#!/bin/sh

# EvoMaintenance script
# Dependencies (all OS): git postgresql-client
# Dependencies (Debian): sudo

# version 0.4.1
# Copyright 2007-2018 Gregory Colpart <reg@evolix.fr>, Jérémy Lecour <jlecour@evolix.fr>, Evolix <info@evolix.fr>

get_system() {
    uname -s
}

get_fqdn() {
    if [ "$(get_system)" = "Linux" ]; then
        hostname --fqdn
    elif [ "$(get_system)" = "OpenBSD" ]; then
        hostname
    else
        echo "OS not detected!"
        exit 1
    fi
}

get_tty() {
    if [ "$(get_system)" = "Linux" ]; then
        ps -o tty= | tail -1
    elif [ "$(get_system)" = "OpenBSD" ]; then
        env | grep SSH_TTY | cut -d"/" -f3
    else
        echo "OS not detected!"
        exit 1
    fi
}

get_who() {
    who=$(LC_ALL=C who -m)

    if [ -n "${who}" ]; then
        echo "${who}"
    else
        LC_ALL=C who | grep $(get_tty) | tr -s ' '
    fi
}

get_begin_date() {
    echo "$(date "+%Y") $(echo $(get_who) | cut -d" " -f3,4,5)"
}

get_ip() {
    ip=$(echo $(get_who) | cut -d" " -f6 | sed -e "s/^(// ; s/)$//")
    [ -z "${ip}" ] && ip="unknown (no tty)"
    [ "${ip}" = ":0" ] && ip="localhost"

    echo "${ip}"
}

get_end_date() {
    date +"%Y %b %d %H:%M"
}

get_now() {
    date +"%Y-%m-%dT%H:%M:%S%z"
}

get_complete_hostname() {
    REAL_HOSTNAME=$(get_fqdn)
    if [ "${HOSTNAME}" = "${REAL_HOSTNAME}" ]; then
        echo "${HOSTNAME}"
    else
        echo "${HOSTNAME} (${REAL_HOSTNAME})"
    fi
}

get_repository_status() {
    dir=$1
    # tell Git where to find the repository and the work tree (no need to `cd …` there)
    export GIT_DIR="${dir}/.git" GIT_WORK_TREE="${dir}"
    # If the repository and the work tree exist, try to commit changes
    if test -d "${GIT_DIR}" && test -d "${GIT_WORK_TREE}"; then
        CHANGED_LINES=$(${GIT_BIN} status --porcelain | wc -l | tr -d ' ')
        if [ "${CHANGED_LINES}" != "0" ]; then
            STATUS=$(${GIT_BIN} status --short | tail -n 10)
            printf "%s\n%s\n" "${GIT_DIR} (last 10 lines)" "${STATUS}" | sed -e '/^$/d'
        fi
    fi
    # unset environment variables to prevent accidental influence on other git commands
    unset GIT_DIR GIT_WORK_TREE
}

print_summary() {
  BLOB=$(cat <<END
Host      : $HOSTNAME_TEXT
User      : $USER
IP        : $IP
Begin     : $BEGIN_DATE
End       : $END_DATE
Message   : $MESSAGE
END
)
  echo "${BLOB}"
  echo ""
}

print_options() {
    echo "********** Options ****************"
    echo "MESSAGE: ${MESSAGE}"
    echo "OPT_COMMIT: ${OPT_COMMIT}"
    echo "OPT_DB: ${OPT_DB}"
    echo "OPT_MAIL: ${OPT_MAIL}"
    echo "DRY_RUN: ${DRY_RUN}"
    echo "***********************************\n"
}

hook_commit() {

    if test -x "${GIT_BIN}"; then
        # loop on possible directories managed by GIT
        for dir in ${GIT_REPOSITORIES}; do
            # tell Git where to find the repository and the work tree (no need to `cd …` there)
            export GIT_DIR="${dir}/.git" GIT_WORK_TREE="${dir}"
            # If the repository and the work tree exist, try to commit changes
            if test -d "${GIT_DIR}" && test -d "${GIT_WORK_TREE}"; then
                CHANGED_LINES=$(${GIT_BIN} status --porcelain | wc -l | tr -d ' ')
                if [ "${CHANGED_LINES}" != "0" ]; then
                    if [ "${DRY_RUN}" = "1" ]; then
                        STATS=$(${GIT_BIN} diff --stat | tail -1)
                        GIT_COMMITS=$(printf "%s\n%s : %s" "${GIT_COMMITS}" "${GIT_DIR}" "${STATS}" | sed -e '/^$/d')
                    else
                        ${GIT_BIN} add --all
                        ${GIT_BIN} commit --message "${MESSAGE}" --author="${USER} <${USER}@evolix.net>" --quiet
                        # Add the SHA to the log file if something has been committed
                        SHA=$(${GIT_BIN} rev-parse --short HEAD)
                        STATS=$(${GIT_BIN} show --stat | tail -1)
                        # append commit data, without empty lines
                        GIT_COMMITS=$(printf "%s\n%s : %s –%s" "${GIT_COMMITS}" "${GIT_DIR}" "${SHA}" "${STATS}" | sed -e '/^$/d')
                    fi
                fi
            fi
            # unset environment variables to prevent accidental influence on other git commands
            unset GIT_DIR GIT_WORK_TREE
        done
        if [ -n "${GIT_COMMITS}" ]; then
            if [ "${VERBOSE}" = "1" ]; then
                echo "\n\n********** Commits ****************\n${GIT_COMMITS}\n***********************************"
            fi
            if [ "${DRY_RUN}" != "1" ]; then
                echo "${GIT_COMMITS}" >> "${LOGFILE}"
            fi
        fi
    fi
}

