# -*- mode:sh -*-
# vim:syn=sh
# Little common functions

# push a mirror attached to us.
# Arguments (using an array named SIGNAL_OPTS):
#
# $MIRROR      - Name for the mirror, also basename for the logfile
# $HOSTNAME    - Hostname to push to
# $USERNAME    - Username there
# $SSHPROTO    - Protocol version, either 1 or 2.
# $SSHKEY      - the ssh private key file to use for this push
# $SSHOPTS     - any other option ssh accepts, passed blindly, be careful
# $PUSHLOCKOWN - own lockfile name to touch after stage1 in pushtype=staged
# $PUSHTYPE    - what kind of push should be done?
#                all    - normal, just push once with ssh backgrounded and finish
#                staged - staged. first push stage1, then wait for $PUSHLOCKs to appear,
#                         then push stage2
# $PUSHARCHIVE - what archive to sync? (Multiple mirrors behind one ssh key!)
# $PUSHCB      - do we want a callback?
# $PUSHKIND    - whats going on? are we doing mhop push or already stage2?
# $FROMFTPSYNC - set to true if we run from within ftpsync.
#
# This function assumes that the variable LOG is set to a directory where
# logfiles can be written to.
# Additionally $PUSHLOCKS has to be defined as a set of space delimited strings
# (list of "lock"files) to wait for if you want pushtype=staged
#
# Pushes might be done in background (for type all).
signal () {
    ARGS="SIGNAL_OPTS[*]"
    local ${!ARGS}

    MIRROR=${MIRROR:-""}
    HOSTNAME=${HOSTNAME:-""}
    USERNAME=${USERNAME:-""}
    SSHPROTO=${SSHPROTO:-""}
    SSHKEY=${SSHKEY:-""}
    SSHOPTS=${SSHOPTS:-""}
    PUSHLOCKOWN=${PUSHLOCKOWN:-""}
    PUSHTYPE=${PUSHTYPE:-"all"}
    PUSHARCHIVE=${PUSHARCHIVE:-""}
    PUSHCB=${PUSHCB:-""}
    PUSHKIND=${PUSHKIND:-"all"}
    FROMFTPSYNC=${FROMFTPSYNC:-"false"}

    # And now get # back to space...
    SSHOPTS=${SSHOPTS/\#/ }

    # Defaults we always want, no matter what
    SSH_OPTIONS="-o user=${USERNAME} -o BatchMode=yes -o ServerAliveInterval=45 -o ConnectTimeout=45 -o PasswordAuthentication=no"

    # If there are userdefined ssh options, add them.
    if [[ -n ${SSH_OPTS} ]]; then
        SSH_OPTIONS="${SSH_OPTIONS} ${SSH_OPTS}"
    fi

    # Does this machine need a special key?
    if [[ -n ${SSHKEY} ]]; then
        SSH_OPTIONS="${SSH_OPTIONS} -i ${SSHKEY}"
    fi

    # Does this machine have an extra own set of ssh options?
    if [[ -n ${SSHOPTS} ]]; then
        SSH_OPTIONS="${SSH_OPTIONS} ${SSHOPTS}"
    fi

    # Set the protocol version
    if [[ ${SSHPROTO} -ne 1 ]] && [[ ${SSHPROTO} -ne 2 ]] && [[ ${SSHPROTO} -ne 99 ]]; then
        # Idiots, we only want 1 or 2. Cant decide? Lets force 2.
        SSHPROTO=2
    fi

    if [[ -n ${SSHPROTO} ]] && [[ ${SSHPROTO} -ne 99 ]]; then
        SSH_OPTIONS="${SSH_OPTIONS} -${SSHPROTO}"
    fi

    date -u >> "${LOGDIR}/${MIRROR}.log"

    PUSHARGS=""
    # PUSHARCHIVE empty or not, we always add the sync:archive: command to transfer.
    # Otherwise, if nothing else is added, ssh -f would not work ("no command to execute")
    # But ftpsync does treat "sync:archive:" as the main archive, so this works nicely.
    PUSHARGS="${PUSHARGS} sync:archive:${PUSHARCHIVE}"

    # We have a callback wish, tell downstreams
    if [[ -n ${PUSHCB} ]]; then
        PUSHARGS="${PUSHARGS} sync:callback"
    fi
    # If we are running an mhop push AND our downstream is one to receive it, tell it.
    if [[ mhop = ${PUSHKIND} ]] && [[ mhop = ${PUSHTYPE} ]]; then
        PUSHARGS="${PUSHARGS} sync:mhop"
    fi

    if [[ all = ${PUSHTYPE} ]]; then
        # Default normal "fire and forget" push. We background that, we do not care about the mirrors doings
        PUSHARGS1="sync:all"
        signal_ssh "normal" "${MIRROR}" "${HOSTNAME}" $SSH_OPTIONS "${PUSHARGS} ${PUSHARGS1}"
    elif [[ staged = ${PUSHTYPE} ]] || [[ mhop = ${PUSHTYPE} ]]; then
        # Want a staged push. Fine, lets do that. Not backgrounded. We care about the mirrors doings.
        # Only send stage1 if we havent already send it. When called with stage2, we already did.
        if [[ stage2 != ${PUSHKIND} ]]; then
            # Step1: Do a push to only sync stage1, do not background
            PUSHARGS1="sync:stage1"
            signal_ssh "first stage" "${MIRROR}" "${HOSTNAME}" $SSH_OPTIONS "${PUSHARGS} ${PUSHARGS1}"
            touch "${PUSHLOCKOWN}"

