package agent

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

// A terminal opened with a folder starts its shell there; a folder that is
// not there leaves it at home.
func TestStartPTYDir(t *testing.T) {
	dir, err := filepath.EvalSymlinks(t.TempDir())
	if err != nil {
		t.Fatal(err)
	}
	sub := filepath.Join(dir, "sub dir")
	if err := os.Mkdir(sub, 0o755); err != nil {
		t.Fatal(err)
	}
	if got := ptyPwd(t, sub); got != sub {
		t.Fatalf("pwd = %q, want %q", got, sub)
	}
	home, _ := filepath.EvalSymlinks(homeDir(""))
	if got := ptyPwd(t, filepath.Join(dir, "missing")); got != home {
		t.Fatalf("pwd for a missing folder = %q, want home %q", got, home)
	}
}

// ptyPwd opens a terminal at dir and returns where its shell is.
func ptyPwd(t *testing.T, dir string) string {
	t.Helper()
	t.Setenv("SHELL", "/bin/sh")
	p, err := StartPTY("", dir)
	if err != nil {
		t.Fatal(err)
	}
	defer p.Close()
	if _, err := p.Write([]byte("echo \"@@$(pwd -P)@@\"\n")); err != nil {
		t.Fatal(err)
	}
	var out strings.Builder
	buf := make([]byte, 4096)
	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		n, err := p.Read(buf)
		out.Write(buf[:n])
		s := out.String()
		// The echoed command line has "@@$(pwd" in it; the answer does not.
		for _, part := range strings.Split(s, "@@") {
			if strings.HasPrefix(part, "/") && strings.Contains(s, part+"@@") {
				return part
			}
		}
		if err != nil {
			break
		}
	}
	t.Fatalf("no pwd in %q", out.String())
	return ""
}