//
//  WorkoutLibrary.swift
//  WorkoutsPlus
//
//  Created by Felix Förtsch on 10.08.24.
//

import SwiftUI
import SwiftData

struct WorkoutLibrary: View {
		@Environment(\.modelContext) private var modelContext
		@EnvironmentObject private var navigationManager: NavigationManager
		@Default(\.isWorkingOut) var isWorkingOut
		
		@Binding var activeWorkoutSession: WorkoutSession?
		
		@Query(sort: \Workout.name) private var workouts: [Workout]
		
		@State private var newWorkout: Workout = Workout(name: "")
		@State private var newWorkoutName: String = ""
		@State private var isAddingWorkout: Bool = false
		@FocusState private var isInputFieldFocused: Bool
		
		@State private var searchText: String = ""
		var filteredItems: [Workout] {
				if searchText.isEmpty { return workouts }
				else { return workouts.filter { $0.name.localizedCaseInsensitiveContains(searchText) }
				}
		}
		
		var body: some View {
				
				Group {
						List {
								ForEach(filteredItems) { workout in
										NavigationLink {
												WorkoutDetail(activeWorkoutSession: $activeWorkoutSession, workout: workout)
										} label: {
												Image(systemName: workout.workoutIconSystemName)
														.foregroundStyle(workout.workoutIconColorName.color)
												Text(workout.name)
										}
										.swipeActions(edge: .leading) {
												if !isWorkingOut {
														Button {
																activeWorkoutSession = workout.start()
																navigationManager.navigateFromRoot(to: .activeWorkoutSession)
														} label: {
																Label("Quick Start Workout", systemImage: "play")
																		.tint(.green)
														}
												}
										}
								}
								
								.onDelete(perform: deleteWorkout)
								if filteredItems.isEmpty {
										ContentUnavailableView.search(text: searchText)
								}
								if isAddingWorkout {
										// TODO: On tap-out of the text field, it should lose focus
										TextField("New Workout", text: $newWorkoutName, onCommit: {
												save(workout: newWorkout)
										})
										.textInputAutocapitalization(.words)
										.focused($isInputFieldFocused)
								}
								// TODO: When pressing the button again, it should check if something is being added already and if yes, save it.
								AddItemButton(label: "Workout", action: addWorkout)
						}
						.searchable(text: $searchText)
				}
				.navigationTitle("Workouts")
				.toolbar {
						ToolbarItem() {
								EditButton()
						}
				}
		}
		
		private func addWorkout() {
				withAnimation {
						newWorkout = Workout(name: "")
						newWorkoutName = ""
						isAddingWorkout = true
						isInputFieldFocused = true
				}
		}
		
		private func save(workout: Workout) {
				withAnimation {
						newWorkout.name = newWorkoutName
						if !workout.name.isEmpty {
								modelContext.insert(workout)
								try? modelContext.save()
						}
						isAddingWorkout = false
				}
		}
		
		private func deleteWorkout(offsets: IndexSet) {
				withAnimation {
						for index in offsets {
								modelContext.delete(workouts[index])
						}
						try? modelContext.save()
				}
		}
}

#Preview("With Sample Data") {
		@Previewable @State var activeWorkoutSession: WorkoutSession?
		NavigationStack {
				WorkoutLibrary(activeWorkoutSession: $activeWorkoutSession)
		}
		.modelContainer(SampleData.shared.modelContainer)
}

#Preview("Empty Database") {
		@Previewable @State var activeWorkoutSession: WorkoutSession?
		NavigationStack {
				WorkoutLibrary(activeWorkoutSession: $activeWorkoutSession)
		}
		.modelContainer(for: Workout.self, inMemory: true)
}