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=${target.tagName}');
  }
  if (DebugFlags.enableBackgroundLogs && identifier.startsWith('--tw-gradient-')) {
    // Tailwind gradients rely heavily on custom properties. Log these at a low
    // verbosity gate so we can diagnose bad tokenization (e.g., stray ';').
    cssLogger.finer('[Background][var][set] id=$identifier value="$value"');
  }
  // 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();
  }

  // CSS-wide keywords have special meaning for custom properties too.
  // Custom properties are inherited, so:
  //   --x: inherit; / --x: unset;
  // behaves like removing the local override and inheriting from the parent.
  final String trimmed = value.trim();
  final String lower = trimmed.toLowerCase();
  if (lower == INHERIT || lower == 'unset') {
    _identifierStorage?.remove(identifier);
    _variableStorage?.remove(identifier);
    if (_identifierStorage != null && _identifierStorage!.isEmpty) _identifierStorage = null;
    if (_variableStorage != null && _variableStorage!.isEmpty) _variableStorage = null;

    if (DebugFlags.shouldLogCssVar(identifier, deps)) {
      cssLogger.info('[var][set] id=$identifier stored-as=inherit prev=${prevRaw ?? 'null'}');
    }

    if (_propertyDependencies.containsKey(identifier)) {
      _notifyCSSVariableChanged(identifier, trimmed, prevRaw);
    } else {
      _clearColorCacheForVariable(identifier);
      if (DebugFlags.shouldLogCssVar(identifier)) {
        cssLogger.info('[var][notify] id=$identifier no-deps; cleared-color-cache-only');
      }
    }
    return;
  }

  // Canonicalize CSS-wide keyword case for custom properties.
  if (lower == INITIAL) {
    value = INITIAL;
  }

  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');
    }

  }
}