// Copyright 2019 Yunion
//
// 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 core

import (
	"fmt"

	"yunion.io/x/log"

	schedapi "yunion.io/x/onecloud/pkg/apis/scheduler"
	"yunion.io/x/onecloud/pkg/scheduler/api"
)

func ResultHelp(result *SchedResultItemList, schedInfo *api.SchedInfo) *ScheduleResult {
	out := new(ScheduleResult)
	out.Result = transToSchedResult(result, schedInfo)
	return out
}

func ResultHelpForForcast(result *SchedResultItemList, _ *api.SchedInfo) *ScheduleResult {
	out := new(ScheduleResult)
	out.ForecastResult = transToSchedForecastResult(result)
	return out
}

func ResultHelpForTest(result *SchedResultItemList, schedInfo *api.SchedInfo) *ScheduleResult {
	out := new(ScheduleResult)
	out.TestResult = transToSchedTestResult(result, schedInfo.SuggestionLimit)
	return out
}

type IResultHelper interface {
	ResultHelp(result *SchedResultItemList, schedInfo *api.SchedInfo) *ScheduleResult
}

// ResultHelperFunc type is an adapter to allwo the use of ordinary functions as a ResultHelper.
// If f is a function with the appropriate signature, ResultHelperFunc(f) is a ResultHelper that calls f.
type SResultHelperFunc func(result *SchedResultItemList, schedInfo *api.SchedInfo) *ScheduleResult

func (r SResultHelperFunc) ResultHelp(result *SchedResultItemList, schedInfo *api.SchedInfo) *ScheduleResult {
	return r(result, schedInfo)
}

func transToSchedResult(result *SchedResultItemList, schedInfo *api.SchedInfo) *schedapi.ScheduleOutput {
	if schedInfo.Backup || len(schedInfo.InstanceGroupsDetail) > 0 {
		return transToInstanceGroupSchedResult(result, schedInfo)
	} else {
		return transToRegionSchedResult(result.Data, int64(schedInfo.Count), schedInfo.SessionId)
	}
}

// trans to region sched results
func transToRegionSchedResult(result SchedResultItems, count int64, sid string) *schedapi.ScheduleOutput {
	apiResults := make([]*schedapi.CandidateResource, 0)
	succCount := 0
	storageUsed := NewStorageUsed()
	for _, nr := range result {
		for {
			if nr.Count <= 0 {
				break
			}
			tr := nr.ToCandidateResource(storageUsed)
			tr.SessionId = sid
			apiResults = append(apiResults, tr)
			nr.Count--
			succCount++
		}
	}

	for {
		if int64(succCount) >= count {
			break
		}
		er := &schedapi.CandidateResource{Error: "Out of resource"}
		apiResults = append(apiResults, er)
		succCount++
	}

	return &schedapi.ScheduleOutput{
		Candidates: apiResults,
	}
}

func hostInResultItemsIndex(hostId string, hosts SchedResultItems) int {
	for i := 0; i < len(hosts); i++ {
		if hosts[i].ID == hostId {
			return i
		}
	}
	return -1
}

func transToSchedTestResult(result *SchedResultItemList, limit int64) interface{} {
	return &api.SchedTestResult{
		Data:   result.Data,
		Total:  int64(result.Data.Len()),
		Limit:  limit,
		Offset: 0,
	}
}

func transToSchedForecastResult(result *SchedResultItemList) *api.SchedForecastResult {
	unit := result.Unit
	schedData := unit.SchedData()
	filteredCandidates := make([]api.FilteredCandidate, 0)
	ret := &api.SchedForecastResult{
		ReqCount: int64(schedData.Count),
	}

	// build filteredCandidates
	failedLogs := unit.LogManager.FailedLogs()
	logIndex := func(item *SchedResultItem) string {
		getter := item.Candidater.Getter()
		name := getter.Name()
		id := getter.Id()
		return fmt.Sprintf("%s:%s", name, id)
	}
	for _, item := range result.Data {
		if item.Capacity > 0 {
			continue
		}
		filteredCandidate := api.FilteredCandidate{
			ID:   item.ID,
			Name: item.Name,
		}
		for preName, capa := range item.CapacityDetails {
			if capa > 0 {
				continue
			}
			filteredCandidate.FilterName = preName
		}
		failedLog := failedLogs.Get(logIndex(item))
		if failedLog == nil {
			log.Errorf("candidate %q capacity is 0 but no failedLog found", item.Name)
			continue
		}
		for _, msg := range failedLog.Messages {
			filteredCandidate.Reasons = append(filteredCandidate.Reasons, msg.Info)
		}
		filteredCandidates = append(filteredCandidates, filteredCandidate)
	}
	ret.FilteredCandidates = filteredCandidates

	var (
		output     = transToSchedResult(result, schedData)
		readyCount int64
	)
	for _, candi := range output.Candidates {
		if len(candi.Error) == 0 {
			readyCount++
			ret.Candidates = append(ret.Candidates, candi)
			continue
		}
		ret.NotAllowReasons = append(ret.NotAllowReasons, candi.Error)
	}

	ret.AllowCount = readyCount
	if ret.AllowCount < ret.ReqCount {
		ret.CanCreate = false
	} else {
		ret.CanCreate = true
	}
	return ret
}