#!/bin/bash 
#
# ============LICENSE_START=======================================================
# ONAP
# ================================================================================
# Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
# ================================================================================
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ============LICENSE_END=========================================================

# #####################################################################
#
# Upgrade/Downgrade SQL File Name Format:  
#
# 	<VERSION>-<pdp|feature-name>[-description](.upgrade|.downgrade).sql
#
# This tool operates on a migration working directory at
# 
#	$POLICY_HOME/etc/db/migration
#
# Upgrade/Downgrade files for each schema (aka database) names to be maintained 
# by this tool are located at
#
#	$POLICY_HOME/etc/db/migration/<schema-name>/sql
#
# The nature of the migration directories is dynamic.
# Other tooling aware of when migrations are needed are in charge to populate
# the migrations directory accordingly.   
#
# One of these tools is the 'features' when a feature with DB requirements
# is 'enabled', the upgrade scripts will be made present in the migration directory.
# When a features is 'disabled' downgrade scripts will be made available in the
# migration directory.
#
# The 'policy' tool via its operations 'status' or 'start' will signal the 
# need to perform upgrade or downgrade for a given schema.
#
# At any given time the following invariant must be preserved in any given
# $POLICY_HOME/etc/db/migration/<schema-name>/sql directory
#
# 	There is only upgrade scripts, or only downgrade scripts, or none.
#
# #####################################################################

METADATA_DB=migration
METADATA_TABLE="${METADATA_DB}".metadata_versions
MIGRATION_DIR="${POLICY_HOME}"/etc/db/migration

ZERO_VERSION="0"
UPGRADE_SQL_SUFFIX=".upgrade.sql"
DOWNGRADE_SQL_SUFFIX=".downgrade.sql"

SQL_QUOTES="SET SESSION SQL_MODE=ANSI_QUOTES;"

#####################################################
# usage
#####################################################

function usage() {
	echo
	echo -e "syntax: $(basename "$0") "
	echo -e "\t -s <schema-name> "
	echo -e "\t [-b <migration-dir>] "
	echo -e "\t [-f <from-version>]"
	echo -e "\t [-t <target-version>]"
	echo -e "\t -o <operations> "
	echo 
	echo -e "\t where <operations>=upgrade|downgrade|auto|version|erase|report"
	echo
	echo
	echo -e "Configuration Options:"
	echo -e "\t -s|--schema|--database:  schema to operate on ('ALL' to apply on all)"		
	echo -e "\t -b|--basedir: overrides base DB migration directory"
	echo -e "\t -f|--from: overrides current release version for operations"
	echo -e "\t -t|--target: overrides target release to upgrade/downgrade"
	echo
	echo -e "Operations:"
	echo -e "\t upgrade: upgrade operation"
	echo -e "\t downgrade: performs a downgrade operation"
	echo -e "\t auto: autonomous operation, determines upgrade or downgrade"
	echo -e "\t version: returns current version, and in conjunction if '-f' sets the current version"
	echo -e "\t erase: erase all data related <schema> (use with care)"
	echo -e "\t report: migration detailed report on an schema"
	echo -e "\t ok: is the migration status valid"
	echo
	echo
}

#####################################################
# ensure global metadata
#####################################################

function ensure_metadata
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local sql rc
	
    sql="CREATE DATABASE IF NOT EXISTS ${METADATA_DB};"
	${MYSQL} --execute "${sql}"
	rc=$?
	if [[ ${rc} != 0 ]]; then
		return ${rc}
	fi
    
    sql="CREATE TABLE IF NOT EXISTS ${METADATA_TABLE} "
    sql+="(name VARCHAR(60) NOT NULL, version VARCHAR(20), PRIMARY KEY(name));"
	${MYSQL} --execute "${sql}"
	return $?
}


#####################################################
# ensure metadata on a per schema basis
#####################################################

function ensure_metadata_schema
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local sql rc
	
	sql="CREATE TABLE IF NOT EXISTS ${METADATA_HISTORY} "
	sql+="(script VARCHAR(80) NOT NULL, operation VARCHAR(10), success VARCHAR(1), "
	sql+="atTime TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, "
	sql+="PRIMARY KEY(script));"
	${MYSQL} --execute "${sql}"
	rc=$?
	if [[ ${rc} != 0 ]]; then
		return ${rc}
	fi
	
	sql="CREATE DATABASE IF NOT EXISTS ${SCHEMA_DB};"
	${MYSQL} --execute "${sql}"
	return $?
}


