import ArgumentParser
import Foundation

@main
struct CapTrain: AsyncParsableCommand {
    
    private static let defaultIterations = 10
    
    @Flag(name: .shortAndLong, help: "Resume the previous training session (default: false)")
    var resume: Bool = false
    
    @Option(name: .shortAndLong, help: "The path to the configuration file. The file must be a json object containing command line arguments. Command line options take precedence over configuration file options")
    var configuration: String?
    
    @Option(name: .shortAndLong, help: "The number of iterations to train (default: 10)")
    var iterations: Int?
    
    @Option(name: .shortAndLong, help: "The url of the caps server to retrieve images and upload the classifier")
    var server: String?
    
    @Option(name: .shortAndLong, help: "The authentication token for the server")
    var authentication: String?
    
    @Option(name: .shortAndLong, help: "The path to the folder where the content (images, classifier, thumbnails) is stored")
    var folder: String?
    
    @Flag(name: .long, help: "Only upload the previous classifier")
    var skipTraining: Bool = false

    func run() async throws {
        let configurationFile = try configurationFile()
        let iterations = iterations ?? configurationFile?.iterations ?? CapTrain.defaultIterations
        guard let contentFolder = folder ?? configurationFile?.folder else {
            throw TrainingError.missingArguments("folder")
        }
        guard let serverPath = server ?? configurationFile?.server else {
            throw TrainingError.missingArguments("server")
        }
        guard let authentication = authentication ?? configurationFile?.authentication else {
            throw TrainingError.missingArguments("authentication")
        }
        let configuration = Configuration(
            contentFolder: contentFolder,
            trainingIterations: iterations,
            serverPath: serverPath,
            authenticationToken: authentication)
        
        let creator = try ClassifierCreator(configuration: configuration, resume: resume)
        try await creator.run(skipTraining: skipTraining)
    }
    
    private func configurationFile() throws -> ConfigurationFile? {
        guard let configuration else {
            return nil
        }
        let configurationFileUrl = URL(fileURLWithPath: configuration)
        return try ConfigurationFile(at: configurationFileUrl)
    }
}