//
//  ydnabApp.swift
//  ydnab
//
//  Created by Andrea Franceschini on 20/09/2020.
//

import UIKit
import SwiftUI
import os.log

class AppDelegate : NSObject, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        let applicationSupportURL = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
        #if DEBUG
        print(applicationSupportURL.path)
        #endif
        guard !applicationSupportURL.path.isEmpty else {
            print("Couldn't find Application Support path... something is wrong here.")
            // TODO: Crash
            return false
        }
        let budgetsListURL = URL(fileURLWithPath: "Budgets.json", relativeTo: applicationSupportURL)
        if !FileManager.default.fileExists(atPath: budgetsListURL.path) {
            // TODO: Run onboarding, create first budget
            let budget: [BudgetSection] = [
                BudgetSection(name: "Everyday Expenses", categories: [
                    BudgetCategory(name: "Groceries"),
                    BudgetCategory(name: "Eating out"),
                    BudgetCategory(name: "Medical"),
                    BudgetCategory(name: "Clothing"),
                    BudgetCategory(name: "Household goods")
                ]),
                BudgetSection(name: "Travel", categories: [
                    BudgetCategory(name: "Transport"),
                    BudgetCategory(name: "Fuel"),
                    BudgetCategory(name: "Accommodation")
                ]),
                BudgetSection(name: "Rainy Days", categories: [
                    BudgetCategory(name: "Emergencies"),
                    BudgetCategory(name: "Car insurance")
                ]),
                BudgetSection(name: "Monthly Expenses", categories: [
                    BudgetCategory(name: "Rent"),
                    BudgetCategory(name: "Mobile")
                ]),
                BudgetSection(name: "Savings Goals", categories: [
                    BudgetCategory(name: "Savings"),
                    BudgetCategory(name: "Holidays")
                ])
            ]
            let budgetsList: BudgetsList = [
                BudgetInfo(name: "Default Budget",
                           localeIdentifier: "en-us",
                           sections: budget)
            ]

            let jsonBudget: Data
            do {
                let encoder = JSONEncoder()
                encoder.outputFormatting = .prettyPrinted
                jsonBudget = try encoder.encode(budgetsList)
                try jsonBudget.write(to: budgetsListURL)
            } catch {
                print("Couldn't encode budgets list.")
                print("Error: \(error)")
                // TODO: Crash?
                return false
            }
        }
        return true
    }
}

@main
struct ydnabApp: App {

    let persistenceController = PersistenceController.shared

    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate

    @Environment(\.scenePhase) private var scenePhase
    @AppStorage("lastLoadedBudgetId") private var lastLoadedBudgetId = ""

    var body: some Scene {
        WindowGroup {
            NavigationView {
                BudgetsListView(currentBudgetId: UUID(uuidString: lastLoadedBudgetId))

            }
            .environment(\.managedObjectContext, persistenceController.container.viewContext)
        }
        .onChange(of: scenePhase) { phase in
            print(phase)
            switch phase {
            case .background:
                let context = persistenceController.container.viewContext
                if context.hasChanges {
                    do {
                        try context.save()
                    } catch {
                        print(error)
                    }
                }
            default:
                print(phase)
            }
        }
    }
}