レポートの生成

package main

import (
	"errors"
	"fmt"
	"sort"
	"strconv"
	"strings"
)

type Product struct {
	Price    float64
	Quantity int
}

func updateStock(inventory map[string]Product, productName string, change int) error {
	product, exists := inventory[productName]
	if !exists {
		return errors.New("product not found: " + productName)
	}
	
	newQuantity := product.Quantity + change
	if newQuantity < 0 {
		return fmt.Errorf("insufficient stock: cannot reduce %s by %d, only %d available", productName, -change, product.Quantity)
	}
	
	product.Quantity = newQuantity
	inventory[productName] = product
	return nil
}

func main() {
	var inventoryData string
	var updateRequests string
	fmt.Scanln(&inventoryData)
	fmt.Scanln(&updateRequests)
	
	// Parse existing inventory
	inventory := make(map[string]Product)
	inventoryEntries := strings.Split(inventoryData, ",")
	
	for _, entry := range inventoryEntries {
		parts := strings.Split(entry, ":")
		name := parts[0]
		price, _ := strconv.ParseFloat(parts[1], 64)
		quantity, _ := strconv.Atoi(parts[2])
		
		inventory[name] = Product{
			Price:    price,
			Quantity: quantity,
		}
	}
	
	// Parse update requests
	updateEntries := strings.Split(updateRequests, ",")
	
	fmt.Println("Processing Stock Updates:")
	
	totalUpdates := len(updateEntries)
	successfulUpdates := 0
	failedUpdates := 0
	var failedProducts []string
	
	for _, update := range updateEntries {
		parts := strings.Split(update, ":")
		productName := parts[0]
		change, _ := strconv.Atoi(parts[1])
		
		err := updateStock(inventory, productName, change)
		if err != nil {
			fmt.Printf("%s: Update failed - %s\n", productName, err.Error())
			failedUpdates++
			failedProducts = append(failedProducts, productName)
		} else {
			newQuantity := inventory[productName].Quantity
			if change > 0 {
				fmt.Printf("%s: Added %d units - New stock: %d\n", productName, change, newQuantity)
			} else if change < 0 {
				fmt.Printf("%s: Removed %d units - New stock: %d\n", productName, -change, newQuantity)
			} else {
				fmt.Printf("%s: No change - Current stock: %d\n", productName, newQuantity)
			}
			successfulUpdates++
		}
	}
	
	// Update summary
	fmt.Println("Update Summary:")
	fmt.Printf("Updates processed: %d\n", totalUpdates)
	fmt.Printf("Updates successful: %d\n", successfulUpdates)
	fmt.Printf("Updates failed: %d\n", failedUpdates)
	
	// Display updated inventory in alphabetical order
	fmt.Println("Updated Inventory:")
	var productNames []string
	for name := range inventory {
		productNames = append(productNames, name)
	}
	sort.Strings(productNames)
	
	for _, name := range productNames {
		product := inventory[name]
		fmt.Printf("- %s: $%.2f (Stock: %d)\n", name, product.Price, product.Quantity)
	}
	
	// Calculate final statistics
	totalProducts := len(inventory)
	totalItems := 0
	totalValue := 0.0
	
	for _, product := range inventory {
		totalItems += product.Quantity
		totalValue += product.Price * float64(product.Quantity)
	}
	
	fmt.Println("Final Inventory Statistics:")
	fmt.Printf("Total Products: %d\n", totalProducts)
	fmt.Printf("Total Items in Stock: %d\n", totalItems)
	fmt.Printf("Total Inventory Value: $%.2f\n", totalValue)
	
	// List failed updates
	if len(failedProducts) > 0 {
		fmt.Printf("Failed updates: %s\n", strings.Join(failedProducts, ","))
	} else {
		fmt.Println("All stock updates were processed successfully")
	}
}