package via

import (
	"errors"
	"strings"
	"testing"
)

// probeQueue scripts one answer per channel the probe visits, so a test can say
// which channels the keyboard has.
func probeQueue(present ...Channel) [][]byte {
	queue := make([][]byte, 0, probeChannelMax)
	for c := 1; c <= probeChannelMax; c++ {
		buf := make([]byte, 32)
		if containsChannel(present, Channel(c)) {
			buf[0] = byte(CustomGet)
			buf[3] = 160
		} else {
			buf[0] = byte(Unhandled)
		}
		buf[1] = byte(c)
		buf[2] = probeValueID
		queue = append(queue, buf)
	}
	return queue
}

func containsChannel(channels []Channel, want Channel) bool {
	for _, c := range channels {
		if c == want {
			return true
		}
	}
	return false
}

func TestDetectChannelsFindsTheAnsweredChannels(t *testing.T) {
	transport := &fakeTransport{queue: probeQueue(ChannelRgblight, ChannelRgbMatrix, ChannelAudio)}
	protocol := Protocol{handle: transport}

	got, err := protocol.DetectChannels()
	if err != nil {
		t.Fatalf("DetectChannels() error = %v", err)
	}

	want := []Channel{ChannelRgblight, ChannelRgbMatrix, ChannelAudio}
	if len(got) != len(want) {
		t.Fatalf("DetectChannels() = %v, want %v", got, want)
	}
	for i := range want {
		if got[i] != want[i] {
			t.Errorf("DetectChannels()[%d] = %d, want %d", i, got[i], want[i])
		}
	}
}

func TestDetectChannelsAsksBrightnessOnEveryChannelFromOneToFifteen(t *testing.T) {
	transport := &fakeTransport{queue: probeQueue()}
	protocol := Protocol{handle: transport}

	if _, err := protocol.DetectChannels(); err != nil {
		t.Fatalf("DetectChannels() error = %v", err)
	}

	if len(transport.reports) != probeChannelMax {
		t.Fatalf("requests = %d, want %d", len(transport.reports), probeChannelMax)
	}
	for i, report := range transport.reports {
		wantChannel := byte(i + 1)
		if report[0] != byte(CustomGet) {
			t.Errorf("request %d command = 0x%02x, want 0x%02x", i, report[0], CustomGet)
		}
		if report[1] != wantChannel {
			t.Errorf("request %d channel = %d, want %d", i, report[1], wantChannel)
		}
		if report[2] != probeValueID {
			t.Errorf("request %d value = 0x%02x, want 0x%02x (brightness)", i, report[2], probeValueID)
		}
	}
}

// A channel list missing entries is indistinguishable from a complete one, so a
// transport failure has to abort the probe instead of shrinking it.
func TestDetectChannelsFailsOnATransportErrorMidProbe(t *testing.T) {
	transport := &fakeTransport{
		queue:        probeQueue(ChannelRgblight, ChannelRgbMatrix, ChannelAudio),
		readErr:      errors.New("read: interrupted system call"),
		readErrAfter: 3,
	}
	protocol := Protocol{handle: transport}

	_, err := protocol.DetectChannels()
	if err == nil {
		t.Fatal("DetectChannels() expected an error, got nil")
	}
	if !strings.Contains(err.Error(), "channel 4") {
		t.Errorf("error = %q, want it to name the channel that failed", err)
	}
}

func TestDetectChannelsReportsNoChannelsWhenNoneArePresent(t *testing.T) {
	transport := &fakeTransport{queue: probeQueue()}
	protocol := Protocol{handle: transport}

	got, err := protocol.DetectChannels()
	if err != nil {
		t.Fatalf("DetectChannels() error = %v", err)
	}
	if len(got) != 0 {
		t.Errorf("DetectChannels() = %v, want empty", got)
	}
}

func TestChannelSubsystemNames(t *testing.T) {
	tests := []struct {
		channel Channel
		want    string
	}{
		{ChannelBacklight, "backlight"},
		{ChannelRgblight, "rgblight"},
		{ChannelRgbMatrix, "rgb_matrix"},
		{ChannelAudio, "audio"},
		{ChannelLedMatrix, "led_matrix"},
		{Channel(9), ""},
	}

	for _, tt := range tests {
		if got := tt.channel.Subsystem(); got != tt.want {
			t.Errorf("Channel(%d).Subsystem() = %q, want %q", tt.channel, got, tt.want)
		}
	}
}