/*
 * Copyright (C) 2010-2016 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#import "BrowserWindowController.h"

#import "AppDelegate.h"
#import <WebKit/WKFrameInfo.h>
#import <WebKit/WKNavigationActionPrivate.h>
#import <WebKit/WKNavigationDelegatePrivate.h>
#import <WebKit/WKPreferencesPrivate.h>
#import <WebKit/WKUIDelegate.h>
#import <WebKit/WKUIDelegatePrivate.h>
#import <WebKit/WKWebViewConfigurationPrivate.h>
#import <WebKit/WKWebViewPrivate.h>
#import <WebKit/WKWebViewPrivateForTesting.h>
#import <WebKit/WKWebsiteDataStorePrivate.h>
#import <WebKit/WebNSURLExtras.h>
#import <WebKit/_WKIconLoadingDelegate.h>
#import <WebKit/_WKInspector.h>
#import <WebKit/_WKLinkIconParameters.h>
#import <WebKit/_WKUserInitiatedAction.h>

static void* keyValueObservingContext = &keyValueObservingContext;

@interface PlaywrightNSTextFinder : NSTextFinder

@property (nonatomic, copy) dispatch_block_t hideInterfaceCallback;

@end

@implementation PlaywrightNSTextFinder

- (void)performAction:(NSTextFinderAction)op
{
    [super performAction:op];

    if (op == NSTextFinderActionHideFindInterface && _hideInterfaceCallback)
        _hideInterfaceCallback();
}

@end

@interface BrowserWindowController () <NSTextFinderBarContainer, WKNavigationDelegate, WKUIDelegate, _WKIconLoadingDelegate, NSSharingServicePickerDelegate, NSSharingServiceDelegate>
@end

@implementation BrowserWindowController {
    IBOutlet NSProgressIndicator *progressIndicator;
    IBOutlet NSButton *reloadButton;
    IBOutlet NSButton *backButton;
    IBOutlet NSButton *forwardButton;
    IBOutlet NSButton *share;
    IBOutlet NSToolbar *toolbar;
    IBOutlet NSTextField *urlText;
    IBOutlet NSView *containerView;
    IBOutlet NSButton *toggleUseShrinkToFitButton;

    WKWebViewConfiguration *_configuration;
    WKWebView *_webView;
    BOOL _zoomTextOnly;
    BOOL _isPrivateBrowsingWindow;
    NSAlert* _alert;

    BOOL _useShrinkToFit;

    PlaywrightNSTextFinder *_textFinder;
    NSView *_textFindBarView;
    BOOL _findBarVisible;
}

- (id)initWithWindow:(NSWindow *)window
{
    self = [super initWithWindow:window];
    return self;
}

- (void)windowDidLoad
{
    [share sendActionOn:NSEventMaskLeftMouseDown];
    [super windowDidLoad];
}

- (IBAction)openLocation:(id)sender
{
    [[self window] makeFirstResponder:urlText];
}

- (NSString *)addProtocolIfNecessary:(NSString *)address
{
    if ([address rangeOfString:@"://"].length > 0)
        return address;

    if ([address hasPrefix:@"data:"])
        return address;

    if ([address hasPrefix:@"about:"])
        return address;

    return [@"http://" stringByAppendingString:address];
}

- (IBAction)share:(id)sender
{
    NSSharingServicePicker *picker = [[NSSharingServicePicker alloc] initWithItems:@[ self.currentURL ]];
    picker.delegate = self;
    [picker showRelativeToRect:NSZeroRect ofView:sender preferredEdge:NSRectEdgeMinY];
}

- (IBAction)showHideWebView:(id)sender
{
    self.mainContentView.hidden = !self.mainContentView.isHidden;
}

- (CGFloat)pageScaleForMenuItemTag:(NSInteger)tag
{
    if (tag == 1)
        return 1;
    if (tag == 2)
        return 1.25;
    if (tag == 3)
        return 1.5;
    if (tag == 4)
        return 2.0;

    return 1;
}

- (void)awakeFromNib
{
    _webView = [[WKWebView alloc] initWithFrame:[containerView bounds] configuration:_configuration];
    _webView._windowOcclusionDetectionEnabled = NO;

