NearFuture/NearFuture/StatsView.swift

//
//  StatsView.swift
//  NearFuture
//
//  Created by Nihaal Sharma on 05/01/2025.
//

import SwiftUI
import Charts

struct StatsView: View {
	@ObservedObject var viewModel: EventViewModel
	
	var body: some View {
		NavigationStack {
			List {
				Section(header: Text("Upcoming Events")) {
					let upcomingEvents = viewModel.events.filter { $0.date > Date() }
					Text("\(upcomingEvents.count) upcoming event\(upcomingEvents.count == 1 ? "" : "s")")
						.font(.headline)
						.foregroundStyle(Color.accentColor)
					let pastEvents = viewModel.events.filter { $0.date < Date() }
					Text("\(pastEvents.count) past event\(pastEvents.count == 1 ? "" : "s")")
						.foregroundStyle(.gray)
				}
				
				Section("Events by Month") {
					let eventsByMonth = Dictionary(grouping: viewModel.events, by: { $0.date })
					ForEach(eventsByMonth.keys.sorted(), id: \.self) { month in
						let count = eventsByMonth[month]?.count ?? 0
						Text("\(count) - \(month.formatted(date: .long, time: .omitted))")
					}
				}
				
				Section("Event Count") {
					let eventCount = viewModel.events.count
					Text("\(eventCount) event\(eventCount == 1 ? "" : "s")")
						.font(.headline)
						.foregroundStyle(Color.accentColor)
					
					ForEach(Event.RecurrenceType.allCases, id: \.self) { recurrence in
						let count = viewModel.events.filter { $0.recurrence == recurrence }.count
						let recurrenceStr = recurrence.rawValue.capitalized
						var description: String {
							if recurrenceStr == "None" {
								return "One-Time event\(count == 1 ? "" : "s")"
							} else {
								return "\(recurrenceStr) event\(count == 1 ? "" : "s")"
							}
						}
						Text("\(count) \(description)")
							.font(.subheadline)
							.foregroundStyle(Color.secondary)
					}
				}
			}
			.navigationTitle("Statistics")
			.navigationBarTitleDisplayMode(.inline)
		}
	}
}

#Preview {
	StatsView(
		viewModel: EventViewModel()
	)
}