Arkhia-Full-Stack-Test

backend/.env

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+PORT=4000

backend/Dockerfile

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+FROM node:alpine
+WORKDIR /app/backend
+COPY package*.json ./
+RUN npm install
+COPY . .
+EXPOSE 4000
+CMD ["node", "index.js"]
+
+
+

backend/config/allowedOrigins.js

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+const allowedOrigins = [
+    'http://localhost:3000',
+]
+
+module.exports = allowedOrigins;

backend/config/corsOptions.js

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+const allowedOrigins = require('./allowedOrigins')
+
+const corsOptions = {
+    origin: (origin, callback) => {
+        if (allowedOrigins.indexOf(origin) !== -1) {
+            callback(null, true)
+        } else {
+            callback(new Error('Not allowed by CORS'))
+        }
+    },
+    credentials: true,
+    optionsSuccessStatus: 200
+}
+
+module.exports = corsOptions 

backend/controllers/exchangeControllers.js

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+const axios = require("axios");
+
+const exchange = async (req, res) => {
+  const { coin, currency } = req.query;
+
+  try {
+    // Fetch the markets for the specified coin
+    const response = await axios.get(
+      `https://api.coinstats.app/public/v1/markets?coinId=${coin}&currency=${currency}`
+    );
+    const data = response.data;
+
+    const markets = data;
+
+    if (!markets || markets.length === 0) {
+      res
+        .status(404)
+        .json({ error: "No markets found for the specified coin" });
+      return;
+    }
+
+    if (markets.length === 0) {
+      res
+        .status(404)
+        .json({ error: "No markets found for the selected currency" });
+    } else if (markets.length === 1) {
+      // Only one market supports the selected currency
+      const exchange = markets[0].exchange;
+      res.json({ exchange });
+    } else {
+      // Multiple markets support the selected currency, find the one with the lowest price
+      let minPrice = Number.MAX_VALUE;
+      let minPriceExchange = "";
+
+      markets.forEach((market) => {
+        if (market.price < minPrice) {
+          minPrice = market.price;
+          minPriceExchange = market.exchange;
+        }
+      });
+
+      res.json({ exchange: minPriceExchange });
+    }
+  } catch (error) {
+    console.error("Error fetching markets:", error);
+    res.status(500).json({ error: "Internal server error" });
+  }
+};
+
+module.exports = {
+  exchange,
+};

backend/index.js

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+require("dotenv").config();
+const express = require("express");
+const cors = require('cors')
+const corsOptions = require('./config/corsOptions')
+const app = express();
+const PORT = process.env.PORT || 4000;
+
+
+app.use(cors(corsOptions))
+
+app.use(require("./routes/exchangeRoutes"));
+
+
+app.listen(PORT, () => {
+  console.log(`Backend server is running on port ${PORT}`);
+});