1package emoji
  2
  3import (
  4	"fmt"
  5	"strings"
  6	"unicode"
  7)
  8
  9// Parse replaces emoji aliases (:pizza:) with unicode representation.
 10func Parse(input string) string {
 11	var matched strings.Builder
 12	var output strings.Builder
 13
 14	for _, r := range input {
 15		// when it's not `:`, it might be inner or outer of the emoji alias
 16		if r != ':' {
 17			// if matched is empty, it's the outer of the emoji alias
 18			if matched.Len() == 0 {
 19				output.WriteRune(r)
 20				continue
 21			}
 22
 23			matched.WriteRune(r)
 24
 25			// if it's space, the alias's not valid.
 26			// reset matched for breaking the emoji alias
 27			if unicode.IsSpace(r) {
 28				output.WriteString(matched.String())
 29				matched.Reset()
 30			}
 31			continue
 32		}
 33
 34		// r is `:` now
 35		// if matched is empty, it's the beginning of the emoji alias
 36		if matched.Len() == 0 {
 37			matched.WriteRune(r)
 38			continue
 39		}
 40
 41		// it's the end of the emoji alias
 42		alias := matched.String() + ":"
 43
 44		code, ok := emojiMap[alias]
 45		if ok {
 46			output.WriteString(code)
 47			matched.Reset()
 48		} else {
 49			// TODO: check for country codes: `flag-[a-z]{2}`
 50			output.WriteString(matched.String())
 51			// it might be the beginning of the another emoji alias
 52			matched.Reset()
 53			matched.WriteRune(r)
 54		}
 55	}
 56
 57	// if matched not empty, add it to output
 58	if matched.Len() != 0 {
 59		output.WriteString(matched.String())
 60		matched.Reset()
 61	}
 62
 63	return output.String()
 64}
 65
 66// Map returns the emojis map.
 67// Key is the alias of the emoji.
 68// Value is the code of the emoji.
 69func Map() map[string]string {
 70	return emojiMap
 71}
 72
 73// AppendAlias adds new emoji pair to the emojis map.
 74func AppendAlias(alias, code string) error {
 75	if c, ok := emojiMap[alias]; ok {
 76		return fmt.Errorf("emoji already exist: %q => %+q", alias, c)
 77	}
 78
 79	for _, r := range alias {
 80		if unicode.IsSpace(r) {
 81			return fmt.Errorf("emoji alias is not valid: %q", alias)
 82		}
 83	}
 84
 85	emojiMap[alias] = code
 86
 87	return nil
 88}
 89
 90// Exist checks existence of the emoji by alias.
 91func Exist(alias string) bool {
 92	_, ok := emojiMap[alias]
 93
 94	return ok
 95}
 96
 97// Find returns the emoji code by alias.
 98func Find(alias string) (string, bool) {
 99	code, ok := emojiMap[alias]
100	if !ok {
101		return "", false
102	}
103
104	return code, true
105}