const functions = require("firebase-functions");
const express = require("express");
const cors = require("cors");
const axios = require("axios");
const admin = require("firebase-admin");

admin.initializeApp();
const db = admin.firestore();

const app = express();
app.use(cors({ origin: true }));
app.use(express.json());

const SP_API_CONFIG = {
  clientId: functions.config().spapi.client_id,
  clientSecret: functions.config().spapi.client_secret,
  refreshToken: functions.config().spapi.refresh_token,
  endpoint: "https://sellingpartnerapi-fe.amazon.com",
  tokenUrl: "https://api.amazon.com/auth/o2/token",
};

let cachedToken = null;
let tokenExpiry = null;

async function getAccessToken() {
  const now = Date.now();
  if (cachedToken && tokenExpiry && now < tokenExpiry) {
    return cachedToken;
  }
  try {
    console.log("Requesting access token...");
    const response = await axios.post(
      SP_API_CONFIG.tokenUrl,
      new URLSearchParams({
        grant_type: "refresh_token",
        client_id: SP_API_CONFIG.clientId,
        client_secret: SP_API_CONFIG.clientSecret,
        refresh_token: SP_API_CONFIG.refreshToken,
      }),
      { headers: { "Content-Type": "application/x-www-form-urlencoded" } }
    );
    console.log("Access token obtained");
    cachedToken = response.data.access_token;
    tokenExpiry = now + (response.data.expires_in - 60) * 1000;
    return cachedToken;
  } catch (error) {
    console.error("LWA Token Error:", error.message);
    throw error;
  }
}

async function spApiRequest(method, path, params, data) {
  const token = await getAccessToken();
  const url = SP_API_CONFIG.endpoint + path;
  const response = await axios({
    method: method,
    url: url,
    params: params || {},
    data: data || null,
    headers: {
      "x-amz-access-token": token,
      "User-Agent": "MySellerTool/1.0",
    },
  });
  return response.data;
}

// ----------------------------------------
// /inventory
// ----------------------------------------
app.get("/inventory", async (req, res) => {
  try {
    const result = await spApiRequest("GET", "/fba/inventory/v1/summaries", {
      granularityType: "Marketplace",
      granularityId: "A1VC38T7YXB528",
      marketplaceIds: "A1VC38T7YXB528",
    }, null);
    res.json({ success: true, data: result });
  } catch (error) {
    console.error("Error:", error.message);
    res.status(500).json({ success: false, error: error.message });
  }
});

// ----------------------------------------
// /status-check
// 全商品のstatus・quantity内訳を高速確認（価格・手数料取得なし）
// ----------------------------------------
app.get("/status-check", async (req, res) => {
  try {
    const sellerId = req.query.sellerId || "A3S9S4T21BT6AO";
    let allItems = [];
    let nextToken = null;
    let pageCount = 0;
    const maxPages = 20;

    do {
      pageCount++;
      const params = {
        marketplaceIds: "A1VC38T7YXB528",
        includedData: "summaries,attributes",
      };
      if (nextToken) params.pageToken = nextToken;

      const result = await spApiRequest("GET", "/listings/2021-08-01/items/" + sellerId, params, null);
      const items = result.items || [];

      for (const item of items) {
        const summary = item.summaries ? item.summaries[0] : null;
        if (!summary) continue;
        const qtyAttr = item.attributes && item.attributes.fulfillment_availability && item.attributes.fulfillment_availability[0];
        const quantity = qtyAttr ? qtyAttr.quantity : 0;
        allItems.push({
          sku: item.sku,
          asin: summary.asin,
          status: summary.status,
          condition: summary.conditionType,
          quantity: quantity,
        });
      }

      nextToken = result.pagination && result.pagination.nextToken ? result.pagination.nextToken : null;
    } while (nextToken && pageCount < maxPages);

