#!/bin/bash

# Copyright 2013 Percona LLC and/or its affiliates

POSITIONAL=()
while [[ $# -gt 0 ]]
do
key="$1"

case $key in
    -h|--host)
    HOST="$2"
    shift # past argument
    shift # past value
    ;;
    -u|--user)
    USER="$2"
    shift # past argument
    shift # past value
    ;;
    -p|--password)
    PASSWORD="$2"
    shift # past argument
    shift # past value
    ;;
    --no-password)
    NOPW=YES
    shift # past argument
    ;;
    --help)
    HELP=YES
    shift # past argument
    ;;
    *)    # unknown option
    POSITIONAL+=("$1") # save it in an array for later
    shift # past argument
    ;;
esac
done

set -- "${POSITIONAL[@]}" # restore positional parameters
DBFROM=$1
DBTO=$2

echo "Renaming database ${DBFROM} to ${DBTO} on host ${HOST} with user name ${USER}..."
if [ -n "$NOPW" ]; then
	echo "Not using password."
else
	echo "Using password."
fi

if [ -n "$HELP" ]; then
    echo "rename_db <old_db> <new_db> -h <server> -u <user> -p <password> or --no-password"
    exit 1
fi

if [ -n "$NOPW" ]; then
    MYSQL="mysql -h $HOST -u $USER"
else
    MYSQL="mysql -h $HOST -u $USER -p$PASSWORD"
fi

db_exists=`$MYSQL -e "show databases like '$DBTO'" -sss`
if [ -n "$db_exists" ]; then
    echo "ERROR: New database already exists: $DBTO"
    exit 1
fi
echo "OK: New database doesn't exist"

TIMESTAMP=`date +%s`
character_set=`$MYSQL -e "SELECT default_character_set_name FROM information_schema.SCHEMATA WHERE schema_name = '$DBFROM'" -sss`
TABLES=`$MYSQL -e "select TABLE_NAME from information_schema.tables where table_schema='$DBFROM' and TABLE_TYPE='BASE TABLE'" -sss`
STATUS=$?
if [ "$STATUS" != 0 ] || [ -z "$TABLES" ]; then
    echo "Error retrieving tables from $DBFROM"
    exit 1
fi
echo "create database $DBTO DEFAULT CHARACTER SET $character_set"
$MYSQL -e "create database $DBTO DEFAULT CHARACTER SET $character_set"
TRIGGERS=`$MYSQL $DBFROM -e "show triggers" | grep Trigger: | awk '{print $DBFROM}'`
VIEWS=`$MYSQL -e "select TABLE_NAME from information_schema.tables where table_schema='$DBFROM' and TABLE_TYPE='VIEW'" -sss`
if [ -n "$VIEWS" ]; then
    mysqldump -h $HOST $DBFROM $VIEWS > /tmp/${DBFROM}_views${TIMESTAMP}.dump
fi
mysqldump -h $HOST $DBFROM -d -t -R -E > /tmp/${DBFROM}_triggers${TIMESTAMP}.dump
for TRIGGER in $TRIGGERS; do
    echo "drop trigger $TRIGGER"
    $MYSQL $DBFROM -e "drop trigger $TRIGGER"
done
for TABLE in $TABLES; do
    echo "rename table $DBFROM.$TABLE to $DBTO.$TABLE"
    $MYSQL $DBTO -e "SET FOREIGN_KEY_CHECKS=0; rename table $DBFROM.$TABLE to $DBTO.$TABLE"
done
if [ -n "$VIEWS" ]; then
    echo "Loading views..."
    $MYSQL $DBTO < /tmp/${DBFROM}_views${TIMESTAMP}.dump
    echo "Done."
fi
echo "Loading triggers, routines and events..."
$MYSQL $DBTO < /tmp/${DBFROM}_triggers${TIMESTAMP}.dump
TABLES=`$MYSQL -e "select TABLE_NAME from information_schema.tables where table_schema='$DBFROM' and TABLE_TYPE='BASE TABLE'" -sss`
if [ -z "$TABLES" ]; then
    echo "Dropping database $DBFROM"
    $MYSQL $DBFROM -e "drop database $DBFROM"
fi
if [ `$MYSQL -e "select count(*) from mysql.columns_priv where db='$DBFROM'" -sss` -gt 0 ]; then
    COLUMNS_PRIV="    UPDATE mysql.columns_priv set db='$DBTO' WHERE db='$DBFROM';"
fi
if [ `$MYSQL -e "select count(*) from mysql.procs_priv where db='$DBFROM'" -sss` -gt 0 ]; then
    PROCS_PRIV="    UPDATE mysql.procs_priv set db='$DBTO' WHERE db='$DBFROM';"
fi
if [ `$MYSQL -e "select count(*) from mysql.tables_priv where db='$DBFROM'" -sss` -gt 0 ]; then
    TABLES_PRIV="    UPDATE mysql.tables_priv set db='$DBTO' WHERE db='$DBFROM';"
fi
if [ `$MYSQL -e "select count(*) from mysql.db where db='$DBFROM'" -sss` -gt 0 ]; then
    DB_PRIV="    UPDATE mysql.db set db='$DBTO' WHERE db='$DBFROM';"
fi
echo "Rename Done."
if [ -n "$COLUMNS_PRIV" ] || [ -n "$PROCS_PRIV" ] || [ -n "$TABLES_PRIV" ] || [ -n "$DB_PRIV" ]; then
    echo "IF YOU WANT TO RENAME the GRANTS YOU NEED TO RUN ALL OUTPUT BELOW:"
    if [ -n "$COLUMNS_PRIV" ]; then echo "$COLUMNS_PRIV"; fi
    if [ -n "$PROCS_PRIV" ]; then echo "$PROCS_PRIV"; fi
    if [ -n "$TABLES_PRIV" ]; then echo "$TABLES_PRIV"; fi
    if [ -n "$DB_PRIV" ]; then echo "$DB_PRIV"; fi
    echo "    flush privileges;"
fi