#!/bin/bash

SRCDIR=/var/www
DSTDIR=/var/www/backups

main()
{
    #  Process arguments
    if [ $# = 1 ]; then
        SITENAME=$1
    else
        if [ $# = 0 ]; then
            SITENAMES=( $(ls $SRCDIR | fgrep . ) )
        else
            SITENAMES=( "$@" )
        fi
        while :; do
            for ((I=0; I<${#SITENAMES[*]}; I++)); do
                echo "$((I+1))) ${SITENAMES[$I]}"
            done
            echo "q) quit"
            echo
            read -p "Choice: " CHOICE
            if ! [[ $CHOICE =~ ^(q|[1-9][0-9]*)$ ]]; then
                echo "invalid choice"
            elif [ $CHOICE = q ]; then
                echo "quiting ..."
                exit
            elif [ $CHOICE -gt ${#SITENAMES[*]} ]; then
                echo "$CHOICE: no such number listed above"
            else
                SITENAME=${SITENAMES[$((CHOICE-1))]}
                echo
                break
            fi
            echo
        done
    fi


    #  Sanity checks and derivations
    DATABASE=${SITENAME//./}

    #  Guts
    cd $SRCDIR

    while :; do
        echo "Site-Name: $SITENAME"
        echo
        echo "l) list old checkpoints (names will be displayed in 'YYYYMMDDHHMMSS' format)"
        echo "c) create checkpoint (i.e. save current state so you can restore to this later)"
        echo "r) restore old checkpoint (you'll be asked which one to restore)"
        echo "d) delete old checkpoint (you'll be asked which one to delete)"
        echo "q) quit"
        echo
        read -p "Choice: " CHOICE
        if ! [[ $CHOICE =~ ^[qcrdl]$ ]]; then
            echo "invalid choice"
        elif [ $CHOICE = q ]; then
            echo "quiting ..."
            exit
        elif [ $CHOICE = c ]; then
            CAPACITY=$(df -P . | sed -nr 's/.* ([1-9][0-9]*)%.*/\1/p')
            if [ $CAPACITY -gt 80 ]; then
                echo "there is not enough space to create a new checkpoint (hint: use 'd' to delete any unwanted checkpoints or contact Alexis)"
                echo
                continue
            fi
            CHECKPOINT_ID=$(date +%Y%m%d%H%M%S)
            echo -n "$CHECKPOINT_ID: creating checkpointing (this can take a minute, don't panic) ... "
            tar czf $DSTDIR/$SITENAME.$CHECKPOINT_ID.tar.gz $SITENAME
            mysqldump --lock-tables --databases $DATABASE | gzip > $DSTDIR/$SITENAME.$CHECKPOINT_ID.sql.gz
            #  Only touch the flag file once everything else is done.
            touch $DSTDIR/$SITENAME.$CHECKPOINT_ID.flg
            echo
            echo "$CHECKPOINT_ID: checkpoint created (hint: note down that id and something about what it contains)"
        elif [ $CHOICE = r ]; then
            read -p "Checkpoint-ID: " CHECKPOINT_ID
            if [ ! -f $DSTDIR/$SITENAME.$CHECKPOINT_ID.flg ]; then
                echo "$CHECKPOINT_ID: no checkpoint found with this id (hint: use 'l' to list known checkpoints and if it really does exist then contact Alexis)"
                echo
                continue
            fi
            UNTAR_DIR=$(mktemp -d)
            echo -n "$CHECKPOINT_ID: restoring checkpoint (this can take a minute, don't panic) ... "
            tar xzfC $DSTDIR/$SITENAME.$CHECKPOINT_ID.tar.gz $UNTAR_DIR
            rsync -a --delete $UNTAR_DIR/$SITENAME/ $SITENAME/
            zcat $DSTDIR/$SITENAME.$CHECKPOINT_ID.sql.gz | mysql $DATABASE
            rm -fr $UNTAR_DIR
            echo 
            echo "$CHECKPOINT_ID: checkpoint restored"
        elif [ $CHOICE = d ]; then
            read -p "Checkpoint-ID: " CHECKPOINT_ID
            if [ ! -f $DSTDIR/$SITENAME.$CHECKPOINT_ID.flg ]; then
                echo "$CHECKPOINT_ID: no checkpoint found with this id (hint: use 'l' to list known checkpoints and if it really does exist then contact Alexis)"
                echo
                continue
            fi
            echo -n "$CHECKPOINT_ID: deleting checkpoint ... "
            rm $DSTDIR/$SITENAME.$CHECKPOINT_ID.{flg,tar.gz,sql.gz} 
            echo
            echo "$CHECKPOINT_ID: checkpoint deleted"
        elif [ $CHOICE = l ]; then
            ls $DSTDIR | sed -nr "s@^$SITENAME\.(.*)\.flg\$@\\1@p" | sort -u
        else
            echo "this should not happen (hint: tell Alexis it did!)"
        fi
        echo
    done
}

main "$@"