export interface LearningTopicAssignment {
  source?: string | null;
  status?: string | null;
  scenarioName?: string | null;
}

const normalized = (value?: string | null) => value?.trim() || '';

export const selectLearningTopic = (
  assignments: readonly LearningTopicAssignment[],
  fallbackTopic: string
) => {
  const scenarioAssignments = assignments.filter((item) =>
    normalized(item.source) !== 'daily' && Boolean(normalized(item.scenarioName))
  );
  const selected = scenarioAssignments.find((item) => normalized(item.status) !== '已完成')
    || scenarioAssignments[0];

  return normalized(selected?.scenarioName) || fallbackTopic;
};

export const buildLearningTopics = (
  assignments: readonly LearningTopicAssignment[],
  fallbackTopic: string,
  quickQuestions: readonly string[]
) => {
  const values = [
    fallbackTopic,
    ...assignments
      .filter((item) => normalized(item.source) !== 'daily')
      .map((item) => normalized(item.scenarioName)),
    ...quickQuestions
  ];
  const topics: string[] = [];

  values.forEach((value) => {
    const topic = normalized(value);
    if (topic && !topics.includes(topic)) {
      topics.push(topic);
    }
  });

  return topics;
};