MyClub/internal/services/badwords.go

package services

import (
	"regexp"
	"strings"
)

// A compact list of Czech and English bad words with family-friendly replacements.
// Note: This is a lightweight, non-exhaustive list intended for community sites.
var badWordMap = map[string]string{
	// Czech
	"kráva": "osobo",
	"debil": "nezdvořák",
	"idiot": "nešika",
	"blbec": "popleta",
	"pitomec": "nezbeda",
	"trouba": "popleta",
	"sprostý": "nevhodný",
	"sráč": "strašpytel",
	"čůrák": "šibal",
	"kokot": "popleta",
	"kretén": "nešika",
	"hovno": "ťuťo",
	"nasrat": "naštvat",
	"nasr**": "naštv**",
	"prdel": "zadek",
	"píča": "potížistka",
	"piča": "potížistka",
	"zmrd": "nezbeda",
	"sračka": "nepěknost",
	"sračky": "nepěknosti",
	"posrat": "pokazit",
	"posranej": "zkalený",
	"šukat": "láskovat",
	"mrdat": "lumpačit",
	"mrdka": "neplecha",
	"kurva": "mrška",
	"zasran": "nepříjemn",
	"do prdele": "sakryš",
	"čubka": "neposedná",
	"svině": "nezdárná",
	
	// English
	"shit": "shoot",
	"fuck": "flip",
	"fucking": "flipping",
	"asshole": "meanie",
	"bitch": "rascal",
	"bastard": "rascal",
	"dick": "goof",
	"dickhead": "goof",
	"cock": "goof",
	"pussy": "rascal",
	"cunt": "rascal",
	"crap": "crud",
	"damn": "darn",
}

// Compiled replacement patterns and sensitive patterns
type compiledReplacement struct {
	re *regexp.Regexp
	replacement string
}

var compiledRepls []compiledReplacement
var sensitiveRegexps []*regexp.Regexp

func init() {
	// Build compiled replacements from explicit words/phrases
	for w, rep := range badWordMap {
		var pat string
		if strings.Contains(w, " ") {
			// phrase: allow flexible spacing
			pat = "(?i)\\b" + strings.ReplaceAll(regexp.QuoteMeta(w), " ", "\\s+") + "\\b"
		} else {
			pat = "(?i)\\b" + regexp.QuoteMeta(w) + "[a-zá-ž0-9]*\\b"
		}
		compiledRepls = append(compiledRepls, compiledReplacement{ re: regexp.MustCompile(pat), replacement: rep })
	}

	// Add Czech stems with diacritic + leet tolerant patterns
	czStems := []struct{ stem, rep string }{
		{"kurv", "mrška"}, {"píc", "potížistka"}, {"pic", "potížistka"}, {"mrd", "lumpačit"}, {"šuk", "láskovat"}, {"srač", "nepěknost"}, {"hovn", "ťuťo"}, {"zmrd", "nezbeda"}, {"čubk", "neposedná"}, {"svin", "nezdárná"}, {"kokot", "popleta"}, {"čur", "šibal"}, {"cur", "šibal"},
		{"debil", "nezdvořák"}, {"idiot", "nešika"}, {"kretén", "nešika"}, {"blbec", "popleta"}, {"prdel", "zadek"},
	}
	for _, it := range czStems {
		pat := "(?i)\\b" + diacriticLeetPattern(it.stem) + "[a-zá-ž0-9]*\\b"
		compiledRepls = append(compiledRepls, compiledReplacement{ re: regexp.MustCompile(pat), replacement: it.rep })
	}

