// Copyright 2019 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.

// +build !noprocesses

package collector

import (
	"github.com/go-kit/kit/log"
	"io/ioutil"
	"strconv"
	"strings"
	"testing"

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

func TestPerfCollector(t *testing.T) {
	paranoidBytes, err := ioutil.ReadFile("/proc/sys/kernel/perf_event_paranoid")
	if err != nil {
		t.Skip("Procfs not mounted, skipping perf tests")
	}
	paranoidStr := strings.Replace(string(paranoidBytes), "\n", "", -1)
	paranoid, err := strconv.Atoi(paranoidStr)
	if err != nil {
		t.Fatalf("Expected perf_event_paranoid to be an int, got: %s", paranoidStr)
	}
	if paranoid >= 1 {
		t.Skip("Skipping perf tests, set perf_event_paranoid to 0")
	}
	collector, err := NewPerfCollector(log.NewNopLogger())
	if err != nil {
		t.Fatal(err)
	}

	// Setup background goroutine to capture metrics.
	metrics := make(chan prometheus.Metric)
	defer close(metrics)
	go func() {
		for range metrics {
		}
	}()
	if err := collector.Update(metrics); err != nil {
		t.Fatal(err)
	}
}

func TestPerfCPUFlagToCPUs(t *testing.T) {
	tests := []struct {
		name   string
		flag   string
		exCpus []int
		errStr string
	}{
		{
			name:   "valid single cpu",
			flag:   "1",
			exCpus: []int{1},
		},
		{
			name:   "valid range cpus",
			flag:   "1-5",
			exCpus: []int{1, 2, 3, 4, 5},
		},
		{
			name:   "valid double digit",
			flag:   "10",
			exCpus: []int{10},
		},
		{
			name:   "valid double digit range",
			flag:   "10-12",
			exCpus: []int{10, 11, 12},
		},
		{
			name:   "valid double digit stride",
			flag:   "10-20:5",
			exCpus: []int{10, 15, 20},
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			cpus, err := perfCPUFlagToCPUs(test.flag)
			if test.errStr != "" {
				if err != nil {
					t.Fatal("expected error to not be nil")
				}
				if test.errStr != err.Error() {
					t.Fatalf(
						"expected error %q, got %q",
						test.errStr,
						err.Error(),
					)
				}
				return
			}
			if err != nil {
				t.Fatal(err)
			}
			if len(cpus) != len(test.exCpus) {
				t.Fatalf(
					"expected cpus %v, got %v",
					test.exCpus,
					cpus,
				)
			}
			for i := range cpus {
				if test.exCpus[i] != cpus[i] {
					t.Fatalf(
						"expected cpus %v, got %v",
						test.exCpus,
						cpus,
					)
				}
			}
		})
	}
}