import { createHash } from "crypto";

/**
 * Generate SHA-256 content hash for change detection.
 * Accepts an object (preferred) or a plain string (legacy scrapers).
 */
export function contentHash(data: Record<string, unknown> | string): string {
  const normalized = typeof data === "string"
    ? data
    : JSON.stringify(data, Object.keys(data).sort());
  return createHash("sha256").update(normalized).digest("hex").slice(0, 16);
}

/**
 * Parse price string into number.
 * Handles: "$12.50", "12,50 €", "US$12.50", "12.50 USD"
 */
export function parsePrice(raw: string): { price: number; currency: string } {
  if (!raw) return { price: 0, currency: "USD" };

  const currency = raw.includes("€")
    ? "EUR"
    : raw.includes("£")
      ? "GBP"
      : raw.includes("¥")
        ? "CNY"
        : raw.includes("$") || raw.toLowerCase().includes("usd")
          ? "USD"
          : "";

  // Require an explicit currency symbol OR a price pattern like "1,234.56"
  // This prevents stock counts ("1914"), page numbers, or CSS values from being parsed as prices
  if (!currency) {
    // No currency symbol — only accept if the text is clearly a decimal price (e.g. "1234.56")
    const decimalMatch = raw.match(/^\s*[\d,]+\.\d{2}\s*$/);
    if (!decimalMatch) return { price: 0, currency: "USD" };
  }

  // Extract the numeric value: take the last price-like number in the string
  // (handles cases like "$1,063.02" or "USD 1,063.02" or "1,063.02 USD")
  const allNumbers = raw.match(/[\d]{1,3}(?:[,.][\d]{3})*(?:[.,]\d{1,2})?|\d+\.\d{1,2}/g);
  if (!allNumbers || allNumbers.length === 0) return { price: 0, currency: currency || "USD" };

  // Use the LARGEST number found — avoids picking up "2" from "2 in stock" over "1063.02"
  const prices = allNumbers.map(n => parseFloat(n.replace(/,/g, "")));
  const price = Math.max(...prices);

  return { price: isNaN(price) ? 0 : price, currency: currency || "USD" };
}

/**
 * Determine stock level from various text representations.
 */
export function parseStockLevel(
  raw: string
): "in_stock" | "low_stock" | "out_of_stock" | "on_request" | "discontinued" {
  const lower = raw.toLowerCase();
  if (lower.includes("in stock") || lower.includes("auf lager") || lower.includes("available"))
    return "in_stock";
  if (lower.includes("low stock") || lower.includes("few left") || lower.includes("limited"))
    return "low_stock";
  if (
    lower.includes("out of stock") ||
    lower.includes("sold out") ||
    lower.includes("nicht verfügbar") ||
    lower.includes("unavailable")
  )
    return "out_of_stock";
  if (lower.includes("discontinued") || lower.includes("eol") || lower.includes("end of life"))
    return "discontinued";
  return "on_request";
}

/**
 * Extract numeric quantity from stock text.
 * "23 in stock" → 23, "500+ available" → 500
 */
export function parseQuantity(raw: string): number | undefined {
  const match = raw.match(/(\d+)\+?\s*(in stock|available|auf lager|stück|units|pcs)/i);
  return match ? parseInt(match[1]) : undefined;
}

/**
 * Parse lead time from text.
 * "Ships in 3-5 days" → 5, "2 weeks" → 14
 */
export function parseLeadTime(raw: string): number | undefined {
  const dayMatch = raw.match(/(\d+)\s*(business\s+)?days?/i);
  if (dayMatch) return parseInt(dayMatch[1]);
  const weekMatch = raw.match(/(\d+)\s*weeks?/i);
  if (weekMatch) return parseInt(weekMatch[1]) * 7;
  return undefined;
}