merged with fixes

internal/domain/privacy_evaluate.go

@@ -0,0 +1,89 @@
+package domain
+
+import "slices"
+
+func EvaluatePrivacy(rules PrivacyRules, ctx PrivacyContext) bool {
+	if ctx.OwnerUserID != 0 && ctx.OwnerUserID == ctx.ViewerUserID {
+		return true
+	}
+	if len(rules.Rules) == 0 {
+		rules.Rules = DefaultPrivacyRules(rules.Key)
+	}
+	for _, rule := range rules.Rules {
+		if explicitDisallowMatches(rule, ctx) {
+			return false
+		}
+	}
+	for _, rule := range rules.Rules {
+		if explicitAllowMatches(rule, ctx) {
+			return true
+		}
+	}
+	for _, rule := range rules.Rules {
+		switch rule.Kind {
+		case PrivacyRuleDisallowContacts:
+			if ctx.ViewerIsContact {
+				return false
+			}
+		case PrivacyRuleAllowContacts:
+			if ctx.ViewerIsContact {
+				return true
+			}
+		}
+	}
+	for _, rule := range rules.Rules {
+		switch rule.Kind {
+		case PrivacyRuleDisallowAll:
+			return false
+		case PrivacyRuleAllowAll:
+			return true
+		}
+	}
+	return false
+}
+
+func explicitDisallowMatches(rule PrivacyRule, ctx PrivacyContext) bool {
+	switch rule.Kind {
+	case PrivacyRuleDisallowUsers:
+		return slices.Contains(rule.UserIDs, ctx.ViewerUserID)
+	case PrivacyRuleDisallowChatParticipants:
+		return intersects(rule.ChatIDs, ctx.SharedChatIDs)
+	case PrivacyRuleDisallowBots:
+		return ctx.ViewerIsBot
+	default:
+		return false
+	}
+}
+
+func explicitAllowMatches(rule PrivacyRule, ctx PrivacyContext) bool {
+	switch rule.Kind {
+	case PrivacyRuleAllowUsers:
+		return slices.Contains(rule.UserIDs, ctx.ViewerUserID)
+	case PrivacyRuleAllowChatParticipants:
+		return intersects(rule.ChatIDs, ctx.SharedChatIDs)
+	case PrivacyRuleAllowCloseFriends:
+		return ctx.ViewerCloseFriend
+	case PrivacyRuleAllowPremium:
+		return ctx.ViewerIsPremium
+	case PrivacyRuleAllowBots:
+		return ctx.ViewerIsBot
+	default:
+		return false
+	}
+}
+
+func intersects(a, b []int64) bool {
+	if len(a) == 0 || len(b) == 0 {
+		return false
+	}
+	set := make(map[int64]struct{}, len(a))
+	for _, id := range a {
+		set[id] = struct{}{}
+	}
+	for _, id := range b {
+		if _, ok := set[id]; ok {
+			return true
+		}
+	}
+	return false
+}