/**
 * OEM Reference Price Scraper — Mouser Electronics API
 *
 * Source:  api.mouser.com (free REST API, no bot-detection)
 * Target:  Juniper, Cisco, Arista OEM transceiver PIDs already in our DB
 * Stores:  price_observations  (marketplace='mouser', condition='new')
 *
 * API key: Free registration at mouser.com/api — set MOUSER_API_KEY env var
 *   endpoint: POST https://api.mouser.com/api/v1.0/search/keyword
 *
 * Rate limit: 30 req/min on free tier → 2s delay between requests
 *
 * Note: DigiKey + Arrow both require Playwright to bypass Cloudflare/Akamai.
 * Mouser offers a free REST API with the same data — hence this implementation.
 */

import { pool, ensureVendor, upsertPriceObservation } from "../utils/db";
import { contentHash } from "../utils/hash";

const MOUSER_API_BASE = "https://api.mouser.com/api/v1.0";
const MOUSER_API_KEY = process.env["MOUSER_API_KEY"] ?? "";
const DELAY_MS = 2_100; // ≤ 30 req/min on free tier

// ── Types ─────────────────────────────────────────────────────────────────────

interface MouserPriceBreak {
  Quantity: number;
  Price: string;    // e.g. "1,234.56" or "1234.56"
  Currency: string; // e.g. "EUR"
}

interface MouserPart {
  ManufacturerPartNumber: string;
  MouserPartNumber: string;
  Availability: string;       // e.g. "117 auf Lager"
  DataSheetUrl: string;
  Description: string;
  LeadTime: string;           // e.g. "10 Weeks"
  Min: string;                // min order qty
  ProductDetailUrl: string;
  PriceBreaks: MouserPriceBreak[];
  AvailabilityInStock: string;
}

interface MouserSearchResponse {
  Errors: Array<{ Code: string; Message: string }>;
  SearchResults: {
    NumberOfResult: number;
    Parts: MouserPart[];
  } | null;
}

// ── Helpers ───────────────────────────────────────────────────────────────────

function sleep(ms: number): Promise<void> {
  return new Promise((r) => setTimeout(r, ms));
}

/** Parse Mouser price string "1.234,56" (DE locale) or "1234.56" (US) */
function parseMouserPrice(raw: string, currency: string): number | null {
  if (!raw || raw === "") return null;
  // German locale uses comma decimal, dot thousands → "1.234,56"
  // US locale uses dot decimal → "1234.56"
  const cleaned = currency === "EUR"
    ? raw.replace(/\./g, "").replace(",", ".")   // "1.234,56" → "1234.56"
    : raw.replace(/,/g, "");                      // "1,234.56" → "1234.56"
  const n = parseFloat(cleaned);
  return Number.isFinite(n) && n > 0 ? n : null;
}

/** Extract quantity from availability string like "117 auf Lager" or "117 In Stock" */
function parseAvailability(avail: string): { qty: number; stockLevel: string } {
  if (!avail) return { qty: 0, stockLevel: "out_of_stock" };
  const lower = avail.toLowerCase();

  // Check for discontinued / not available
  if (lower.includes("nicht verfügbar") || lower.includes("not available") || lower.includes("obsolete")) {
    return { qty: 0, stockLevel: "discontinued" };
  }

  // Extract number
  const match = avail.match(/(\d[\d,.]*)(?:\s|$)/);
  const qty = match ? parseInt(match[1].replace(/[,.]/, ""), 10) : 0;

  if (qty === 0) return { qty: 0, stockLevel: "out_of_stock" };
  if (qty < 10) return { qty, stockLevel: "low_stock" };
  return { qty, stockLevel: "in_stock" };
}

/** Get the 1-unit price (or lowest break price) in EUR */
function extractPrice(part: MouserPart): { price: number; currency: string } | null {
  const breaks = part.PriceBreaks;
  if (!breaks || breaks.length === 0) return null;

  // Sort by quantity ascending, take qty=1 or first available
  const sorted = [...breaks].sort((a, b) => a.Quantity - b.Quantity);
  const first = sorted[0];
  if (!first) return null;

  const currency = (first.Currency ?? "EUR").toUpperCase();
  const price = parseMouserPrice(first.Price, currency);
  if (price === null) return null;

  return { price, currency };
}

// ── API call ──────────────────────────────────────────────────────────────────

async function searchMouser(partNumber: string): Promise<MouserPart | null> {
  if (!MOUSER_API_KEY) return null;

  const url = `${MOUSER_API_BASE}/search/keyword?apiKey=${MOUSER_API_KEY}&langId=1&searchWithSapnningRows=false`;

  let resp: Response;
  try {
    resp = await fetch(url, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Accept: "application/json",
      },
      body: JSON.stringify({
        SearchByKeywordRequest: {
          keyword: partNumber,
          records: 5,
          startingRecord: 0,
          searchOptions: "1",       // Exact match preferred
          searchWithSapnningRows: false,
        },
      }),
      signal: AbortSignal.timeout(15_000),
    });
  } catch (err: unknown) {
    console.warn(`  [Mouser] Fetch error for ${partNumber}: ${(err as Error).message.slice(0, 60)}`);
    return null;
  }

  if (!resp.ok) {
    if (resp.status === 429) {
      console.warn(`  [Mouser] Rate limited — backing off 30s`);
      await sleep(30_000);
    } else {
      console.warn(`  [Mouser] HTTP ${resp.status} for ${partNumber}`);
    }
    return null;
  }

  const data = (await resp.json()) as MouserSearchResponse;

  if (data.Errors && data.Errors.length > 0) {
    const errMsg = data.Errors.map((e) => e.Message).join("; ");
    console.warn(`  [Mouser] API error for ${partNumber}: ${errMsg.slice(0, 80)}`);
    return null;
  }

  const parts = data.SearchResults?.Parts ?? [];
  if (parts.length === 0) return null;

  const norm = partNumber.toUpperCase().trim();