	// English stems (simple suffix handling)
	en := []struct{ rawPattern, rep string }{
		{`(?i)\bshit(ty|head|s|ting)?\b`, "shoot"},
		{`(?i)\bfuck(ing|er|ers|ed|s)?\b`, "flip"},
		{`(?i)\bass(hole|hat|es)?\b`, "meanie"},
		{`(?i)\bbitch(es|y)?\b`, "rascal"},
		{`(?i)\bbastard(s)?\b`, "rascal"},
		{`(?i)\bdick(head|s)?\b`, "goof"},
		{`(?i)\bcock(s|ing)?\b`, "goof"},
		{`(?i)\bpussy\b`, "rascal"},
		{`(?i)\bcunt(s)?\b`, "rascal"},
		{`(?i)\bcrap(py|s)?\b`, "crud"},
		{`(?i)\bdamn(ed|s|ing)?\b`, "darn"},
	}
	for _, e := range en {
		compiledRepls = append(compiledRepls, compiledReplacement{ re: regexp.MustCompile(e.rawPattern), replacement: e.rep })
	}

	// Sensitive stems (trigger moderation)
	sensStems := []string{"kurv", "píc", "pic", "mrd", "šuk", "čur", "cur", "kokot", "cunt", "fuck"}
	for _, s := range sensStems {
		// Czech stems get diacritic+leet tolerant pattern; English raw
		var re *regexp.Regexp
		if isASCII(s) {
			re = regexp.MustCompile("(?i)\\b" + regexp.QuoteMeta(s) + "[a-z0-9]*\\b")
		} else {
			re = regexp.MustCompile("(?i)\\b" + diacriticLeetPattern(s) + "[a-zá-ž0-9]*\\b")
		}
		sensitiveRegexps = append(sensitiveRegexps, re)
	}
}

// FilterBadWords replaces bad words with friendlier counterparts while preserving approximate case.
func FilterBadWords(s string) (string, bool) {
	if strings.TrimSpace(s) == "" { return s, false }
	out := s
	replaced := false
	for _, cr := range compiledRepls {
		out2 := cr.re.ReplaceAllStringFunc(out, func(m string) string {
			replaced = true
			// preserve basic case style
			if isTitle(m) { return title(cr.replacement) }
			if isUpper(m) { return strings.ToUpper(cr.replacement) }
			return cr.replacement
		})
		out = out2
	}
	return out, replaced
}

// ContainsSensitiveWords returns true and the matched words if content contains strong/explicit terms.
func ContainsSensitiveWords(s string) (bool, []string) {
	if strings.TrimSpace(s) == "" { return false, nil }
	found := []string{}
	for _, re := range sensitiveRegexps {
		if loc := re.FindStringIndex(s); loc != nil {
			found = append(found, s[loc[0]:loc[1]])
		}
	}
	if len(found) == 0 { return false, nil }
	return true, found
}

func isUpper(s string) bool { return s == strings.ToUpper(s) }
func isTitle(s string) bool { return len(s) > 0 && strings.ToUpper(s[:1]) == s[:1] && strings.ToLower(s[1:]) == s[1:] }
func title(s string) string { if len(s)==0 {return s}; return strings.ToUpper(s[:1]) + s[1:] }

// Helpers for Czech diacritics + simple leetspeak
func diacriticLeetPattern(stem string) string {
	var b strings.Builder
	for _, r := range stem {
		b.WriteString(expandRune(r))
	}
	return b.String()
}

func expandRune(r rune) string {
    switch r {
    case 'a', 'A': return "[aá@4]"
    case 'e', 'E': return "[eéě3]"
    case 'i', 'I', 'l', 'L': return "[iíl1!]"
    case 'o', 'O': return "[oó0]"
    case 'u', 'U': return "[uúů]"
    case 'y', 'Y': return "[yý]"
    case 'c', 'C': return "[cč]"
    case 's', 'S': return "[sš5]"
    case 'z', 'Z': return "[zž2]"
    case 'r', 'R': return "[rř]"
    case 't', 'T': return "[tť7]"
    case 'n', 'N': return "[nň]"
    case 'd', 'D': return "[dď]"
    case 'p', 'P': return "[p]"
    case 'k', 'K': return "[k]"
    case 'm', 'M': return "[m]"
    case 'v', 'V': return "[v]"
    case 'h', 'H': return "[h]"
    case 'g', 'G': return "[g]"
    default:
        // escape everything else
        return regexp.QuoteMeta(string(r))
    }
}

func isASCII(s string) bool {
    for i := 0; i < len(s); i++ { if s[i] >= 128 { return false } }
    return true
}