class TokenUsage {
  final int inputTokens;
  final int outputTokens;
  final int cacheCreationInputTokens;
  final int cacheReadInputTokens;

  const TokenUsage({
    this.inputTokens = 0,
    this.outputTokens = 0,
    this.cacheCreationInputTokens = 0,
    this.cacheReadInputTokens = 0,
  });

  int get totalTokens =>
      inputTokens + outputTokens + cacheCreationInputTokens + cacheReadInputTokens;

  TokenUsage operator +(TokenUsage other) => TokenUsage(
        inputTokens: inputTokens + other.inputTokens,
        outputTokens: outputTokens + other.outputTokens,
        cacheCreationInputTokens:
            cacheCreationInputTokens + other.cacheCreationInputTokens,
        cacheReadInputTokens:
            cacheReadInputTokens + other.cacheReadInputTokens,
      );

  factory TokenUsage.fromJson(Map<String, dynamic> json) {
    return TokenUsage(
      inputTokens: json['input_tokens'] as int? ?? 0,
      outputTokens: json['output_tokens'] as int? ?? 0,
      cacheCreationInputTokens:
          json['cache_creation_input_tokens'] as int? ?? 0,
      cacheReadInputTokens: json['cache_read_input_tokens'] as int? ?? 0,
    );
  }
}