package pty

import (
	"bytes"
	"errors"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"
	"testing"
	"time"
)

func TestStartUsesWorkDir(t *testing.T) {
	dir := t.TempDir()
	p, err := Start([]string{"sh", "-c", "pwd"}, nil, dir, 80, 24)
	if err != nil {
		t.Fatalf("Start: %v", err)
	}
	defer p.Close()

	var out bytes.Buffer
	buf := make([]byte, 256)
	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		n, err := p.Read(buf)
		if n > 0 {
			out.Write(buf[:n])
			if strings.Contains(out.String(), dir) {
				break
			}
		}
		if err != nil {
			break
		}
	}
	_ = p.Wait()

	if got := strings.TrimSpace(out.String()); got != dir {
		t.Fatalf("pwd output = %q, want %q", got, dir)
	}
}

func TestCloseKillsProcessGroup(t *testing.T) {
	dir := t.TempDir()
	pidFile := filepath.Join(dir, "sleep.pid")
	env := append(os.Environ(), "PIDFILE="+pidFile)
	p, err := Start([]string{"sh", "-c", "sleep 30 & echo $! > \"$PIDFILE\"; wait"}, env, "", 80, 24)
	if err != nil {
		t.Fatalf("Start: %v", err)
	}
	deadline := time.Now().Add(5 * time.Second)
	var childPID int
	for time.Now().Before(deadline) {
		b, err := os.ReadFile(pidFile)
		if err == nil {
			childPID, _ = strconv.Atoi(strings.TrimSpace(string(b)))
			if childPID > 0 {
				break
			}
		}
		time.Sleep(20 * time.Millisecond)
	}
	if childPID <= 0 {
		_ = p.Close()
		t.Fatalf("background child pid was not written")
	}

	if err := p.Close(); err != nil {
		t.Fatalf("Close: %v", err)
	}
	_ = p.Wait()

	deadline = time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		err := syscall.Kill(childPID, 0)
		if errors.Is(err, syscall.ESRCH) {
			return
		}
		time.Sleep(20 * time.Millisecond)
	}
	t.Fatalf("background child pid %d still exists after PTY.Close", childPID)
}