//
//  RecipeTabView.swift
//  Nextcloud Cookbook iOS Client
//
//  Created by Vincent Meilinger on 23.01.24.
//

import Foundation
import OSLog
import SwiftUI


struct RecipeTabView: View {
    @EnvironmentObject var appState: AppState
    @EnvironmentObject var groceryList: GroceryListManager
    @EnvironmentObject var viewModel: RecipeTabView.ViewModel
    @Environment(\.horizontalSizeClass) private var horizontalSizeClass

    private let gridColumns = [GridItem(.adaptive(minimum: 160), spacing: 12)]

    private var showEditViewBinding: Binding<Bool> {
        Binding(
            get: { false },
            set: { if $0 { viewModel.navigateToNewRecipe() } }
        )
    }

    private var nonEmptyCategories: [Category] {
        appState.categories.filter { $0.recipe_count > 0 }
    }

    private var totalRecipeCount: Int {
        appState.categories.reduce(0) { $0 + $1.recipe_count }
    }

    var body: some View {
        NavigationSplitView {
            NavigationStack(path: $viewModel.sidebarPath) {
                ScrollView {
                    VStack(alignment: .leading, spacing: 20) {
                        // Recently Viewed
                        if !appState.recentRecipes.isEmpty {
                            RecentRecipesSection()
                        }

                        // Categories header
                        if !nonEmptyCategories.isEmpty {
                            Text("Categories")
                                .font(.title2)
                                .bold()
                                .padding(.horizontal)
                        }

                        // Category grid
                        if nonEmptyCategories.isEmpty {
                            VStack(spacing: 12) {
                                Image(systemName: "book.closed")
                                    .font(.system(size: 48))
                                    .foregroundStyle(.secondary)
                                Text("No cookbooks found")
                                    .font(.headline)
                                    .foregroundStyle(.secondary)
                                Text("Pull to refresh or check your server connection.")
                                    .font(.subheadline)
                                    .foregroundStyle(.tertiary)
                                    .multilineTextAlignment(.center)
                            }
                            .frame(maxWidth: .infinity)
                            .padding(.top, 40)
                        } else {
                            LazyVGrid(columns: gridColumns, spacing: 12) {
                                // All Recipes card
                                if totalRecipeCount > 0 {
                                    Button {
                                        viewModel.navigateToAllRecipes()
                                    } label: {
                                        AllRecipesCategoryCardView()
                                    }
                                    .buttonStyle(.plain)
                                }

                                ForEach(nonEmptyCategories) { category in
                                    Button {
                                        if horizontalSizeClass == .compact {
                                            viewModel.navigateToCategory(category)
                                        } else {
                                            viewModel.selectedCategory = category
                                            viewModel.showAllRecipesInDetail = false
                                        }
                                    } label: {
                                        CategoryCardView(
                                            category: category,
                                            isSelected: !viewModel.showAllRecipesInDetail && viewModel.selectedCategory?.name == category.name
                                        )
                                    }
                                    .buttonStyle(.plain)
                                }
                            }
                            .padding(.horizontal)
                        }
                    }
                    .padding(.vertical)
                }
                .navigationTitle("Recipes")
                .toolbar {
                    RecipeTabViewToolBar()
                }
                .navigationDestination(for: SidebarDestination.self) { destination in
                    switch destination {
                    case .settings:
                        SettingsView()
                            .environmentObject(appState)
                            .environmentObject(groceryList)
                    case .newRecipe:
                        RecipeView(viewModel: RecipeView.ViewModel())
                            .environmentObject(appState)
                            .environmentObject(groceryList)
                    case .category(let category):
                        RecipeListView(
                            categoryName: category.name,
                            showEditView: showEditViewBinding
                        )
                        .id(category.id)
                        .environmentObject(appState)
                        .environmentObject(groceryList)
                    case .allRecipes:
                        AllRecipesListView(showEditView: showEditViewBinding)
                            .environmentObject(appState)
                            .environmentObject(groceryList)
                    }
                }
                .navigationDestination(for: Recipe.self) { recipe in
                    RecipeView(viewModel: RecipeView.ViewModel(recipe: recipe))
                        .environmentObject(appState)
                        .environmentObject(groceryList)
                }
            }
        } detail: {
            NavigationStack {
                if viewModel.showAllRecipesInDetail {
                    AllRecipesListView(showEditView: showEditViewBinding)
                } else if let category = viewModel.selectedCategory {
                    RecipeListView(
                        categoryName: category.name,
                        showEditView: showEditViewBinding
                    )
                    .id(category.id)
                }
            }
        }
        .tint(.nextcloudBlue)
        .task {
            let connection = await appState.checkServerConnection()
            DispatchQueue.main.async {
                viewModel.serverConnection = connection
            }
        }
        .refreshable {
            let connection = await appState.checkServerConnection()
            DispatchQueue.main.async {
                viewModel.serverConnection = connection
            }
            await appState.getCategories()
            for category in appState.categories {
                await appState.getCategory(named: category.name, fetchMode: .preferServer)
                await appState.getCategoryImage(for: category.name)
            }
        }
    }
    
