package dbmetrics

import (
	"context"
	"testing"

	"github.com/prometheus/client_golang/prometheus"
	dto "github.com/prometheus/client_model/go"
	"github.com/stretchr/testify/assert"
	corev1 "k8s.io/api/core/v1"
)

func TestDatabaseUsageMetrics(t *testing.T) {
	testPrefix := "test"

	dbm := New(testPrefix)
	assert.NotNil(t, dbm.statusWritesTotal)
	assert.NotNil(t, dbm.errorsTotal)

	obj := corev1.ObjectReference{
		Kind: "test-kind",
		Name: "test-name",
	}

	status := "test-status"
	ctx := context.Background()

	writesVal := getCounterValue(dbm.statusWritesTotal, status, obj.Kind)
	assert.Equal(t, 0.0, writesVal)

	errorsVal := getCounterValue(dbm.errorsTotal, obj.Kind, obj.Name)
	assert.Equal(t, 0.0, errorsVal)

	for val := 1.0; val < 5.0; val++ {
		// test DatabaseWritesTotal metrics
		dbm.RecordDBStatusWritesTotal(ctx, obj.Kind, status)
		writesVal = getCounterValue(dbm.statusWritesTotal, status, obj.Kind)
		assert.Equal(t, val, writesVal)

		// test DatabaseErrorsTotal metrics
		dbm.RecordDBErrorsTotal(ctx, obj.Kind, obj.Name)
		errorsVal = getCounterValue(dbm.errorsTotal, obj.Kind, obj.Name)
		assert.Equal(t, val, errorsVal)
	}

	// Check the metric for a different status.
	status = "test-status-two"

	writesVal = getCounterValue(dbm.statusWritesTotal, status, obj.Kind)
	assert.Equal(t, 0.0, writesVal)

	for val := 1.0; val < 5.0; val++ {
		// test DatabaseWritesTotal metrics
		dbm.RecordDBStatusWritesTotal(ctx, obj.Kind, status)
		writesVal = getCounterValue(dbm.statusWritesTotal, status, obj.Kind)
		assert.Equal(t, val, writesVal)
	}
}

func getCounterValue(metric *prometheus.CounterVec, labels ...string) float64 {
	var m = &dto.Metric{}
	if err := metric.WithLabelValues(labels...).Write(m); err != nil {
		return 0
	}
	return m.Counter.GetValue()
}