    _webView.allowsMagnification = YES;
    _webView.allowsBackForwardNavigationGestures = YES;

    [_webView setAutoresizingMask:(NSViewWidthSizable | NSViewHeightSizable)];
    [containerView addSubview:_webView];

    [progressIndicator bind:NSHiddenBinding toObject:_webView withKeyPath:@"loading" options:@{ NSValueTransformerNameBindingOption : NSNegateBooleanTransformerName }];
    [progressIndicator bind:NSValueBinding toObject:_webView withKeyPath:@"estimatedProgress" options:nil];

    [_webView addObserver:self forKeyPath:@"title" options:0 context:keyValueObservingContext];
    [_webView addObserver:self forKeyPath:@"URL" options:0 context:keyValueObservingContext];

    _webView.navigationDelegate = self;
    _webView.UIDelegate = self;

    _webView._observedRenderingProgressEvents = _WKRenderingProgressEventFirstLayout
        | _WKRenderingProgressEventFirstVisuallyNonEmptyLayout
        | _WKRenderingProgressEventFirstPaintWithSignificantArea
        | _WKRenderingProgressEventFirstLayoutAfterSuppressedIncrementalRendering
        | _WKRenderingProgressEventFirstPaintAfterSuppressedIncrementalRendering;

    _webView.customUserAgent = @"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_2) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0.4 Safari/605.1.15";

    _webView._usePlatformFindUI = NO;

    _textFinder = [[PlaywrightNSTextFinder alloc] init];
    _textFinder.incrementalSearchingEnabled = YES;
    _textFinder.incrementalSearchingShouldDimContentView = NO;
    _textFinder.client = _webView;
    _textFinder.findBarContainer = self;
    _textFinder.hideInterfaceCallback = ^{
        [_webView _hideFindUI];
    };

    _zoomTextOnly = NO;
}

- (instancetype)initWithConfiguration:(WKWebViewConfiguration *)configuration
{
    if (!(self = [super initWithWindowNibName:@"BrowserWindow"]))
        return nil;
    _configuration = [configuration copy];
    _isPrivateBrowsingWindow = !_configuration.websiteDataStore.isPersistent;
    self.window.styleMask &= ~NSWindowStyleMaskFullSizeContentView;
    [self.window makeKeyAndOrderFront:nil];
    return self;
}

- (void)dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];

    [progressIndicator unbind:NSHiddenBinding];
    [progressIndicator unbind:NSValueBinding];

    [_textFinder release];
    [_webView release];
    [_configuration release];

    [super dealloc];
}

- (IBAction)fetch:(id)sender
{
    [urlText setStringValue:[self addProtocolIfNecessary:urlText.stringValue]];
    NSURL *url = [NSURL _webkit_URLWithUserTypedString:urlText.stringValue];
    [_webView loadRequest:[NSURLRequest requestWithURL:url]];
}

- (IBAction)setPageScale:(id)sender
{
    CGFloat scale = [self pageScaleForMenuItemTag:[sender tag]];
    [_webView _setPageScale:scale withOrigin:CGPointZero];
}

- (CGFloat)viewScaleForMenuItemTag:(NSInteger)tag
{
    if (tag == 1)
        return 1;
    if (tag == 2)
        return 0.75;
    if (tag == 3)
        return 0.5;
    if (tag == 4)
        return 0.25;

    return 1;
}

- (IBAction)setViewScale:(id)sender
{
    CGFloat scale = [self viewScaleForMenuItemTag:[sender tag]];
    CGFloat oldScale = [_webView _viewScale];

    if (scale == oldScale)
        return;

    [_webView _setLayoutMode:_WKLayoutModeDynamicSizeComputedFromViewScale];

    NSRect oldFrame = self.window.frame;
    NSSize newFrameSize = NSMakeSize(oldFrame.size.width * (scale / oldScale), oldFrame.size.height * (scale / oldScale));
    [self.window setFrame:NSMakeRect(oldFrame.origin.x, oldFrame.origin.y - (newFrameSize.height - oldFrame.size.height), newFrameSize.width, newFrameSize.height) display:NO animate:NO];

