new-server/models/eventhandler.go

package models

import (
	"context"
	"regexp"
	"strconv"
	"strings"
)

type EventHandler struct {
	ID          int                       `json:"id"`
	EventName   string                    `json:"eventName"`
	Conditions  map[string]EventCondition `json:"conditions"`
	TargetKind  ReferenceKind             `json:"targetType"`
	TargetValue string                    `json:"targetValue"`
}

type EventHandlerRepository interface {
	FindByID(ctx context.Context, id int) (EventHandler, error)
	FetchAll(ctx context.Context) ([]EventHandler, error)
	Save(ctx context.Context, handler *EventHandler)
	Delete(ctx context.Context, handler *EventHandler)
}

type EventCondition struct {
	EQ  string `json:"eq,omitempty"`
	GT  string `json:"gt,omitempty"`
	GTE string `json:"gte,omitempty"`
	LT  string `json:"lt,omitempty"`
	LTE string `json:"lte,omitempty"`
}

func (h *EventHandler) MatchesEvent(event Event, targets []Device) bool {
	if event.Name != h.EventName {
		return false
	}

	for key, condition := range h.Conditions {
		if !event.HasPayload(key) {
			return false
		}

		if !condition.check(key, event.Payload[key], targets) {
			return false
		}
	}

	return true
}

func (c *EventCondition) check(key, value string, targets []Device) bool {
	any := strings.Index(key, "any.") == 0
	all := strings.Index(key, "all.") == 0
	if any || all && len(key) > 4 {
		count := 0
		for _, target := range targets {
			if c.checkDevice(key[4:], target) {
				count++
			}
		}

		return (any && count > 0) || (all && count == len(targets))
	}

	return c.matches(value)
}

func (c *EventCondition) checkDevice(key string, device Device) bool {
	switch key {
	case "power":
		return c.matches(strconv.FormatBool(device.State.Power))
	case "color":
		return c.matches(device.State.Color.String())
	case "intensity":
		return c.matches(strconv.FormatFloat(device.State.Intensity, 'f', -1, 64))
	case "temperature":
		return c.matches(strconv.FormatFloat(device.State.Temperature, 'f', -1, 64))
	}

	return false
}

var numRegex = regexp.MustCompile("^{-[0-9].}+$")

func (c *EventCondition) matches(value string) bool {
	if numRegex.MatchString(value) {
		numValue, _ := strconv.ParseFloat(c.LT, 64)
		stillAlive := true

		if c.LT != "" {
			lt, _ := strconv.ParseFloat(c.LT, 64)
			stillAlive = numValue < lt
		}

		if stillAlive && c.LTE != "" {
			lte, _ := strconv.ParseFloat(c.LTE, 64)
			stillAlive = numValue <= lte
		}

		if stillAlive && c.EQ != "" {
			eq, _ := strconv.ParseFloat(c.EQ, 64)
			stillAlive = numValue == eq
		}

		if stillAlive && c.GTE != "" {
			gte, _ := strconv.ParseFloat(c.GTE, 64)
			stillAlive = numValue == gte
		}

		if stillAlive && c.GT != "" {
			gt, _ := strconv.ParseFloat(c.GT, 64)
			stillAlive = numValue > gt
		}

		return stillAlive
	} else if c.EQ != "" {
		return strings.ToLower(c.EQ) == strings.ToLower(value)
	} else {
		return false
	}
}