    enum SidebarDestination: Hashable {
        case settings
        case newRecipe
        case category(Category)
        case allRecipes
    }

    class ViewModel: ObservableObject {
        @Published var sidebarPath = NavigationPath()

        @Published var presentLoadingIndicator: Bool = false
        @Published var presentConnectionPopover: Bool = false
        @Published var serverConnection: Bool = false

        @Published var selectedCategory: Category? = nil
        @Published var showAllRecipesInDetail: Bool = false

        func navigateToSettings() {
            sidebarPath.append(SidebarDestination.settings)
        }

        func navigateToNewRecipe() {
            sidebarPath.append(SidebarDestination.newRecipe)
        }

        func navigateToCategory(_ category: Category) {
            selectedCategory = category
            showAllRecipesInDetail = false
            sidebarPath.append(SidebarDestination.category(category))
        }

        func navigateToAllRecipes() {
            selectedCategory = nil
            showAllRecipesInDetail = true
            sidebarPath.append(SidebarDestination.allRecipes)
        }
    }
}



fileprivate struct RecipeTabViewToolBar: ToolbarContent {
    @EnvironmentObject var appState: AppState
    @EnvironmentObject var viewModel: RecipeTabView.ViewModel
    
    var body: some ToolbarContent {
        // Top left menu toolbar item
        ToolbarItem(placement: .topBarLeading) {
            Menu {
                Button {
                    Task {
                        viewModel.presentLoadingIndicator = true
                        UserSettings.shared.lastUpdate = Date.distantPast
                        await appState.getCategories()
                        for category in appState.categories {
                            await appState.getCategory(named: category.name, fetchMode: .preferServer)
                        }
                        await appState.updateAllRecipeDetails()
                        viewModel.presentLoadingIndicator = false
                    }
                } label: {
                    Text("Refresh all")
                    Image(systemName: "icloud.and.arrow.down")
                }
                
                Button {
                    viewModel.navigateToSettings()
                } label: {
                    Text("Settings")
                    Image(systemName: "gearshape")
                }
            } label: {
                Image(systemName: "ellipsis.circle")
            }
        }
        
        // Server connection indicator
        ToolbarItem(placement: .topBarTrailing) {
            Button {
                Logger.view.debug("Check server connection")
                viewModel.presentConnectionPopover = true
            } label: {
                if viewModel.presentLoadingIndicator {
                    ProgressView()
                } else if viewModel.serverConnection {
                    Image(systemName: "checkmark.icloud")
                } else {
                    Image(systemName: "xmark.icloud")
                }
            }.popover(isPresented: $viewModel.presentConnectionPopover) {
                VStack(alignment: .leading) {
                    Text(viewModel.serverConnection ? LocalizedStringKey("Connected to server.") : LocalizedStringKey("Unable to connect to server."))
                        .bold()
                        
                    Text("Last updated: \(DateFormatter.utcToString(date: UserSettings.shared.lastUpdate))")
                        .font(.caption)
                        .foregroundStyle(Color.secondary)
                }
                .padding()
                .presentationCompactAdaptation(.popover)
            }
        }
        
        // Create new recipes
        ToolbarItem(placement: .topBarTrailing) {
            Button {
                Logger.view.debug("Add new recipe")
                viewModel.navigateToNewRecipe()
            } label: {
                Image(systemName: "plus.circle.fill")
            }
        }
    
    }
}