//
//  BrowseView.swift
//  SideStoreUI
//
//  Created by Fabian Thies on 18.11.22.
//  Copyright © 2022 Fabian Thies. All rights reserved.
//

import SwiftUI
import SFSafeSymbols
import AltStoreCore

struct BrowseView: View {
    @SwiftUI.FetchRequest(sortDescriptors: [
        NSSortDescriptor(keyPath: \StoreApp.sourceIdentifier, ascending: true),
        NSSortDescriptor(keyPath: \StoreApp.sortIndex, ascending: true),
        NSSortDescriptor(keyPath: \StoreApp.name, ascending: true),
        NSSortDescriptor(keyPath: \StoreApp.bundleIdentifier, ascending: true)
    ], predicate: NSPredicate(format: "%K != %@", #keyPath(StoreApp.bundleIdentifier), StoreApp.altstoreAppID))
    var apps: FetchedResults<StoreApp>
    
    var filteredApps: [StoreApp] {
        apps.items(matching: self.searchText)
    }
    
    @State
    var selectedStoreApp: StoreApp?
    
    @State var searchText = ""
    
    @State var isShowingSourcesView = false
    
    var body: some View {
        ScrollView {
            VStack(alignment: .leading) {
                if searchText.isEmpty {
                    VStack(alignment: .leading, spacing: 32) {
                        promotedCategoriesView
                        
                        Text(L10n.BrowseView.Section.AllApps.title)
                            .font(.title2)
                            .bold()
                    }
                }

                if searchText.isEmpty, filteredApps.count == 0 {
                    HintView {
                        Text("You don't have any apps yet.")
                            .bold()

                        Text("Apps are provided by \"sources\". The specification for them is an open standard, so everyone can create their own source. To get you started, we have compiled a list of \"Trusted Sources\" which you can check out by tapping the button below.")
                            .font(.callout)
                            .foregroundColor(.secondary)

                        SwiftUI.Button {
                            self.isShowingSourcesView = true
                        } label: {
                            Label("Add Source", systemSymbol: .plus)
                        }
                        .buttonStyle(FilledButtonStyle())
                        .padding(.top, 8)
                    }
                } else {
                    LazyVStack(spacing: 32) {
                        ForEach(filteredApps, id: \.bundleIdentifier) { app in
                            NavigationLink {
                                AppDetailView(storeApp: app)
                            } label: {
                                BrowseAppPreviewView(storeApp: app)
                            }
                            .buttonStyle(PlainButtonStyle())
                        }
                    }
                }
            }
            .padding()
            .searchable(text: self.$searchText, placeholder: L10n.BrowseView.search)
        }
        .background(Color(UIColor.systemGroupedBackground).ignoresSafeArea())
        .navigationTitle(L10n.BrowseView.title)
        .toolbar {
            ToolbarItem(placement: .navigationBarLeading) {
                SwiftUI.Button {
                    self.isShowingSourcesView = true
                } label: {
                    Text(L10n.BrowseView.Actions.sources)
                }
                .sheet(isPresented: self.$isShowingSourcesView) {
                    NavigationView {
                        SourcesView()
                    }
                }
            }
            
            ToolbarItem(placement: .navigationBarTrailing) {
                SwiftUI.Button {
                    
                } label: {
                    Image(systemSymbol: .lineHorizontal3DecreaseCircle)
                        .imageScale(.large)
                }

            }
        }
    }
    
    var promotedCategoriesView: some View {
        VStack {
            HStack {
                Text(L10n.BrowseView.Section.PromotedCategories.title)
                    .font(.title2)
                    .bold()
                Spacer()
                SwiftUI.Button(action: {}, label: {
                    Text(L10n.BrowseView.Section.PromotedCategories.showAll)
                })
                .font(.callout)
            }
            
            LazyVGrid(columns: [GridItem(.flexible()), GridItem(.flexible())]) {
                PromotedCategoryView()
                    .shadow(color: .black.opacity(0.1), radius: 8, y: 5)
                
                PromotedCategoryView()
                    .shadow(color: .black.opacity(0.1), radius: 8, y: 5)
            }
        }
    }
}

struct BrowseView_Previews: PreviewProvider {
    static var previews: some View {
        NavigationView {
            BrowseView()
        }
    }
}


struct PromotedCategoryView: View {
    
    var body: some View {
        ZStack {
            GeometryReader { proxy in
                RadialGradient(colors: [
                    Color(UIColor(hexString: "477E84")!),
                    Color(UIColor.secondarySystemBackground),
                    Color(UIColor.secondarySystemBackground),
                    Color(UIColor(hexString: "C38FF5")!)
                ], center: .bottomLeading, startRadius: 0, endRadius: proxy.size.width)
            }
            
            HStack {
                Image(systemSymbol: .dpadRightFill)
                Text(L10n.BrowseView.Categories.gamesAndEmulators)
                    .multilineTextAlignment(.leading)
            }
            .foregroundColor(.accentColor)
            .padding()
        }
        .aspectRatio(21/9, contentMode: .fill)
        .frame(maxWidth: .infinity)
        .clipShape(RoundedRectangle(cornerRadius: 12))
    }
}