#####################################################
# target_release
#####################################################

function target_release
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local sql sqlName upgradeSqls downgradeSqls
	
	TARGET_UPGRADE_RELEASE=${ZERO_VERSION}
	TARGET_DOWNGRADE_RELEASE=${ZERO_VERSION}
	
	upgradeSqls=$(ls -v -r "${UPGRADE_DIR}"/*"${UPGRADE_SQL_SUFFIX}" 2> /dev/null)
	for sql in ${upgradeSqls}; do
		sqlName=$(basename "${sql}")
		TARGET_UPGRADE_RELEASE="${sqlName%-*}"
		break
	done
	
	# default unless overriden
	TARGET_DOWNGRADE_RELEASE="${ZERO_VERSION}"
}

#####################################################
# is_upgrade
#####################################################

function is_upgrade
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local upgradeSqls
	
	upgradeSqls=$(ls "${UPGRADE_DIR}"/*"${UPGRADE_SQL_SUFFIX}" 2> /dev/null)
	if [[ -z ${upgradeSqls} ]]; then
		return 1
	else
		return 0
	fi
}


#####################################################
# is_downgrade
#####################################################

function is_downgrade
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local downgradeSqls
	
	downgradeSqls=$(ls "${DOWNGRADE_DIR}"/*"${DOWNGRADE_SQL_SUFFIX}" 2> /dev/null)
	if [[ -z ${downgradeSqls} ]]; then
		return 1
	else
		return 0
	fi
}


#####################################################
# current_release
#####################################################

function current_release
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local rc
	local query="SELECT version FROM ${METADATA_TABLE} WHERE name='${SCHEMA}'"
	
	CURRENT_RELEASE=$(${MYSQL} --skip-column-names --silent --execute "${query}")	
	if [[ -z ${CURRENT_RELEASE} ]]; then
		set_current_release "${ZERO_VERSION}"
		return $?
	fi
	
	return 0
}


#####################################################
# set_current_release
#####################################################

function set_current_release
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} $* --"
		set -x
	fi
	
	CURRENT_RELEASE="${1}"
	
	local sql="INSERT INTO ${METADATA_TABLE} (name, version) "
	sql+="VALUES('${SCHEMA}', '${CURRENT_RELEASE}') "
	sql+="ON DUPLICATE KEY UPDATE version='${CURRENT_RELEASE}';"
					
	${MYSQL} --execute "${sql}"
	return $?
}


#####################################################
# execute sql script history
#####################################################

function track_script
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} $* --"
		set -x
	fi
	
	local script="${1}" operation="${2}" success="${3}"	
	local sql="INSERT INTO ${METADATA_HISTORY}(script,operation,success,atTime) "
	sql+="VALUES ('${script}','${operation}','${success}',now()) "
	sql+="ON DUPLICATE KEY UPDATE operation=values(operation), success=values(success), atTime=values(atTime);"
				
	${MYSQL} --execute "${sql}"
	return $?
}


#####################################################
# execute sql script
#####################################################

function run_script
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} $* --"
		set -x
	fi
	
	local operation="${1}" script="${2}" scriptPath="${3}"
	
	echo
	echo "> ${operation} ${script}"
	
	${MYSQL} --verbose < "${scriptPath}"
	local rc=$?
	if [[ ${rc} != 0 ]]; then
		success="0"
	else
		success="1"
	fi
	
	track_script "${script}" "${operation}" "${success}"
	
	return ${rc}
}

#####################################################
# upgrade
#####################################################

function upgrade
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local sqlName sqlFile schemaVersion upgradeSqls rc
	
	${MYSQL} --execute "USE ${SCHEMA_DB}"
	
	echo "upgrade: ${CURRENT_RELEASE} -> ${TARGET_UPGRADE_RELEASE}"
	
	if [[ ${CURRENT_RELEASE} < ${TARGET_UPGRADE_RELEASE} ]]; then 
		upgradeSqls=$(ls -v "${UPGRADE_DIR}"/*"${UPGRADE_SQL_SUFFIX}" 2> /dev/null)
	    for sqlFile in ${upgradeSqls}; do
	    	sqlName=$(basename "${sqlFile}")
			schemaVersion="${sqlName%-*}"
	    	if [ "${schemaVersion}" -gt "${CURRENT_RELEASE}" ] && \
	    		[ "${schemaVersion}" -le "${TARGET_UPGRADE_RELEASE}" ]; then
	    		run_script "upgrade" "${sqlName}" "${sqlFile}"
	    		rc=$?
				if [[ ${rc} != 0 ]]; then
	        		echo "${SCHEMA}: upgrade aborted at ${schemaVersion} by script ${sqlName}"
	        		set_current_release "${schemaVersion}"
	        		return ${rc}
	        	fi
	    	fi
	    done
   	