    [_webView _setViewScale:scale];
}

static BOOL areEssentiallyEqual(double a, double b)
{
    double tolerance = 0.001;
    return (fabs(a - b) <= tolerance);
}

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-implementations"
- (BOOL)validateMenuItem:(NSMenuItem *)menuItem
#pragma GCC diagnostic pop
{
    SEL action = menuItem.action;

    if (action == @selector(saveAsPDF:))
        return YES;
    if (action == @selector(saveAsWebArchive:))
        return YES;

    if (action == @selector(zoomIn:))
        return [self canZoomIn];
    if (action == @selector(zoomOut:))
        return [self canZoomOut];
    if (action == @selector(resetZoom:))
        return [self canResetZoom];

    if (action == @selector(toggleZoomMode:))
        [menuItem setState:_zoomTextOnly ? NSControlStateValueOn : NSControlStateValueOff];
    else if (action == @selector(showHideWebInspector:))
        [menuItem setTitle:_webView._inspector.isVisible ? @"Close Web Inspector" : @"Show Web Inspector"];

    if (action == @selector(setPageScale:))
        [menuItem setState:areEssentiallyEqual([_webView _pageScale], [self pageScaleForMenuItemTag:[menuItem tag]])];

    if (action == @selector(setViewScale:))
        [menuItem setState:areEssentiallyEqual([_webView _viewScale], [self viewScaleForMenuItemTag:[menuItem tag]])];

    return YES;
}

- (IBAction)reload:(id)sender
{
    [_webView reload];
}

- (IBAction)goBack:(id)sender
{
    [_webView goBack];
}

- (IBAction)goForward:(id)sender
{
    [_webView goForward];
}

- (IBAction)toggleZoomMode:(id)sender
{
    if (_zoomTextOnly) {
        _zoomTextOnly = NO;
        double currentTextZoom = _webView._textZoomFactor;
        _webView._textZoomFactor = 1;
        _webView.pageZoom = currentTextZoom;
    } else {
        _zoomTextOnly = YES;
        double currentPageZoom = _webView._pageZoomFactor;
        _webView._textZoomFactor = currentPageZoom;
        _webView.pageZoom = 1;
    }
}

- (IBAction)resetZoom:(id)sender
{
    if (![self canResetZoom])
        return;

    if (_zoomTextOnly)
        _webView._textZoomFactor = 1;
    else
        _webView.pageZoom = 1;
}

- (BOOL)canResetZoom
{
    return _zoomTextOnly ? (_webView._textZoomFactor != 1) : (_webView.pageZoom != 1);
}

- (IBAction)showHideWebInspector:(id)sender
{
    _WKInspector *inspector = _webView._inspector;
    if (inspector.isVisible)
        [inspector hide];
    else
        [inspector show];
}

- (NSURL *)currentURL
{
    return _webView.URL;
}

- (NSView *)mainContentView
{
    return _webView;
}

- (BOOL)validateUserInterfaceItem:(id <NSValidatedUserInterfaceItem>)item
{
    SEL action = item.action;

    if (action == @selector(goBack:) || action == @selector(goForward:))
        return [_webView validateUserInterfaceItem:item];

    return YES;
}

- (void)validateToolbar
{
    [toolbar validateVisibleItems];
}

- (BOOL)windowShouldClose:(id)sender
{
    return YES;
}

- (void)windowWillClose:(NSNotification *)notification
{
    [_webView removeObserver:self forKeyPath:@"title"];
    [_webView removeObserver:self forKeyPath:@"URL"];
    [_webView removeFromSuperview];
    _textFinder.hideInterfaceCallback = nil;
    [self release];

