Simple DB

main.swift

import Foundation

struct DatabaseEntry: Codable {
  let desc: String
  let category: String
  let added: Date
  let data: [String: String]
}

extension DatabaseEntry: CustomStringConvertible {
  var description: String {
    return "\(category) \(added) | \(desc); \(data)"
  }
}

class Database: Codable {
  private var values = [DatabaseEntry]()

  func addFromArgs(_ args: ArraySlice<String>) {
    guard args.count >= 2 else {
      fatalError("Must give a description and category when adding")
    }

    var data = [String: String]()
    var idx = args.index(2, offsetBy: 1, limitedBy: args.endIndex)

    while let i = idx, let valIdx = args.index(i, offsetBy: 1, limitedBy: args.endIndex), valIdx != args.endIndex {
      let field = args[i]
      let val = args[valIdx]

      data[field] = val

      idx = args.index(valIdx, offsetBy: 1, limitedBy: args.endIndex)
    }


    values.append(DatabaseEntry(desc: args[1], category: args[2], added: Date(), data: data))
  }

  func printAll() {
    for item in values.sorted(by: { $0.added < $1.added }) {
      print(item)
    }
  }

  func printLatest() {
    guard let last = values.last else {
      return
    }

    print(last)
  }

  func printLatestInCategories() {
    var seenCats = Set<String>()

    for thing in values.sorted(by: { $0.added > $1.added }) where !seenCats.contains(thing.category) {
      print(thing)

      seenCats.insert(thing.category)
    }
  }
}

let args = Array(CommandLine.arguments.dropFirst())

guard !args.isEmpty else {
  fatalError("Must give at least one command")
}

let manager = FileManager.default
let dbLoc = "\(manager.currentDirectoryPath)/db.json"
let dec = JSONDecoder()
let enc = JSONEncoder()

let db: Database

if let dbFile = manager.contents(atPath: dbLoc) {
  db = try dec.decode(Database.self, from: dbFile)
} else {
  db = Database()
}

switch args[0] {
case "add":
  db.addFromArgs(args.dropFirst())
  manager.createFile(atPath: dbLoc, contents: try enc.encode(db))
case "all":
  db.printAll()
case "last":
  db.printLatest()
case "categories":
  db.printLatestInCategories()
case _:
  fatalError("")
}