// WriteLongRunningProcesses rewrites current state of long running processes for given instance
func WriteLongRunningProcesses(instanceKey *InstanceKey, processes []Process) error {
	writeFunc := func() error {
		db, err := db.OpenOrchestrator()
		if err != nil {
			return log.Errore(err)
		}

		_, err = sqlutils.Exec(db, `
			delete from 
					database_instance_long_running_queries
				where
					hostname = ?
					and port = ?
			`,
			instanceKey.Hostname,
			instanceKey.Port)
		if err != nil {
			return log.Errore(err)
		}

		for _, process := range processes {
			_, merr := sqlutils.Exec(db, `
	        	insert into database_instance_long_running_queries (
	        		hostname,
	        		port,
	        		process_id,
	        		process_started_at,
					process_user,
					process_host,
					process_db,
					process_command,
					process_time_seconds,
					process_state,
					process_info
				) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
				instanceKey.Hostname,
				instanceKey.Port,
				process.Id,
				process.StartedAt,
				process.User,
				process.Host,
				process.Db,
				process.Command,
				process.Time,
				process.State,
				process.Info,
			)
			if merr != nil {
				err = merr
			}
		}
		if err != nil {
			return log.Errore(err)
		}

		return nil
	}
	return ExecDBWriteFunc(writeFunc)
}

// FailStaleSeeds marks as failed seeds where no progress have been seen recently
func FailStaleSeeds() error {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	_, err = sqlutils.Exec(db, `
				update 
						agent_seed 
					set 
						is_complete=1, 
						is_successful=0 
					where 
						is_complete=0 
						and (
							select 
									max(state_timestamp) as last_state_timestamp 
								from 
									agent_seed_state 
								where 
									agent_seed.agent_seed_id = agent_seed_state.agent_seed_id
						) < now() - interval ? minute`,
		config.Config.StaleSeedFailMinutes,
	)
	return err
}

// EndDowntime will remove downtime flag from an instance
func EndDowntime(instanceKey *InstanceKey) error {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	res, err := sqlutils.Exec(db, `
			update
				database_instance_downtime
			set  
				downtime_active = NULL,
				end_timestamp = NOW()
			where
				hostname = ? 
				and port = ?
				and downtime_active = 1
			`,
		instanceKey.Hostname,
		instanceKey.Port,
	)
	if err != nil {
		return log.Errore(err)
	}

	if affected, _ := res.RowsAffected(); affected == 0 {
		err = fmt.Errorf("Instance is not in downtime mode: %+v", instanceKey)
	} else {
		// success
		AuditOperation("end-downtime", instanceKey, "")
	}
	return err
}

// submitSeedStateEntry submits a seed state: a single step in the overall seed process
func submitSeedStateEntry(seedId int64, action string, errorMessage string) (int64, error) {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return 0, log.Errore(err)
	}

	res, err := sqlutils.Exec(db, `
			insert 
				into agent_seed_state (
					agent_seed_id, state_timestamp, state_action, error_message
				) VALUES (
					?, NOW(), ?, ?
				)
			`,
		seedId,
		action,
		errorMessage,
	)
	if err != nil {
		return 0, log.Errore(err)
	}
	id, err := res.LastInsertId()

	return id, err
}

// UpdateAgentInfo  updates some agent state in backend table
func UpdateAgentInfo(hostname string, agent Agent) error {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	_, err = sqlutils.Exec(db, `
        	update 
        		host_agent 
        	set
        		last_seen = NOW(),
        		mysql_port = ?,
        		count_mysql_snapshots = ?
			where 
				hostname = ?`,
		agent.MySQLPort,
		len(agent.LogicalVolumes),
		hostname,
	)
	if err != nil {
		return log.Errore(err)
	}

	return nil
}

// WriteClusterDomainName will write (and override) the domain name of a cluster
func WriteClusterDomainName(clusterName string, domainName string) error {
	writeFunc := func() error {
		db, err := db.OpenOrchestrator()
		if err != nil {
			return log.Errore(err)
		}

		_, err = sqlutils.Exec(db, `
			insert into  
					cluster_domain_name (cluster_name, domain_name, last_registered)
				values
					(?, ?, NOW())
				on duplicate key update
					domain_name=values(domain_name),
					last_registered=values(last_registered)
			`,
			clusterName,
			domainName)
		if err != nil {
			return log.Errore(err)
		}

		return nil
	}
	return ExecDBWriteFunc(writeFunc)
}

// AttemptElection tries to grab leadership (become active node)
func AttemptElection() (bool, error) {

	db, err := db.OpenOrchestrator()
	if err != nil {
		return false, log.Errore(err)
	}

	sqlResult, err := sqlutils.Exec(db, `
			update active_node set 
				hostname = ?,
				token = ?,
				last_seen_active = now()
			where
				anchor = 1
				and (
					last_seen_active < now() - interval ? second
					or hostname = ''
					or (hostname = ? and token = ?)
				)					
			`,
		ThisHostname, ProcessToken.Hash, config.Config.ActiveNodeExpireSeconds, ThisHostname, ProcessToken.Hash,
	)
	if err != nil {
		return false, log.Errore(err)
	}
	rows, err := sqlResult.RowsAffected()
	return (rows > 0), err
}