    // Post two events (don't ask me why!) to spin event loop and drain
    // automatically created autorelease pools that will release our window.
    // See https://www.mikeash.com/pyblog/more-fun-with-autorelease.html
    // for some discussion.
    NSEvent* event1 = [NSEvent
      otherEventWithType:NSEventTypeApplicationDefined
                location:NSMakePoint(0, 0)
           modifierFlags:0
               timestamp:[[NSDate date] timeIntervalSince1970]
            windowNumber:0
                 context:nil
                 subtype:0
                   data1:0
                   data2:0];
    [NSApp postEvent:event1 atStart:YES];
    NSEvent* event2 = [NSEvent
      otherEventWithType:NSEventTypeApplicationDefined
                location:NSMakePoint(0, 0)
           modifierFlags:0
               timestamp:[[NSDate date] timeIntervalSince1970]
            windowNumber:0
                 context:nil
                 subtype:0
                   data1:0
                   data2:0];
    [NSApp postEvent:event2 atStart:NO];
}

- (void)webViewDidClose:(WKWebView *)webView {
    [self.window close];
}

#define DefaultMinimumZoomFactor (.5)
#define DefaultMaximumZoomFactor (3.0)
#define DefaultZoomFactorRatio (1.2)

- (CGFloat)currentZoomFactor
{
    return _zoomTextOnly ? _webView._textZoomFactor : _webView.pageZoom;
}

- (void)setCurrentZoomFactor:(CGFloat)factor
{
    if (_zoomTextOnly)
        _webView._textZoomFactor = factor;
    else
        _webView.pageZoom = factor;
}

- (BOOL)canZoomIn
{
    return self.currentZoomFactor * DefaultZoomFactorRatio < DefaultMaximumZoomFactor;
}

- (void)zoomIn:(id)sender
{
    if (!self.canZoomIn)
        return;

    self.currentZoomFactor *= DefaultZoomFactorRatio;
}

- (BOOL)canZoomOut
{
    return self.currentZoomFactor / DefaultZoomFactorRatio > DefaultMinimumZoomFactor;
}

- (void)zoomOut:(id)sender
{
    if (!self.canZoomIn)
        return;

    self.currentZoomFactor /= DefaultZoomFactorRatio;
}

- (void)updateTitle:(NSString *)title
{
    if (!title) {
        NSURL *url = _webView.URL;
        title = url.lastPathComponent ?: url._web_userVisibleString;
    }

    self.window.title = [NSString stringWithFormat:@"%@%@ [%d]%@", _isPrivateBrowsingWindow ? @"🙈 " : @"", title, _webView._webProcessIdentifier, @""];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if (context != keyValueObservingContext || object != _webView)
        return;

    if ([keyPath isEqualToString:@"title"])
        [self updateTitle:_webView.title];
    else if ([keyPath isEqualToString:@"URL"])
        [self updateTextFieldFromURL:_webView.URL];
}

- (nullable WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures
{
    // WebView lifecycle will control the BrowserWindowController life times.
    BrowserWindowController *controller = [[BrowserWindowController alloc] initWithConfiguration:configuration];
    return controller->_webView;
}

- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(void))completionHandler
{
    NSAlert* alert = [[NSAlert alloc] init];

    [alert setMessageText:[NSString stringWithFormat:@"JavaScript alert dialog from %@.", [frame.request.URL absoluteString]]];
    [alert setInformativeText:message];
    [alert addButtonWithTitle:@"OK"];

    _alert = alert;
    [alert beginSheetModalForWindow:self.window completionHandler:^void (NSModalResponse response) {
        completionHandler();
        [alert release];
        _alert = nil;
    }];
}

- (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL result))completionHandler
{
    NSAlert* alert = [[NSAlert alloc] init];

    [alert setMessageText:[NSString stringWithFormat:@"JavaScript confirm dialog from %@.", [frame.request.URL  absoluteString]]];
    [alert setInformativeText:message];

    [alert addButtonWithTitle:@"OK"];
    [alert addButtonWithTitle:@"Cancel"];

    _alert = alert;
    [alert beginSheetModalForWindow:self.window completionHandler:^void (NSModalResponse response) {
        completionHandler(response == NSAlertFirstButtonReturn);
        [alert release];
        _alert = nil;
    }];
}

- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString *result))completionHandler
{
    NSAlert* alert = [[NSAlert alloc] init];

    [alert setMessageText:[NSString stringWithFormat:@"JavaScript prompt dialog from %@.", [frame.request.URL absoluteString]]];
    [alert setInformativeText:prompt];

    [alert addButtonWithTitle:@"OK"];
    [alert addButtonWithTitle:@"Cancel"];

