//
//  YearAndMonthPicker.swift
//  ydnab
//
//  Created by Andrea Franceschini on 03/10/2020.
//

import SwiftUI

/// Allows to chose the month and year to view.
struct YearAndMonthPicker: View {
    @Binding var month: Int
    @Binding var monthName: String
    @Binding var year: Int
    @State var locale: Locale

    private var monthNames: [String] {
        var c = Calendar(identifier: .gregorian)
        c.locale = locale
        return c.monthSymbols
    }

    var columns: [GridItem] = [
        GridItem(spacing: 8),
        GridItem(spacing: 8),
        GridItem(spacing: 8)
    ]

    var body: some View {
        VStack {
            HStack {
                Button(action: { year -= 1 }) {
                    Image(systemName: "chevron.backward.square")
                        .imageScale(.large)
                }
                Spacer()
                Text(String(year)).bold()
                Spacer()
                Button(action: { year += 1 }) {
                    Image(systemName: "chevron.forward.square")
                        .imageScale(.large)
                }
            }

            GeometryReader { geometry in
                LazyVGrid(columns: columns, spacing: 4) {
                    ForEach(monthNames.indices) { i in
                        Button(action: {
                                month = i
                                monthName = monthNames[i]
                        }, label: {
                            Text(monthNames[i])
                                .frame(minWidth: geometry.size.width / 3,
                                       idealWidth: geometry.size.width / 3,
                                       maxWidth: geometry.size.width / 3,
                                       minHeight: geometry.size.height / 4,
                                       idealHeight: geometry.size.height / 4,
                                       maxHeight: geometry.size.height / 4,
                                       alignment: .center)
                        })
                        .background(month == i ? Color("bgActive") : Color("bgInactive"))
                        .foregroundColor(month == i ? Color.white : Color("AccentColor"))
                    }
                }
            }
        }
        .padding(.bottom, 22)
    }
}