    // status別集計
    const statusCount = {};
    const statusAndQtyCount = { active_with_qty: 0, active_no_qty: 0, inactive_with_qty: 0, inactive_no_qty: 0 };
    for (const item of allItems) {
      const s = item.status || "UNKNOWN";
      statusCount[s] = (statusCount[s] || 0) + 1;
      if (s === "ACTIVE" && item.quantity > 0) statusAndQtyCount.active_with_qty++;
      if (s === "ACTIVE" && item.quantity === 0) statusAndQtyCount.active_no_qty++;
      if (s !== "ACTIVE" && item.quantity > 0) statusAndQtyCount.inactive_with_qty++;
      if (s !== "ACTIVE" && item.quantity === 0) statusAndQtyCount.inactive_no_qty++;
    }

    res.json({
      success: true,
      total: allItems.length,
      statusCount,
      statusAndQtyCount,
      items: allItems,
    });
  } catch (error) {
    console.error("Error:", error.message);
    res.status(500).json({ success: false, error: error.message });
  }
});

// ----------------------------------------
// /products-with-pricing
// ----------------------------------------
app.get("/products-with-pricing", async (req, res) => {
  try {
    const sellerId = req.query.sellerId || "A3S9S4T21BT6AO";
    const limit = parseInt(req.query.limit) || 100;
    const onlyInStock = req.query.onlyInStock === "true";

    const listingsResult = await spApiRequest("GET", "/listings/2021-08-01/items/" + sellerId, {
      marketplaceIds: "A1VC38T7YXB528",
      includedData: "summaries,attributes,issues,offers",
    }, null);

    let items = listingsResult.items || [];
    if (onlyInStock) {
      items = items.filter(function(item) {
        const qtyAttr = item.attributes && item.attributes.fulfillment_availability && item.attributes.fulfillment_availability[0];
        return qtyAttr && qtyAttr.quantity > 0;
      });
    }
    items = items.slice(0, limit);

    const products = [];
    for (const item of items) {
      const summary = item.summaries ? item.summaries[0] : null;
      if (!summary) continue;

      const asin = summary.asin;
      const sku = item.sku;
      const priceAttr = item.attributes && item.attributes.purchasable_offer && item.attributes.purchasable_offer[0];
      const ourPrice = priceAttr && priceAttr.our_price && priceAttr.our_price[0] && priceAttr.our_price[0].schedule && priceAttr.our_price[0].schedule[0]
        ? priceAttr.our_price[0].schedule[0].value_with_tax : 0;
      const qtyAttr = item.attributes && item.attributes.fulfillment_availability && item.attributes.fulfillment_availability[0];
      const quantity = qtyAttr ? qtyAttr.quantity : 0;

      let lowestPrice = null;
      let rivalOffers = [];
      await new Promise(function(resolve) { setTimeout(resolve, 1000); });
      try {
        const rivalResult = await spApiRequest("GET", "/products/pricing/v0/items/" + asin + "/offers", {
          MarketplaceId: "A1VC38T7YXB528",
          ItemCondition: "New"
        }, null);
        const offers = rivalResult.payload && rivalResult.payload.Offers ? rivalResult.payload.Offers : [];
        rivalOffers = offers.map(function(offer) {
          return {
            price: offer.ListingPrice && offer.ListingPrice.Amount ? offer.ListingPrice.Amount : 0,
            shipping: offer.Shipping && offer.Shipping.Amount ? offer.Shipping.Amount : 0,
            isFBA: offer.IsFulfilledByAmazon,
          };
        });
        if (offers.length > 0) {
          lowestPrice = Math.min.apply(Math, offers.map(function(o) {
            return (o.ListingPrice && o.ListingPrice.Amount ? o.ListingPrice.Amount : 0)
              + (o.Shipping && o.Shipping.Amount ? o.Shipping.Amount : 0);
          }));
        }
      } catch (err) {
        console.log("Rival price error (" + asin + "):", err.message);
      }

