//
//  ViewController.swift
//  browser
//
//  Created by Artem Talko on 25.09.2023.
//

import UIKit
import SnapKit
import WebKit
import Combine
import Realm

final class BrowserHomeViewController: UIViewController {
    let mainView = BrowserHomeView()
    
    private let searchingViewController: SearchingViewController
    private let searchResultViewController: SearchResultViewController
    private let tabsViewController: TabsViewController
    
    private var subscriptions: Set<AnyCancellable>
    private var searchRequestURL: String
    private let images = StringConstants.browserHomeVCImages
    private var currentTabId: Int?
    
    private var url: String? {
        didSet {
            searchRequestURL = url ?? String()
            openSearchResult()
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = ColorConstants.lightGray
        
        initViewController()
    }
    
    override func viewWillAppear(_ animated: Bool) {
        keyboardObserver()
    }
    
    private func initViewController() {
        setupCollectionView()
        addTargets()
        setupSearchBarComponentsAction()
        setupSearchingViewController()
        progressObserver()
    }
    
    override func viewIsAppearing(_ animated: Bool) {
        navigationController?.isNavigationBarHidden = true
    }
    
    override func loadView() {
        view = mainView
    }
    
    init(url: String?, currentTabId: Int?) {
        searchResultViewController = SearchResultViewController(searchLink: String())
        searchingViewController = SearchingViewController(dataForReq: [])
        tabsViewController = TabsViewController()
        
        subscriptions = []
        searchRequestURL = URLConstants.googleURL
        
        super.init(nibName: nil, bundle: nil)
        self.url = url
        self.currentTabId = currentTabId
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        NotificationCenter.default.removeObserver(self)
    }
}


//MARK: CollectionView Setup
extension BrowserHomeViewController: UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        images.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: TabCollectionViewCell.cellID, for: indexPath) as? TabCollectionViewCell else {
            return TabCollectionViewCell()
        }
        let finalCell = setupCellForCollectionView(cell, indexPath)
        
        return finalCell
    }
    
    func setupCellForCollectionView(_ cell: TabCollectionViewCell, _ indexPath: IndexPath) -> TabCollectionViewCell {
        let imageName = images[indexPath.item]
        cell.tabCellImage.image = UIImage(named: imageName)
        cell.tabCellLabel.text = imageName
        
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: 72.sizeW, height: 104.sizeH)
    }
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        searchRequestURL = StringConstants.browserHomeVCurl[indexPath.row]
        openSearchResult()
    }
}


//MARK: - Keyboard extention
extension BrowserHomeViewController {
    private func keyboardObserver() {
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillDisappear), name: UIResponder.keyboardWillHideNotification, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
    }
}


//MARK: - Action
extension BrowserHomeViewController {
    @objc
    private func searchBarTextChanged() {
        if let text = mainView.searchBarContainer.searchBarView.searchTextFieldView.text {
            searchRequestURL = text
            mainView.searchBarContainer.searchBarView.cleanTextFieldButton.isHidden = false
            if searchRequestURL.isEmpty {
                searchResultAction()
            } else {
                Task {
                    await searchAndReloadTableView()
                }
            }
        }
    }
    
    @objc
    private func searchResultAction() {
        mainView.searchBarContainer.searchBarView.searchTextFieldView.text = nil
        mainView.searchBarContainer.searchBarView.cleanTextFieldButton.isHidden = true
        
        removeChildViewController()
    }
    
    @objc
    private func keyboardWillShow(_ notification: Notification) {
        guard let keyboardFrame = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else { return
        }
        let keyboardHeight = keyboardFrame.height
        self.mainView.animateSearchBar(keyboardHeight)
    }
    
    @objc
    private func keyboardWillDisappear() {
        mainView.animateSearchBarDismiss()
    }
    
    @objc
    private func settingButtonTapped(_ sender: UIButton) {
        let settingViewController = SettingViewController()
        openAdditionViewController(settingViewController)
    }
    
    @objc
    private func removeAdButtonTapped(_ sender: UIButton) {
        let removeAdViewController = RemoveAdvertViewController()
        openAdditionViewController(removeAdViewController)
    }
    
    @objc
    private func removeSearchingViewController(_ sender: UIButton) {
        searchResultAction()
    }
}