    	set_current_release "${TARGET_UPGRADE_RELEASE}"
	fi
	
	return 0
}

#####################################################
# downgrade
#####################################################

function downgrade
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local sqlName sqlFile schemaVersion downgradeSqls rc
	
	${MYSQL} --execute "USE ${SCHEMA_DB}"
	
	echo "downgrade: ${CURRENT_RELEASE} -> ${TARGET_DOWNGRADE_RELEASE}"
	
	if [[ ${CURRENT_RELEASE} > ${TARGET_DOWNGRADE_RELEASE} ]]; then 
		downgradeSqls=$(ls -v -r "${DOWNGRADE_DIR}"/*"${DOWNGRADE_SQL_SUFFIX}" 2> /dev/null)
		for sqlFile in ${downgradeSqls}; do
	    	sqlName=$(basename "${sqlFile}")
			schemaVersion="${sqlName%-*}"
	    	if [ "${schemaVersion}" -le "${CURRENT_RELEASE}" ] && \
	    		[ "${schemaVersion}" -gt "${TARGET_DOWNGRADE_RELEASE}" ]; then
	        	run_script "downgrade" "${sqlName}" "${sqlFile}"
	        	rc=$?
				if [[ ${rc} != 0 ]]; then
	        		echo "${SCHEMA}: downgrade aborted at ${schemaVersion} by script ${sqlName}"
	        		set_current_release "${schemaVersion}"
	        		return ${rc}
	        	fi
	    	fi
	    done
    	
    	set_current_release "${TARGET_DOWNGRADE_RELEASE}"
	fi
	
	return 0
}

#####################################################
# erase
#####################################################

function erase
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local updateMetadata="UPDATE ${METADATA_TABLE} SET version='${ZERO_VERSION}';"
	${MYSQL} --execute "${updateMetadata}"
	
	local deleteHistory="DELETE FROM ${METADATA_HISTORY};"
	${MYSQL} --execute "${deleteHistory}"
	
	local dropDB="DROP DATABASE IF EXISTS ${SCHEMA_DB}";
	${MYSQL} --execute "${dropDB}"
}

#####################################################
# report
#####################################################

function report
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local versionSql="SELECT * FROM ${METADATA_TABLE} WHERE name='${SCHEMA}';"
	${MYSQL} --execute "${versionSql}"
	
	local historySql="SELECT * FROM ${METADATA_HISTORY} ORDER BY atTime ASC;"
	${MYSQL} --execute "${historySql}"
	
	okay
}

function okay
{
	if [[ ${DEBUG} == y ]]; then
		echo "-- ${FUNCNAME[0]} --"
		set -x
	fi
	
	local rc=0
	if is_upgrade; then
		if [[ ${CURRENT_RELEASE} == "${TARGET_UPGRADE_RELEASE}" ]]; then
			echo "${SCHEMA}: OK @ ${CURRENT_RELEASE}"
		else
			echo "${SCHEMA}: upgrade available: ${CURRENT_RELEASE} -> ${TARGET_UPGRADE_RELEASE}"
			rc=1
		fi
	else
		if [[ ${CURRENT_RELEASE} == "${TARGET_DOWNGRADE_RELEASE}" ]]; then
			echo "${SCHEMA}: OK @ ${CURRENT_RELEASE}"
		else
			echo "${SCHEMA}: downgrade available: ${CURRENT_RELEASE} -> ${TARGET_DOWNGRADE_RELEASE}"
			rc=1
		fi
	fi
	
	return ${rc}
}

#####################################################
# MAIN
#####################################################

if [[ ${DEBUG} == y ]]; then
	echo "-- $0 $* --"
	set -x
fi

until [[ -z "$1" ]]; do
	case $1 in
		-s|--schema|--database)	shift
								SCHEMA=$1
								;;
		-b|--basedir)   shift
						MIGRATION_DIR=$1		
						;;
		-t|--target)    shift
						INPUT_TARGET_RELEASE=$1		
						;;
		-f|--from)      shift
						INPUT_CURRENT_RELEASE=$1		
						;;
		-o|--operation) shift
						OPERATION=$1		
						;;
		*)				usage
						exit 1
						;;
	esac
	shift
done

