setCSSVariable method

Implementation

@override
void setCSSVariable(String identifier, String value) {
  final List<String>? deps = _propertyDependencies[identifier];
  if (DebugFlags.shouldLogCssVar(identifier, deps)) {
    cssLogger.info('[var][set] id=$identifier new="$value" target=${target.tagName}');
  }
  // Snapshot old value before mutation for transition heuristics.
  // Prefer the exact prior token text, including alias var(...) if present.
  String? prevRaw = _identifierStorage != null ? _identifierStorage![identifier] : null;
  if (prevRaw == null && _variableStorage != null && _variableStorage![identifier] != null) {
    // Preserve the alias token form, e.g., 'var(--a[, fallback])'.
    prevRaw = _variableStorage![identifier]!.toString();
  }

  if (isSingleVarFunction(value)) {
    CSSVariable? variable = CSSVariable.tryParse(this, value);
    if (variable != null) {
      _variableStorage ??= HashMap<String, CSSVariable>();
      _variableStorage![identifier] = variable;
      if (DebugFlags.shouldLogCssVar(identifier, deps)) {
        cssLogger.info('[var][set] id=$identifier stored-as=alias prev=${prevRaw ?? 'null'}');
      }

    } else {
      _identifierStorage ??= HashMap<String, String>();
      _identifierStorage![identifier] = value;
      if (DebugFlags.shouldLogCssVar(identifier, deps)) {
        cssLogger.info('[var][set] id=$identifier stored-as=raw prev=${prevRaw ?? 'null'}');
      }

    }
  } else {
    _identifierStorage ??= HashMap<String, String>();
    _identifierStorage![identifier] = value;
    if (DebugFlags.shouldLogCssVar(identifier, deps)) {
      cssLogger.info('[var][set] id=$identifier stored-as=raw prev=${prevRaw ?? 'null'}');
    }

  }
  if (_propertyDependencies.containsKey(identifier)) {
    if (DebugFlags.shouldLogCssVar(identifier, _propertyDependencies[identifier])) {
      cssLogger.info('[var][notify] id=$identifier deps=${_propertyDependencies[identifier]?.join(',') ?? '[]'}');
    }

    _notifyCSSVariableChanged(identifier, value, prevRaw);
  } else {
    // No dependencies recorded yet (e.g., first parse may have used a cached color string).
    // Clear common color cache keys so next parse recomputes with the new variable value.
    _clearColorCacheForVariable(identifier);
    if (DebugFlags.shouldLogCssVar(identifier)) {
      cssLogger.info('[var][notify] id=$identifier no-deps; cleared-color-cache-only');
    }

  }
}