WebViewDelegate.m

/*
 
 Copyright 2014 Takashi Mizuhiki
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
 http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 
 */

#import <mach/mach_time.h>

#import "WebViewDelegate.h"

@interface WebViewDelegate () {
    BOOL _sysexEnabled;
}
@end

@implementation WebViewDelegate

- (void)invokeJSCallback_onNotReady:(WKWebView *)webView
{
    [webView evaluateJavaScript:@"_callback_onNotReady();" completionHandler:nil];
}

- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message
{
    if ([message.name isEqualToString:@"onready"] == YES) {
        __block uint64_t timestampOrigin = 0;

        mach_timebase_info_data_t base;
        mach_timebase_info(&base);

        NSDictionary *dict = message.body;
        
        NSDictionary *MIDIoptions = dict[@"options"];
        NSString *url = dict[@"url"];

        _sysexEnabled = NO;
        id sysexOption = MIDIoptions[@"sysex"];
        if ([sysexOption isKindOfClass:[NSNumber class]] && [sysexOption boolValue] == YES) {
            if (_confirmSysExAvailability) {
                if (_confirmSysExAvailability(url) == NO) {
                    [self invokeJSCallback_onNotReady:message.webView];
                    return;
                } else {
                    _sysexEnabled = YES;
                }
            } else {
                [self invokeJSCallback_onNotReady:message.webView];
                return;
            }
        }
        
        if (_midiDriver.isAvailable == NO) {
            [self invokeJSCallback_onNotReady:message.webView];
            return;
        }
        
        // Setup the callback for receiving MIDI message.
        _midiDriver.onMessageReceived = ^(ItemCount index, NSData *receivedData, uint64_t timestamp) {
            NSMutableArray *array = [NSMutableArray arrayWithCapacity:[receivedData length]];
            BOOL sysexIncluded = NO;
            for (int i = 0; i < [receivedData length]; i++) {
                unsigned char byte = ((unsigned char *)[receivedData bytes])[i];
                [array addObject:[NSNumber numberWithUnsignedChar:byte]];

                if (byte == 0xf0) {
                    sysexIncluded = YES;
                }
            }
            
            if (_sysexEnabled == NO && sysexIncluded == YES) {
                // should throw InvalidAccessError exception here
                return;
            }

            NSData *dataJSON = [NSJSONSerialization dataWithJSONObject:array options:0 error:nil];
            NSString *dataJSONStr = [[NSString alloc] initWithData:dataJSON encoding:NSUTF8StringEncoding];

            double deltaTime_ms = (double)(timestamp - timestampOrigin) * base.numer / base.denom / 1000000.0;
            [message.webView evaluateJavaScript:[NSString stringWithFormat:@"_callback_receiveMIDIMessage(%lu, %f, %@);", index, deltaTime_ms, dataJSONStr] completionHandler:nil];
        };

        __weak MIDIDriver *midiDriver = _midiDriver;
        _midiDriver.onDestinationPortAdded = ^(ItemCount index) {
            NSDictionary *info = [midiDriver portinfoFromDestinationEndpointIndex:index];
            NSData *JSON = [NSJSONSerialization dataWithJSONObject:info options:0 error:nil];
            NSString *JSONStr = [[NSString alloc] initWithData:JSON encoding:NSUTF8StringEncoding];

            [message.webView evaluateJavaScript:[NSString stringWithFormat:@"_callback_addDestination(%lu, %@);", index, JSONStr] completionHandler:nil];
        };

        _midiDriver.onSourcePortAdded = ^(ItemCount index) {
            NSDictionary *info = [midiDriver portinfoFromSourceEndpointIndex:index];
            NSData *JSON = [NSJSONSerialization dataWithJSONObject:info options:0 error:nil];
            NSString *JSONStr = [[NSString alloc] initWithData:JSON encoding:NSUTF8StringEncoding];
            
            [message.webView evaluateJavaScript:[NSString stringWithFormat:@"_callback_addSource(%lu, %@);", index, JSONStr] completionHandler:nil];
        };
        
        _midiDriver.onDestinationPortRemoved = ^(ItemCount index) {
            [message.webView evaluateJavaScript:[NSString stringWithFormat:@"_callback_removeDestination(%lu);", index] completionHandler:nil];
        };
        
        _midiDriver.onSourcePortRemoved = ^(ItemCount index) {
            [message.webView evaluateJavaScript:[NSString stringWithFormat:@"_callback_removeSource(%lu);", index] completionHandler:nil];
        };
        
        // Send all MIDI ports information when the setup request is received.
        ItemCount srcCount  = [_midiDriver numberOfSources];
        ItemCount destCount = [_midiDriver numberOfDestinations];

        NSMutableArray *srcs  = [NSMutableArray arrayWithCapacity:srcCount];
        NSMutableArray *dests = [NSMutableArray arrayWithCapacity:destCount];


        for (ItemCount srcIndex = 0; srcIndex < srcCount; srcIndex++) {
            NSDictionary *info = [_midiDriver portinfoFromSourceEndpointIndex:srcIndex];
            if (info == nil) {
                [self invokeJSCallback_onNotReady:message.webView];
                return;
            }
            [srcs addObject:info];
        }

        for (ItemCount destIndex = 0; destIndex < destCount; destIndex++) {
            NSDictionary *info = [_midiDriver portinfoFromDestinationEndpointIndex:destIndex];
            if (info == nil) {
                [self invokeJSCallback_onNotReady:message.webView];
                return;
            }
            [dests addObject:info];
        }

        
        NSData *srcsJSON = [NSJSONSerialization dataWithJSONObject:srcs options:0 error:nil];
        if (srcsJSON == nil) {
            [self invokeJSCallback_onNotReady:message.webView];
            return;
        }
        NSString *srcsJSONStr = [[NSString alloc] initWithData:srcsJSON encoding:NSUTF8StringEncoding];

        NSData *destsJSON = [NSJSONSerialization dataWithJSONObject:dests options:0 error:nil];
        if (destsJSON == nil) {
            [self invokeJSCallback_onNotReady:message.webView];
            return;
        }
        NSString *destsJSONStr = [[NSString alloc] initWithData:destsJSON encoding:NSUTF8StringEncoding];

        timestampOrigin = mach_absolute_time();

        [message.webView evaluateJavaScript:[NSString stringWithFormat:@"_callback_onReady(%@, %@);", srcsJSONStr, destsJSONStr] completionHandler:nil];
        
        return;
    } else if ([message.name isEqualToString:@"send"] == YES) {
        NSDictionary *dict = message.body;
        
        NSArray *array = dict[@"data"];
        NSMutableData *data = [NSMutableData dataWithCapacity:[array count]];
        BOOL sysexIncluded = NO;
        for (NSNumber *number in array) {
            uint8_t byte = [number unsignedIntegerValue];
            [data appendBytes:&byte length:1];

            if (byte == 0xf0) {
                sysexIncluded = YES;
            }
        }

        if (_sysexEnabled == NO && sysexIncluded == YES) {
            return;
        }
        
        ItemCount outputIndex = [dict[@"outputPortIndex"] unsignedLongValue];
        float deltatime = [dict[@"deltaTime"] floatValue];
        [_midiDriver sendMessage:data toDestinationIndex:outputIndex deltatime:deltatime];

        return;
    } else if ([message.name isEqualToString:@"clear"] == YES) {
        NSDictionary *dict = message.body;
        ItemCount outputIndex = [dict[@"outputPortIndex"] unsignedLongValue];
        
        [_midiDriver clearWithDestinationIndex:outputIndex];
    }
}

@end