package distworker

import (
	"fmt"
	"os"
	"path/filepath"
	"strconv"
	"testing"
)

func TestReadLinuxHostMetrics(t *testing.T) {
	root := t.TempDir()
	if err := os.WriteFile(filepath.Join(root, "meminfo"), []byte("MemTotal:       100 kB\nMemAvailable:   25 kB\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(root, "loadavg"), []byte("1.5 2.5 3.5 1/1 1\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(root, "uptime"), []byte("42.9 0\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	total, available, one, five, fifteen, uptime, ok := readLinuxHostMetrics(root)
	if !ok || total != 102400 || available != 25600 || one != 1.5 || five != 2.5 || fifteen != 3.5 || uptime != 42 {
		t.Fatalf("unexpected host metric parse: %d %d %g %g %g %d %t", total, available, one, five, fifteen, uptime, ok)
	}
}

func TestCollectProcessesLimitsAndSortsByRSS(t *testing.T) {
	root := t.TempDir()
	for i := 1; i <= maxServerMetricProcesses+2; i++ {
		dir := filepath.Join(root, strconv.Itoa(i))
		if err := os.Mkdir(dir, 0o700); err != nil {
			t.Fatal(err)
		}
		status := fmt.Sprintf("Name:\tproc%d\nVmRSS:\t%d kB\n", i, i)
		if err := os.WriteFile(filepath.Join(dir, "status"), []byte(status), 0o600); err != nil {
			t.Fatal(err)
		}
	}
	processes := collectProcesses(root)
	if len(processes) != maxServerMetricProcesses || processes[0].PID != maxServerMetricProcesses+2 {
		t.Fatalf("unexpected bounded process snapshot: %#v", processes)
	}
}

func TestReadCPUCounters(t *testing.T) {
	path := filepath.Join(t.TempDir(), "stat")
	if err := os.WriteFile(path, []byte("cpu  10 2 8 70 10 0 0 0\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	total, idle, ok := readCPUCounters(path)
	if !ok || total != 100 || idle != 80 {
		t.Fatalf("unexpected cpu counters: %d %d %t", total, idle, ok)
	}
}