package main

import (
	"context"
	"github.com/aws/aws-lambda-go/lambda"
	"math/rand"
	"strconv"
	"time"
)

type StockEvent struct {
	StockPrice int `json:"stockPrice"`
}

type TransactionResult struct {
	Id              string `json:"id"`
	Price           string `json:"price"`
	TransactionType string `json:"transactionType"`
	Qty             string `json:"qty"`
	Timestamp       string `json:"timestamp"`
}

func handler(ctx context.Context, event StockEvent) (TransactionResult, error) {
	// Sample Lambda function which mocks the operation of buying a random number
	// of shares for a stock.

	// For demonstration purposes, this Lambda function does not actually perform any
	// actual transactions. It simply returns a mocked result.

	// Parameters
	// ----------
	// event: StockEvent, required
	//     Input event to the Lambda function

	// Returns
	// ------
	//     TransactionResult: Object containing details of the stock buying transaction

	// Get the price of the stock provided as input
	stockPrice := event.StockPrice

	// Mocked result of a stock buying transaction
	return TransactionResult{
		Id:              strconv.FormatInt(rand.Int63n(1000), 10),    // Unique ID for the transaction
		Price:           strconv.FormatInt(int64(stockPrice), 10),    // Price of each share
		TransactionType: "buy",                                       // Type of transaction (buy/sell)
		Qty:             strconv.FormatInt((rand.Int63n(9) + 1), 10), // Number of shares bought/sold (We are mocking this as a random integer between 1 and 10)
		Timestamp:       time.Now().Format(time.RFC850),              // Timestamp of the when the transaction was completed
	}, nil
}

func main() {
	rand.Seed(11)

	lambda.Start(handler)
}