// Copyright 2021 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//go:build !nocpu
// +build !nocpu

package collector

import (
	"reflect"
	"testing"

	"github.com/go-kit/log"
	"github.com/prometheus/procfs"
)

func makeTestCPUCollector(s []procfs.CPUStat) *cpuCollector {
	dup := make([]procfs.CPUStat, len(s))
	copy(dup, s)
	return &cpuCollector{
		logger:   log.NewNopLogger(),
		cpuStats: dup,
	}
}

func TestCPU(t *testing.T) {
	firstCPUStat := []procfs.CPUStat{{
		User:      100.0,
		Nice:      100.0,
		System:    100.0,
		Idle:      100.0,
		Iowait:    100.0,
		IRQ:       100.0,
		SoftIRQ:   100.0,
		Steal:     100.0,
		Guest:     100.0,
		GuestNice: 100.0,
	}}

	c := makeTestCPUCollector(firstCPUStat)
	want := []procfs.CPUStat{{
		User:      101.0,
		Nice:      101.0,
		System:    101.0,
		Idle:      101.0,
		Iowait:    101.0,
		IRQ:       101.0,
		SoftIRQ:   101.0,
		Steal:     101.0,
		Guest:     101.0,
		GuestNice: 101.0,
	}}
	c.updateCPUStats(want)
	got := c.cpuStats
	if !reflect.DeepEqual(want, got) {
		t.Fatalf("should have %v CPU Stat: got %v", want, got)
	}

	c = makeTestCPUCollector(firstCPUStat)
	jumpBack := []procfs.CPUStat{{
		User:      99.9,
		Nice:      99.9,
		System:    99.9,
		Idle:      99.9,
		Iowait:    99.9,
		IRQ:       99.9,
		SoftIRQ:   99.9,
		Steal:     99.9,
		Guest:     99.9,
		GuestNice: 99.9,
	}}
	c.updateCPUStats(jumpBack)
	got = c.cpuStats
	if reflect.DeepEqual(jumpBack, got) {
		t.Fatalf("should have %v CPU Stat: got %v", firstCPUStat, got)
	}

	c = makeTestCPUCollector(firstCPUStat)
	resetIdle := []procfs.CPUStat{{
		User:      102.0,
		Nice:      102.0,
		System:    102.0,
		Idle:      1.0,
		Iowait:    102.0,
		IRQ:       102.0,
		SoftIRQ:   102.0,
		Steal:     102.0,
		Guest:     102.0,
		GuestNice: 102.0,
	}}
	c.updateCPUStats(resetIdle)
	got = c.cpuStats
	if !reflect.DeepEqual(resetIdle, got) {
		t.Fatalf("should have %v CPU Stat: got %v", resetIdle, got)
	}
}