//MARK: - Helpers
extension BrowserHomeViewController {
    private func didTabButtonTapped(type: ToolbarElementType) {
        switch type {
        case .history:
            let historyViewController = HistoryViewController()
            present(historyViewController, animated: true, completion: nil)
            break
        case .tabs:
            tabsButtonHandler()
            break
        case .back:
            searchResultViewController.mainView.searchResultView.goBack()
            break
        case .forward:
            searchResultViewController.mainView.searchResultView.goForward()
            break
        case .share:
            let items = [URL(string: searchRequestURL)]
            let shareView = UIActivityViewController(activityItems: items as [Any], applicationActivities: nil)
            present(shareView, animated: true)
            break
        }
    }
    
    private func searchAndReloadTableView() async {
        let sitesFromSearch: [String] = await BrowserSearchService().searchSuggest(searchRequestURL)
        if !sitesFromSearch.isEmpty {
            searchingViewController.searchRequestData = sitesFromSearch
        }
        addingSearchingViewController(searchingViewController)
    }
    
    private func setupCollectionView() {
        mainView.frequentlyVisitedCollectionView.dataSource = self
        mainView.frequentlyVisitedCollectionView.delegate = self
        mainView.frequentlyVisitedCollectionView.register(TabCollectionViewCell.self, forCellWithReuseIdentifier: TabCollectionViewCell.cellID)
    }
    
    private func addTargets() {
        mainView.settingButton.addTarget(self, action:  #selector(settingButtonTapped(_ :)), for: .touchUpInside)
        mainView.removeAddButton.addTarget(self, action: #selector(removeAdButtonTapped(_ :)), for: .touchUpInside)
        mainView.searchBarContainer.searchBarView.searchTextFieldView.addTarget(self, action: #selector(searchBarTextChanged), for: .editingChanged)
        searchingViewController.mainView.searchingButton.addTarget(self, action: #selector(removeSearchingViewController(_ :)), for: .touchUpInside)
        addToolbarTargets()
    }
    
    private func addToolbarTargets() {
        mainView.toolbarView.action = didTabButtonTapped
    }
    
    private func openAdditionViewController(_ viewController: UIViewController) {
        viewController.modalPresentationStyle = .fullScreen
        present(viewController, animated: true, completion: nil)
    }
    
    private func setupSearchingViewController() {
        searchingViewController.searchCell = { [self] cell in
            guard let cell = cell as? SearchingTableViewCell else {
                return
            }
            searchRequestURL = "https://www.google.com/search?q=" + (cell.searchLabel.text ?? "")
            openSearchResult()
            mainView.searchBarContainer.searchBarView.searchTextFieldView.endEditing(true)
        }
    }
    
    private func openSearchResult() {
        let finalSearchRequest = searchRequestURL.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)
        searchResultViewController.searchLink = finalSearchRequest ?? ""
        if let localUrl = URL(string: finalSearchRequest ?? "") {
            let request = URLRequest(url: localUrl)
            searchResultViewController.mainView.searchResultView.load(request)
        }
        addingSearchingViewController(searchResultViewController)
    }
    
    private func tabsButtonHandler() {
        if currentTabId == nil {
            addNewTab()
            navigationController?.popViewController(animated: true)
        } else {
            updateCurrentTab()
        }
    }
    
    private func addNewTab() {
        if let childViewController = self.children.first as? SearchResultViewController {
            guard let siteTitle = childViewController.mainView.searchResultView.title else {
                return
            }
            guard let siteUrl = childViewController.mainView.searchResultView.url else {
                return
            }
            let finalUrl = siteUrl.absoluteString
            let lastVisit = DateManager.shared.currentDate
            let wkWVForSnapshot = childViewController.mainView.searchResultView
            
            SnapshotService.shared.makeWKWebViewSnapshot(wkWVForSnapshot) { snapshotForDB in
                TabManager.shared.saveTab(tabTitle: siteTitle, snapshotImage: snapshotForDB, tabUrl: finalUrl)
            }
            HistoryDBManager.shared.saveToHistory(siteTitle: siteTitle, siteUrl: finalUrl, lastVisit: lastVisit)
        } else {
            let homeViewSnapshot = SnapshotService.shared.makeSnapshot(mainView)
            TabManager.shared.saveTab(tabTitle: "Start Page", snapshotImage: homeViewSnapshot, tabUrl: "homeUrl")
            currentTabId = tabsViewController.getCellIndex().row
        }
    }
    
    private func updateCurrentTab() {
        let allTabs = TabManager.shared.getAllTabs()
        let chosenTab = allTabs[self.currentTabId ?? Int()]
        let gottedCellId = chosenTab.tabId
        let imageForUpdatedTab = SnapshotService.shared.makeSnapshot(self.mainView)
        if let childViewController = self.children.first as? SearchResultViewController {
            guard let siteTitle = childViewController.mainView.searchResultView.title else {
                return
            }
            guard let siteUrl = childViewController.mainView.searchResultView.url?.absoluteString else {
                return
            }
            let lastDate = DateManager.shared.currentDate
            