// EndMaintenance will terminate an active maintenance via maintenanceToken
func EndMaintenance(maintenanceToken int64) error {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	res, err := sqlutils.Exec(db, `
			update
				database_instance_maintenance
			set  
				maintenance_active = NULL,
				end_timestamp = NOW()
			where
				database_instance_maintenance_id = ? 
			`,
		maintenanceToken,
	)
	if err != nil {
		return log.Errore(err)
	}
	if affected, _ := res.RowsAffected(); affected == 0 {
		err = fmt.Errorf("Instance is not in maintenance mode; token = %+v", maintenanceToken)
	} else {
		// success
		instanceKey, _ := ReadMaintenanceInstanceKey(maintenanceToken)
		AuditOperation("end-maintenance", instanceKey, fmt.Sprintf("maintenanceToken: %d", maintenanceToken))
	}
	return err
}

// ExecOrchestrator will execute given query on the orchestrator backend database.
func ExecOrchestrator(query string, args ...interface{}) (sql.Result, error) {
	db, err := OpenOrchestrator()
	if err != nil {
		return nil, err
	}
	res, err := sqlutils.Exec(db, query, args...)
	return res, err
}

// ExecInstance executes a given query on the given MySQL topology instance
func ExecInstance(instanceKey *InstanceKey, query string, args ...interface{}) (sql.Result, error) {
	db, err := db.OpenTopology(instanceKey.Hostname, instanceKey.Port)
	if err != nil {
		return nil, err
	}
	res, err := sqlutils.Exec(db, query, args...)
	return res, err
}

// ExpireDowntime will remove the maintenance flag on old downtimes
func ExpireDowntime() error {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	{
		res, err := sqlutils.Exec(db, `
			delete from
				database_instance_downtime
			where
				downtime_active is null
				and end_timestamp < NOW() - INTERVAL ? DAY 
			`,
			config.Config.MaintenancePurgeDays,
		)
		if err != nil {
			return log.Errore(err)
		}
		if rowsAffected, _ := res.RowsAffected(); rowsAffected > 0 {
			AuditOperation("expire-downtime", nil, fmt.Sprintf("Purged %d historical entries", rowsAffected))
		}
	}
	{
		res, err := sqlutils.Exec(db, `
			update
				database_instance_downtime
			set  
				downtime_active = NULL				
			where
				downtime_active = 1
				and end_timestamp < NOW() 
			`,
		)
		if err != nil {
			return log.Errore(err)
		}
		if rowsAffected, _ := res.RowsAffected(); rowsAffected > 0 {
			AuditOperation("expire-downtime", nil, fmt.Sprintf("Expired %d entries", rowsAffected))
		}
	}

	return err
}

// ExecOrchestrator will execute given query on the orchestrator backend database.
func ExecOrchestrator(query string, args ...interface{}) (sql.Result, error) {
	if config.Config.DatabaselessMode__experimental {
		return DummySqlResult{}, nil
	}
	db, err := OpenOrchestrator()
	if err != nil {
		return nil, err
	}
	res, err := sqlutils.Exec(db, query, args...)
	return res, err
}

// ForgetLongUnseenAgents will remove entries of all agents that have long since been last seen.
func ForgetLongUnseenAgents() error {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	_, err = sqlutils.Exec(db, `
			delete 
				from host_agent 
			where 
				last_submitted < NOW() - interval ? hour`,
		config.Config.UnseenAgentForgetHours,
	)
	return err
}

// AttemptRecoveryRegistration tries to add a recovery entry; if this fails that means recovery is already in place.
func AttemptRecoveryRegistration(analysisEntry *inst.ReplicationAnalysis) (bool, error) {

	db, err := db.OpenOrchestrator()
	if err != nil {
		return false, log.Errore(err)
	}

	sqlResult, err := sqlutils.Exec(db, `
			insert ignore 
				into topology_recovery (
					hostname, 
					port, 
					in_active_period, 
					start_active_period, 
					end_active_period_unixtime, 
					processing_node_hostname, 
					processcing_node_token,
					analysis,
					cluster_name,
					cluster_alias,
					count_affected_slaves,
					slave_hosts
				) values (
					?,
					?,
					1,
					NOW(),
					0,
					?,
					?,
					?,
					?,
					?,
					?,
					?
				)
			`, analysisEntry.AnalyzedInstanceKey.Hostname, analysisEntry.AnalyzedInstanceKey.Port, ThisHostname, ProcessToken.Hash,
		string(analysisEntry.Analysis), analysisEntry.ClusterDetails.ClusterName, analysisEntry.ClusterDetails.ClusterAlias, analysisEntry.CountSlaves, analysisEntry.GetSlaveHostsAsString(),
	)
	if err != nil {
		return false, log.Errore(err)
	}
	rows, err := sqlResult.RowsAffected()
	return (err == nil && rows > 0), err
}

