#!/bin/bash

#----------------------------------------------------------------------------
DATABASE="mythconverg"
DATABASE_DIR="/var/lib/mysql/$DATABASE"
BACKUP_LIST="./root ./home ./etc
             ./var/www/mythweb/.htaccess ./var/lib/alsa/asound.state"
RESTORE_LIST="./root ./home ./etc/mythtv/modules ./etc/lirc ./etc/htdigest
              ./etc/apache2/apache2.conf ./var/www/mythweb/.htaccess
              ./etc/X11/xorg.conf ./etc/asound.conf ./etc/default/aumix
              ./var/lib/alsa/asound.state ./etc/mplayer/mplayer.conf
              ./etc/localtime ./etc/timezone"
# Both BLACK_LIST and IGNORE_LIST need to have only one file per line
# They also can't have any extra whitespace...
# Files and directories we should refuse to restore
BLACK_LIST='./etc/fstab
./etc/modules
./proc
./dev
./lib
./var/lib
./myth
./myth/backup
./home/mythtv/.my.cnf
./root/.my.cnf
./home/mythtv/.Xauthority
./root/.Xauthority'
# Files we ignore as differences
IGNORE_LIST='./home/mythtv/.upgrade
./home/mythtv/.configure
./home/mythtv/.newcard
./home/mythtv/.xscreensaver
./home/mythtv/appletrailer.xml
./root/ati-driver-installer-8-01-x86.x86_64.run
./root/ati-driver-installer-8-3-x86.x86_64.run
./root/mythstreamweb.tar
./home/mythtv/.Xauthority
./root/.Xauthority'
BACKUP_DIR="/myth/backup"
BACKUP_EXTRAS="$BACKUP_DIR/backup.list"
RESTORE_EXTRAS="$BACKUP_DIR/restore.list"
BACKUP_TAR="$BACKUP_DIR/savedfiles.tar"
BACKUP_SQL="$BACKUP_DIR/$DATABASE.sql"
DROP_SQL="/usr/local/share/knoppmyth/drop.sql"
# Do we really still need to update from myth-0.11 to myth-0.12 ?
UPDATE_SQL="/usr/share/mythtv/sql/0.11-to-0.12.sql"
UPDATE_FILES="/usr/local/bin/restore_fixups.sh"
COMPRESSION=".gz"
SOUNDS="/usr/share/sounds"
PLAYER="/usr/bin/aplay"
#----------------------------------------------------------------------------

play_sound () {
    ($PLAYER $SOUNDS/$1 >& /dev/null)&
}

# Filter against an exclude list like the black list or the ignore list above
filter_list () {
    /bin/grep -vxF "$*" |
    /usr/bin/sort -u
}

# Some people just can't read or follow directions... :-/
# This should track the directory names in the default backup list above
# We also use this to short circuit a certain incredibly dumb stunt
filter_redundant () {
    filter_list "$(echo $BACKUP_LIST ./myth | /usr/bin/tr -s ' ' '\n')" |
    /bin/egrep -v '^\./(root|home|etc|myth)/' |
    /usr/bin/sort -u
}

get_extras () {
    # One entry per line, and normalize the prefix
    /usr/bin/tr ' ' '\n' <"$1" |
    /usr/bin/awk '/^$/ {next}
                  /^\.\// {print $0 ; next}
                  /^\// {print "." $0 ; next}
                  { print "./" $0}'
}

[ -f "$BACKUP_EXTRAS" ] &&
    BACKUP_LIST="$BACKUP_LIST $(get_extras $BACKUP_EXTRAS |
                                filter_redundant)"

[ -f "$RESTORE_EXTRAS" ] &&
    RESTORE_LIST="$RESTORE_LIST $(get_extras $RESTORE_EXTRAS |
                                  filter_list "$BLACK_LIST")"

# Build tar exclusion parameters out of $BLACK_LIST
EXCLUSION=""
case $0 in
*restore)
    for file in $BLACK_LIST ; do
        EXCLUSION="$EXCLUSION --exclude $file "
    done
    ;;
*)
    ;;
esac

shrink () {
    case "$COMPRESSION" in
    .gz)
        /bin/gzip -9 "$@"
        ;;
    .bz2)
        /bin/bzip2 -9 "$@"
        ;;
    *)
        ;;
    esac
}

expand () {
    case "$*" in
    *.gz)
        /bin/gunzip "$@"
        ;;
    *.bz2)
        /bin/bunzip2 "$@"
        ;;
    -c\ *)
        /bin/cat $2 /dev/null
        ;;
    -t\ *)
        return 0
        ;;
    *)
        echo 1>&2 "Error, unknown file type!"
        return 1
        ;;
    esac
}

single_format () {
    candidates=$(/bin/ls -1 "$1.gz" "$1.bz2" "$1" 2>/dev/null)
    case $(echo "$candidates" | /usr/bin/wc -l) in
    1)  return 0  # One is good!
    	;;
    0)  echo "Error, no $1 found!"
    	return 1
        ;;
    *)  echo "Warning, multiple formats for $1 found!"
    	echo "Candidates are: $candidates"
        ;;
    esac
}

compression_type () {
    for compression in .gz .bz2 "" ; do
        if [ -f "$1$compression" ] ; then
            echo "$compression"
            return 0
        fi
    done
    return 1
}

backup_roller () { # Gets the rollover sequence to use.
    prev_i=$1 ; shift
    for i in "$@" ; do
        for c in .gz .bz2 "" ; do
            for f in $BACKUP_SQL $BACKUP_TAR ; do
                /bin/rm -f $f$c$prev_i
                if [ -f "$f$c$i" ] ; then
                    echo "Moving $f$c$i to $f$c$prev_i"
                    /bin/mv -f $f$c$i $f$c$prev_i
                fi
            done
        done
        prev_i="$i"
    done
}

