Two factor authentication support (#630)

* Initial commit for 2FA support

Signed-off-by: Andrew <write@imaginarycode.com>

* Add vendored files

* Add missing depends

* A few clean ups

* Added improvements, proper encryption

* Better encryption key

* Simplify "key" generation

* Make 2FA enrollment page more robust

* Fix typo

* Rename twofa/2FA to TwoFactor

* UNIQUE INDEX -> UNIQUE

vendor/github.com/boombuler/barcode/scaledbarcode.go

@@ -0,0 +1,115 @@
+package barcode
+
+import (
+	"errors"
+	"fmt"
+	"image"
+	"image/color"
+	"math"
+)
+
+type wrapFunc func(x, y int) color.Color
+
+type scaledBarcode struct {
+	wrapped     Barcode
+	wrapperFunc wrapFunc
+	rect        image.Rectangle
+}
+
+func (bc *scaledBarcode) Content() string {
+	return bc.wrapped.Content()
+}
+
+func (bc *scaledBarcode) Metadata() Metadata {
+	return bc.wrapped.Metadata()
+}
+
+func (bc *scaledBarcode) ColorModel() color.Model {
+	return bc.wrapped.ColorModel()
+}
+
+func (bc *scaledBarcode) Bounds() image.Rectangle {
+	return bc.rect
+}
+
+func (bc *scaledBarcode) At(x, y int) color.Color {
+	return bc.wrapperFunc(x, y)
+}
+
+func (bc *scaledBarcode) CheckSum() int {
+	return bc.wrapped.CheckSum()
+}
+
+// Scale returns a resized barcode with the given width and height.
+func Scale(bc Barcode, width, height int) (Barcode, error) {
+	switch bc.Metadata().Dimensions {
+	case 1:
+		return scale1DCode(bc, width, height)
+	case 2:
+		return scale2DCode(bc, width, height)
+	}
+
+	return nil, errors.New("unsupported barcode format")
+}
+
+func scale2DCode(bc Barcode, width, height int) (Barcode, error) {
+	orgBounds := bc.Bounds()
+	orgWidth := orgBounds.Max.X - orgBounds.Min.X
+	orgHeight := orgBounds.Max.Y - orgBounds.Min.Y
+
+	factor := int(math.Min(float64(width)/float64(orgWidth), float64(height)/float64(orgHeight)))
+	if factor <= 0 {
+		return nil, fmt.Errorf("can not scale barcode to an image smaller then %dx%d", orgWidth, orgHeight)
+	}
+
+	offsetX := (width - (orgWidth * factor)) / 2
+	offsetY := (height - (orgHeight * factor)) / 2
+
+	wrap := func(x, y int) color.Color {
+		if x < offsetX || y < offsetY {
+			return color.White
+		}
+		x = (x - offsetX) / factor
+		y = (y - offsetY) / factor
+		if x >= orgWidth || y >= orgHeight {
+			return color.White
+		}
+		return bc.At(x, y)
+	}
+
+	return &scaledBarcode{
+		bc,
+		wrap,
+		image.Rect(0, 0, width, height),
+	}, nil
+}
+
+func scale1DCode(bc Barcode, width, height int) (Barcode, error) {
+	orgBounds := bc.Bounds()
+	orgWidth := orgBounds.Max.X - orgBounds.Min.X
+	factor := int(float64(width) / float64(orgWidth))
+
+	if factor <= 0 {
+		return nil, fmt.Errorf("can not scale barcode to an image smaller then %dx1", orgWidth)
+	}
+	offsetX := (width - (orgWidth * factor)) / 2
+
+	wrap := func(x, y int) color.Color {
+		if x < offsetX {
+			return color.White
+		}
+		x = (x - offsetX) / factor
+
+		if x >= orgWidth {
+			return color.White
+		}
+		return bc.At(x, 0)
+	}
+
+	return &scaledBarcode{
+		bc,
+		wrap,
+		image.Rect(0, 0, width, height),
+	}, nil
+
+}