            # Step2: Wait for all the other "lock"files to appear.
            # In case we did not have all PUSHLOCKS and still continued, note it
            # This is a little racy, especially if the other parts decide to do this
            # at the same time, but it wont hurt more than a mail too much, so I don't care much
            if ! wait_for_pushlocks ${PUSHDELAY}; then
                msg "Failed to wait for all other mirrors. Failed ones are:" >> "${LOGDIR}/${MIRROR}.log"
                for file in ${PUSHLOCKS}; do
                    if [[ ! -f ${file} ]]; then
                        msg "${file}" >> "${LOGDIR}/${MIRROR}.log"
                        log "Missing Pushlockfile ${file} after waiting for more than ${PUSHDELAY} seconds, continuing"
                    fi
                done
            fi
            rm -f "${PUSHLOCKOWN}"
        fi

        # Step3: It either timed out or we have all the "lock"files, do the rest
        # If we are doing mhop AND are called from ftpsync - we now exit.
        # That way we notify our uplink that we and all our clients are done with their
        # stage1. It can then finish its own, and if all our upstreams downlinks are done,
        # it will send us stage2.
        # If we are not doing mhop or are not called from ftpsync, we start stage2
        if [[ true = ${FROMFTPSYNC} ]] && [[ mhop = ${PUSHKIND} ]]; then
            return
        else
            PUSHARGS2="sync:stage2"
            signal_ssh "second stage" "${MIRROR}" "${HOSTNAME}" $SSH_OPTIONS "${PUSHARGS} ${PUSHARGS2}"
        fi
    else
        # Can't decide? Then you get nothing.
        return
    fi
}

signal_ssh() {
    local t=$1
    local mirror_log="${LOGDIR}/${2}.log"
    local hostname=$3
    shift 3

    msg "Sending ${t} trigger" >> $mirror_log
    output=$(ssh -n $hostname "$@" 2>&1 | tee -a $mirror_log)
    if [[ $? -eq 255 ]]; then
        error_mailf "${t} trigger failed: $hostname" -b "$output"
    else
        log "${t} trigger succeeded: $hostname"
    fi
}

wait_for_pushlocks() {
  local tries=0
  local found
  local total
  local timeout=${1}; shift
  # We do not wait forever
  while [[ ${tries} -lt ${timeout} ]]; do
      total=0
      found=0
      for file in ${PUSHLOCKS}; do
          total=$(( total + 1 ))
          if [[ -f ${file} ]]; then
              found=$(( found + 1 ))
          fi
      done
      if [[ ${total} -eq ${found} ]] || [[ -f ${LOCKDIR}/all_stage1 ]]; then
          break
      fi
      tries=$(( tries + 5 ))
      sleep 5
  done
  # Regardless of the state of our siblings, hitting one timeout cancels all waits
  touch "${LOCKDIR}/all_stage1"
  if [[ ${tries} -ge ${timeout} ]]; then
    return 1
  else
    return 0
  fi
}

# callback, used by ftpsync
callback () {
    # Defaults we always want, no matter what
    SSH_OPTIONS="-o BatchMode=yes -o ServerAliveInterval=45 -o ConnectTimeout=45 -o PasswordAuthentication=no"
    ssh -n $SSH_OPTIONS -i "$3" -o"user $1" "$2" callback:${HOSTNAME}
}

# open log file
open_log() {
    local log=$1
    shift
    exec 4>&1 1>>$log
}

# assemble log message (basically echo it together with a timestamp)
#
# Set $PROGRAM to a string to have it added to the output.
msg() {
    if [[ -z "${PROGRAM}" ]]; then
        echo "$(date +"%b %d %H:%M:%S") $(hostname -s) [$$] $@"
    else
        echo "$(date +"%b %d %H:%M:%S") $(hostname -s) ${PROGRAM}[$$]: $@"
    fi
}

# log something
log() {
    msg "$@"
}

# log the message using log() but then also send a mail
# to the address configured in MAILTO (if non-empty)
error () {
    log "$@"
    LOG_ERROR=1
    mailf -s "[$PROGRAM@$(hostname -s)] ERROR: $*" -b "$*" ${MAILTO}
}

# log the message using log() but then also send a mail
# to the address configured in MAILTO (if non-empty)
error_mailf () {
    local m="$1"
    shift
    log "$m"
    LOG_ERROR=1
    mailf -s "[$PROGRAM@$(hostname -s)] ERROR: $m" "$@" ${MAILTO}
}