hook_db() {
    SQL_DETAILS=$(echo "${MESSAGE}" | sed "s/'/''/g")
    PG_QUERY="INSERT INTO evomaint(hostname,userid,ipaddress,begin_date,end_date,details) VALUES ('${HOSTNAME}','${USER}','${IP}','${BEGIN_DATE}',now(),'${SQL_DETAILS}')"

    if [ "${VERBOSE}" = "1" ]; then
        echo "\n\n********** DB query **************\n${PG_QUERY}\n***********************************"
    fi
    if [ "${DRY_RUN}" != "1" ]; then
        echo "${PG_QUERY}" | psql ${PGDB} ${PGTABLE} -h ${PGHOST}
    fi
}

hook_mail() {
    MAIL_TEXTE=$(echo "${MESSAGE}" | sed -e "s@/@\\\\\/@g ; s@&@\\\\&@")
    MAIL_GIT_COMMITS=$(echo "${GIT_COMMITS}" | sed -e "s@/@\\\\\/@g ; s@&@\\\\&@")
    MAIL_CONTENT=$(sed -e "s/__TO__/${EVOMAINTMAIL}/ ; s/__HOSTNAME__/${HOSTNAME_TEXT}/ ; s/__USER__/${USER}/ ; s/__BEGIN_DATE__/${BEGIN_DATE}/ ; s/__END_DATE__/${END_DATE}/ ; s/__GIT_COMMITS__/${MAIL_GIT_COMMITS}/ ; s/__TEXTE__/${MAIL_TEXTE}/ ; s/__IP__/${IP}/ ; s/__FULLFROM__/${FULLFROM}/ ; s/__FROM__/${FROM}/ ; s/__URGENCYFROM__/${URGENCYFROM}/ ; s/__URGENCYTEL__/${URGENCYTEL}/" /usr/share/scripts/evomaintenance.tpl)

    if [ "${VERBOSE}" = "1" ]; then
        echo "\n\n********** Mail *******************\n${MAIL_CONTENT}\n***********************************"
    fi
    if [ "${DRY_RUN}" != "1" ]; then
        echo "${MAIL_CONTENT}" | ${SENDMAIL_BIN} -oi -t -f ${FROM}
    fi
}

hook_log() {
  echo "----------- $(get_now) ---------------" >> "${LOGFILE}"
  echo "${BLOB}" >> "${LOGFILE}"
}

# load configuration if present.
test -f /etc/evomaintenance.cf && . /etc/evomaintenance.cf

[ -n "${HOSTNAME}" ]     || HOSTNAME=$(get_fqdn)
[ -n "${EVOMAINTMAIL}" ] || EVOMAINTMAIL=evomaintenance-$(echo "${HOSTNAME}" | cut -d- -f1)@${REALM}
[ -n "${LOGFILE}" ]      || LOGFILE=/var/log/evomaintenance.log

[ -n "${OPT_COMMIT}" ]   || OPT_COMMIT=1
[ -n "${OPT_DB}" ]       || OPT_DB=1
[ -n "${OPT_MAIL}" ]     || OPT_MAIL=1
[ -n "${DRY_RUN}" ]      || DRY_RUN=0
[ -n "${VERBOSE}" ]      || VERBOSE=0

# initialize variables
MESSAGE=""
GIT_COMMITS=""

# Parse options
# based on https://gist.github.com/deshion/10d3cb5f88a21671e17a
while :; do
    case $1 in
        # -h|-\?|--help)   # Call a "show_help" function to display a synopsis, then exit.
        #     show_help
        #     exit
        #     ;;
        -m|--message)
            # message options, with value speparated by space
            if [ -n "$2" ]; then
                MESSAGE=$2
                shift
            else
                printf 'ERROR: "--message" requires a non-empty option argument.\n' >&2
                exit 1
            fi
            ;;
        --message=?*)
            # message options, with value speparated by =
            MESSAGE=${1#*=}
            ;;
        --message=)
            # message options, without value
            printf 'ERROR: "--message" requires a non-empty option argument.\n' >&2
            exit 1
            ;;
        --no-commit)
            # disable commit hook
            OPT_COMMIT=0
            ;;
        --commit)
            # enable commit hook
            OPT_COMMIT=1
            ;;
        --no-db)
            # disable DB hook
            OPT_DB=0
            ;;
        --db)
            # enable DB hook
            OPT_DB=1
            ;;
        --no-mail)
            # disable mail hook
            OPT_MAIL=0
            ;;
        --mail)
            # enable mail hook
            OPT_MAIL=1
            ;;
        -n|--dry-run)
            # disable actual commands
            DRY_RUN=1
            ;;
        -v|--verbose)
            # print verbose information
            VERBOSE=1
            ;;
        --)
            # End of all options.
            shift
            break
            ;;
        -?*)
            # ignore unknown options
            printf 'WARN: Unknown option (ignored): %s\n' "$1" >&2
            ;;
        *)
            # Default case: If no more options then break out of the loop.
            break
    esac