case ${OPERATION} in
	upgrade)	;;
	downgrade)	;;
	auto)	;;
	version)	;;
	erase)		;;
	report)		;;
	ok)			;;
	*)			echo "error: invalid operation provided"
				usage
				exit 1
				;;
esac

if [[ -z ${SCHEMA} ]]; then
	echo "error: a database name must be provided"
	usage
	exit 2
fi

source "${POLICY_HOME}"/etc/profile.d/base.conf

if [[ -z ${SQL_HOST} ]] || [[ -z ${SQL_USER} ]] || [[ -z ${SQL_PASSWORD} ]]; then
	echo "error: no database has been set up" 
	exit 4
fi

MYSQL="mysql -u${SQL_USER} -p${SQL_PASSWORD} -h ${SQL_HOST}";
if ! ${MYSQL} -h"${SQL_HOST}" --execute "show databases;" > /dev/null 2>&1; then
	echo "error: No DB connectivity to ${SQL_HOST} for ${SQL_USER}"
	exit 5
fi

if [[ ${SCHEMA} == ALL ]]; then
	SCHEMA="*"
fi

SCHEMA_S=$(ls -d "${MIGRATION_DIR}"/${SCHEMA}/ 2> /dev/null)
if [[ -z ${SCHEMA_S} ]]; then
	echo "error: no databases available"
	exit 0
fi

if ! ensure_metadata; then
	echo "error: migration metadata not accessible"
	exit 7
fi

rc=0
for dbPath in ${SCHEMA_S}; do
	SCHEMA=$(basename "${dbPath}")
	SCHEMA_DB="\`${SCHEMA}\`"
	UPGRADE_DIR="${MIGRATION_DIR}"/"${SCHEMA}"/sql
	DOWNGRADE_DIR=${UPGRADE_DIR}
	METADATA_HISTORY="${METADATA_DB}.\`${SCHEMA}_history\`"
	TARGET_RELEASE=${INPUT_TARGET_RELEASE}
	CURRENT_RELEASE=${INPUT_CURRENT_RELEASE}
	
	if is_upgrade && is_downgrade; then
		echo "${SCHEMA}: failure: invalid configuration: ${UPGRADE_SQL_SUFFIX} and "\
			"${DOWNGRADE_SQL_SUFFIX} exist under ${DOWNGRADE_DIR}"
		rc=1
		continue
	fi
	
	if [[ ${operation} == auto ]]; then
		if is_upgrade; then
			operation=upgrade
		else
			operation=downgrade
		fi
	fi
	
	if ! ensure_metadata_schema; then
		echo "${SCHEMA}: failure: metadata not accessible for this schema"
		continue
	fi	
	
	if [[ -z ${TARGET_RELEASE} ]]; then
		target_release
	else
		# user asked to override
		TARGET_UPGRADE_RELEASE="${TARGET_RELEASE}"
		TARGET_DOWNGRADE_RELEASE="${TARGET_RELEASE}"
	fi
	
	if [[ -z ${CURRENT_RELEASE} ]]; then
		if ! current_release; then
			echo "${SCHEMA}: failure: cannot obtain current release"
			continue
		fi
	else
		if ! set_current_release "${CURRENT_RELEASE}"; then
			echo "${SCHEMA}: failure: cannot set current release"
			continue
		fi
	fi
	
	case ${OPERATION} in
		upgrade) 	if upgrade; then
						echo "${SCHEMA}: OK: upgrade (${CURRENT_RELEASE})"
					else
						rc=1
						echo "${SCHEMA}: failure: upgrade to release ${TARGET_UPGRADE_RELEASE} (${CURRENT_RELEASE})"
					fi			
					;;
		downgrade)  if downgrade; then
						echo "${SCHEMA}: OK: downgrade (${CURRENT_RELEASE})"
					else
						rc=1
						echo "${SCHEMA}: failure: downgrade to release ${TARGET_DOWNGRADE_RELEASE} (${CURRENT_RELEASE})"
					fi					
					;;
		version) 	echo "${SCHEMA}: ${CURRENT_RELEASE}"
					;;
		erase) 		erase 
					;;
		report) 	report
					;;
		ok) 		okay
					;;
	esac

done
exit ${rc}