# Code Review Test

### **Overview**

In this code review test, you will be given a Golang codebase for a payment processing service. Your task is to review the code and provide feedback on its quality, correctness, and adherence to best practices.

### **Requirements**

1. Review the codebase for correctness and completeness. Ensure that all requirements specified in the project scope have been met.
2. Review the codebase for adherence to best practices. Evaluate the codebase for maintainability, scalability, performance, and security. Suggest improvements where necessary.
3. Review the codebase for clarity and readability. Evaluate the codebase for ease of understanding, documentation, and comments. Suggest improvements where necessary.

### **Evaluation**

Your code review will be evaluated based on the following criteria:

1. Correctness: Does the codebase meet the requirements specified in the project scope
2. Code quality: Is the codebase well-structured and easy to understand? Does it adhere to best practices for maintainability, scalability, performance, and security
3. Clarity and readability: Is the codebase easy to understand? Is it well-documented and commented

### Codebase

This codebase provides a basic implementation of a payment processing service with an API endpoint **`/api/payments`**. The codebase accepts a JSON payload containing payment information, initiates the payment using the appropriate integration, and returns a JSON response containing the status of the payment request.

This codebase provides a basic implementation of a payment processing service with an API endpoint **`/api/payments`**. The codebase accepts a JSON payload containing payment information, initiates the payment using the appropriate integration, and returns a JSON response containing the status of the payment request.

package main

import (
    "encoding/json"
    "fmt"
    "log"
    "net/http"
)

type PaymentRequest struct {
    Provider string `json:"provider"`
    Amount   int    `json:"amount"`
    UserID   int    `json:"user_id"`
}

type PaymentResponse struct {
    Status  string `json:"status"`
    Message string `json:"message"`
}

var integrationDetails = map[string]IntegrationDetails{
    "Electricity Company": {
        URL:    "https://electricitycompany.com/payments",
        APIKey: "electricity-company-api-key",
    },
    "Internet Provider": {
        URL:    "https://internetprovider.com/payments",
        APIKey: "internet-provider-api-key",
    },
    "Phone Company": {
        URL:    "https://phonecompany.com/payments",
        APIKey: "phone-company-api-key",
    },
    "Water Company": {
        URL:    "https://watercompany.com/payments",
        APIKey: "water-company-api-key",
    },
}

type IntegrationDetails struct {
    URL    string
    APIKey string
}

func main() {
    http.HandleFunc("/api/payments", handlePaymentRequest)
    log.Fatal(http.ListenAndServe(":8080", nil))
}

func handlePaymentRequest(w http.ResponseWriter, r *http.Request) {
    if r.Method != "POST" {
        http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
        return
    }

    decoder := json.NewDecoder(r.Body)
    defer r.Body.Close()

    var paymentRequest PaymentRequest
    if err := decoder.Decode(&paymentRequest); err != nil {
        http.Error(w, "Invalid request payload", http.StatusBadRequest)
        return
    }

    integrationDetails, exists := integrationDetails[paymentRequest.Provider]
    if !exists {
        http.Error(w, "Invalid service provider", http.StatusBadRequest)
        return
    }

    // Code to initiate payment using service provider's API using the integration details

    paymentResponse := PaymentResponse{
        Status:  "success",
        Message: "Payment initiated successfully",
    }

    jsonResponse, err := json.Marshal(paymentResponse)
    if err != nil {
        http.Error(w, "Error encoding JSON response", http.StatusInternalServerError)
        return
    }

    w.Header().Set("Content-Type", "application/json")
    fmt.Fprint(w, string(jsonResponse))
}

.