《移动游戏产品的架构·商业化与发行工程》1.3 mga-biz-lab 的商业化基线

消消：0.55×40% + 0.30×30% + 0.08×15% + 0.07×30%
    = 22.0% + 9.0% + 1.2% + 2.1% = 34.3%

方舟：0.45×30% + 0.40×40% + 0.15×30%
    = 13.5% + 16.0% + 4.5% = 34.0%

// file: src/lab/biz-lab.ts
// tier: L1
// verify: node --test test/lab/biz-lab.test.ts

export type Channel = "app_store" | "google_play" | "android_cn" | "taptap";

export const PLATFORM_CUT: Readonly<Record<Channel, number>> = {
  app_store: 0.30,
  google_play: 0.30,
  android_cn: 0.40,
  taptap: 0.15,
};

export interface PlatformShare {
  readonly channel: Channel;
  readonly share: number;
}

export interface CaseConfig {
  readonly id: string;
  readonly label: string;
  readonly mau: number;
  readonly payingUsers: number;
  readonly monthlyRevenue: number;
  readonly iapRevenue: number;
  readonly adRevenue: number;
  readonly platforms: readonly PlatformShare[];
}

export interface Baseline {
  readonly id: string;
  readonly label: string;
  readonly revenue: number;
  readonly iapShare: number;
  readonly payRate: number;
  readonly arppu: number;
  readonly arpu: number;
  readonly blendedCut: number;
  readonly netRevenue: number;
  readonly netArpu: number;
}

export interface LabReport {
  readonly baselines: readonly Baseline[];
  readonly findings: readonly string[];
  readonly ok: boolean;
}

const SHARE_TOLERANCE = 1e-6;

function assertRevenue(name: string, value: number): void {
  if (!Number.isFinite(value) || value < 0) {
    throw new RangeError(`${name} must be a finite non-negative number, got ${value}`);
  }
}

export function weightedCut(platforms: readonly PlatformShare[]): number {
  if (platforms.length === 0) {
    throw new Error("weightedCut needs at least one platform");
  }
  let shareSum = 0;
  let cut = 0;
  for (const platform of platforms) {
    if (!Number.isFinite(platform.share) || platform.share < 0) {
      throw new RangeError(`invalid share: ${platform.share}`);
    }
    const rate = PLATFORM_CUT[platform.channel];
    if (rate === undefined) {
      throw new RangeError(`unknown channel: ${String(platform.channel)}`);
    }
    shareSum += platform.share;
    cut += platform.share * rate;
  }
  if (Math.abs(shareSum - 1) > SHARE_TOLERANCE) {
    throw new RangeError(`platform shares must sum to 1, got ${shareSum}`);
  }
  return cut;
}

export function buildBaseline(config: CaseConfig): Baseline {
  if (!Number.isInteger(config.mau) || config.mau <= 0) {
    throw new RangeError(`mau must be a positive integer, got ${config.mau}`);
  }
  if (!Number.isInteger(config.payingUsers) || config.payingUsers < 0 || config.payingUsers > config.mau) {
    throw new RangeError(`payingUsers out of range: ${config.payingUsers}`);
  }
  assertRevenue("monthlyRevenue", config.monthlyRevenue);
  assertRevenue("iapRevenue", config.iapRevenue);
  assertRevenue("adRevenue", config.adRevenue);
  if (config.monthlyRevenue <= 0) {
    throw new RangeError("monthlyRevenue must be positive");
  }
  const blendedCut = weightedCut(config.platforms);
  const netRevenue = config.adRevenue + config.iapRevenue * (1 - blendedCut);
  return {
    id: config.id,
    label: config.label,
    revenue: config.monthlyRevenue,
    iapShare: config.iapRevenue / config.monthlyRevenue,
    payRate: config.payingUsers / config.mau,
    arppu: config.payingUsers === 0 ? 0 : config.iapRevenue / config.payingUsers,
    arpu: config.monthlyRevenue / config.mau,
    blendedCut,
    netRevenue,
    netArpu: netRevenue / config.mau,
  };
}

export function auditBaseline(config: CaseConfig, tolerance = 0.01): readonly string[] {
  if (!Number.isFinite(tolerance) || tolerance < 0 || tolerance > 1) {
    throw new RangeError(`tolerance must be in [0, 1], got ${tolerance}`);
  }
  const notes: string[] = [];
  if (config.monthlyRevenue <= 0) {
    notes.push(`${config.id}:monthly_revenue<=0`);
    return notes;
  }
  if (config.iapRevenue < 0 || config.adRevenue < 0) {
    notes.push(`${config.id}:negative_stream`);
  }
  const streamSum = config.iapRevenue + config.adRevenue;
  if (Math.abs(streamSum - config.monthlyRevenue) / config.monthlyRevenue > tolerance) {
    notes.push(`${config.id}:revenue_mismatch`);
  }
  return notes;
}

export function runLab(configs: readonly CaseConfig[]): LabReport {
  if (configs.length === 0) {
    throw new Error("runLab needs at least one case");
  }
  const baselines = configs.map(buildBaseline);
  const findings = configs.flatMap((config) => [...auditBaseline(config)]);
  const ids = new Set(baselines.map((baseline) => baseline.id));
  if (ids.size !== baselines.length) {
    findings.push("duplicate_case_id");
  }
  return { baselines, findings, ok: findings.length === 0 };
}

export function formatBaseline(baseline: Baseline): string {
  const iapPct = (baseline.iapShare * 100).toFixed(1);
  const payPct = (baseline.payRate * 100).toFixed(2);
  const cutPct = (baseline.blendedCut * 100).toFixed(1);
  return `${baseline.id} iap=${iapPct}% pay=${payPct}% arppu=¥${baseline.arppu.toFixed(2)} arpu=¥${baseline.arpu.toFixed(2)} cut=${cutPct}% net_arpu=¥${baseline.netArpu.toFixed(2)}`;
}

export function formatLab(report: LabReport): string {
  const rows = report.baselines.map(formatBaseline);
  return [...rows, `findings=${report.findings.length} ok=${report.ok}`].join("\n");
}

export const CASE_FIXTURES: readonly CaseConfig[] = [
  {
    id: "chaoxi-xiaoxiao",
    label: "潮汐消消",
    mau: 3_200_000,
    payingUsers: 89_600,
    monthlyRevenue: 9_870_000,
    iapRevenue: 6_090_000,
    adRevenue: 3_780_000,
    platforms: [
      { channel: "android_cn", share: 0.55 },
      { channel: "app_store", share: 0.30 },
      { channel: "taptap", share: 0.08 },
      { channel: "google_play", share: 0.07 },
    ],
  },
  {
    id: "chaoxi-fangzhou",
    label: "潮汐方舟",
    mau: 1_000_000,
    payingUsers: 65_000,
    monthlyRevenue: 28_200_000,
    iapRevenue: 27_300_000,
    adRevenue: 900_000,
    platforms: [
      { channel: "app_store", share: 0.45 },
      { channel: "android_cn", share: 0.40 },
      { channel: "google_play", share: 0.15 },
    ],
  },
];

chaoxi-xiaoxiao iap=61.7% pay=2.80% arppu=¥67.97 arpu=¥3.08 cut=34.3% net_arpu=¥2.43
chaoxi-fangzhou iap=96.8% pay=6.50% arppu=¥420.00 arpu=¥28.20 cut=34.0% net_arpu=¥18.92
findings=0 ok=true