package util

import (
	"context"
	"fmt"
	"reflect"
	"time"

	"git.loafle.net/overflow/commons-go/core/interfaces"
)

func ExecuteStarters(instances []interface{}, targetTypes []reflect.Type, reverse bool) error {
	ilen := len(instances)
	tlen := len(targetTypes)

	if 0 == ilen || 0 == tlen {
		return nil
	}

	if reverse {
		for indexI := tlen - 1; indexI >= 0; indexI-- {
			if err := executeStarter(instances, targetTypes[indexI]); nil != err {
				return err
			}
		}
	} else {
		for indexI := 0; indexI < tlen; indexI++ {
			if err := executeStarter(instances, targetTypes[indexI]); nil != err {
				return err
			}
		}
	}
	return nil
}

func executeStarter(instances []interface{}, t reflect.Type) error {
	i := findInstanceByType(instances, t)
	if nil == i {
		return fmt.Errorf("Cannot find instance[%s]", t.String())
	}

	s, ok := i.(interfaces.Starter)
	if !ok {
		return fmt.Errorf("Instance is not Starter[%s]", t.String())
	}

	if err := s.Start(); nil != err {
		return err
	}
	return nil
}

func ExecuteStoppers(instances []interface{}, targetTypes []reflect.Type, reverse bool) error {
	ilen := len(instances)
	tlen := len(targetTypes)

	if 0 == ilen || 0 == tlen {
		return nil
	}

	if reverse {
		for indexI := tlen - 1; indexI >= 0; indexI-- {
			if err := executeStarter(instances, targetTypes[indexI]); nil != err {
				return err
			}
		}
	} else {
		for indexI := 0; indexI < tlen; indexI++ {
			if err := executeStarter(instances, targetTypes[indexI]); nil != err {
				return err
			}
		}
	}
	return nil
}

func executeStopper(instances []interface{}, t reflect.Type) error {
	i := findInstanceByType(instances, t)
	if nil == i {
		return fmt.Errorf("Cannot find instance[%s]", t.String())
	}

	s, ok := i.(interfaces.Stopper)
	if !ok {
		return fmt.Errorf("Instance is not Stopper[%s]", t.String())
	}

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	if err := s.Stop(ctx); nil != err {
		return err
	}
	return nil
}

func findInstanceByType(instances []interface{}, t reflect.Type) interface{} {
	if 0 == len(instances) {
		return nil
	}

	for _, i := range instances {
		if reflect.TypeOf(i) == t {
			return i
		}
	}

	return nil
}