# run a hook
# needs array variable HOOK setup with HOOKNR being a number an HOOKSCR
# the script to run.
hook () {
    ARGS='HOOK[@]'
    local "${!ARGS}"
    if [[ -n ${HOOKSCR} ]]; then
        log "Running hook $HOOKNR: ${HOOKSCR}"
        set +e
        ${HOOKSCR}
        result=$?
        set -e
        if [[ ${result} -ne 0 ]] ; then
            error "Back from hook $HOOKNR, got returncode ${result}"
        else
            log "Back from hook $HOOKNR, got returncode ${result}"
        fi
        return $result
    else
        return 0
    fi
}

# Return the list of 2-stage mirrors.
get2stage() {
    egrep -s '^(staged|mhop)' "${MIRRORS}" | {
        while read MTYPE MLNAME MHOSTNAME MUSER MPROTO MKEYFILE; do
            PUSHLOCKS="${LOCKDIR}/${MLNAME}.stage1 ${PUSHLOCKS}"
        done
        echo "$PUSHLOCKS"
    }
}

# Rotate logfiles
savelog() {
    torotate="$1"
    count=${2:-${LOGROTATE}}
    while [[ ${count} -gt 0 ]]; do
        prev=$(( count - 1 ))
        if [[ -e ${torotate}.${prev} ]]; then
            mv "${torotate}.${prev}" "${torotate}.${count}"
        fi
        count=$prev
    done
    if [[ -e ${torotate} ]]; then
        mv "${torotate}" "${torotate}.0"
    fi
}

# Return rsync version
rsync_protocol() {
    RSYNC_VERSION="$(${RSYNC} --version)"
    RSYNC_REGEX="(protocol[ ]+version[ ]+([0-9]+))"    
    if [[ ${RSYNC_VERSION} =~ ${RSYNC_REGEX} ]]; then
        echo ${BASH_REMATCH[2]}
    fi
    unset RSYNC_VERSION RSYNC_REGEX
}

extract_trace_field() {
    local field="$1"
    local file="$2"
    local value=$(awk -F': ' "\$1==\"$field\" {print \$2; exit}" "$file" 2>/dev/null)
    [[ $value ]] || return 1
    echo $value
}

extract_trace_field_string() {
    local field="$1"
    local string="$2"
    local value=$(awk -F': ' "\$1==\"$field\" {print \$2; exit}" <<< "$string" 2>/dev/null)
    [[ $value ]] || return 1
    echo $value
}

extract_trace_serial() {
    extract_trace_field 'Archive serial' "$1"
    return $?
}

extract_trace_serial_string() {
    extract_trace_field_string 'Archive serial' "$1"
    return $?
}

# Search config files in various locations
search_config() {
  local file
  for i in ${CONFDIRS[@]}; do
    file="$i/$1"
    if [ -f "$file" ]; then
      echo "$file"
      return
    fi
  done
}

# Read config file
read_config() {
  local name=$(echo "$1" | sed -e 's/[^A-Za-z0-9._-]/_/g')
  local config=$(search_config "$name")
  if [ "$config" ]; then
    . "$config"
    CURRENT_CONFIG="$config"
    return 0
  else
    echo "Can't read config file ${name}!" >&2
    exit 78 # EX_CONFIG
  fi
}

# Create lock dir
create_lockdir() {
  mkdir -p "$LOCKDIR"
}

# Create log dir
create_logdir() {
  mkdir -p "$LOGDIR"
}

join_by() {
    local IFS="$1"
    shift
    echo $*
}

# Sends mail
# mailf [-a attachment] [-b body] [-s subject] to-addr ...
mailf() {
    local boundary="==--$RANDOM--$RANDOM--$RANDOM--=="
    local attachment=()
    local body=()
    local subject=

    OPTIND=1
    while getopts ":a:b:s:" arg; do
        case $arg in
            a)
                attachment+=("$OPTARG")
                ;;
            b)
                body+=("$OPTARG")
                ;;
            s)
                subject="$OPTARG"
                ;;
        esac
    done
    shift $((OPTIND-1))

    (
        cat <<EOF
Subject: ${subject}
To: $(join_by ', ' "$@")
Auto-Submitted: auto-generated
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary=${boundary}

EOF
        if [[ ${body[@]:-} ]]; then
            for a in "${body[@]}"; do
                cat <<EOF
--${boundary}
Content-type: text/plain

EOF
                echo "$a"
            done
        fi
        if [[ ${attachment[@]:-} ]]; then
            for a in "${attachment[@]}"; do
                cat <<EOF
--${boundary}
Content-type: text/plain; name="$(basename $a)"

EOF
                cat "$a" || echo "Failed to attach $a"
            done
        fi
        cat <<EOF
--${boundary}--
EOF
    ) | /usr/sbin/sendmail -i -- "$@" || :
}