// AuditOperation creates and writes a new audit entry by given params
func AuditOperation(auditType string, instanceKey *InstanceKey, message string) error {

	if instanceKey == nil {
		instanceKey = &InstanceKey{}
	}

	if config.Config.AuditLogFile != "" {
		f, err := os.OpenFile(config.Config.AuditLogFile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0600)
		if err != nil {
			return log.Errore(err)
		}

		defer f.Close()
		text := fmt.Sprintf("%s\t%s\t%s\t%d\t%s\t\n", time.Now().Format(log.TimeFormat), auditType, instanceKey.Hostname, instanceKey.Port, message)
		if _, err = f.WriteString(text); err != nil {
			return log.Errore(err)
		}
	}

	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	_, err = sqlutils.Exec(db, `
			insert 
				into audit (
					audit_timestamp, audit_type, hostname, port, message
				) VALUES (
					NOW(), ?, ?, ?, ?
				)
			`,
		auditType,
		instanceKey.Hostname,
		instanceKey.Port,
		message,
	)
	if err != nil {
		return log.Errore(err)
	}

	return err
}

// HealthTest attempts to write to the backend database and get a result
func HealthTest() (*HealthStatus, error) {
	health := HealthStatus{Healthy: false, Hostname: ThisHostname, Token: ProcessToken.Hash}

	db, err := db.OpenOrchestrator()
	if err != nil {
		health.Error = err
		return &health, log.Errore(err)
	}

	sqlResult, err := sqlutils.Exec(db, `
			insert into node_health 
				(hostname, token, last_seen_active)
			values
				(?, ?, NOW())
			on duplicate key update
				token=values(token),
				last_seen_active=values(last_seen_active)
			`,
		ThisHostname, ProcessToken.Hash,
	)
	if err != nil {
		health.Error = err
		return &health, log.Errore(err)
	}
	rows, err := sqlResult.RowsAffected()
	if err != nil {
		health.Error = err
		return &health, log.Errore(err)
	}
	health.Healthy = (rows > 0)
	activeHostname, activeToken, isActive, err := ElectedNode()
	if err != nil {
		health.Error = err
		return &health, log.Errore(err)
	}
	health.ActiveNode = fmt.Sprintf("%s;%s", activeHostname, activeToken)
	health.IsActiveNode = isActive

	health.AvailableNodes, err = readAvailableNodes()

	return &health, nil
}

// UpdateAgentLastChecked updates the last_check timestamp in the orchestrator backed database
// for a given agent
func UpdateAgentLastChecked(hostname string) error {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	_, err = sqlutils.Exec(db, `
        	update 
        		host_agent 
        	set
        		last_checked = NOW()
			where 
				hostname = ?`,
		hostname,
	)
	if err != nil {
		return log.Errore(err)
	}

	return nil
}

// updateSeedStateEntry updates seed step state
func updateSeedStateEntry(seedStateId int64, reason error) error {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	_, err = sqlutils.Exec(db, `
			update 
				agent_seed_state
					set error_message = ?
				where
					agent_seed_state_id = ?
			`,
		reason.Error(),
		seedStateId,
	)
	if err != nil {
		return log.Errore(err)
	}

	return reason
}

func CreateElectionAnchor(force bool) error {
	db, err := db.OpenOrchestrator()
	if err != nil {
		return log.Errore(err)
	}

	statement := `insert ignore`
	if force {
		statement = `replace`
	}

	_, err = sqlutils.Exec(db, statement+`
			 into active_node
				(anchor, last_seen_active, hostname)
			values
				(1, now() - interval (? + 1) second, '')
		`, config.Config.ActiveNodeExpireSeconds)
	if err != nil {
		return log.Errore(err)
	}
	return nil

}

// GrabElection forcibly grabs leadership. Use with care!!
func GrabElection() (bool, error) {

	db, err := db.OpenOrchestrator()
	if err != nil {
		return false, log.Errore(err)
	}

	sqlResult, err := sqlutils.Exec(db, `
			update active_node set 
				hostname = ?,
				token = ?,
				last_seen_active = now()
			where
				anchor = 1
			`,
		ThisHostname, ProcessToken.Hash,
	)
	if err != nil {
		return false, log.Errore(err)
	}
	rows, err := sqlResult.RowsAffected()
	return (rows > 0), err
}