    NSTextField* input = [[NSTextField alloc] initWithFrame:NSMakeRect(0, 0, 200, 24)];
    [input setStringValue:defaultText];
    [alert setAccessoryView:input];

    _alert = alert;
    [alert beginSheetModalForWindow:self.window completionHandler:^void (NSModalResponse response) {
        [input validateEditing];
        completionHandler(response == NSAlertFirstButtonReturn ? [input stringValue] : nil);
        [alert release];
        _alert = nil;
    }];
}

- (void)webView:(WKWebView *)webView handleJavaScriptDialog:(BOOL)accept value:(NSString *)value
{
    if (!_alert)
        return;
    NSTextField* input = (NSTextField*)_alert.accessoryView;
    if (accept && input && value)
        [input setStringValue:value];
    [self.window endSheet:_alert.window returnCode: accept ? NSAlertFirstButtonReturn : NSModalResponseCancel];
}

#if __has_feature(objc_generics)
- (void)webView:(WKWebView *)webView runOpenPanelWithParameters:(WKOpenPanelParameters *)parameters initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSArray<NSURL *> * URLs))completionHandler
#else
- (void)webView:(WKWebView *)webView runOpenPanelWithParameters:(WKOpenPanelParameters *)parameters initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSArray *URLs))completionHandler
#endif
{
    NSOpenPanel *openPanel = [NSOpenPanel openPanel];

    openPanel.allowsMultipleSelection = parameters.allowsMultipleSelection;

    [openPanel beginSheetModalForWindow:webView.window completionHandler:^(NSInteger result) {
        if (result == NSModalResponseOK)
            completionHandler(openPanel.URLs);
        else
            completionHandler(nil);
    }];
}

- (void)_webView:(WebView *)sender runBeforeUnloadConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL result))completionHandler
{
    NSAlert *alert = [[NSAlert alloc] init];

    alert.messageText = [NSString stringWithFormat:@"JavaScript before unload dialog from %@.", [frame.request.URL absoluteString]];
    alert.informativeText = message;

    [alert addButtonWithTitle:@"Leave Page"];
    [alert addButtonWithTitle:@"Stay On Page"];

    _alert = alert;
    [alert beginSheetModalForWindow:self.window completionHandler:^void (NSModalResponse response) {
        completionHandler(response == NSAlertFirstButtonReturn);
        [alert release];
        _alert = nil;
    }];
}

- (WKDragDestinationAction)_webView:(WKWebView *)webView dragDestinationActionMaskForDraggingInfo:(id)draggingInfo
{
    return WKDragDestinationActionAny;
}

- (void)updateTextFieldFromURL:(NSURL *)URL
{
    if (!URL)
        return;

    if (!URL.absoluteString.length)
        return;

    urlText.stringValue = [URL _web_userVisibleString];
}

- (void)loadURLString:(NSString *)urlString
{
    // FIXME: We shouldn't have to set the url text here.
    [urlText setStringValue:urlString];
    [self fetch:nil];
}

- (void)loadHTMLString:(NSString *)HTMLString
{
    [_webView loadHTMLString:HTMLString baseURL:nil];
}

static NSSet *dataTypes()
{
    return [WKWebsiteDataStore allWebsiteDataTypes];
}

- (IBAction)fetchWebsiteData:(id)sender
{
    [_configuration.websiteDataStore _fetchDataRecordsOfTypes:dataTypes() withOptions:_WKWebsiteDataStoreFetchOptionComputeSizes completionHandler:^(NSArray *websiteDataRecords) {
        NSLog(@"did fetch website data %@.", websiteDataRecords);
    }];
}

- (IBAction)fetchAndClearWebsiteData:(id)sender
{
    [_configuration.websiteDataStore fetchDataRecordsOfTypes:dataTypes() completionHandler:^(NSArray *websiteDataRecords) {
        [_configuration.websiteDataStore removeDataOfTypes:dataTypes() forDataRecords:websiteDataRecords completionHandler:^{
            [_configuration.websiteDataStore fetchDataRecordsOfTypes:dataTypes() completionHandler:^(NSArray *websiteDataRecords) {
                NSLog(@"did clear website data, after clearing data is %@.", websiteDataRecords);
            }];
        }];
    }];
}

