const db = require("../models");
const Product = db.Product;
const fs = require("fs");
const csv = require("csv-parser");
const path = require("path");
const UnitMaster = db.UnitMaster;

exports.createProduct = async (req, res) => {
  try {

    const data = await Product.create(req.body);

    res.status(201).send({'status':"success",'message':"created successfully",'data': data }); 

  } catch (error) {
    res.status(500).send({'status':"failed",'message':err.message });
  }
};

exports.getAllProducts = async (req, res) => {
  try {

    const data = await Product.findAll({
      include: [
        {
          model: UnitMaster,
          as: "unit",
          attributes: ["uom"],
        },
      ],
    });

     res.status(200).send({'status':"success",'message':"Fetched successfully",'product_count': data.length, 'data': data }); 

  } catch (error) {
    res.status(500).send({'status':"failed",'message':err.message });
  }
};

exports.getProductById = async (req, res) => {
  try {

    const data = await Product.findByPk(req.params.id);

    if (!data) res.status(404).send({'status':"failed",'message':"Record Not found",'data': "" }); 

    res.status(200).send({'status':"success",'message':"Fetched successfully",'data': data }); 

  } catch (error) {
    res.status(500).send({'status':"failed",'message':err.message });
  }
};

exports.updateProduct = async (req, res) => {
  try {

    const [updated] = await Product.update(req.body, { where: { id: req.params.id } });

    if (!updated) res.status(404).send({'status':"failed",'message':"Record Not found",'data': "" }); 

    res.status(200).send({'status':"success",'message':"Updated successfully",'data': "" }); 

  } catch (error) {
    res.status(500).send({'status':"failed",'message':err.message });
  }
};

exports.deleteProduct = async (req, res) => {
  try {

    const deleted = await Product.destroy({ where: { id: req.params.id } });

    if (!deleted) res.status(404).send({'status':"failed",'message':"Record Not found",'data': "" }); 

    res.status(200).send({'status':"success",'message':"Deleted successfully",'data': "" }); 

  } catch (error) {
    res.status(500).send({'status':"failed",'message':err.message });
  }
};
exports.uploadProductsFromCSV = async (req, res) => {
  try {
    // Check if file exists
    if (!req.file) {
      return res.status(400).send({ status: "failed", message: "No file uploaded" });
    }

    const filePath = req.file.path;

    // Validate file type
    if (!req.file.originalname.endsWith(".csv")) {
      fs.unlinkSync(filePath);
      return res.status(400).send({
        status: "failed",
        message: "Invalid file type. Only CSV files are allowed.",
      });
    }

    // Validate userId
    if (!req.body.userId || isNaN(req.body.userId)) {
      fs.unlinkSync(filePath);
      return res.status(400).send({
        status: "failed",
        message: "Invalid or missing userId. Must be an integer.",
      });
    }

    const results = [];
    const userId = parseInt(req.body.userId);

    console.log(userId, "userId");

    // Read CSV and clean headers/values
    fs.createReadStream(filePath)
      .pipe(csv())
      .on("data", (row) => {
        // Trim all keys and values to handle spaces in header names or values
        const cleanRow = {};
        for (const key in row) {
          cleanRow[key.trim()] = row[key] ? row[key].trim() : null;
        }
        results.push(cleanRow);
      })
      .on("end", async () => {
        try {
          // Check for empty CSV
          if (results.length === 0) {
            fs.unlinkSync(filePath);
            return res.status(400).send({
              status: "failed",
              message: "CSV file is empty or invalid.",
            });
          }

          console.log(results, "results");

          // Fetch existing products by hs_code
          const hsCodes = results.map((r) => r.hs_code);
          const existingProducts = await Product.findAll({
            where: { hs_code: hsCodes },
          });

          const existingHsCodes = existingProducts.map((p) => p.hs_code);

          const toInsert = [];
          const duplicates = [];

          // Process CSV rows
          for (const row of results) {
            const hsCode = row.hs_code?.trim();
            const productName = row.product_name?.trim();
            const description = row.hs_description?.trim();

            if (!hsCode || !productName) continue; // skip invalid rows

            if (existingHsCodes.includes(hsCode)) {
              duplicates.push(hsCode);
            } else {
              toInsert.push({
                hs_code: hsCode,
                product_name: productName,
                hs_description: description,
                created_by: userId,
                created_at: new Date(),
              });
            }
          }

          // Bulk insert new records
          let inserted = [];
          if (toInsert.length > 0) {
            inserted = await Product.bulkCreate(toInsert, { validate: true });
          }

          // Delete file after processing
          fs.unlinkSync(filePath);

          // Send success response
          return res.status(200).send({
            status: "success",
            message: `${inserted.length} products inserted successfully.`,
            inserted_count: inserted.length,
            duplicate_hs_codes: duplicates,
          });
        } catch (err) {
          if (fs.existsSync(filePath)) fs.unlinkSync(filePath);
          return res.status(500).send({
            status: "failed",
            message: err.message,
          });
        }
      });
  } catch (error) {
    return res.status(500).send({ status: "failed", message: error.message });
  }
};

exports.downloadProductSample = async (req, res) => {
  try {
    const filePath = path.join(__dirname, "../writable/uploads/sample_files/products_upload_sample.csv");
    return res.download(filePath, "products_upload_sample.csv");
  } catch (err) {
    return res.status(500).send({ status: "failed", message: err.message });
  }
};