package collector

import (
	"sync/atomic"

	"github.com/prometheus/client_golang/prometheus"
)

type baseCollector struct {
	device  string
	product string

	up             *prometheus.Desc
	scrapeDuration *prometheus.Desc
	scrapeErrors   *prometheus.Desc
	errorCount     atomic.Uint64
}

func newBaseCollector(device, product string) baseCollector {
	labels := []string{"device", "product"}
	return baseCollector{
		device:  device,
		product: product,
		up: prometheus.NewDesc(
			"shelly_up",
			"Whether the last status request to the Shelly device succeeded (1) or failed (0).",
			labels,
			nil,
		),
		scrapeDuration: prometheus.NewDesc(
			"shelly_scrape_duration_seconds",
			"Duration of the last Shelly device status request in seconds.",
			labels,
			nil,
		),
		scrapeErrors: prometheus.NewDesc(
			"shelly_scrape_errors_total",
			"Total number of failed Shelly device status requests.",
			labels,
			nil,
		),
	}
}

func (c *baseCollector) describe(channel chan<- *prometheus.Desc) {
	channel <- c.up
	channel <- c.scrapeDuration
	channel <- c.scrapeErrors
}

func (c *baseCollector) collect(channel chan<- prometheus.Metric, success bool, durationSeconds float64) {
	up := float64(0)
	if success {
		up = 1
	} else {
		c.errorCount.Add(1)
	}
	labels := []string{c.device, c.product}
	channel <- prometheus.MustNewConstMetric(c.up, prometheus.GaugeValue, up, labels...)
	channel <- prometheus.MustNewConstMetric(c.scrapeDuration, prometheus.GaugeValue, durationSeconds, labels...)
	channel <- prometheus.MustNewConstMetric(c.scrapeErrors, prometheus.CounterValue, float64(c.errorCount.Load()), labels...)
}