- (IBAction)clearWebsiteData:(id)sender
{
    [_configuration.websiteDataStore removeDataOfTypes:dataTypes() modifiedSince:[NSDate distantPast] completionHandler:^{
        NSLog(@"Did clear website data.");
    }];
}

- (IBAction)printWebView:(id)sender
{
    [[_webView printOperationWithPrintInfo:[NSPrintInfo sharedPrintInfo]] runOperationModalForWindow:self.window delegate:nil didRunSelector:nil contextInfo:nil];
}

#pragma mark WKNavigationDelegate

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler
{
    LOG(@"decidePolicyForNavigationAction");

    if (navigationAction._canHandleRequest) {
        decisionHandler(WKNavigationActionPolicyAllow);
        return;
    }
    decisionHandler(WKNavigationActionPolicyCancel);
}

- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler
{
    if (![navigationResponse.response isKindOfClass:[NSHTTPURLResponse class]]) {
      decisionHandler(WKNavigationResponsePolicyAllow);
      return;
    }
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)navigationResponse.response;

    NSString *disposition = [[httpResponse allHeaderFields] objectForKey:@"Content-Disposition"];
    if (disposition && [disposition hasPrefix:@"attachment"]) {
        decisionHandler(_WKNavigationResponsePolicyBecomeDownload);
        return;
    }
    decisionHandler(WKNavigationResponsePolicyAllow);
}

- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation *)navigation
{
    LOG(@"didStartProvisionalNavigation: %@", navigation);
}

- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(WKNavigation *)navigation
{
    LOG(@"didReceiveServerRedirectForProvisionalNavigation: %@", navigation);
}

- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(WKNavigation *)navigation withError:(NSError *)error
{
    LOG(@"didFailProvisionalNavigation: %@navigation, error: %@", navigation, error);
}

- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation
{
    LOG(@"didCommitNavigation: %@", navigation);
    [self updateTitle:nil];
}

- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation
{
    LOG(@"didFinishNavigation: %@", navigation);
}

- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *__nullable credential))completionHandler
{
    LOG(@"didReceiveAuthenticationChallenge: %@", challenge);
    if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodHTTPBasic]) {
        NSAlert *alert = [[NSAlert alloc] init];
        NSView *container = [[[NSView alloc] initWithFrame:NSMakeRect(0, 0, 200, 48)] autorelease];
        NSTextField *userInput = [[[NSTextField alloc] initWithFrame:NSMakeRect(0, 24, 200, 24)] autorelease];
        NSTextField *passwordInput = [[[NSSecureTextField alloc] initWithFrame:NSMakeRect(0, 0, 200, 24)] autorelease];

        [alert setMessageText:[NSString stringWithFormat:@"Log in to %@:%lu.", challenge.protectionSpace.host, challenge.protectionSpace.port]];
        [alert addButtonWithTitle:@"Log in"];
        [alert addButtonWithTitle:@"Cancel"];
        [container addSubview:userInput];
        [container addSubview:passwordInput];
        [alert setAccessoryView:container];
        [userInput setNextKeyView:passwordInput];
        [alert.window setInitialFirstResponder:userInput];

        [alert beginSheetModalForWindow:self.window completionHandler:^(NSModalResponse response) {
            [userInput validateEditing];
            if (response == NSAlertFirstButtonReturn)
                completionHandler(NSURLSessionAuthChallengeUseCredential, [[[NSURLCredential alloc] initWithUser:[userInput stringValue] password:[passwordInput stringValue] persistence:NSURLCredentialPersistenceForSession] autorelease]);
            else
                completionHandler(NSURLSessionAuthChallengeRejectProtectionSpace, nil);
            [alert release];
        }];
        return;
    }
    completionHandler(NSURLSessionAuthChallengeRejectProtectionSpace, nil);
}

- (void)webView:(WKWebView *)webView didFailNavigation:(WKNavigation *)navigation withError:(NSError *)error
{
    LOG(@"didFailNavigation: %@, error %@", navigation, error);
}