      let fee = 0;
      await new Promise(function(resolve) { setTimeout(resolve, 1000); });
      try {
        const feeResult = await spApiRequest("POST", "/products/fees/v0/listings/" + encodeURIComponent(sku) + "/feesEstimate", {
          marketplaceId: "A1VC38T7YXB528"
        }, {
          FeesEstimateRequest: {
            MarketplaceId: "A1VC38T7YXB528",
            IsAmazonFulfilled: false,
            PriceToEstimateFees: {
              ListingPrice: { CurrencyCode: "JPY", Amount: parseFloat(ourPrice) },
              Shipping: { CurrencyCode: "JPY", Amount: 0 }
            },
            Identifier: sku
          }
        });
        const feeData = feeResult.payload && feeResult.payload.FeesEstimateResult && feeResult.payload.FeesEstimateResult.FeesEstimate && feeResult.payload.FeesEstimateResult.FeesEstimate.TotalFeesEstimate
          ? feeResult.payload.FeesEstimateResult.FeesEstimate.TotalFeesEstimate.Amount : 0;
        fee = parseFloat(feeData);
      } catch (err) {
        console.log("Fee error (" + asin + "):", err.message);
      }

      products.push({
        asin, sku,
        name: summary.itemName,
        image: summary.mainImage ? summary.mainImage.link : null,
        condition: summary.conditionType,
        status: summary.status,
        ourPrice, quantity, lowestPrice, rivalOffers, fee
      });
    }

    res.json({ success: true, products, total: products.length, totalAvailable: listingsResult.numberOfResults });
  } catch (error) {
    console.error("Error:", error.message);
    res.status(500).json({ success: false, error: error.message });
  }
});

// ----------------------------------------
// /all-in-stock-products
// quantity>0 かつ status=ACTIVE のみ取得
// ----------------------------------------
app.get("/all-in-stock-products", async (req, res) => {
  try {
    const sellerId = req.query.sellerId || "A3S9S4T21BT6AO";
    let allInStockProducts = [];
    let nextToken = null;
    let pageCount = 0;
    const maxPages = 20;

    do {
      pageCount++;
      console.log("Fetching page " + pageCount + "...");

      const params = {
        marketplaceIds: "A1VC38T7YXB528",
        includedData: "summaries,attributes,issues,offers",
      };
      if (nextToken) params.pageToken = nextToken;

      const listingsResult = await spApiRequest("GET", "/listings/2021-08-01/items/" + sellerId, params, null);
      const items = listingsResult.items || [];

      for (const item of items) {
        const summary = item.summaries ? item.summaries[0] : null;
        if (!summary) continue;

        const qtyAttr = item.attributes && item.attributes.fulfillment_availability && item.attributes.fulfillment_availability[0];
        const quantity = qtyAttr ? qtyAttr.quantity : 0;
        const status = summary.status;

        // 在庫あり かつ ACTIVEのみ
        if (quantity <= 0 || status !== "ACTIVE") continue;

        const asin = summary.asin;
        const sku = item.sku;
        const priceAttr = item.attributes && item.attributes.purchasable_offer && item.attributes.purchasable_offer[0];
        const ourPrice = priceAttr && priceAttr.our_price && priceAttr.our_price[0] && priceAttr.our_price[0].schedule && priceAttr.our_price[0].schedule[0]
          ? priceAttr.our_price[0].schedule[0].value_with_tax : 0;

