package com.example.data;

import java.util.List;

/**
 * One named series of numbers plus the categories they are indexed by — the
 * shape every chart on the dashboard is fed with, axis-based or not (a pie
 * chart reads the categories as slice labels and ignores the series name).
 * <p>
 * {@code nameKey} and {@code categoryKeys} are <em>translation keys</em>, not
 * display text: the data layer must stay free of a {@code UI} and its locale,
 * so resolving them against the bundle is the view's job. Values and keys are
 * defensively copied, so a data set handed out by a
 * {@link ChartDataService} cannot be modified by its consumer.
 */
public record ChartSeries(String nameKey, List<Double> values, List<String> categoryKeys) {

    public ChartSeries {
        values = List.copyOf(values);
        categoryKeys = List.copyOf(categoryKeys);
        if (values.size() != categoryKeys.size()) {
            throw new IllegalArgumentException(
                    "each value needs a category: %d values, %d categories"
                            .formatted(values.size(), categoryKeys.size()));
        }
    }
}