- (void)webViewWebContentProcessDidTerminate:(WKWebView *)webView
{
    NSLog(@"WebContent process crashed; reloading");
    [self reload:nil];
}

- (void)_webView:(WKWebView *)webView renderingProgressDidChange:(_WKRenderingProgressEvents)progressEvents
{
    if (progressEvents & _WKRenderingProgressEventFirstLayout)
        LOG(@"renderingProgressDidChange: %@", @"first layout");

    if (progressEvents & _WKRenderingProgressEventFirstVisuallyNonEmptyLayout)
        LOG(@"renderingProgressDidChange: %@", @"first visually non-empty layout");

    if (progressEvents & _WKRenderingProgressEventFirstPaintWithSignificantArea)
        LOG(@"renderingProgressDidChange: %@", @"first paint with significant area");

    if (progressEvents & _WKRenderingProgressEventFirstLayoutAfterSuppressedIncrementalRendering)
        LOG(@"renderingProgressDidChange: %@", @"first layout after suppressed incremental rendering");

    if (progressEvents & _WKRenderingProgressEventFirstPaintAfterSuppressedIncrementalRendering)
        LOG(@"renderingProgressDidChange: %@", @"first paint after suppressed incremental rendering");
}

- (void)webView:(WKWebView *)webView shouldLoadIconWithParameters:(_WKLinkIconParameters *)parameters completionHandler:(void (^)(void (^)(NSData*)))completionHandler
{
    completionHandler(^void (NSData *data) {
        LOG(@"Icon URL %@ received icon data of length %u", parameters.url, (unsigned)data.length);
    });
}

#pragma mark Find in Page

- (IBAction)performTextFinderAction:(id)sender
{
    [_textFinder performAction:[sender tag]];
}

- (NSView *)findBarView
{
    return _textFindBarView;
}

- (void)setFindBarView:(NSView *)findBarView
{
    _textFindBarView = findBarView;
    _findBarVisible = YES;
    [_textFindBarView setFrame:NSMakeRect(0, 0, containerView.bounds.size.width, _textFindBarView.frame.size.height)];
}

- (BOOL)isFindBarVisible
{
    return _findBarVisible;
}

- (void)setFindBarVisible:(BOOL)findBarVisible
{
    _findBarVisible = findBarVisible;
    if (findBarVisible)
        [containerView addSubview:_textFindBarView];
    else
        [_textFindBarView removeFromSuperview];
}

- (NSView *)contentView
{
    return _webView;
}

- (void)findBarViewDidChangeHeight
{
}

- (void)_webView:(WKWebView *)webView requestMediaCaptureAuthorization: (_WKCaptureDevices)devices decisionHandler:(void (^)(BOOL authorized))decisionHandler
{
    decisionHandler(true);
}

- (void)_webView:(WKWebView *)webView includeSensitiveMediaDeviceDetails:(void (^)(BOOL includeSensitiveDetails))decisionHandler
{
    decisionHandler(false);
}

- (IBAction)saveAsPDF:(id)sender
{
    NSSavePanel *panel = [NSSavePanel savePanel];
    panel.allowedFileTypes = @[ @"pdf" ];
    [panel beginSheetModalForWindow:self.window completionHandler:^(NSInteger result) {
        if (result == NSModalResponseOK) {
            [_webView createPDFWithConfiguration:nil completionHandler:^(NSData *pdfSnapshotData, NSError *error) {
                [pdfSnapshotData writeToURL:[panel URL] options:0 error:nil];
            }];
        }
    }];
}

- (IBAction)saveAsWebArchive:(id)sender
{
    NSSavePanel *panel = [NSSavePanel savePanel];
    panel.allowedFileTypes = @[ @"webarchive" ];
    [panel beginSheetModalForWindow:self.window completionHandler:^(NSInteger result) {
        if (result == NSModalResponseOK) {
            [_webView createWebArchiveDataWithCompletionHandler:^(NSData *archiveData, NSError *error) {
                [archiveData writeToURL:[panel URL] options:0 error:nil];
            }];
        }
    }];
}

- (WKWebView *)webView
{
    return _webView;
}

@end