package via

import (
	"bytes"
	"testing"
)

type fakeTransport struct {
	reportIDs    []byte
	reports      [][]byte
	response     []byte
	queue        [][]byte
	readCalls    int
	readErr      error
	readErrAfter int
}

func (f *fakeTransport) SendReport(reportID byte, report []byte) (int, error) {
	f.reportIDs = append(f.reportIDs, reportID)
	f.reports = append(f.reports, bytes.Clone(report))
	return len(report), nil
}

func (f *fakeTransport) Read(buf []byte) (int, error) {
	f.readCalls++
	if f.readErr != nil && f.readCalls > f.readErrAfter {
		return 0, f.readErr
	}
	if len(f.queue) > 0 {
		next := f.queue[0]
		f.queue = f.queue[1:]
		return copy(buf, next), nil
	}
	if len(f.response) > 0 {
		return copy(buf, f.response), nil
	}
	if len(f.reports) > 0 {
		return copy(buf, f.reports[len(f.reports)-1]), nil
	}
	return copy(buf, make([]byte, 32)), nil
}

func (f *fakeTransport) Close() error { return nil }

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

	if err := protocol.SetValue(ChannelRgblight, 0x02, 0x00); err != nil {
		t.Fatalf("SetValue() error = %v", err)
	}

	want := make([]byte, 32)
	want[0] = 0x07
	want[1] = 0x02
	want[2] = 0x02
	want[3] = 0x00

	if len(transport.reports) != 1 {
		t.Fatalf("SendReport() calls = %d, want 1", len(transport.reports))
	}
	if transport.reportIDs[0] != 0x00 {
		t.Errorf("report ID = 0x%02x, want 0x00", transport.reportIDs[0])
	}
	if !bytes.Equal(transport.reports[0], want) {
		t.Errorf("report = %v, want %v", transport.reports[0], want)
	}
}

func TestSetValueConsumesQMKResponse(t *testing.T) {
	response := make([]byte, 32)
	response[0] = 0x07
	response[1] = 0x02
	response[2] = 0x02
	response[3] = 0x00
	transport := &fakeTransport{response: response}
	protocol := Protocol{handle: transport}

	if err := protocol.SetValue(ChannelRgblight, 0x02, 0x00); err != nil {
		t.Fatalf("SetValue() error = %v", err)
	}
	if transport.readCalls != 1 {
		t.Errorf("Read() calls = %d, want 1", transport.readCalls)
	}
}

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

	if err := protocol.SetColor(ChannelRgblight, 0x2a, 0x80); err != nil {
		t.Fatalf("SetColor() error = %v", err)
	}

	want := make([]byte, 32)
	want[0] = 0x07
	want[1] = 0x02
	want[2] = 0x04
	want[3] = 0x2a
	want[4] = 0x80

	if !bytes.Equal(transport.reports[0], want) {
		t.Errorf("report = %v, want %v", transport.reports[0], want)
	}
}

func TestGetValueReturnsQMKValueData(t *testing.T) {
	response := make([]byte, 32)
	response[0] = 0x08
	response[1] = 0x02
	response[2] = 0x01
	response[3] = 0xc8
	transport := &fakeTransport{response: response}
	protocol := Protocol{handle: transport}

	got, err := protocol.GetValue(ChannelRgblight, 0x01)
	if err != nil {
		t.Fatalf("GetValue() error = %v", err)
	}
	if !bytes.Equal(got, []byte{0xc8}) {
		t.Errorf("GetValue() = %v, want [192]", got)
	}

	want := make([]byte, 32)
	want[0] = 0x08
	want[1] = 0x02
	want[2] = 0x01
	if !bytes.Equal(transport.reports[0], want) {
		t.Errorf("request = %v, want %v", transport.reports[0], want)
	}
}

func TestGetValueRejectsUnhandledResponse(t *testing.T) {
	response := make([]byte, 32)
	response[0] = 0xff
	protocol := Protocol{handle: &fakeTransport{response: response}}

	if _, err := protocol.GetValue(ChannelRgblight, 0x01); err == nil {
		t.Fatal("GetValue() error = nil, want unhandled response error")
	}
}

func TestSetValueWritesEachImpact80EffectChannel(t *testing.T) {
	transport := &fakeTransport{}
	protocol := Protocol{handle: transport}
	cases := []struct {
		channel Channel
		effect  byte
	}{
		{ChannelRgblight, 4},
		{ChannelRgbMatrix, 5},
		{ChannelAudio, 4},
	}

	for _, tc := range cases {
		if err := protocol.SetValue(tc.channel, 0x02, tc.effect); err != nil {
			t.Fatalf("SetValue(%d) error = %v", tc.channel, err)
		}
	}

	if len(transport.reports) != len(cases) {
		t.Fatalf("SendReport() calls = %d, want %d", len(transport.reports), len(cases))
	}
	for i, tc := range cases {
		report := transport.reports[i]
		if report[0] != 0x07 || report[1] != byte(tc.channel) || report[2] != 0x02 || report[3] != tc.effect {
			t.Errorf("effect report %d = %v, want channel 0x%02x effect %d", i, report, tc.channel, tc.effect)
		}
	}
}

func TestGetValueReturnsTwoByteColor(t *testing.T) {
	response := make([]byte, 32)
	response[0] = 0x08
	response[1] = 0x03
	response[2] = 0x04
	response[3] = 0x2a
	response[4] = 0x80
	transport := &fakeTransport{response: response}
	protocol := Protocol{handle: transport}

	got, err := protocol.GetValue(ChannelRgbMatrix, 0x04)
	if err != nil {
		t.Fatalf("GetValue() error = %v", err)
	}
	if !bytes.Equal(got, []byte{0x2a, 0x80}) {
		t.Errorf("GetValue() = %v, want [42 128]", got)
	}

	want := make([]byte, 32)
	want[0] = 0x08
	want[1] = 0x03
	want[2] = 0x04
	if !bytes.Equal(transport.reports[0], want) {
		t.Errorf("request = %v, want %v", transport.reports[0], want)
	}
}