Working auth and photo json endpoint

Signed-off-by: Kris Nóva <kris@nivenly.com>

vendor/github.com/google/open-location-code/go/shorten.go

@@ -0,0 +1,120 @@
+package olc
+
+import (
+	"errors"
+	"fmt"
+	"math"
+	"strings"
+)
+
+// MinTrimmableCodeLen is the minimum length of a code that is able to be shortened.
+const MinTrimmableCodeLen = 6
+
+var (
+	pairResolutions = [...]float64{20.0, 1.0, .05, .0025, .000125}
+)
+
+// Shorten removes characters from the start of an OLC code.
+//
+// This uses a reference location to determine how many initial characters
+// can be removed from the OLC code. The number of characters that can be
+// removed depends on the distance between the code center and the reference
+// location.
+//
+// The minimum number of characters that will be removed is four. At most eight
+// characters will be removed.
+//
+// The reference location must be within 50% of the maximum range. This ensures
+// that the shortened code will be able to be recovered using slightly different
+// locations.
+func Shorten(code string, lat, lng float64) (string, error) {
+	if err := CheckFull(code); err != nil {
+		return code, err
+	}
+	if strings.IndexByte(code, Padding) >= 0 {
+		return code, errors.New("cannot shorten padded code")
+	}
+	code = strings.ToUpper(code)
+	area, err := Decode(code)
+	if err != nil {
+		return code, err
+	}
+	if area.Len < MinTrimmableCodeLen {
+		return code, fmt.Errorf("code length must be at least %d", MinTrimmableCodeLen)
+	}
+
+	lat, lng = clipLatitude(lat), normalizeLng(lng)
+
+	// How close are the latitude and longitude to the code center.
+	centerLat, centerLng := area.Center()
+	distance := math.Max(math.Abs(centerLat-lat), math.Abs(centerLng-lng))
+
+	for i := len(pairResolutions) - 2; i >= 1; i-- {
+		// Check if we're close enough to shorten. The range must be less than 1/2
+		// the resolution to shorten at all, and we want to allow some safety, so
+		// use 0.3 instead of 0.5 as a multiplier.
+		if distance < pairResolutions[i]*0.3 {
+			// Trim it.
+			return code[(i+1)*2:], nil
+		}
+	}
+	return code, nil
+}
+
+// RecoverNearest recovers the nearest matching code to a specified location.
+//
+// Given a short Open Location Code with from four to eight digits missing,
+// this recovers the nearest matching full code to the specified location.
+func RecoverNearest(code string, lat, lng float64) (string, error) {
+	// Return uppercased code if a full code was passed.
+	if err := CheckFull(code); err == nil {
+		return strings.ToUpper(code), nil
+	}
+	// Return error if not a short code
+	if err := CheckShort(code); err != nil {
+		return code, ErrNotShort
+	}
+	// Ensure that latitude and longitude are valid.
+	lat, lng = clipLatitude(lat), normalizeLng(lng)
+
+	// Clean up the passed code.
+	code = strings.ToUpper(code)
+
+	// Compute the number of digits we need to recover.
+	padLen := sepPos - strings.IndexByte(code, Separator)
+
+	// The resolution (height and width) of the padded area in degrees.
+	resolution := math.Pow(20, float64(2-(padLen/2)))
+
+	// Distance from the center to an edge (in degrees).
+	halfRes := float64(resolution) / 2
+
+	// Use the reference location to pad the supplied short code and decode it.
+	area, err := Decode(Encode(lat, lng, 0)[:padLen] + code)
+	if err != nil {
+		return code, err
+	}
+
+	// How many degrees latitude is the code from the reference? If it is more
+	// than half the resolution, we need to move it south or north but keep it
+	// within -90 to 90 degrees.
+	centerLat, centerLng := area.Center()
+	if lat+halfRes < centerLat && centerLat-resolution >= -latMax {
+		// If the proposed code is more than half a cell north of the reference location,
+		// it's too far, and the best match will be one cell south.
+		centerLat -= resolution
+	} else if lat-halfRes > centerLat && centerLat+resolution <= latMax {
+		// If the proposed code is more than half a cell south of the reference location,
+		// it's too far, and the best match will be one cell north.
+		centerLat += resolution
+	}
+
+	// How many degrees longitude is the code from the reference?
+	if lng+halfRes < centerLng {
+		centerLng -= resolution
+	} else if lng-halfRes > centerLng {
+		centerLng += resolution
+	}
+
+	return Encode(centerLat, centerLng, area.Len), nil
+}