//
//  Conversion.swift
//  Simoleon
//
//  Created by Dennis Concepción Martín on 18/07/2021.
//

import SwiftUI

struct Conversion: View {
    var fetchUserSettings: Bool
    @State var currencyPair: String
    
    @State private var amountToConvert = "1000"
    @State private var price: Double = 1.00
    @State private var showingConversion = false
    @State private var showingCurrencySelector = false
    @State private var isEditing = false
    
    @Environment(\.managedObjectContext) private var viewContext
    @FetchRequest(sortDescriptors: []) private var defaultCurrency: FetchedResults<DefaultCurrency>
    
    let currencyMetadata: [String: CurrencyMetadataModel] = parseJson("CurrencyMetadata.json")
    
    var body: some View {
        ScrollView(showsIndicators: false) {
            VStack(alignment: .leading) {
                HStack {
                    Button(action: { showingCurrencySelector = true }) {
                        RoundedRectangle(cornerRadius: 15)
                            .foregroundColor(Color(.secondarySystemBackground))
                            .frame(height: 60)
                            .overlay(CurrencyRow(currencyPair: currencyPair).padding(.horizontal))
                    }
                    
                    FavouriteButton(currencyPair: currencyPair)
                }
                
                ConversionBox(
                    currencyPair: $currencyPair,
                    amountToConvert: $amountToConvert,
                    price: $price,
                    showingConversion: $showingConversion,
                    showingCurrencySelector: $showingCurrencySelector,
                    isEditing: $isEditing
                )
            }
            .padding()
            .onAppear {
                if fetchUserSettings {
                    fetchingUserSettings()
                }
                
                request(currencyPair)
            }
            .onChange(of: showingCurrencySelector, perform: { showingCurrencySelector in
                if !showingCurrencySelector {
                    request(currencyPair)
                }
            })
            .sheet(isPresented: $showingCurrencySelector) {
                CurrencySelector(currencyPair: $currencyPair, showingCurrencySelector: $showingCurrencySelector)
            }
        }
        .navigationTitle(Text("Convert", comment: "Navigation title"))
        .toolbar {
            ToolbarItem(placement: .cancellationAction) {
                if isEditing {
                    Button(action: {
                        UIApplication.shared.dismissKeyboard()
                        isEditing = false
                    }) {
                        Text("Cancel", comment: "Button to stop editing textfield")
                    }
                }
            }
        }
        .if(UIDevice.current.userInterfaceIdiom == .phone && fetchUserSettings) { content in
            NavigationView { content }
        }
    }
    
    private func request(_ currencyPair: String) {
        let url = "\(readConfig("API_URL")!)quotes?pairs=\(currencyPair)&api_key=\(readConfig("API_KEY")!)"
        
        Simoleon.request(url: url, model: [CurrencyQuoteModel].self) { response in
            self.showingConversion = false
            if let price = response.first?.price {
                self.price = price
                self.showingConversion =  true
            } else {
                // Handle error
            }
        }
    }
    
    /*
     1) Fetch default currency from User Settings
     2) Change State var currencyPair
     */
    private func fetchingUserSettings() {
        if let defaultCurrency = defaultCurrency.first {
            self.currencyPair = defaultCurrency.pair ?? "USD/GBP"
        }
    }
}


struct Conversion_Previews: PreviewProvider {
    static var previews: some View {
        Conversion(fetchUserSettings: true, currencyPair: "USD/GBP")
    }
}