# Given "subset A B" return true if is A a subset of B
subset () {
    cnt=$(/usr/bin/diff $1 $2 | /bin/grep '^<' | /usr/bin/wc -l)
    [ "$cnt" -eq 0 ] && return 0
    /usr/bin/diff $1 $2
}

mysql_cmd () {
    /usr/bin/mysql -u root $DATABASE -sBe "$*"
}

mysql_stdin () {
    /usr/bin/mysql -u root $DATABASE -sB
}

check_files () {
    OBJECT_LIST="$*"
    LIVE_FILES=/tmp/live_files_$$
    SAVED_FILES=/tmp/saved_files_$$

    echo "Checking for the existance of the backup tar file..."
    single_format "$BACKUP_TAR"
    c=$(compression_type "$BACKUP_TAR") ||
        { echo "Error, missing tar file - '$BACKUP_TAR$c'." ; return 1 ; }
    echo "Using file $BACKUP_TAR$c"
    echo "Backup tar file exists. Checking the compression..."
    expand -t $BACKUP_TAR$c ||
        { echo "Error, bad compressed tarball - '$BACKUP_TAR$c'." ; return 1 ; }
    echo "Compression looks OK. Checking backup tar file contents..."

    echo "Generating a list of the backup contents..."
    {
    expand -c $BACKUP_TAR$c |
      /bin/tar tf - $OBJECT_LIST $EXCLUSION |
      /bin/sed '/\/$/s///' |
      filter_list "$IGNORE_LIST" >$SAVED_FILES
    } 2>&1 | /bin/sed -e '/Error exit delayed from previous errors/d'

    echo "Generating a list of the directory contents..."
    cd /
    /usr/bin/find $OBJECT_LIST \( -type d -or -type f -or -type l \) -print |
      filter_list "$IGNORE_LIST" >$LIVE_FILES

    echo "Comparing directory versus backup contents..."
    case $0 in
    *backup) # backup must contain everything selected from the directories
        subset $LIVE_FILES $SAVED_FILES
        ;;
    *restore) # directories must contain everything selected from the backup
        subset $SAVED_FILES $LIVE_FILES
        ;;
    *)
        /usr/bin/diff $LIVE_FILES $SAVED_FILES
        ;;
    esac
    FILE_STATUS=$?
    /bin/rm $LIVE_FILES $SAVED_FILES
    if [ $FILE_STATUS -eq 0 ] ; then
        echo "Live and saved file lists match."
    else
        echo "Warning, file lists are not identical!"
    fi
    return $FILE_STATUS
}

has_records () {
    filename="$1"
    description="$2"
    if [ $(/usr/bin/wc -l < "$filename") -eq 0 ] ; then
        echo "Warning, could not get record counts from $description!"
        return 1
    fi
    if [ $(/usr/bin/awk '{cnt+=$2} END {print cnt}' < "$filename") -eq 0 ] ; then
        echo "Warning, total record count from $description is zero!"
        return 1
    fi
    return 0
}

check_tables () {
    LIVE_TABLES=/tmp/live_tables_$$
    SAVED_TABLES=/tmp/saved_tables_$$

    echo "Checking for the existance of the DB dump file..."
    single_format "$BACKUP_SQL"
    c=$(compression_type "$BACKUP_SQL") ||
        { echo "Error, missing DB dump - '$BACKUP_SQL$c'" ; return 1 ; }
    echo "Using file $BACKUP_SQL$c"
    echo "DB dump file exists. Checking the compression..."
    expand -t $BACKUP_SQL$c ||
        { echo "Error, bad compressed DB dump - '$BACKUP_SQL$c'." ; return 1 ; }
    echo "Compression looks OK. Checking DB dump contents..."

    echo "Generating a list of tables and record counts in the DB dump..."
    expand -c "$BACKUP_SQL$c" |
      /usr/bin/awk '/CREATE TABLE/ { tbl = $3; gsub("`","",tbl); records[tbl] = 0; } \
        /INSERT INTO/  { tbl = $3; gsub("`","",tbl); \
                         n = split(substr($0,index($0,"VALUES (")+7),vals,"\\),\\("); \
                         records[tbl] += n; } \
        END { for (tbl in records) print tbl, records[tbl]; }' |
      /bin/sed 's/mythlog [0-9]*/mythlog 0/' |
      /usr/bin/sort >$SAVED_TABLES
    has_records "$SAVED_TABLES" "DB dump" || return 1

    echo "Generating a list of tables and record counts in the live DB..."
    for tbl in $(mysql_cmd "show tables") ; do
        mysql_cmd "select '$tbl', count(*) from $tbl"
    done |
      /usr/bin/tr -s '\t' ' ' |
      /bin/sed 's/mythlog [0-9]*/mythlog 0/' |
      /usr/bin/sort >$LIVE_TABLES
    has_records "$LIVE_TABLES" "live DB" || return 1

    echo "Comparing live versus saved tables..."
    case $0 in
    *restore) # database must include everything from the backup
        subset $SAVED_TABLES $LIVE_TABLES
        ;;
    *)        # backup must exactly match the database
        /usr/bin/diff $LIVE_TABLES $SAVED_TABLES
        ;;
    esac
    TABLE_STATUS=$?
    /bin/rm $LIVE_TABLES $SAVED_TABLES
    if [ $TABLE_STATUS -eq 0 ] ; then
        echo "Live and saved table lists match."
    else
        echo "Warning, table lists are not identical!"
    fi
    return $TABLE_STATUS
}

check_files_and_tables () {
    STATUS=0
    echo
    check_files "$@" || STATUS=1
    echo
    check_tables || STATUS=1
    echo
    return $STATUS
}

true # Make sure that this shows success