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