package main

import (
	"os"
	"testing"
)

// TestIsCharDeviceRejectsNonConsoles pins down the half of the check that can
// be tested without a terminal: a pipe, a regular file and a closed handle
// must all read as "not a console", because each of them means something other
// than a person waiting at a keyboard.
//
// Getting this wrong in this direction is the dangerous one: it would drop a
// script or a build pipeline into an interactive prompt and hang it forever.
func TestIsCharDeviceRejectsNonConsoles(t *testing.T) {
	r, w, err := os.Pipe()
	if err != nil {
		t.Fatalf("pipe: %v", err)
	}
	defer r.Close()
	defer w.Close()

	tmp, err := os.CreateTemp(t.TempDir(), "out")
	if err != nil {
		t.Fatalf("temp file: %v", err)
	}
	defer tmp.Close()

	devNull, err := os.Open(os.DevNull)
	if err != nil {
		t.Fatalf("open %s: %v", os.DevNull, err)
	}
	defer devNull.Close()

	for _, tc := range []struct {
		name string
		file *os.File
		want bool
	}{
		{"read end of a pipe", r, false},
		{"write end of a pipe", w, false},
		{"regular file", tmp, false},
		// os.DevNull IS a character device on Unix, so this case documents a
		// real limitation rather than asserting a value that differs by
		// platform: `prog < /dev/null` on Unix looks interactive on stdin.
		// It is harmless, because stdout must ALSO be a console, and a script
		// redirecting stdin almost always redirects stdout too.
	} {
		if got := isCharDevice(tc.file); got != tc.want {
			t.Errorf("isCharDevice(%s) = %v, want %v", tc.name, got, tc.want)
		}
	}
	_ = devNull
}

// TestIsCharDeviceHandlesAClosedFile makes sure a handle we cannot stat is
// treated as "not a console" rather than panicking or defaulting to true.
func TestIsCharDeviceHandlesAClosedFile(t *testing.T) {
	f, err := os.CreateTemp(t.TempDir(), "closed")
	if err != nil {
		t.Fatalf("temp file: %v", err)
	}
	f.Close()
	if isCharDevice(f) {
		t.Error("isCharDevice(closed file) = true, want false")
	}
}

// TestInteractiveConsoleNeedsBothEnds asserts the AND: one console end is not
// enough. Under `go test` stdout is not a terminal, so this must be false.
func TestInteractiveConsoleNeedsBothEnds(t *testing.T) {
	if interactiveConsole() {
		t.Error("interactiveConsole() = true under `go test`, where output is captured; " +
			"the guided prompt would hang any non-interactive run")
	}
}

// TestSuggestedTargetIsCheckable guards the one-keypress default. LinkGuard's
// guided prompt offers an address rather than a folder, so there is nothing to
// stat; the equivalent promise is that pressing Enter produces a target the
// program can actually probe, rather than an address it will reject.
func TestSuggestedTargetIsCheckable(t *testing.T) {
	got := suggestedTarget()
	if got == "" {
		t.Fatal("suggestedTarget() = \"\", so pressing Enter offers the reader nothing")
	}
	target := classifyTarget(got)
	switch target.Type {
	case "tcp", "http", "dns":
	default:
		t.Errorf("classifyTarget(%q).Type = %q, which is not a kind LinkGuard can probe", got, target.Type)
	}
	if target.Target == "" {
		t.Errorf("classifyTarget(%q) produced an empty address", got)
	}
}

// TestClassifyTargetPicksTheRightCheck pins the rule that turns one typed
// answer into a probe kind, because getting it wrong sends a web address to
// the DNS resolver and reports a broken site as healthy.
func TestClassifyTargetPicksTheRightCheck(t *testing.T) {
	for _, tc := range []struct {
		in   string
		want string
	}{
		{"https://example.com", "http"},
		{"http://example.com/health", "http"},
		{"HTTPS://EXAMPLE.COM", "http"},
		{"db.internal:5432", "tcp"},
		{"127.0.0.1:8080", "tcp"},
		{"example.com", "dns"},
		{"example.com:notaport", "dns"},
	} {
		if got := classifyTarget(tc.in).Type; got != tc.want {
			t.Errorf("classifyTarget(%q).Type = %q, want %q", tc.in, got, tc.want)
		}
	}
}