Files for Serverless Swift article

Item.swift

public enum Style: String, Codable {
    case croissant
    case naan
    case pumpernickel
    case rye
}

public struct Item: Codable {
    public let amount: Int
    public let style: Style
}

main.swift

import Foundation
import BreadsRUsModels

let inputData = FileHandle.standardInput.readDataToEndOfFile()
let decoder = JSONDecoder()

func jsonify(response: String, payload: String) -> String {
    let result = "{ \"response\" : \"\(response)\", \"payload\" : \"\(payload)\"}"
    return result
}

do {
    let order = try decoder.decode(Order.self, from: inputData) 
    let receipt = order.receipt()
    print(jsonify(response: "success", payload: receipt.description))
} catch {
    print(jsonify(response: "error", payload: "In a real app, this would have useful information."))
}

Order.swift

public struct Order: Codable {
    public private(set) var items: [Item]

    public init() {
        items = []
    }
    
    public mutating func add(item: Item) {
        items.append(item)
    }

    public func receipt() -> Receipt {
        return Receipt.receipt(for: items)
    }
}

Package.swift

// swift-tools-version:4.0
import PackageDescription

let package = Package(
    name: "BreadsRUs",
    dependencies: [
    ],
    targets: [
        .target(
            name: "BreadsRUsModels",
            dependencies: []),
        .target(
            name: "app",
            dependencies: ["BreadsRUsModels"]),
    ]
)

Receipt.swift

import Foundation

// Dummy. Replace with some sort of database access or similar
// to fetch the current price.
func Price(for style: Style) -> Double {
    switch style {
    case .croissant:
        return 1.23
    case .naan:
        return 0.87
    case .pumpernickel:
        return 0.64
    case .rye:
        return 0.62
    }
}

public struct Receipt: Codable, CustomStringConvertible {
    public private(set) var items: [Item]
    public let orderDate: Date

    func lineItem(for item: Item) -> Double {
        return Double(item.amount) * Price(for: item.style)
    }
    
    var total: Double {
        return items.reduce(0.0) { return $0 + lineItem(for: $1) }
    }

    public var description: String {
        func line(for item: Item) -> String {
            return "\(item.amount) \(item.style.rawValue.uppercased()) @ \(Price(for: item.style)) = \(lineItem(for: item))"
        }
        var result = "Receipt for Order on \(orderDate)\n"
        result += "---------\n"

        _ = items.map { result += line(for: $0) + "\n"} 

        result += "---------\n"
        result += "Total: \(total)\n\n"
        return result
    }

    public init(with items: [Item] = []) {
        self.items = items
        orderDate = Date()
    }

    public mutating func add(item: Item) {
        items.append(item)
    }

    static func receipt(for items: [Item]) -> Receipt {
        return Receipt(with: items)
    }
}