// -*- Mode: objc; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*-
//
// This file is part of the LibreOffice project.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#import "config.h"

#import <cassert>
#import <cstdlib>
#import <cstring>

#import <LibreOfficeKit/LibreOfficeKitInit.h>

#import "AppDelegate.h"
#import "DocumentBrowserViewController.h"
#import "DocumentViewController.h"
#import "Document.h"

#import "FakeSocket.hpp"
#import "Log.hpp"
#import "LOOLWSD.hpp"
#import "Util.hpp"

static LOOLWSD *loolwsd = nullptr;

NSString *app_locale;
LibreOfficeKit *lo_kit;

static void download(NSURL *source, NSURL *destination) {
    [[[NSURLSession sharedSession] downloadTaskWithURL:source
                                     completionHandler:^(NSURL *location, NSURLResponse *response, NSError *error) {
                if (error == nil && [response isKindOfClass:[NSHTTPURLResponse class]] && [(NSHTTPURLResponse*)response statusCode] == 200) {
                    NSError *error = nil;
                    NSURL *resultingItem = nil;
                    if ([[NSFileManager defaultManager] replaceItemAtURL:destination
                                                           withItemAtURL:location
                                                          backupItemName:nil
                                                                 options:NSFileManagerItemReplacementUsingNewMetadataOnly
                                                        resultingItemURL:&resultingItem
                                                                error:&error]) {
                        LOG_INF("Downloaded " <<
                                [[source absoluteString] UTF8String] <<
                                " as " << [[destination absoluteString] UTF8String]);
                    } else {
                        LOG_ERR("Failed to replace " <<
                                [[destination absoluteString] UTF8String] <<
                                " with " << [[location absoluteString] UTF8String] <<
                                ": " << [[error description] UTF8String]);
                    }
                } else if (error != nil) {
                    LOG_ERR("Failed to download " <<
                            [[source absoluteString] UTF8String] <<
                            ": " << [[error description] UTF8String]);
                } else {
                    LOG_ERR("Failed to download " <<
                            [[source absoluteString] UTF8String]);
                }
            }] resume];
}

static void downloadTemplate(NSURL *source, NSURL *destination) {
    download(source, destination);
    // Download also a thumbnail
    download([NSURL URLWithString:[[source absoluteString] stringByAppendingString:@".png"]],
             [NSURL URLWithString:[[destination absoluteString] stringByAppendingString:@".png"]]);
}

static void updateTemplates(NSData *data, NSURLResponse *response)
{
    static NSString *downloadedTemplates = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingString:@"/downloadedTemplates/"];

    // The data downloaded is a template list file, and should have one URL per line, corresponding
    // to a template document. For each URL, we check whether we have the corresponding template
    // document, and whether it is the same version (timestamp is older or the same). If not, we
    // download the new version. Finally we remove any earlier downloaded templates not mentioned in the list
    // file.

    NSMutableSet<NSString *> *urlHashes = [NSMutableSet setWithCapacity:10];

    const char *p = static_cast<const char*>([data bytes]);
    const char *endOfData = p + [data length];
    while (p < endOfData) {
        const char *endOfLine = static_cast<const char*>(std::memchr(p, '\n', [data length]));
        if (endOfLine == NULL)
            endOfLine = endOfData;

        // Allow comment lines staring with a hash sign.
        if (*p != '#') {
            const int length = endOfLine - p;
            std::vector<char> buf(length+1);
            std::memcpy(buf.data(), p, length);
            buf[length] = 0;

            NSString *line = [NSString stringWithUTF8String:buf.data()];

            NSURL *url = [NSURL URLWithString:line];
            NSString *baseName = [url lastPathComponent];

            NSString *hash = [[NSData dataWithBytes:buf.data() length:length] base64EncodedStringWithOptions:0];
            [urlHashes addObject:hash];

            NSString *directoryForTemplate = [downloadedTemplates stringByAppendingString:hash];

            NSURL *fileForTemplate = [NSURL fileURLWithPath:[directoryForTemplate stringByAppendingString:[@"/" stringByAppendingString:baseName]]];

            // If we have that template, check whether it is up-to-date
            BOOL isDirectory;
            if ([[NSFileManager defaultManager] fileExistsAtPath:directoryForTemplate isDirectory:&isDirectory] &&
                isDirectory) {
                NSMutableURLRequest *req = [[NSURLRequest requestWithURL:url] mutableCopy];
                [req setHTTPMethod:@"HEAD"];
                [[[NSURLSession sharedSession] dataTaskWithRequest:req
                                                 completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                            if (error == nil && [response isKindOfClass:[NSHTTPURLResponse class]] && [(NSHTTPURLResponse*)response statusCode] == 200) {
                                NSString *lastModified = [[(NSHTTPURLResponse*)response allHeaderFields] objectForKey:@"Last-Modified"];
                                NSDateFormatter *df = [[NSDateFormatter alloc] init];
                                df.dateFormat = @"EEE, dd MMM yyyy HH:mm:ss z";
                                NSDate *templateDate = [df dateFromString:lastModified];

