FabrizioBrancati/SwiftyBot

//
//  Response.swift
//  SwiftyBot
//
//  The MIT License (MIT)
//
//  Copyright (c) 2016 - 2019 Fabrizio Brancati.
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.

import Foundation
import Vapor

/// Google Assistant response
public struct Response: Codable {
    /// Response payload.
    public private(set) var payload: Payload
}

// MARK: - Response Extension

/// Response extension.
public extension Response {
    /// Declared in an extension to not override default `init` function.
    ///
    /// - Parameter request: Message request.
    /// - Throws: Decoding errors.
    init(for request: Vapor.Request) throws {
        /// Set the default payload.
        payload = Payload(
            google: GooglePayload(
                richResponse: RichResponse(
                    items: [
                        RichResponseItem(
                            simpleResponse: SimpleResponse(
                                textToSpeech: "I'm sorry but there was an error",
                                displayText: "I am sorry but there was an error 😢"
                            )
                        )
                    ]
                )
            )
        )
        
        /// Decode the request.
        let messageRequest = try request.content.syncDecode(Request.self)
        
        /// Check if the message was about help.
        if messageRequest.is(intent: .help) {
            /// Set the text to speech.
            /// Also set the display text, because differs from text to speech.
            payload.set(
                textToSpeech: """
                    Welcome to SwiftyBot, an example on how to create a Google Assistant bot with Swift using Vapor.

                    Say hi to get a welcome message, ask for help or ask for the bot purpose to get a help message, ask to buy something to get a carousel message, any other sentence will get a fallback message.
                    """,
                displayText: """
                    Welcome to SwiftyBot, an example on how to create a Google Assistant bot with Swift using Vapor.

                    Say hi - Welcome message
                    Ask for help / Ask for the bot purpose - Help message
                    Ask to buy something - Carousel message
                    Any other sentence - Fallback message
                    """
            )
        /// Check if the message was about the carousel.
        } else if messageRequest.is(intent: .carousel) {
            /// Set the text to speech for devices that cannot display a carousel.
            /// Also set the display text, because differs from text to speech.
            payload.set(
                textToSpeech: "You can not display carousel items on this device, sorry",
                displayText: "You can't display carousel items on this device, sorry 😞"
            )
            /// Create the carousel with all the examples.
            payload.set(
                systemIntent: SystemIntent(
                    intent: .option,
                    data: IntentData(
                        type: .option,
                        carousel: Carousel(
                            items: CarouselItem.allExamples
                        )
                    )
                )
            )
        }
    }
}

// MARK: - Response Handling

/// Response extension.
public extension Response {
    /// Create a response for a request.
    ///
    /// - Parameter request: Assistant request.
    /// - Returns: Returns the message `HTTPResponse`.
    /// - Throws: Decoding errors.
    func create(on request: Vapor.Request) throws -> HTTPResponse {
        /// Create the JSON response.
        /// More info [here](https://dialogflow.com/docs/fulfillment/how-it-works#response_format).
        var httpResponse = HTTPResponse(status: .ok, headers: ["Content-Type": "application/json"])
        /// Encode the response.
        try JSONEncoder().encode(self, to: &httpResponse, on: request.eventLoop)
        return httpResponse
    }
}