func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    do {
        try DiagnosticsLogger.setup()
    } catch {
        print("Failed to setup the Diagnostics Logger")
    }
    return true
}

import UIKit
import MessageUI
import Diagnostics

class ViewController: UIViewController {

    @IBAction func sendDiagnostics(_ sender: UIButton) {
        /// Create the report.
        let report = DiagnosticsReporter.create()

        guard MFMailComposeViewController.canSendMail() else {
            /// For debugging purposes you can save the report to desktop when testing on the simulator.
            /// This allows you to iterate fast on your report.
            report.saveToDesktop()
            return
        }

        let mail = MFMailComposeViewController()
        mail.mailComposeDelegate = self
        mail.setToRecipients(["support@yourcompany.com"])
        mail.setSubject("Diagnostics Report")
        mail.setMessageBody("An issue in the app is making me crazy, help!", isHTML: false)

        /// Add the Diagnostics Report as an attachment.
        mail.addDiagnosticReport(report)

        present(mail, animated: true)
    }

}

extension ViewController: MFMailComposeViewControllerDelegate {
    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        controller.dismiss(animated: true)
    }
}

import AppKit
import Diagnostics

func send(report: DiagnosticsReport) {
    let service = NSSharingService(named: NSSharingService.Name.composeEmail)!
    service.recipients = ["support@yourcompany.com"]
    service.subject = "Diagnostics Report"
            
    let url = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("Diagnostics-Report.html")
    
    // remove previous report
    try? FileManager.default.removeItem(at: url)

    do {
        try report.data.write(to: url)
    } catch {
        print("Failed with error: \(error)")
    }

    service.perform(withItems: [url])
}

let userDefaultsReporter = UserDefaultsReporter(
    userDefaults: UserDefaults(suiteName: "a.userdefaults.instance"),
    keys: ["key_1"]
)

let diagnosticsReport = DiagnosticsReporter.create(using: [userDefaultsReporter])

struct DiagnosticsDictionaryFilter: DiagnosticsReportFilter {

    // This demonstrates how a filter can be used to filter out sensible data.
    static func filter(_ diagnostics: Diagnostics) -> Diagnostics {
        guard let dictionary = diagnostics as? [String: Any] else { return diagnostics }
        return dictionary.filter { keyValue -> Bool in
            if keyValue.key == "App Display Name" {
                // Filter out the key with the value "App Display Name"
                return false
            } else if keyValue.key == "AppleLanguages" {
                // Filter out a user defaults key.
                return false
            }
            return true
        }
    }
}

let report = DiagnosticsReporter.create(using: reporters, filters: [DiagnosticsDictionaryFilter.self])

/// Support logging simple `String` messages.
DiagnosticsLogger.log(message: "Application started")

/// Support logging `Error` types.
DiagnosticsLogger.log(error: ExampleError.missingData)

var reporters = DiagnosticsReporter.DefaultReporter.allReporters
let documentsURL = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
let directoryTreesReporter = DirectoryTreesReporter(
    directories: [
        documentsURL
    ]
)
reporters.insert(directoryTreesReporter, at: 1)

/// An example Custom Reporter.
struct CustomReporter: DiagnosticsReporting {
    static func report() -> DiagnosticsChapter {
        let diagnostics: [String: String] = [
            "Logged In": Session.isLoggedIn.description
        ]

        return DiagnosticsChapter(title: "My custom report", diagnostics: diagnostics)
    }
}

var reporters = DiagnosticsReporter.DefaultReporter.allReporters
reporters.insert(CustomReporter.self, at: 1)
let report = DiagnosticsReporter.create(using: reporters)

struct SmartInsightsProvider: SmartInsightsProviding {
    func smartInsights(for chapter: DiagnosticsChapter) -> [SmartInsightProviding] {
        guard let html = chapter.diagnostics as? HTML else { return [] }
        if html.errorLogs.contains(where: { $0.contains("AppDelegate.ExampleLocalizedError") }) {
            return [
                SmartInsight(
                    name: "Localized data",
                    result: .warn(message: "An error was found regarding missing localisation.")
                )
            ]
        }
        return []
    }
}

DiagnosticsChapter(title: "UserDefaults", diagnostics: userDefaults, formatter: <#HTMLFormatting.Type#>)

import PackageDescription

let package = Package(
    name: "MyProject",
    platforms: [
       .macOS(.v10_15)
    ],
    dependencies: [
        .package(url: "https://github.com/WeTransfer/Diagnostics.git", .upToNextMajor(from: "1.8.0"))
    ],
    targets: [
        .target(
            name: "MyProject",
            dependencies: ["Diagnostics"]),
        .testTarget(
            name: "MyProjectTests",
            dependencies: ["MyProject"]),
    ]
)