#!/bin/bash
ARCHPATH='/path/to/backup/daily/'
SUBDIR='backup_data'
SKIPDBS=('mysql')
FULLRESTORE=false
SETPOSDB=db_for_master_log_position
CFG='~/.my.cnf'
DRY_RUN=false
NOPROMPT=false
CMD=''
#---

while [[ $# -gt 0 ]]; do
    case $1 in
    -d|--dry-run) 
        DRY_RUN=true 
        CMD=echo
        $PIPE
        shift 1
        ;;
    -a|--arch)
        ARCHPATH=$2
        shift 2
        ;;
    -s|--subdir)
        SUBDIR=$2
        shift 2
        ;;
    -k|--skip)
        SKIPDBS=($2)
        shift 2
        ;;
    -f|--full)
        FULLRESTORE=true
        shift 1
        ;;
    -p|--pos)
        SETPOSDB=$2
        shift 2
        ;;
    -c|--cfg)
        CFG=$2
        shift 2
        ;;
    -n|--noprompt )
        NOPROMPT=true
        shift 1
        ;;
    *) echo 'error in command line parsing' >&2
        exit 1
    esac
done

ARCHPATH="${ARCHPATH%/}/"
SUBDIR="${SUBDIR%/}/"


echo "restore with options:"
echo -e "\tarchive path    = $ARCHPATH"
echo -e "\tsubdirectory    = $SUBDIR"
echo -e "\tDBs to skip     = ${SKIPDBS[@]}"
echo -e "\tfull restore    = $FULLRESTORE"
echo -e "\tDB for position = $SETPOSDB"
echo -e "\tconfig file     = $CFG"
echo -e "\tdry run         = $DRY_RUN"
echo -e "\n"

if [[ -f "$CFG" ]]; then
    if [[ ! $(grep user ~/.my.cnf) ]]; then
        echo "ERROR: 'user' field not found in '$CFG'"
        exit 1
    fi
    if [[ ! $(grep password ~/.my.cnf) ]]; then
        echo "ERROR: 'password' field not found in '$CFG'"
        exit 1
    fi
else
    echo "ERROR: configuration file '$CFG' not found"
    exit 1
fi

if [[ $NOPROMPT == false ]]; then
    read -n 1 -p "restore? [Y/n] " reply; 
    if [[ $reply == [Nn] ]]; then 
        echo -e "\naborting"
        exit 1
    fi
fi

echo -e "\nrestoring" 

START=$(date +%s)

echo -e "\n--START: $(date +%F\ %T)\nrestoring most recent backups from $ARCHPATH"
echo -e "\tstopping replication\n";
$CMD mysql -e "STOP SLAVE;"

NEWDATE=$(ls -1r "$ARCHPATH" | head -1)
NEWPATH="$ARCHPATH$NEWDATE$SUBDIR"

if [[ $FULLRESTORE == false ]]; then
    OLDDATE=$(ls -1rt "$ARCHPATH" | head -1)
    OLDPATH="$ARCHPATH$OLDATE$SUBDIR"
    echo "compartive restoration selected:  files from '$NEWDATE' will be compared to '$OLDDATE'"
else
    echo "full restorion selected: comparisons will not be made, all non-excluded databases will be restored"
fi

for FILE in $NEWPATH/*.gz; do
    FILE=$(basename $FILE)
    STARTLOOP=$(date +%s)
    echo -e "\n$(date +%F\ %T) | $FILE:"
        
    if [[ "${SETPOSDB}" =~ ${FILE%%.*} ]]; then echo -e "\t-- recognized $FILE for master position and log file";SETPOSFILE=$(realpath $FILE); fi;
    if [[ "${SKIPDBS[*]}" =~ ${FILE%%.*} ]]; then echo -e "\t-- skipping $FILE";continue; fi; 

    if [[ ! -z $OLDDATE ]]; then 
        OLDSIZE=$(stat -c %s $OLDPATH$FILE)
    else
        OLDSIZE=0
    fi

    NEWSIZE=$(stat -c %s $NEWPATH/$FILE)
    
    if [[ $OLDSIZE != $NEWSIZE ]]; then
    	DB=$(echo $FILE | cut -f1 -d'.')
        echo -e "\tDROPPING/CREATING '$DB'
        pv $NEWPATH$FILE | gunzip | mysql $DB"
        $CMD mysql -e "DROP DATABASE IF EXISTS $DB"
        $CMD mysql -e "CREATE DATABASE $DB"
        if [[ -z $CMD ]]; then pv $NEWPATH$FILE | gunzip | mysql $DB; fi
    fi
    ENDLOOP=$(date +%s)
    EXCTIME=$(expr $ENDLOOP - $STARTLOOP)
    printf '\t%02dh:%02dm:%02ds\n' $((EXCTIME/3600)) $((EXCTIME%3600/60)) $((EXCTIME%60))        
done

if [[ -z $SETPOSFILE ]]; then
    SETPOSSTMT=$(zcat $SETPOSFILE | head -40 | grep MASTER | sed 's/-- //')
    echo "\n$SETPOSSTMT\n"
    $CMD mysql -e "$SETPOS"
fi

if [[ $NOPROMPT == false ]]; then
    read -n 1 -p "restart replication? [Y/n] " reply; 
    if [[ $reply == [Nn] ]]; then 
        echo -e "\naborting"
        exit 1
    fi
fi

echo -e "restarting replication"
$CMD mysql -e "START SLAVE"

END=$(date +%s)
EXCTIME=$(expr $END - $START)
printf 'total runtime: %02dh:%02dm:%02ds\n' $((EXCTIME/3600)) $((EXCTIME%3600/60)) $((EXCTIME%60))
echo "--END: $(date +%F\ %T)\n\n"