export type CombatFeedbackTargetKind = 'player' | 'companion' | 'hostile';

export interface CombatFeedbackHealthSample {
  key: string;
  kind: CombatFeedbackTargetKind;
  hp: number;
}

export interface CombatFeedbackEvent {
  id: string;
  targetKey: string;
  kind: CombatFeedbackTargetKind;
  delta: number;
}

export function buildCombatFeedbackEvents(
  previousSamples: Map<string, CombatFeedbackHealthSample>,
  currentSamples: CombatFeedbackHealthSample[],
  sequence: number,
) {
  let nextSequence = sequence;
  const events: CombatFeedbackEvent[] = [];

  currentSamples.forEach(sample => {
    const previous = previousSamples.get(sample.key);
    if (!previous) return;

    const delta = sample.hp - previous.hp;
    if (delta === 0) return;

    nextSequence += 1;
    events.push({
      id: `${sample.key}:${nextSequence}`,
      targetKey: sample.key,
      kind: sample.kind,
      delta,
    });
  });

  return {
    events,
    nextSequence,
  };
}