  // Prefer exact MPN match
  const exact = parts.find((p) => (p.ManufacturerPartNumber ?? "").toUpperCase().trim() === norm);
  return exact ?? parts[0] ?? null;
}

// ── Main ──────────────────────────────────────────────────────────────────────

export async function scrapeMouser(): Promise<void> {
  console.log("=== OEM Reference Price Scraper (Mouser Electronics API) ===\n");

  if (!MOUSER_API_KEY) {
    console.error(
      "  ERROR: MOUSER_API_KEY not set.\n" +
      "  Register free at https://www.mouser.com/api-hub/ → get API key → set env var.\n" +
      "  Free tier: 1000 queries/month — enough for 475 Juniper PIDs."
    );
    return;
  }

  // Register Mouser as a vendor (distributor = reseller type)
  const vendorId = await ensureVendor(
    "Mouser Electronics",
    "reseller",
    "https://www.mouser.de",
    "https://www.mouser.de/Search/Refine?Keyword="
  );
  console.log(`  Vendor ID: ${vendorId}`);

  // Load OEM transceiver PIDs
  const TARGET_VENDORS = ["Juniper Networks", "Cisco Systems", "Arista Networks", "FS.COM", "SmartOptics"];
  const { rows: transceivers } = await pool.query<{
    id: string;
    part_number: string;
    form_factor: string;
    speed: string;
    vendor_name: string;
  }>(
    `SELECT t.id, t.part_number, t.form_factor, t.speed, v.name AS vendor_name
     FROM transceivers t
     JOIN vendors v ON v.id = t.vendor_id
     WHERE v.name = ANY($1)
       AND t.part_number IS NOT NULL
       AND t.part_number NOT ILIKE '%Transceiver%'
       AND t.part_number NOT ILIKE '%-Transceivers'
       AND LENGTH(t.part_number) BETWEEN 4 AND 35
     ORDER BY v.name, t.part_number`,
    [TARGET_VENDORS]
  );

  console.log(`  Found ${transceivers.length} OEM PIDs to price-check\n`);

  let found = 0;
  let notFound = 0;
  let errors = 0;

  for (let i = 0; i < transceivers.length; i++) {
    const tx = transceivers[i];

    if (i > 0 && i % 20 === 0) {
      console.log(
        `  [${i}/${transceivers.length}] found=${found} not_found=${notFound} errors=${errors}`
      );
    }

    const part = await searchMouser(tx.part_number);

    if (!part) {
      notFound++;
      await sleep(DELAY_MS);
      continue;
    }

    const priceData = extractPrice(part);
    if (!priceData) {
      notFound++;
      await sleep(DELAY_MS);
      continue;
    }

    const { qty, stockLevel } = parseAvailability(part.Availability);
    const productUrl = part.ProductDetailUrl
      ? `https://www.mouser.de${part.ProductDetailUrl}`
      : `https://www.mouser.de/Search/Refine?Keyword=${encodeURIComponent(tx.part_number)}`;

    const hash = contentHash(
      `mouser:${tx.id}:${priceData.price}:${priceData.currency}:${stockLevel}`
    );

    try {
      await upsertPriceObservation({
        transceiverId: tx.id,
        sourceVendorId: vendorId,
        price: priceData.price,
        currency: priceData.currency,
        stockLevel,
        quantityAvailable: qty,
        url: productUrl,
        contentHash: hash,
      });
      found++;
      console.log(
        `  ✓ ${tx.part_number.padEnd(32)} ${priceData.currency} ${priceData.price.toFixed(2).padStart(9)}  ${stockLevel.padEnd(13)}  qty=${qty}`
      );
    } catch (err: unknown) {
      errors++;
      console.warn(
        `  ✗ DB error ${tx.part_number}: ${(err as Error).message.slice(0, 60)}`
      );
    }

    await sleep(DELAY_MS);
  }

  console.log(`\n=== Mouser OEM Scraper Complete ===`);
  console.log(`  Processed:  ${transceivers.length}`);
  console.log(`  Found:      ${found}`);
  console.log(`  Not found:  ${notFound}`);
  console.log(`  DB errors:  ${errors}\n`);
}

// ── CLI ───────────────────────────────────────────────────────────────────────

if (require.main === module) {
  scrapeMouser()
    .then(() => pool.end())
    .catch((err: unknown) => {
      console.error("Fatal:", err);
      pool.end();
      process.exit(1);
    });
}