Print session list for tweet of #iOSDCRC

TimetableTweet.swift

import Foundation

extension Date {
    func toString(with dateFormat: String) -> String {
        let dateFormatter = DateFormatter()
        dateFormatter.locale = Locale(identifier: "ja_JP")
        dateFormatter.timeZone = TimeZone(identifier: "Asia/Tokyo")
        dateFormatter.dateFormat = dateFormat
        return dateFormatter.string(from: self)
    }
}

struct Event: Codable, Equatable {
    let title: String
    let description: String
    let startAt: Date
    let endAt: Date
    let tracks: [Track]
    
    private enum CodingKeys: String, CodingKey {
        case title
        case description
        case startAt = "start_at"
        case endAt = "end_at"
        case tracks
    }
    
    struct Track: Codable, Equatable {
        let name: String
        let hashtag: String
        let sessions: [Session]
        
        private enum CodingKeys: String, CodingKey {
            case name
            case hashtag
            case sessions
        }
        
        struct Session: Codable, Equatable {
            let title: String
            let description: String
            let author: String?
            let url: URL?
            let startAt: Date
            let endAt: Date
            
            private enum CodingKeys: String, CodingKey {
                case title
                case description
                case author
                case url
                case startAt = "start_at"
                case endAt = "end_at"
            }
        }
    }
}

let bundle = Bundle.main

guard let path = bundle.path(forResource: "iosdcrc", ofType: "json") else {
    fatalError("path not found")
}

guard let data = try? Data(contentsOf: URL(fileURLWithPath: path)) else {
    fatalError("data get failed")
}

do {
    let jsonDecoder = JSONDecoder()
    jsonDecoder.dateDecodingStrategy = .iso8601
    let events = try jsonDecoder.decode([Event].self, from: data)
    
    events.forEach { (event) in
        print(event.description)
        
        event.tracks.forEach({ (track) in
            print(track.name)
            
            track.sessions.forEach({ (session) in
                var components: [String] = [session.title.replacingOccurrences(of: "\n", with: " ")]
                if let author = session.author {
                    components.append(author)
                }
                components.append(track.hashtag)
                
                print("Next: \(session.startAt.toString(with: "HH:mm~")) [\(track.name)] \(components.joined(separator: " "))\n")
            })
        })
    }
} catch {
    fatalError("timetable get failed \(error)")
}