export interface WorkEffortItem {
  estimateHours: number;
  actualHours: number;
  progress: number;
}

export interface WorkEffortSummary {
  estimateHours: number;
  actualHours: number;
  progress: number;
}

export function roundHalfHour(hours: number): number {
  if (!Number.isFinite(hours) || hours <= 0) return 0;
  return Math.round(hours * 2) / 2;
}

export function roundEstimateHours(hours: number): number {
  if (!Number.isFinite(hours) || hours <= 0) return 0;
  return Number(hours.toFixed(2));
}

export function aggregateWorkEffort(items: WorkEffortItem[]): WorkEffortSummary {
  if (items.length === 0) return { estimateHours: 0, actualHours: 0, progress: 0 };

  const estimateHours = roundEstimateHours(items.reduce((sum, item) => sum + Math.max(0, item.estimateHours || 0), 0));
  const actualHours = roundHalfHour(items.reduce((sum, item) => sum + Math.max(0, item.actualHours || 0), 0));

  if (estimateHours <= 0) {
    return {
      estimateHours,
      actualHours,
      progress: Math.round(items.reduce((sum, item) => sum + item.progress, 0) / items.length),
    };
  }

  const weightedProgress = items.reduce((sum, item) => {
    const estimate = Math.max(0, item.estimateHours || 0);
    return sum + estimate * item.progress;
  }, 0);

  return {
    estimateHours,
    actualHours,
    progress: Math.round(weightedProgress / estimateHours),
  };
}