export interface LevelBenchmark {
  level: number;
  xpToNextLevel: number;
  cumulativeXpRequired: number;
  referenceStrength: number;
  baseHp: number;
  baseMana: number;
  baselineDamageScale: number;
}

export const MAX_PLAYER_LEVEL = 20;

function clampLevel(value: unknown) {
  if (typeof value !== 'number' || !Number.isFinite(value)) {
    return 1;
  }

  return Math.min(MAX_PLAYER_LEVEL, Math.max(1, Math.floor(value)));
}

function roundMetric(value: number, digits = 3) {
  return Number(value.toFixed(digits));
}

function computeXpToNextLevel(level: number) {
  const scale = Math.max(0, level - 1);
  return 60 + 20 * scale + 8 * scale * scale;
}

function buildLevelBenchmarks(maxLevel: number) {
  const benchmarks: LevelBenchmark[] = [];
  let cumulativeXpRequired = 0;

  for (let level = 1; level <= maxLevel; level += 1) {
    const scale = level - 1;
    const xpToNextLevel = level >= maxLevel ? 0 : computeXpToNextLevel(level);

    benchmarks.push({
      level,
      xpToNextLevel,
      cumulativeXpRequired,
      referenceStrength: 100 + 16 * scale + 6 * scale * scale,
      baseHp: 180 + 24 * scale + 10 * scale * scale,
      baseMana: 80 + 14 * scale + 6 * scale * scale,
      baselineDamageScale: roundMetric(1 + 0.12 * scale + 0.03 * scale * scale),
    });

    cumulativeXpRequired += xpToNextLevel;
  }

  return benchmarks;
}

const LEVEL_BENCHMARKS = buildLevelBenchmarks(MAX_PLAYER_LEVEL);
const LEVEL_BENCHMARKS_BY_LEVEL = new Map(
  LEVEL_BENCHMARKS.map((benchmark) => [benchmark.level, benchmark]),
);

export function getLevelBenchmark(level: number) {
  return (
    LEVEL_BENCHMARKS_BY_LEVEL.get(clampLevel(level)) ?? LEVEL_BENCHMARKS[0]!
  );
}