hswro-alarm-bot/filters.go

package main

import (
	"log"

	"github.com/probakowski/go-satel"
)

func FilterByType(ev <-chan satel.Event, allowedTypes []satel.ChangeType) <-chan satel.Event {
	returnChan := make(chan satel.Event)

	if len(allowedTypes) == 0 {
		// no allowed types == all types are allowed
		go func() {
			for e := range ev {
				returnChan <- e
			}
			close(returnChan)
		}()
	} else {
		go func() {
			for e := range ev {
				for _, allowedType := range allowedTypes {
					if allowedType == e.Type {
						returnChan <- e
						continue
					}
				}
			}
			close(returnChan)
		}()
	}

	return returnChan
}

func FilterByIndex(ev <-chan satel.Event, allowedIndexes []int) <-chan satel.Event {
	returnChan := make(chan satel.Event)

	if len(allowedIndexes) == 0 {
		// no allowed indexes == all indexes are allowed
		go func() {
			for e := range ev {
				returnChan <- e
			}
			close(returnChan)
		}()
	} else {
		go func() {
			for e := range ev {
				for _, allowedIndex := range allowedIndexes {
					if allowedIndex == e.Index {
						returnChan <- e
						continue
					}
				}
			}
			close(returnChan)
		}()
	}

	return returnChan
}

func FilterByLastSeen(ev <-chan satel.Event, dataStore *DataStore, logger *log.Logger) <-chan satel.Event {
	returnChan := make(chan satel.Event)

	go func() {
		for e := range ev {
			lastSeen := dataStore.GetSystemState()
			val, ok := lastSeen[EventKey{e.Type, e.Index}]
			if !ok || val.Value != e.Value {
				returnChan <- e
				dataStore.SetSystemState(EventKey{e.Type, e.Index}, EventValue{e.Value})
			}
		}
		close(returnChan)
	}()

	return returnChan
}

func CallWhenClosed(ev <-chan satel.Event, cbk func()) <-chan satel.Event {
	returnChan := make(chan satel.Event)

	go func() {
		for e := range ev {
			returnChan <- e
		}
		cbk()
		close(returnChan)
	}()

	return returnChan
}