//
//  BrowserWindowController.swift
//  Gemini
//
//  Created by Shadowfacts on 7/15/20.
//

import Cocoa
import SwiftUI
import Combine
import BrowserCore

class BrowserWindowController: NSWindowController {

    @IBOutlet weak var toolbar: NSToolbar!
    
    private var locationTextField: NSTextField?
    
    private var urlUpdater: Cancellable?
    
    let navigator = NavigationManager(url: AppDelegate.homePage)
    
    convenience init() {
        self.init(windowNibName: "BrowserWindowController")
    }
    
    override func windowDidLoad() {
        super.windowDidLoad()
        
        contentViewController = NSHostingController(rootView: ContentView(navigator: navigator))
        
        urlUpdater = navigator.$currentURL.sink(receiveValue: self.currentURLChanged(_:))
    }
    
    private func currentURLChanged(_ newValue: URL) {
        locationTextField?.stringValue = newValue.absoluteString
        
        window?.title = newValue.absoluteString
    }
    
    override func newWindowForTab(_ sender: Any?) {
        (NSApp.delegate as! AppDelegate).createNewWindowTab(attachedTo: window!)
    }
    
}

extension NSToolbarItem.Identifier {
    static let locationField = NSToolbarItem.Identifier("Gemini.locationField")
    static let goBack = NSToolbarItem.Identifier("Gemini.goBack")
    static let goForward = NSToolbarItem.Identifier("Gemini.goForward")
}

extension BrowserWindowController: NSToolbarDelegate {
    func toolbarAllowedItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] {
        return [
            .space,
            .flexibleSpace,
            .locationField,
            .goBack,
            .goForward
        ]
    }
    
    func toolbarDefaultItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] {
        return [
            .goBack,
            .goForward,
            .flexibleSpace,
            .locationField,
            .flexibleSpace,
        ]
    }
    
    func toolbar(_ toolbar: NSToolbar, itemForItemIdentifier itemIdentifier: NSToolbarItem.Identifier, willBeInsertedIntoToolbar flag: Bool) -> NSToolbarItem? {
        if itemIdentifier == .locationField {
            return createLocationFieldToolbarItem()
        } else if itemIdentifier == .goBack {
            return createBackToolbarItem()
        } else if itemIdentifier == .goForward {
            return createForwardToolbarItem()
        }
        return NSToolbarItem(itemIdentifier: itemIdentifier)
    }
    
    private func createLocationFieldToolbarItem() -> NSToolbarItem {
        let item = NSToolbarItem(itemIdentifier: .locationField)
        item.label = "Location"
        item.paletteLabel = "Location"
        let textField = NSTextField(string: navigator.currentURL.absoluteString)
        textField.delegate = self
        NSLayoutConstraint.activate([
            textField.heightAnchor.constraint(equalToConstant: 22),
            textField.widthAnchor.constraint(lessThanOrEqualToConstant: 500),
            textField.widthAnchor.constraint(greaterThanOrEqualToConstant: 250)
        ])
        locationTextField = textField
        item.view = textField
        return item
    }
    
    private func createBackToolbarItem() -> NSToolbarItem {
        let item = NSToolbarItem(itemIdentifier: .goBack)
        if #available(macOS 10.16, *) {
            item.image = NSImage(systemSymbolName: "chevron.left", accessibilityDescription: "Go Back")
        } else {
            item.image = NSImage(named: NSImage.goBackTemplateName)
        }
        item.label = "Go Back"
        item.paletteLabel = "Go Back"
        item.toolTip = "Go to the previous page"
        item.target = navigator
        item.action = #selector(NavigationManager.back)
        item.isBordered = true
        if #available(macOS 10.16, *) {
            item.isNavigational = true
        }
        return item
    }
    
    private func createForwardToolbarItem() -> NSToolbarItem {
        let item = NSToolbarItem(itemIdentifier: .goForward)
        if #available(macOS 10.16, *) {
            item.image = NSImage(systemSymbolName: "chevron.right", accessibilityDescription: "Go Forward")
        } else {
            item.image = NSImage(named: NSImage.goForwardTemplateName)
        }
        item.label = "Go Forward"
        item.paletteLabel = "Go Forward"
        item.toolTip = "Go to the next page"
        item.target = navigator
        item.action = #selector(NavigationManager.forward)
        item.isBordered = true
        if #available(macOS 10.16, *) {
            item.isNavigational = true
        }
        return item
    }
    
}

extension NavigationManager: NSToolbarItemValidation {
    public func validateToolbarItem(_ item: NSToolbarItem) -> Bool {
        if item.itemIdentifier == .goBack {
            return !backStack.isEmpty
        } else if item.itemIdentifier == .goForward {
            return !forwardStack.isEmpty
        } else {
            return true
        }
    }
}

extension BrowserWindowController: NSTextFieldDelegate {
    func controlTextDidEndEditing(_ obj: Notification) {
        guard let textField = locationTextField else { return }
        guard let newURL = URL(string: textField.stringValue) else {
            let alert = NSAlert()
            alert.alertStyle = .warning
            alert.messageText = "You specified a malformed URL"
            alert.addButton(withTitle: "OK")
            return
        }
        navigator.changeURL(newURL)
    }
}