/**
 * axel/quote 响应契约解析（阶段0 录证专用，与 RPA normalize 解耦）
 *
 * 真实结构（2026-06 录证）:
 *   body.data.rates.standard.{ lowest, fastest, bestValue }
 *   body.data.rates.guaranteed.{ lowest, fastest, bestValue? }
 *   body.data.availableRates.{ rate_<id>: RateObject }
 */

export type AxelRateTier = {
  id?: string;
  price?: number;
  finalPrice?: number;
  baseQuotePrice?: number;
  days?: number;
  serviceLevel?: string;
  serviceType?: string;
  quoteType?: string;
  serviceCommitment?: string;
  serviceCommitmentDescription?: string;
};

export type AxelQuoteContract = {
  sourcePath: string;
  dataRates: {
    standard: Record<string, AxelRateTier>;
    guaranteed: Record<string, AxelRateTier>;
  } | null;
  availableRateCount: number;
  /** 四档映射：standard/guaranteed × lowest/fastest */
  fourTierCoverage: {
    standardLowest: boolean;
    standardFastest: boolean;
    guaranteedLowest: boolean;
    guaranteedFastest: boolean;
  };
  pricedLeafCount: number;
};

function readData(body: unknown): Record<string, unknown> | null {
  if (body == null || typeof body !== "object" || Array.isArray(body)) {
    return null;
  }
  const data = (body as Record<string, unknown>).data;
  if (data == null || typeof data !== "object" || Array.isArray(data)) {
    return null;
  }
  return data as Record<string, unknown>;
}

function asTierMap(value: unknown): Record<string, AxelRateTier> | null {
  if (value == null || typeof value !== "object" || Array.isArray(value)) {
    return null;
  }
  return value as Record<string, AxelRateTier>;
}

function hasPositivePrice(tier: AxelRateTier): boolean {
  for (const key of ["price", "finalPrice", "baseQuotePrice"] as const) {
    const val = tier[key];
    if (typeof val === "number" && val > 0) {
      return true;
    }
  }
  return false;
}

function countPricedLeavesInAvailableRates(
  availableRates: unknown,
): number {
  if (
    availableRates == null ||
    typeof availableRates !== "object" ||
    Array.isArray(availableRates)
  ) {
    return 0;
  }
  return Object.values(availableRates as Record<string, AxelRateTier>).filter(
    (r) => hasPositivePrice(r),
  ).length;
}

function pickTier(
  branch: Record<string, AxelRateTier> | null | undefined,
  name: string,
): AxelRateTier | null {
  if (!branch) {
    return null;
  }
  const tier = branch[name];
  return tier && hasPositivePrice(tier) ? tier : null;
}

/** 从 axel/quote body 提取契约摘要 */
export function extractAxelQuoteContract(body: unknown): AxelQuoteContract {
  const data = readData(body);
  const dataRatesRaw = data?.rates;
  let dataRates: AxelQuoteContract["dataRates"] = null;

  if (dataRatesRaw && typeof dataRatesRaw === "object" && !Array.isArray(dataRatesRaw)) {
    const dr = dataRatesRaw as Record<string, unknown>;
    dataRates = {
      standard: asTierMap(dr.standard) ?? {},
      guaranteed: asTierMap(dr.guaranteed) ?? {},
    };
  }

  const availableRateCount = countPricedLeavesInAvailableRates(
    data?.availableRates,
  );

  const std = dataRates?.standard;
  const guar = dataRates?.guaranteed;

  const fourTierCoverage = {
    standardLowest: pickTier(std, "lowest") != null,
    standardFastest: pickTier(std, "fastest") != null,
    guaranteedLowest:
      pickTier(guar, "lowest") != null || pickTier(guar, "bestValue") != null,
    guaranteedFastest:
      pickTier(guar, "fastest") != null || pickTier(guar, "bestValue") != null,
  };

  let pricedLeafCount = 0;
  if (std) {
    pricedLeafCount += Object.values(std).filter(hasPositivePrice).length;
  }
  if (guar) {
    pricedLeafCount += Object.values(guar).filter(hasPositivePrice).length;
  }

  return {
    sourcePath: "data.rates",
    dataRates,
    availableRateCount,
    fourTierCoverage,
    pricedLeafCount,
  };
}

/** 阶段0 A3 验收：四档齐全或 data.rates 定价叶子 ≥ 4 */
export function countAxelQuoteTiers(body: unknown): {
  pricedLeafCount: number;
  fourTierOk: boolean;
  availableRateCount: number;
} {
  const c = extractAxelQuoteContract(body);
  const fourTierOk =
    c.fourTierCoverage.standardLowest &&
    c.fourTierCoverage.standardFastest &&
    c.fourTierCoverage.guaranteedLowest &&
    c.fourTierCoverage.guaranteedFastest;

  return {
    pricedLeafCount: Math.max(c.pricedLeafCount, c.availableRateCount),
    fourTierOk,
    availableRateCount: c.availableRateCount,
  };
}