/*
Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
Copyright (C) ITsysCOM GmbH

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>
*/
package engine

import (
	"errors"
	"fmt"

	"github.com/cgrates/cgrates/utils"
)

func CheckVersion(dataDB DataDB) error {
	// get current db version
	if dataDB == nil {
		dataDB = dataStorage
	}
	dbVersion, err := dataDB.GetStructVersion()
	if err != nil {
		if lhList, err := dataDB.GetLoadHistory(1, true, utils.NonTransactional); err != nil || len(lhList) == 0 {
			// no data, write version
			if err := dataDB.SetStructVersion(CurrentVersion); err != nil {
				utils.Logger.Warning(fmt.Sprintf("Could not write current version to db: %v", err))
			}
		} else {
			// has data but no version => run migration
			msg := "Could not detect data structures version: run appropriate migration"
			utils.Logger.Crit(msg)
			return errors.New(msg)
		}
	} else {
		// comparing versions
		if len(CurrentVersion.CompareAndMigrate(dbVersion)) > 0 {
			// write the new values
			msg := "Migration needed: please backup cgr data and run cgr-loader -migrate"
			utils.Logger.Crit(msg)
			return errors.New(msg)
		}
	}
	return nil
}

var (
	CurrentVersion = &StructVersion{
		Destinations:    "1",
		RatingPlans:     "1",
		RatingProfiles:  "1",
		Lcrs:            "1",
		DerivedChargers: "1",
		Actions:         "1",
		ActionPlans:     "1",
		ActionTriggers:  "1",
		SharedGroups:    "1",
		Accounts:        "1",
		CdrStats:        "1",
		Users:           "1",
		Alias:           "1",
		PubSubs:         "1",
		LoadHistory:     "1",
		Cdrs:            "1",
		SMCosts:         "1",
		ResourceConfigs: "1",
		Timings:         "1",
	}
)

type StructVersion struct {
	Destinations    string
	RatingPlans     string
	RatingProfiles  string
	Lcrs            string
	DerivedChargers string
	Actions         string
	ActionPlans     string
	ActionTriggers  string
	SharedGroups    string
	Accounts        string
	CdrStats        string
	Users           string
	Alias           string
	PubSubs         string
	LoadHistory     string
	Cdrs            string
	SMCosts         string
	ResourceConfigs string
	Timings         string
}

type MigrationInfo struct {
	Prefix         string
	DbVersion      string
	CurrentVersion string
}

func (sv *StructVersion) CompareAndMigrate(dbVer *StructVersion) []*MigrationInfo {
	var migrationInfoList []*MigrationInfo
	if sv.Destinations != dbVer.Destinations {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.DESTINATION_PREFIX,
			DbVersion:      dbVer.Destinations,
			CurrentVersion: CurrentVersion.Destinations,
		})

	}
	if sv.RatingPlans != dbVer.RatingPlans {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.RATING_PLAN_PREFIX,
			DbVersion:      dbVer.RatingPlans,
			CurrentVersion: CurrentVersion.RatingPlans,
		})
	}
	if sv.RatingProfiles != dbVer.RatingProfiles {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.RATING_PROFILE_PREFIX,
			DbVersion:      dbVer.RatingProfiles,
			CurrentVersion: CurrentVersion.RatingProfiles,
		})
	}
	if sv.Lcrs != dbVer.Lcrs {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.LCR_PREFIX,
			DbVersion:      dbVer.Lcrs,
			CurrentVersion: CurrentVersion.Lcrs,
		})
	}
	if sv.DerivedChargers != dbVer.DerivedChargers {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.DERIVEDCHARGERS_PREFIX,
			DbVersion:      dbVer.DerivedChargers,
			CurrentVersion: CurrentVersion.DerivedChargers,
		})
	}
	if sv.Actions != dbVer.Actions {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.ACTION_PREFIX,
			DbVersion:      dbVer.Actions,
			CurrentVersion: CurrentVersion.Actions,
		})
	}
	if sv.ActionPlans != dbVer.ActionPlans {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.ACTION_PLAN_PREFIX,
			DbVersion:      dbVer.ActionPlans,
			CurrentVersion: CurrentVersion.ActionPlans,
		})
	}
	if sv.ActionTriggers != dbVer.ActionTriggers {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.ACTION_TRIGGER_PREFIX,
			DbVersion:      dbVer.ActionTriggers,
			CurrentVersion: CurrentVersion.ActionTriggers,
		})
	}
	if sv.SharedGroups != dbVer.SharedGroups {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.SHARED_GROUP_PREFIX,
			DbVersion:      dbVer.SharedGroups,
			CurrentVersion: CurrentVersion.SharedGroups,
		})
	}
	if sv.Accounts != dbVer.Accounts {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.ACCOUNT_PREFIX,
			DbVersion:      dbVer.Accounts,
			CurrentVersion: CurrentVersion.Accounts,
		})
	}
	if sv.CdrStats != dbVer.CdrStats {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.CDR_STATS_PREFIX,
			DbVersion:      dbVer.CdrStats,
			CurrentVersion: CurrentVersion.CdrStats,
		})
	}
	if sv.Users != dbVer.Users {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.USERS_PREFIX,
			DbVersion:      dbVer.Users,
			CurrentVersion: CurrentVersion.Users,
		})
	}
	if sv.Alias != dbVer.Alias {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.ALIASES_PREFIX,
			DbVersion:      dbVer.Alias,
			CurrentVersion: CurrentVersion.Alias,
		})
	}
	if sv.PubSubs != dbVer.PubSubs {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.PUBSUB_SUBSCRIBERS_PREFIX,
			DbVersion:      dbVer.PubSubs,
			CurrentVersion: CurrentVersion.PubSubs,
		})
	}
	if sv.LoadHistory != dbVer.LoadHistory {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.LOADINST_KEY,
			DbVersion:      dbVer.LoadHistory,
			CurrentVersion: CurrentVersion.LoadHistory,
		})
	}
	if sv.Cdrs != dbVer.Cdrs {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.CDRS_SOURCE,
			DbVersion:      dbVer.RatingPlans,
			CurrentVersion: CurrentVersion.RatingPlans,
		})
	}
	if sv.SMCosts != dbVer.SMCosts {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.SMG,
			DbVersion:      dbVer.SMCosts,
			CurrentVersion: CurrentVersion.SMCosts,
		})
	}
	if sv.ResourceConfigs != dbVer.ResourceConfigs {
		migrationInfoList = append(migrationInfoList, &MigrationInfo{
			Prefix:         utils.ResourceConfigsPrefix,
			DbVersion:      dbVer.ResourceConfigs,
			CurrentVersion: CurrentVersion.ResourceConfigs,
		})
	}
	return migrationInfoList
}

func CurrentStorDBVersions() Versions {
	return Versions{utils.COST_DETAILS: 2, utils.Accounts: 2}
}

// Versions will keep trac of various item versions
type Versions map[string]int64 // map[item]versionNr