#!/bin/bash
ARCHPATH='/path/to/backup/daily/'
SUBDIR='backup_data'
SKIPDBS=('mysql' 'schema' 'to' 'skip')
FULLRESTORE=true
SETPOSDB=db_for_master_log_position
CFG='~/.my.cnf'
#---

START=$(date +%s)

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

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

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

if [[ $FULLRESTORE == false ]]; then
    OLDDATE=$(ls -1d $ARCHPATH | head -1)
    echo "compartive restoration selected:  files from '$NEWDATE' will be compared to '$OLDDATE'"
else
    echo "full restorion selected: comparisons will be made, all non-excluded databases will be restored"
fi

NEWDATE=$(ls -1rd $ARCHPATH | head -1)
for FILE in $NEWDATE/$SUBDIR/*.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 $OLDDATE/$SUBDIR/$FILE)
    else
        OLDSIZE=0
    fi

    NEWSIZE=$(stat -c %s $NEWDATE/$SUBDIR/$FILE)
    
    if [[ $OLDSIZE != $NEWSIZE ]]; then
    	DB=$(echo $FILE | cut -f1 -d'.')
        echo -e "\tDROPPING/CREATING '$DB'
        pv $NEWDATE/$SUBDIR/$FILE | gunzip | mysql $DB"
        mysql -e "DROP DATABASE IF EXISTS $DB"
        mysql -e "CREATE DATABASE $DB"
        pv $NEWDATE/$SUBDIR/$FILE | gunzip | mysql $DB
    fi
    ENDLOOP=$(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 $SETPOSFILE | head -40 | rg MASTER | sed 's/-- //')
    echo "\n$SETPOSSTMT\n"
    mysql -e "$SETPOS"
fi

#echo -e "restarting replication"
#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"