ]; then
    log_error "invalid command: ${command}"
    exit 1
fi
shift

# Second, check what's the backend
backend=${1}
if [ -z ${backend} ]; then
    log_error "missing backend"
    usage
    exit 1
fi
is_in_list "${backend}" "memfile mysql pgsql"
if [ ${_inlist} -eq 0 ]; then
    log_error "invalid backend: ${backend}"
    exit 1
fi
shift

# Ok, let's process parameters (if there are any)
while [ ! -z "${1}" ]
do
    option=${1}
    case ${option} in
        # Specify database user
        -u|--user)
            shift
            db_user=${1}
            if [ -z ${db_user} ]; then
                log_error "-u or --user requires a parameter"
                usage
                exit 1
            fi
            ;;
        # Specify database password
        -p|--password)
            shift
            db_password=${1}
            if [ -z ${db_password} ]; then
                log_error "-p or --password requires a parameter"
                usage
                exit 1
            fi
            ;;
        # Specify database name
        -n|--name)
            shift
            db_name=${1}
            if [ -z ${db_name} ]; then
                log_error "-n or --name requires a parameter"
                usage
                exit 1
            fi
            ;;
        -d|--directory)
            shift
            scripts_dir=${1}
            if [ -z ${scripts_dir} ]; then
                log_error "-d or --directory requires a parameter"
                usage
                exit 1
            fi
            ;;
        # specify DHCPv4 lease type
        -4)
            if [ $dump_type -eq 6 ]; then
                log_error "you may not specify both -4 and -6"
                usage
                exit 1
            fi
            dump_type=4
            ;;
        # specify DHCPv6 lease type
        -6)
            if [ $dump_type -eq 4 ]; then
                log_error "you may not specify both -4 and -6"
                usage
                exit 1
            fi
            dump_type=6
            ;;
        # specify output file, currently only used by lease dump
        -o|--output)
            shift
            dump_file=${1}
            if [ -z ${dump_file} ]; then
                log_error "-o or --output requires a parameter"
                usage
                exit 1
            fi
            ;;
        *)
            log_error "invalid option: ${option}"
            usage
            exit 1
    esac
    shift
done

case ${command} in
    # Initialize the database
    lease-init)
        case ${backend} in
            memfile)
                memfile_init
                ;;
            mysql)
                mysql_init
                ;;
            pgsql)
                pgsql_init
                ;;
            esac
        ;;
    lease-version)
        case ${backend} in
            memfile)
                memfile_version
                ;;
            mysql)
                mysql_version
                printf "\n"
                ;;
            pgsql)
                pgsql_version
                ;;
            esac
        ;;
    lease-upgrade)
        case ${backend} in
            memfile)
                memfile_upgrade
                ;;
            mysql)
                mysql_upgrade
                ;;
            pgsql)
                pgsql_upgrade
                ;;
            esac
        ;;
    lease-dump)
        case ${backend} in
            memfile)
                memfile_dump
                ;;
            mysql)
                mysql_dump
                ;;
            pgsql)
                pgsql_dump
                ;;
            esac
        ;;
esac

exit 0
