MovieNight/common/colors.go

136 lines
3.8 KiB
Go

package common
import (
"errors"
"fmt"
"math/rand"
"regexp"
"strconv"
"strings"
"time"
)
func init() {
rand.Seed(int64(time.Now().Nanosecond()))
}
// Colors holds all the valid html color names for MovieNight
// the values in colors must be lowercase so it matches with the color input
// this saves from having to call strings.ToLower(color) every time to check
var Colors = []string{
"aliceblue", "antiquewhite", "aqua", "aquamarine", "azure",
"beige", "bisque", "blanchedalmond", "blueviolet", "brown",
"burlywood", "cadetblue", "chartreuse", "chocolate", "coral",
"cornflowerblue", "cornsilk", "crimson", "cyan", "darkcyan",
"darkgoldenrod", "darkgray", "darkkhaki", "darkmagenta", "darkolivegreen",
"darkorange", "darkorchid", "darksalmon", "darkseagreen", "darkslateblue",
"darkslategray", "darkturquoise", "darkviolet", "deeppink", "deepskyblue",
"dimgray", "dodgerblue", "firebrick", "floralwhite", "forestgreen",
"fuchsia", "gainsboro", "ghostwhite", "gold", "goldenrod",
"gray", "greenyellow", "honeydew", "hotpink", "indigo",
"ivory", "khaki", "lavender", "lavenderblush", "lawngreen",
"lemonchiffon", "lightblue", "lightcoral", "lightcyan", "lightgoldenrodyellow",
"lightgrey", "lightgreen", "lightpink", "lightsalmon", "lightseagreen",
"lightskyblue", "lightslategray", "lightsteelblue", "lightyellow", "lime",
"limegreen", "linen", "magenta", "mediumaquamarine", "mediumorchid",
"mediumpurple", "mediumseagreen", "mediumslateblue", "mediumspringgreen", "mediumturquoise",
"mediumvioletred", "mintcream", "mistyrose", "moccasin", "navajowhite",
"oldlace", "olive", "olivedrab", "orange", "orangered",
"orchid", "palegoldenrod", "palegreen", "paleturquoise", "palevioletred",
"papayawhip", "peachpuff", "peru", "pink", "plum",
"powderblue", "purple", "rebeccapurple", "red", "rosybrown",
"royalblue", "saddlebrown", "salmon", "sandybrown", "seagreen",
"seashell", "sienna", "silver", "skyblue", "slateblue",
"slategray", "snow", "springgreen", "steelblue", "tan",
"teal", "thistle", "tomato", "turquoise", "violet",
"wheat", "white", "whitesmoke", "yellow", "yellowgreen",
}
var (
regexColor = regexp.MustCompile(`^([0-9A-Fa-f]{3}){1,2}$`)
)
// IsValidColor takes a string s and compares it against a list of css color names.
// It also accepts hex codes in the form of #RGB and #RRGGBB
func IsValidColor(s string) bool {
s = strings.TrimLeft(strings.ToLower(s), "#")
for _, c := range Colors {
if s == c {
return true
}
}
if regexColor.MatchString(s) {
r, g, b, err := hex(s)
if err != nil {
return false
}
total := float32(r + g + b)
return total > 0.7 && float32(b)/total < 0.7
}
return false
}
// RandomColor returns a hex color code
func RandomColor() string {
var color string
for !IsValidColor(color) {
color = ""
for i := 0; i < 3; i++ {
s := strconv.FormatInt(rand.Int63n(255), 16)
if len(s) == 1 {
s = "0" + s
}
color += s
}
}
return "#" + color
}
// hex returns R, G, B as values
func hex(s string) (int, int, int, error) {
// Make the string just the base16 numbers
s = strings.TrimLeft(s, "#")
if len(s) == 3 {
var err error
s, err = hexThreeToSix(s)
if err != nil {
return 0, 0, 0, err
}
}
if len(s) == 6 {
R64, err := strconv.ParseInt(s[0:2], 16, 32)
if err != nil {
return 0, 0, 0, err
}
G64, err := strconv.ParseInt(s[2:4], 16, 32)
if err != nil {
return 0, 0, 0, err
}
B64, err := strconv.ParseInt(s[4:6], 16, 32)
if err != nil {
return 0, 0, 0, err
}
return int(R64), int(G64), int(B64), nil
}
return 0, 0, 0, errors.New("incorrect format")
}
func hexThreeToSix(s string) (string, error) {
if len(s) != 3 {
return "", fmt.Errorf("%d is the incorrect length of string for convertsion", len(s))
}
h := ""
for i := 0; i < 3; i++ {
h += string(s[i])
h += string(s[i])
}
return h, nil
}