    shift
done

if [ "${VERBOSE}" = "1" ]; then
    print_options
fi

# Treat unset variables as an error when substituting.
# Only after this line, because some config variables might be missing.
set -u

# Gather information
HOSTNAME_TEXT=$(get_complete_hostname)
# TTY=$(get_tty)
# WHO=$(get_who)
IP=$(get_ip)
BEGIN_DATE=$(get_begin_date)
END_DATE=$(get_end_date)
USER=$(logname)

PATH=${PATH}:/usr/sbin

SENDMAIL_BIN=$(command -v sendmail)
GIT_BIN=$(command -v git)

GIT_REPOSITORIES="/etc /etc/bind"

# initialize variable
GIT_STATUSES=""
# git statuses
if test -x "${GIT_BIN}"; then
    # loop on possible directories managed by GIT
    for dir in ${GIT_REPOSITORIES}; do
        RESULT=$(get_repository_status "${dir}")
        if test -n "${RESULT}"; then
            # append diff data, without empty lines
            GIT_STATUSES=$(printf "%s\n%s\n" "${GIT_STATUSES}" "${RESULT}" | sed -e '/^$/d')
        fi
        unset RESULT
    done
fi

# find out if running in interactive mode, or not
if [ -t 0 ]; then
    INTERACTIVE=1
else
    INTERACTIVE=0
fi

if [ -z "${MESSAGE}" ] && [ "${INTERACTIVE}" = "1" ]; then
    # get input from stdin
    echo "> Please, enter details about your maintenance"
    read -r MESSAGE
fi

if test -z "${MESSAGE}"; then
    echo "no value..."
    exit 1
fi

print_summary

# Log hook
if [ "${DRY_RUN}" != "1" ]; then
    hook_log
fi

# Commit hook
if [ "${INTERACTIVE}" = "1" ]; then
    if test -n "${GIT_STATUSES}" && [ "${OPT_COMMIT}" = "1" ]; then
        echo "/!\ There are some uncommited changes."
        echo "${GIT_STATUSES}"
        echo ""

        y="Y"; n="n"
        answer=""
        while true; do
            echo "Do you want to commit the changes? [${y}${n}] "
            read -r answer
            case $answer in
                [Yy] )
                    hook_commit;
                    break
                    ;;
                [Nn] )
                    break
                    ;;
                "" )
                    if [ "${OPT_COMMIT}" = "1" ]; then
                      hook_commit
                    fi
                    break
                    ;;
                * )
                    echo "answer with a valid choice"
                    ;;
            esac
        done
    fi
else
    if [ "${OPT_COMMIT}" = "1" ]; then
        hook_commit
    fi
fi

# Database hook
if [ "${INTERACTIVE}" = "1" ]; then
    if [ "${OPT_DB}" = "1" ]; then
        y="Y"; n="n"
    else
        y="y"; n="N"
    fi
    answer=""
    while true; do
        echo "Do you want to insert your message into the database? [${y}${n}] "
        read -r answer
        case $answer in
            [Yy] )
                hook_db;
                break
                ;;
            [Nn] )
                break
                ;;
            "" )
                if [ "${OPT_DB}" = "1" ]; then
                  hook_db
                fi
                break
                ;;
            * )
                echo "answer with a valid choice"
                ;;
        esac
    done
else
    if [ "${OPT_DB}" = "1" ]; then
        hook_db
    fi
fi

# Mail hook
if [ "${INTERACTIVE}" = "1" ]; then
    if [ "${OPT_MAIL}" = "1" ]; then
        y="Y"; n="n"
    else
        y="y"; n="N"
    fi
    answer=""
    while true; do
        echo "Do you want to send an email to <${EVOMAINTMAIL}>? [${y}${n}e] "
        read -r answer
        case $answer in
            [Yy] )
                hook_mail;
                break
                ;;
            [Nn] )
                break
                ;;
            [Ee] )
                echo "To: [${EVOMAINTMAIL}] "
                read -r mail_recipient
                if [ -n "${mail_recipient}" ]; then
                    EVOMAINTMAIL="${mail_recipient}"
                    echo "changed to ${EVOMAINTMAIL}"
                fi
                ;;
            "" )
                if [ "${OPT_MAIL}" = "1" ]; then
                    hook_mail
                fi
                break
                ;;
            * )
                echo "answer with a valid choice"
                ;;
        esac
    done
else
    if [ "${OPT_MAIL}" = "1" ]; then
        hook_mail
    fi
fi

exit 0