package profile

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

// drm builds what the kernel would expose, so the cases below are the real ones rather than a
// fake's idea of them: a workstation, a server with a card and no monitor, a machine with no
// graphics at all.
func drm(t *testing.T, connectors map[string]string) {
	t.Helper()
	dir := t.TempDir()
	for name, status := range connectors {
		if err := os.MkdirAll(filepath.Join(dir, name), 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(filepath.Join(dir, name, "status"), []byte(status+"\n"), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	// The card itself has no status file, and skipping it must not be mistaken for an answer.
	if err := os.MkdirAll(filepath.Join(dir, "card0"), 0o755); err != nil {
		t.Fatal(err)
	}
	old := SeatSource
	SeatSource = dir
	t.Cleanup(func() { SeatSource = old })
}

func TestAMachineWithAMonitorHasASeat(t *testing.T) {
	drm(t, map[string]string{"card0-DP-1": "connected", "card0-HDMI-A-1": "disconnected"})

	got := seat{}.Detect(context.Background())
	if !got.Present {
		t.Fatalf("a machine with a connected display has no seat: %s", got.Detail)
	}
	if !strings.Contains(got.Detail, "card0-DP-1") {
		t.Errorf("the answer does not say which connector: %q", got.Detail)
	}
	if strings.Contains(got.Detail, "HDMI") {
		t.Errorf("a disconnected connector was counted: %q", got.Detail)
	}
}

func TestAServerWithAGraphicsCardAndNoMonitorHasNoSeat(t *testing.T) {
	// The case this capability exists for. A display server assigned here would install, start,
	// and have nowhere to draw — and the mesh would have thought it succeeded.
	drm(t, map[string]string{"card0-HDMI-A-1": "disconnected", "card0-DP-1": "disconnected"})

	got := seat{}.Detect(context.Background())
	if got.Present {
		t.Fatal("a machine with nothing plugged in reported a seat")
	}
	// And it says which of the two "no" answers this is, because a person deciding where a
	// desktop goes wants to know whether the hardware is there.
	if !strings.Contains(got.Detail, "no display attached") {
		t.Errorf("the answer does not distinguish this from having no graphics at all: %q", got.Detail)
	}
}

func TestAMachineWithNoGraphicsAtAllHasNoSeat(t *testing.T) {
	// A container, or a phone, where the DRM subsystem is not there to read. The ordinary answer
	// on most nodes and a fault on none of them, so it is a plain "no" rather than an error.
	old := SeatSource
	SeatSource = filepath.Join(t.TempDir(), "not-here")
	t.Cleanup(func() { SeatSource = old })

	got := seat{}.Detect(context.Background())
	if got.Present {
		t.Fatal("a machine with no graphics subsystem reported a seat")
	}
	if got.Detail == "" || strings.Contains(strings.ToLower(got.Detail), "error") {
		t.Errorf("absence was reported as a failure: %q", got.Detail)
	}
}

func TestAnUnknownConnectorIsNotASeat(t *testing.T) {
	// Writeback connectors and some virtual devices report "unknown". Counting those would give
	// a seat to machines that have none — and this workstation has one, so it is not theoretical.
	drm(t, map[string]string{"card0-Writeback-1": "unknown"})

	if (seat{}).Detect(context.Background()).Present {
		t.Fatal("a connector reporting \"unknown\" was counted as a display")
	}
}

func TestTheAnswerSaysHowItKnows(t *testing.T) {
	// Every detector says how, so a wrong answer can be found rather than argued about.
	drm(t, map[string]string{"card0-DP-1": "connected"})
	if !strings.Contains((seat{}).Detect(context.Background()).How, "status") {
		t.Error("the seat detector does not say what it looked at")
	}
}

func TestASeatIsNotAGraphicalSession(t *testing.T) {
	// The two are different questions and the whole point of adding one was that they had been
	// answered by the same thing. A machine can have a seat and no session — that is every
	// workstation before anything is installed on it, and exactly where a display server should
	// be assigned.
	drm(t, map[string]string{"card0-DP-1": "connected"})
	t.Setenv("DISPLAY", "")
	t.Setenv("WAYLAND_DISPLAY", "")

	if !(seat{}).Detect(context.Background()).Present {
		t.Fatal("a machine with a monitor and no session has no seat")
	}
	if (graphicalSession{}).Detect(context.Background()).Present {
		t.Fatal("a machine with no session reported one")
	}
}