/*
   Copyright 2015 Shlomi Noach, courtesy Booking.com

   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.
*/

package logic

import (
	"fmt"
	"github.com/outbrain/golib/log"
	"github.com/outbrain/golib/sqlutils"
	"github.com/outbrain/orchestrator/go/config"
	"github.com/outbrain/orchestrator/go/db"
	"github.com/outbrain/orchestrator/go/inst"
)

// WriteAsyncRequest
func WriteAsyncRequest(asyncRequest *AsyncRequest) error {
	if asyncRequest.OperatedInstanceKey == nil {
		return log.Errorf("WriteAsyncRequest received asyncRequest.OperatedInstanceKey for command %+v", asyncRequest.Command)
	}
	destinationKey := asyncRequest.DestinationKey
	if destinationKey == nil {
		destinationKey = &inst.InstanceKey{}
	}
	writeFunc := func() error {
		_, err := db.ExecOrchestrator(`
			insert into async_request (
					command, hostname, port, destination_hostname, destination_port, pattern, gtid_hint, story, begin_timestamp, end_timestamp
				) values (
					?, ?, ?, ?, ?, ?, ?, ?, NULL, NULL
				)
				`, asyncRequest.Command, asyncRequest.OperatedInstanceKey.Hostname, asyncRequest.OperatedInstanceKey.Port,
			destinationKey.Hostname, destinationKey.Port, asyncRequest.Pattern, string(asyncRequest.GTIDHint), asyncRequest.Story,
		)
		return log.Errore(err)
	}
	return inst.ExecDBWriteFunc(writeFunc)
}

func ReadPendingAsyncRequests(limit int) (res [](*AsyncRequest), err error) {
	limitClause := ``
	args := sqlutils.Args()
	if limit > 0 {
		limitClause = `limit ?`
		args = append(args, limit)
	}
	query := fmt.Sprintf(`
		select
			request_id,
			command,
			hostname,
			port,
			destination_hostname,
			destination_port,
			pattern,
			gtid_hint,
			story
		from
			async_request
		where
			begin_timestamp IS NULL
		order by
			request_id asc
		%s
		`, limitClause)
	err = db.QueryOrchestrator(query, args, func(m sqlutils.RowMap) error {
		asyncRequest := NewEmptyAsyncRequest()
		asyncRequest.Id = m.GetInt64("request_id")
		asyncRequest.Command = m.GetString("command")

		asyncRequest.OperatedInstanceKey = &inst.InstanceKey{}
		asyncRequest.OperatedInstanceKey.Hostname = m.GetString("hostname")
		asyncRequest.OperatedInstanceKey.Port = m.GetInt("port")

		if m.GetString("destination_hostname") != "" {
			asyncRequest.DestinationKey = &inst.InstanceKey{}
			asyncRequest.DestinationKey.Hostname = m.GetString("destination_hostname")
			asyncRequest.DestinationKey.Port = m.GetInt("destination_port")
		}

		asyncRequest.Pattern = m.GetString("pattern")
		asyncRequest.GTIDHint = inst.OperationGTIDHint(m.GetString("gtid_hint"))
		asyncRequest.Story = m.GetString("story")

		res = append(res, asyncRequest)
		return nil
	})

	if err != nil {
		log.Errore(err)
	}
	return res, err
}

func BeginAsyncRequest(asyncRequest *AsyncRequest) (bool, error) {
	sqlResult, err := db.ExecOrchestrator(`
			update
				async_request
			set
				begin_timestamp = NOW()
			where
				request_id = ?
				and begin_timestamp IS NULL
			`, asyncRequest.Id,
	)
	if err != nil {
		return false, log.Errore(err)
	}
	rows, err := sqlResult.RowsAffected()
	return (rows > 0), err

}

// ExpireAsyncRequests will mark "lost" entries as being completed
func ExpireAsyncRequests() error {
	_, err := db.ExecOrchestrator(`
			update
				async_request
			set
				end_timestamp = NOW()
			where
				end_timestamp IS NULL
				and begin_timestamp < NOW() - INTERVAL ? MINUTE
			`, config.Config.MaintenanceExpireMinutes,
	)
	if err != nil {
		log.Errore(err)
	}
	_, err = db.ExecOrchestrator(`
			delete from
				async_request
			where
				end_timestamp IS NOT NULL
				and begin_timestamp < NOW() - INTERVAL ? DAY
			`, config.Config.MaintenancePurgeDays,
	)
	return log.Errore(err)
}