            TabManager.shared.updateTab(tabId: gottedCellId, newTabTitle: siteTitle, newSnapshotImage: imageForUpdatedTab, newTabUrl: siteUrl) { result in
                self.navigationController?.popViewController(animated: true)
            }
            HistoryDBManager.shared.saveToHistory(siteTitle: siteTitle, siteUrl: siteUrl, lastVisit: lastDate)
        } else {
            TabManager.shared.updateTab(tabId: gottedCellId, newTabTitle: "Start Page", newSnapshotImage: imageForUpdatedTab, newTabUrl: "homeUrl") { result in
                self.navigationController?.popViewController(animated: true)
            }
        }
    }
}


//MARK: - ChildVC actions
extension BrowserHomeViewController {
    private func addingSearchingViewController(_ childViewController: UIViewController) {
        if self.children.isEmpty {
            addNewChildViewController(childViewController)
        } else {
            removeChildViewController()
            addNewChildViewController(childViewController)
        }
    }
    
    private func addNewChildViewController(_ child: UIViewController) {
        mainView.addSearchView(child.view)
        child.didMove(toParent: self)
        
        addChild(child)
    }
    
    private func removeChildViewController() {
        if let childViewController = self.children.first as? SearchingViewController {
            childViewController.view.removeFromSuperview()
            childViewController.willMove(toParent: nil)
            childViewController.removeFromParent()
        }
        if let childViewController = self.children.first as? SearchResultViewController {
            childViewController.view.removeFromSuperview()
            childViewController.willMove(toParent: nil)
            childViewController.removeFromParent()
        }
    }
}


//MARK: - SearchBar extention
extension BrowserHomeViewController: UITextFieldDelegate {
    func textFieldDidBeginEditing(_ textField: UITextField) {
        mainView.searchBarContainer.searchBarView.searchTextFieldView.text = nil
        mainView.searchBarContainer.searchBarView.searchTextFieldView.textColor = .black
    }
    
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        
        searchRequestURL = "https://www.google.com/search?q=" + (textField.text ?? "")
        openSearchResult()
        
        return true
    }
    
    func setupSearchBarComponentsAction() {
        mainView.searchBarContainer.searchBarView.searchTextFieldView.autocorrectionType = .no
        mainView.searchBarContainer.searchBarView.searchTextFieldView.delegate = self
        mainView.searchBarContainer.searchBarView.cleanTextFieldButton.addTarget(self, action: #selector(searchResultAction), for: .touchUpInside)
        buttonObserver()
    }
}


//MARK: - WebView extention
extension BrowserHomeViewController {
    private func buttonObserver() {
        searchResultViewController.mainView.searchResultView
            .publisher(for: \.canGoBack)
            .sink { [weak self] canGoBack in
                self?.mainView.toolbarView.backBarButtonItem.isEnabled = canGoBack
            }
            .store(in: &subscriptions)
        
        searchResultViewController.mainView.searchResultView
            .publisher(for: \.canGoForward)
            .sink { [weak self] canGoForward in
                self?.mainView.toolbarView.forwardBarButtonItem.isEnabled = canGoForward
            }
            .store(in: &subscriptions)
        
        searchResultViewController.mainView.searchResultView
            .publisher(for: \.isLoading)
            .sink { [weak self] isLoading in
                guard let self = self else { return }
                if let url = self.searchResultViewController.mainView.searchResultView.url {
                    self.searchRequestURL = url.absoluteString
                }
            }
            .store(in: &subscriptions)
    }
    
    private func progressObserver() {
        searchResultViewController.mainView.searchResultView
            .publisher(for: \.estimatedProgress)
            .sink { [weak self] progress in
                guard let self = self else { return }
                self.mainView.searchBarContainer.searchBarView.progressBar.progress = Float(progress)
                if progress == 1 {
                    self.mainView.searchBarContainer.searchBarView.progressBar.isHidden = true
                    self.mainView.toolbarView.shareBarButtonItem.isEnabled = true
                } else if progress == 0 {
                    self.mainView.searchBarContainer.searchBarView.progressBar.isHidden = true
                } else {
                    self.mainView.searchBarContainer.searchBarView.progressBar.isHidden = false
                    self.mainView.toolbarView.shareBarButtonItem.isEnabled = false
                }
            }
            .store(in: &subscriptions)
    }
}

//MARK: Url managment
extension BrowserHomeViewController {
    func urlManagment(_ url: String) {
        searchRequestURL = url
        openSearchResult()
    }
}