                                NSDate *cachedTemplateDate = [[[NSFileManager defaultManager] attributesOfItemAtPath:[fileForTemplate path] error:nil] objectForKey:NSFileModificationDate];

                                if ([templateDate compare:cachedTemplateDate] == NSOrderedDescending) {
                                    downloadTemplate(url, fileForTemplate);
                                }
                            }
                        }] resume];
            } else {
                // Else download it.
                [[NSFileManager defaultManager] createDirectoryAtPath:directoryForTemplate withIntermediateDirectories:YES attributes:nil error:nil];
                downloadTemplate(url, fileForTemplate);
            }
        }
        if (endOfLine < endOfData)
            p = endOfLine + 1;
        else
            p = endOfData;
    }

    // Remove templates that are no longer mentioned in the list file.
    NSArray<NSString *> *dirContents = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:downloadedTemplates error:nil];
    for (int i = 0; i < [dirContents count]; i++) {
        if (![urlHashes containsObject:[dirContents objectAtIndex:i]]) {
            [[NSFileManager defaultManager] removeItemAtPath:[downloadedTemplates stringByAppendingString:[@"/" stringByAppendingString:[dirContents objectAtIndex:i]]]
                                                       error:nil];
        }
    }
}

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    auto trace = std::getenv("LOOL_LOGLEVEL");
    if (!trace)
        trace = strdup("warning");

    Log::initialize("Mobile", trace, false, false, {});
    Util::setThreadName("main");

    // Having LANG in the environment is expected to happen only when debugging from Xcode. When
    // testing some language one doesn't know it might be risky to simply set one's iPad to that
    // language, as it might be hard to find the way to set it back to a known language.

    char *lang = std::getenv("LANG");
    if (lang != nullptr)
        app_locale = [NSString stringWithUTF8String:lang];
    else
        app_locale = [[NSLocale preferredLanguages] firstObject];

    // Look for the setting indicating the URL for a file containing a list of URLs for template
    // documents to download. If set, start a task to download it, and then to download the listed
    // templates.
    NSString *templateListURL = [[NSUserDefaults standardUserDefaults] stringForKey:@"templateListURL"];
    if (templateListURL != nil) {
        NSURL *url = [NSURL URLWithString:templateListURL];
        if (url != nil) {
            [[[NSURLSession sharedSession] dataTaskWithURL:url
                                         completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                        if (error == nil && [response isKindOfClass:[NSHTTPURLResponse class]] && [(NSHTTPURLResponse*)response statusCode] == 200)
                            updateTemplates(data, response);
                    }] resume];
        }
    }

    // Initialize LibreOfficeKit.

    lo_kit = lok_init_2(nullptr, nullptr);
    lo_kit->pClass->registerCallback(lo_kit, [](int, const char *, void*){}, nullptr);

    fakeSocketSetLoggingCallback([](const std::string& line)
                                 {
                                     LOG_TRC_NOFILE(line);
                                 });

    dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
                   ^{
                       assert(loolwsd == nullptr);
                       char *argv[2];
                       argv[0] = strdup([[NSBundle mainBundle].executablePath UTF8String]);
                       argv[1] = nullptr;
                       Util::setThreadName("app");
                       while (true) {
                           loolwsd = new LOOLWSD();
                           loolwsd->run(1, argv);
                           delete loolwsd;
                           LOG_TRC("One run of LOOLWSD completed");
                       }
                   });
    return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
}

- (void)applicationDidEnterBackground:(UIApplication *)application {
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

- (void)applicationWillEnterForeground:(UIApplication *)application {
    // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
}

- (void)applicationDidBecomeActive:(UIApplication *)application {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

- (void)applicationWillTerminate:(UIApplication *)application {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

- (BOOL)application:(UIApplication *)app openURL:(NSURL *)inputURL options:(NSDictionary<UIApplicationOpenURLOptionsKey, id> *)options {
    // Ensure the URL is a file URL
    if (!inputURL.isFileURL) {
        return NO;
    }

    // Reveal / import the document at the URL
    DocumentBrowserViewController *documentBrowserViewController = (DocumentBrowserViewController *)self.window.rootViewController;
    [documentBrowserViewController revealDocumentAtURL:inputURL importIfNeeded:YES completion:^(NSURL * _Nullable revealedDocumentURL, NSError * _Nullable error) {
        if (error) {
            // Handle the error appropriately
            LOG_ERR("Failed to reveal the document at URL " << [[inputURL description] UTF8String] << " with error: " << [[error description] UTF8String]);
            return;
        }

        // Present the Document View Controller for the revealed URL
        [documentBrowserViewController presentDocumentAtURL:revealedDocumentURL];
    }];
    return YES;
}

// NSURLSessionDataDelegate methods

@end

// vim:set shiftwidth=4 softtabstop=4 expandtab: