package main

import (
	"bytes"
	"errors"
	"strings"
	"testing"

	intrgb "netdome.biz/paul/qmk-rgb/internal/rgb"
	"netdome.biz/paul/qmk-rgb/internal/via"
)

// colorProtocol reports the two byte color the keyboard holds for the color
// value ID, and the single byte brightness for the brightness value ID, so a
// test can describe a keyboard that applied something other than the request.
type colorProtocol struct {
	colorWrites      []colorWrite
	brightnessWrites []uint8
	appliedColor     map[via.Channel][2]uint8
	appliedBright    map[via.Channel]uint8
	shortColorRead   bool
	channels         []via.Channel
	setColorErr      error
	getErr           error
}

type colorWrite struct {
	channel via.Channel
	hue     uint8
	sat     uint8
}

func (p *colorProtocol) SetValue(_ via.Channel, param, value uint8) error {
	if param == uint8(intrgb.Brightness) {
		p.brightnessWrites = append(p.brightnessWrites, value)
	}
	return nil
}

func (p *colorProtocol) SetColor(channel via.Channel, hue, sat uint8) error {
	if p.setColorErr != nil {
		return p.setColorErr
	}
	p.colorWrites = append(p.colorWrites, colorWrite{channel: channel, hue: hue, sat: sat})
	return nil
}

func (p *colorProtocol) GetValue(channel via.Channel, param uint8) ([]byte, error) {
	if p.getErr != nil {
		return nil, p.getErr
	}
	if param == uint8(intrgb.ColorValue) {
		if p.shortColorRead {
			return []byte{0}, nil
		}
		c := p.appliedColor[channel]
		return []byte{c[0], c[1]}, nil
	}
	return []byte{p.appliedBright[channel]}, nil
}

func (p *colorProtocol) Close() error { return nil }

func (p *colorProtocol) DetectChannels() ([]via.Channel, error) {
	if p.channels == nil {
		return []via.Channel{via.ChannelRgblight, via.ChannelRgbMatrix, via.ChannelAudio}, nil
	}
	return p.channels, nil
}

// A color is two bytes on the wire, so the read-back has to look at both. A
// one byte answer would leave the saturation unverified.
func TestSetColorVerifiedReadsBackHueAndSaturation(t *testing.T) {
	proto := &colorProtocol{
		appliedColor: map[via.Channel][2]uint8{via.ChannelRgblight: {99, 255}},
	}

	results, err := setColorVerified(proto, []via.Channel{via.ChannelRgblight}, impact80Display(), 85, 255)
	if err != nil {
		t.Fatalf("setColorVerified() error = %v", err)
	}
	if len(results) != 1 {
		t.Fatalf("results = %d entries, want 1", len(results))
	}

	got := results[0]
	if got.Name != "logo" {
		t.Errorf("results[0].Name = %q, want %q", got.Name, "logo")
	}
	if got.RequestedHue != 85 || got.RequestedSaturation != 255 {
		t.Errorf("requested = hue %d sat %d, want hue 85 sat 255", got.RequestedHue, got.RequestedSaturation)
	}
	if got.Hue != 99 || got.Saturation != 255 {
		t.Errorf("applied = hue %d sat %d, want hue 99 sat 255", got.Hue, got.Saturation)
	}
	if !got.Mismatch() {
		t.Error("Mismatch() = false, want true when the keyboard stored another hue")
	}
}

func TestSetColorVerifiedReportsNoMismatchWhenKeyboardAppliesTheRequest(t *testing.T) {
	proto := &colorProtocol{
		appliedColor: map[via.Channel][2]uint8{via.ChannelRgblight: {0, 255}},
	}

	results, err := setColorVerified(proto, []via.Channel{via.ChannelRgblight}, impact80Display(), 0, 255)
	if err != nil {
		t.Fatalf("setColorVerified() error = %v", err)
	}
	if results[0].Mismatch() {
		t.Error("Mismatch() = true, want false when the keyboard applied the request")
	}
}

// A truncated answer means the keyboard did not report both components, so the
// command must not claim it knows the applied color.
func TestSetColorVerifiedRejectsATruncatedColorRead(t *testing.T) {
	proto := &colorProtocol{shortColorRead: true}

	_, err := setColorVerified(proto, []via.Channel{via.ChannelRgblight}, impact80Display(), 0, 255)
	if err == nil {
		t.Fatal("setColorVerified() expected an error, got nil")
	}
	if !strings.Contains(err.Error(), "logo") {
		t.Errorf("error = %q, want it to name the zone whose read back was unusable", err)
	}
}

func TestSetColorVerifiedPropagatesWriteErrors(t *testing.T) {
	proto := &colorProtocol{setColorErr: errors.New("write refused")}

	_, err := setColorVerified(proto, []via.Channel{via.ChannelRgblight}, impact80Display(), 0, 255)
	if err == nil {
		t.Fatal("setColorVerified() expected an error, got nil")
	}
	if !strings.Contains(err.Error(), "write refused") {
		t.Errorf("error = %q, want the keyboard's own reason", err)
	}
}

func runColor(t *testing.T, proto *colorProtocol, zoneFlag string, args ...string) (stdout, stderr string, err error) {
	t.Helper()

	t.Cleanup(stubColorTarget(t, proto, zoneFlag))

	var out, errOut bytes.Buffer
	cmd := NewColorCmd()
	cmd.SetOut(&out)
	cmd.SetErr(&errOut)
	cmd.SetArgs(args)

	err = cmd.Execute()
	return out.String(), errOut.String(), err
}

func allZonesAppliedColor(hue, sat uint8) map[via.Channel][2]uint8 {
	return map[via.Channel][2]uint8{
		via.ChannelRgblight:  {hue, sat},
		via.ChannelRgbMatrix: {hue, sat},
		via.ChannelAudio:     {hue, sat},
	}
}

func TestColorReportsTheAppliedHueAndSaturation(t *testing.T) {
	// 00ff00 is hue 85 at full saturation.
	proto := &colorProtocol{appliedColor: allZonesAppliedColor(85, 255)}

	stdout, stderr, err := runColor(t, proto, "logo", "00ff00")
	if err != nil {
		t.Fatalf("color returned error: %v", err)
	}
	if strings.TrimSpace(stdout) != "Color set to hue 85 sat 255" {
		t.Errorf("stdout = %q, want the exact success message", stdout)
	}
	if stderr != "" {
		t.Errorf("stderr = %q, want nothing on stderr when the request was met", stderr)
	}
}

// The hex notations carry no brightness, so the command must not write one and
// must not report one.
func TestColorHexNotationLeavesBrightnessAlone(t *testing.T) {
	proto := &colorProtocol{appliedColor: allZonesAppliedColor(0, 255)}

	stdout, _, err := runColor(t, proto, "", "rgb:ff0000")
	if err != nil {
		t.Fatalf("color returned error: %v", err)
	}
	if len(proto.brightnessWrites) != 0 {
		t.Errorf("brightness writes = %v, want none for a hex notation", proto.brightnessWrites)
	}
	if strings.Contains(stdout, "brightness") {
		t.Errorf("stdout = %q, must not report a brightness the command did not set", stdout)
	}
}

// hsv: carries a value, and the keyboard has no value register for it, so the
// value goes to the brightness of the same zones.
func TestColorHSVNotationWritesTheValueAsBrightness(t *testing.T) {
	proto := &colorProtocol{
		appliedColor:  allZonesAppliedColor(85, 255),
		appliedBright: map[via.Channel]uint8{via.ChannelRgblight: 200, via.ChannelRgbMatrix: 200, via.ChannelAudio: 200},
	}

	stdout, _, err := runColor(t, proto, "", "hsv:85,255,200")
	if err != nil {
		t.Fatalf("color returned error: %v", err)
	}
	if len(proto.brightnessWrites) != 3 {
		t.Fatalf("brightness writes = %v, want one per selected zone", proto.brightnessWrites)
	}
	for _, v := range proto.brightnessWrites {
		if v != 200 {
			t.Errorf("brightness write = %d, want 200", v)
		}
	}
	if strings.TrimSpace(stdout) != "Color set to hue 85 sat 255 brightness 200" {
		t.Errorf("stdout = %q, want hue, saturation and brightness", stdout)
	}
}

// The Impact 80 clamps brightness at 160 on logo and side and scales it up on
// the backlight channel, so an hsv: value is reported the way brightness is.
func TestColorHSVSummarisesTheBrightnessTheKeyboardApplied(t *testing.T) {
	proto := &colorProtocol{
		appliedColor:  allZonesAppliedColor(0, 255),
		appliedBright: map[via.Channel]uint8{via.ChannelRgblight: 160, via.ChannelRgbMatrix: 255, via.ChannelAudio: 160},
	}

	stdout, _, err := runColor(t, proto, "", "hsv:0,255,200")
	if err != nil {
		t.Fatalf("color returned error: %v", err)
	}

	for _, want := range []string{
		"logo hue 0 sat 255 brightness 160",
		"backlight hue 0 sat 255 brightness 255",
		"side hue 0 sat 255 brightness 160",
		"requested hue 0 sat 255 brightness 200",
	} {
		if !strings.Contains(stdout, want) {
			t.Errorf("stdout = %q, want it to contain %q", stdout, want)
		}
	}
	if strings.Contains(stdout, "set to") {
		t.Errorf("stdout = %q, must not claim the request was met when a zone clamped it", stdout)
	}
	if strings.Count(strings.TrimSpace(stdout), "\n") != 0 {
		t.Errorf("stdout = %q, want exactly one line", stdout)
	}
}

// A notation the tool cannot parse must fail before the keyboard is opened.
func TestColorRejectsAnUnknownNotationWithoutOpeningTheDevice(t *testing.T) {
	proto := &colorProtocol{}

	opened := false
	originalTarget := openTarget
	originalZone := targetZone
	t.Cleanup(func() {
		openTarget = originalTarget
		targetZone = originalZone
	})
	openTarget = func() (rgbProtocol, targetDeviceData, []via.Channel, error) {
		opened = true
		return proto, targetDeviceData{}, nil, nil
	}
	targetZone = ""

	var out bytes.Buffer
	cmd := NewColorCmd()
	cmd.SetOut(&out)
	cmd.SetErr(&out)
	cmd.SetArgs([]string{"xyz:1"})

	err := cmd.Execute()
	if err == nil {
		t.Fatal("color expected an error, got nil")
	}
	if opened {
		t.Error("the keyboard was opened, want the notation rejected first")
	}
	if len(proto.colorWrites) != 0 {
		t.Errorf("color writes = %v, want none", proto.colorWrites)
	}
}

// stubColorTarget points the color command at one protocol and one --zone value.
func stubColorTarget(t *testing.T, proto *colorProtocol, zoneFlag string) func() {
	t.Helper()

	originalTarget := openTarget
	originalZone := targetZone

	openTarget = func() (rgbProtocol, targetDeviceData, []via.Channel, error) {
		target := targetDeviceData{Display: impact80Display()}
		requested, err := resolveZoneName(zoneFlag, impact80Display(), nil)
		if err != nil {
			return nil, target, nil, err
		}
		target.Requested = requested

		resolved, err := resolveChannels(proto, target)
		if err != nil {
			return nil, target, nil, err
		}
		return proto, target, resolved, nil
	}
	targetZone = zoneFlag

	return func() {
		openTarget = originalTarget
		targetZone = originalZone
	}
}