export const CHICKEN_CHILL_FACTOR_POINTS = [
  { age: 0, factor: 8 },
  { age: 1, factor: 8 },
  { age: 7, factor: 7 },
  { age: 14, factor: 6 },
  { age: 21, factor: 4.5 },
  { age: 28, factor: 3.5 },
  { age: 35, factor: 3.5 },
  { age: 42, factor: 3 },
] as const;

export function chickenChillFactorFromAge(day: number | null | undefined): number | null {
  const age = Number(day);
  if (!Number.isFinite(age) || age < 0) return null;

  const firstPoint = CHICKEN_CHILL_FACTOR_POINTS[0]!;
  if (age <= firstPoint.age) return firstPoint.factor;

  for (let idx = 1; idx < CHICKEN_CHILL_FACTOR_POINTS.length; idx += 1) {
    const previousPoint = CHICKEN_CHILL_FACTOR_POINTS[idx - 1]!;
    const nextPoint = CHICKEN_CHILL_FACTOR_POINTS[idx]!;
    if (age > nextPoint.age) continue;

    const ageRange = nextPoint.age - previousPoint.age;
    if (ageRange <= 0) return nextPoint.factor;

    const progress = (age - previousPoint.age) / ageRange;
    return previousPoint.factor + (nextPoint.factor - previousPoint.factor) * progress;
  }

  return CHICKEN_CHILL_FACTOR_POINTS[CHICKEN_CHILL_FACTOR_POINTS.length - 1]!.factor;
}

export type ExperienceCalc = {
  averageTemp: number | null;
  windSpeed: number | null;
  humidity: number | null;
  humidityAdjustment: number | null;
  chillFactor: number | null;
  chillEffect: number | null;
  experienceTemp: number | null;
};

export function computeExperienceCalc(args: {
  averageTemp: number | null | undefined;
  windSpeed: number | null | undefined;
  humidity: number | null | undefined;
  dayAge: number | null | undefined;
}): ExperienceCalc {
  const toNumber = (value: number | null | undefined): number | null =>
    value != null && Number.isFinite(Number(value)) ? Number(value) : null;

  const averageTemp = toNumber(args.averageTemp);
  const windSpeed = toNumber(args.windSpeed);
  const humidity = toNumber(args.humidity);
  const chillFactor = chickenChillFactorFromAge(args.dayAge);
  const humidityAdjustment = humidity === null ? null : (humidity - 70) / 5;
  const chillEffect =
    windSpeed !== null && chillFactor !== null && humidityAdjustment !== null
      ? windSpeed * chillFactor - humidityAdjustment
      : null;
  const experienceTemp =
    averageTemp !== null && chillEffect !== null ? averageTemp - chillEffect : null;

  return {
    averageTemp,
    windSpeed,
    humidity,
    humidityAdjustment,
    chillFactor,
    chillEffect,
    experienceTemp,
  };
}

export function formatChillFactor(value: number | null | undefined): string {
  if (value === null || value === undefined || !Number.isFinite(Number(value))) return '--';
  return Number(value).toFixed(3).replace('.', ',').replace(/0+$/, '').replace(/,$/, '');
}