        let lowestPrice = null;
        let rivalOffers = [];
        await new Promise(function(resolve) { setTimeout(resolve, 1000); });
        try {
          const rivalResult = await spApiRequest("GET", "/products/pricing/v0/items/" + asin + "/offers", {
            MarketplaceId: "A1VC38T7YXB528",
            ItemCondition: "New"
          }, null);
          const offers = rivalResult.payload && rivalResult.payload.Offers ? rivalResult.payload.Offers : [];
          rivalOffers = offers.map(function(offer) {
            return {
              price: offer.ListingPrice && offer.ListingPrice.Amount ? offer.ListingPrice.Amount : 0,
              shipping: offer.Shipping && offer.Shipping.Amount ? offer.Shipping.Amount : 0,
              isFBA: offer.IsFulfilledByAmazon,
            };
          });
          if (offers.length > 0) {
            lowestPrice = Math.min.apply(Math, offers.map(function(o) {
              return (o.ListingPrice && o.ListingPrice.Amount ? o.ListingPrice.Amount : 0)
                + (o.Shipping && o.Shipping.Amount ? o.Shipping.Amount : 0);
            }));
          }
        } catch (err) {
          console.log("Rival price error (" + asin + "):", err.message);
        }

        let fee = 0;
        await new Promise(function(resolve) { setTimeout(resolve, 1000); });
        try {
          const feeResult = await spApiRequest("POST", "/products/fees/v0/listings/" + encodeURIComponent(sku) + "/feesEstimate", {
            marketplaceId: "A1VC38T7YXB528"
          }, {
            FeesEstimateRequest: {
              MarketplaceId: "A1VC38T7YXB528",
              IsAmazonFulfilled: false,
              PriceToEstimateFees: {
                ListingPrice: { CurrencyCode: "JPY", Amount: parseFloat(ourPrice) },
                Shipping: { CurrencyCode: "JPY", Amount: 0 }
              },
              Identifier: sku
            }
          });
          const feeData = feeResult.payload && feeResult.payload.FeesEstimateResult && feeResult.payload.FeesEstimateResult.FeesEstimate && feeResult.payload.FeesEstimateResult.FeesEstimate.TotalFeesEstimate
            ? feeResult.payload.FeesEstimateResult.FeesEstimate.TotalFeesEstimate.Amount : 0;
          fee = parseFloat(feeData);
        } catch (err) {
          console.log("Fee error (" + asin + "):", err.message);
        }

        allInStockProducts.push({
          asin, sku,
          name: summary.itemName,
          image: summary.mainImage ? summary.mainImage.link : null,
          condition: summary.conditionType,
          status,
          ourPrice, quantity, lowestPrice, rivalOffers, fee
        });
      }

      nextToken = listingsResult.pagination && listingsResult.pagination.nextToken ? listingsResult.pagination.nextToken : null;
    } while (nextToken && pageCount < maxPages);

    res.json({ success: true, products: allInStockProducts, total: allInStockProducts.length, pagesProcessed: pageCount });
  } catch (error) {
    console.error("Error:", error.message);
    res.status(500).json({ success: false, error: error.message });
  }
});

// ----------------------------------------
// /unique-in-stock-products
// ASIN重複除外（同ASINで最安値SKUを残す）
// ----------------------------------------
app.get("/unique-in-stock-products", async (req, res) => {
  try {
    const sellerId = req.query.sellerId || "A3S9S4T21BT6AO";

    const allResponse = await axios.get("https://asia-northeast1-mysellertool-2e842.cloudfunctions.net/api/all-in-stock-products?sellerId=" + sellerId);
    const allProducts = allResponse.data.products;

    const grouped = {};
    for (const p of allProducts) {
      if (!grouped[p.asin]) grouped[p.asin] = [];
      grouped[p.asin].push(p);
    }

    const uniqueProducts = [];
    for (const asin in grouped) {
      const products = grouped[asin];
      products.sort(function(a, b) { return a.ourPrice - b.ourPrice; });
      uniqueProducts.push(products[0]);
    }

    res.json({ success: true, products: uniqueProducts, total: uniqueProducts.length });
  } catch (error) {
    console.error("Error:", error.message);
    res.status(500).json({ success: false, error: error.message });
  }
});

// ----------------------------------------
// exports は必ずファイル末尾に
// ----------------------------------------
exports.api = functions.region("asia-northeast1").runWith({ timeoutSeconds: 540, memory: "1GB" }).https.onRequest(app);