//
//  IndeedJobBrowserWindowController.swift
//  App for Indeed
//

import Cocoa
import WebKit

/// Indeed job listing and apply flow in a `WKWebView`, embedded in the dashboard main panel or hosted in a window.
final class IndeedJobBrowserViewController: NSViewController, WKNavigationDelegate, WKUIDelegate {
    /// When set, a leading **Home** control calls this so the host can hide the embedded browser (same-window UX).
    var onDismissEmbedded: (() -> Void)?
    private let webView: WKWebView = {
        let configuration = WKWebViewConfiguration()
        configuration.preferences.javaScriptCanOpenWindowsAutomatically = true
        return WKWebView(frame: .zero, configuration: configuration)
    }()

    private var pendingURL: URL?

    private let backButton = NSButton()
    private let forwardButton = NSButton()
    private let reloadButton = NSButton()
    private let dismissEmbeddedButton = NSButton(title: "Home", target: nil, action: nil)

    override func loadView() {
        view = NSView(frame: NSRect(x: 0, y: 0, width: 920, height: 720))
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        webView.translatesAutoresizingMaskIntoConstraints = false
        webView.navigationDelegate = self
        webView.uiDelegate = self
        webView.customUserAgent = Self.desktopSafariLikeUserAgent

        configureToolbarButton(backButton, symbolName: "chevron.backward", action: #selector(goBack))
        configureToolbarButton(forwardButton, symbolName: "chevron.forward", action: #selector(goForward))
        configureToolbarButton(reloadButton, symbolName: "arrow.clockwise", action: #selector(reload))

        dismissEmbeddedButton.translatesAutoresizingMaskIntoConstraints = false
        dismissEmbeddedButton.bezelStyle = .rounded
        dismissEmbeddedButton.isBordered = true
        dismissEmbeddedButton.target = self
        dismissEmbeddedButton.action = #selector(dismissEmbedded)
        dismissEmbeddedButton.toolTip = "Return to the previous screen"

        let toolbar = NSView()
        toolbar.translatesAutoresizingMaskIntoConstraints = false
        toolbar.wantsLayer = true
        toolbar.layer?.backgroundColor = NSColor(srgbRed: 247 / 255, green: 247 / 255, blue: 247 / 255, alpha: 1).cgColor

        let barStack: NSStackView
        if onDismissEmbedded != nil {
            barStack = NSStackView(views: [dismissEmbeddedButton, backButton, forwardButton, reloadButton, NSView()])
        } else {
            barStack = NSStackView(views: [backButton, forwardButton, reloadButton, NSView()])
        }
        barStack.orientation = .horizontal
        barStack.spacing = 8
        barStack.alignment = .centerY
        barStack.distribution = .fill
        barStack.translatesAutoresizingMaskIntoConstraints = false

        toolbar.addSubview(barStack)
        view.addSubview(toolbar)
        view.addSubview(webView)

        var layoutConstraints: [NSLayoutConstraint] = [
            toolbar.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            toolbar.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            toolbar.topAnchor.constraint(equalTo: view.topAnchor),
            toolbar.heightAnchor.constraint(equalToConstant: 48),

            barStack.leadingAnchor.constraint(equalTo: toolbar.leadingAnchor, constant: 12),
            barStack.trailingAnchor.constraint(equalTo: toolbar.trailingAnchor, constant: -12),
            barStack.centerYAnchor.constraint(equalTo: toolbar.centerYAnchor),

            backButton.widthAnchor.constraint(equalToConstant: 32),
            backButton.heightAnchor.constraint(equalToConstant: 28),
            forwardButton.widthAnchor.constraint(equalToConstant: 32),
            forwardButton.heightAnchor.constraint(equalToConstant: 28),
            reloadButton.widthAnchor.constraint(equalToConstant: 32),
            reloadButton.heightAnchor.constraint(equalToConstant: 28),

            webView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            webView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            webView.topAnchor.constraint(equalTo: toolbar.bottomAnchor),
            webView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ]
        if onDismissEmbedded != nil {
            layoutConstraints.append(dismissEmbeddedButton.heightAnchor.constraint(equalToConstant: 28))
        }
        NSLayoutConstraint.activate(layoutConstraints)

        updateNavigationButtons()

        if let pendingURL {
            webView.load(URLRequest(url: pendingURL))
            self.pendingURL = nil
        }
    }

    func loadPage(_ url: URL) {
        if isViewLoaded {
            webView.load(URLRequest(url: url))
        } else {
            pendingURL = url
        }
        updateNavigationButtons()
    }

    /// Adds this controller as a child of `parent` and pins `view` to `host` (used by the dashboard main panel).
    func embed(in host: NSView, parent: NSViewController) {
        parent.addChild(self)
        view.translatesAutoresizingMaskIntoConstraints = false
        host.addSubview(view)
        NSLayoutConstraint.activate([
            view.leadingAnchor.constraint(equalTo: host.leadingAnchor),
            view.trailingAnchor.constraint(equalTo: host.trailingAnchor),
            view.topAnchor.constraint(equalTo: host.topAnchor),
            view.bottomAnchor.constraint(equalTo: host.bottomAnchor)
        ])
    }

    private func configureToolbarButton(_ button: NSButton, symbolName: String, action: Selector) {
        button.translatesAutoresizingMaskIntoConstraints = false
        button.bezelStyle = .texturedRounded
        button.isBordered = true
        button.image = NSImage(systemSymbolName: symbolName, accessibilityDescription: nil)
        button.imagePosition = .imageOnly
        button.target = self
        button.action = action
    }

    private func updateNavigationButtons() {
        backButton.isEnabled = webView.canGoBack
        forwardButton.isEnabled = webView.canGoForward
    }

    @objc private func goBack() {
        webView.goBack()
    }

    @objc private func goForward() {
        webView.goForward()
    }

    @objc private func reload() {
        webView.reload()
    }

    @objc private func dismissEmbedded() {
        onDismissEmbedded?()
    }

    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        updateNavigationButtons()
    }

    func webView(_ webView: WKWebView, didCommit navigation: WKNavigation!) {
        updateNavigationButtons()
    }

    /// Target=_blank / `window.open` without a frame: load in this view so apply flows stay in-app.
    func webView(_ webView: WKWebView, createWebViewWith configuration: WKWebViewConfiguration, for navigationAction: WKNavigationAction, windowFeatures: WKWindowFeatures) -> WKWebView? {
        if navigationAction.targetFrame == nil {
            webView.load(navigationAction.request)
        }
        return nil
    }

    /// Desktop Safari UA helps Indeed serve a full desktop apply experience.
    private static let desktopSafariLikeUserAgent = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.4 Safari/605.1.15"
}