/*
    File:       URLGetController.m

    Contains:   Manages the URL Get tab.

    Written by: DTS

    Copyright:  Copyright (c) 2010 Apple Inc. All Rights Reserved.

    Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc.
                ("Apple") in consideration of your agreement to the following
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                following text and disclaimers in all such redistributions of
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                or logos of Apple Inc. may be used to endorse or promote
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                this notice, no other rights or licenses, express or implied,
                are granted by Apple herein, including but not limited to any
                patent rights that may be infringed by your derivative works or
                by other works in which the Apple Software may be incorporated.

                The Apple Software is provided by Apple on an "AS IS" basis. 
                APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
                WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT,
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                THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
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*/

#import "URLGetController.h"

#import "AppDelegate.h"

#pragma mark * URLGetController

@interface URLGetController ()

// Properties that don't need to be seen by the outside world.

@property (nonatomic, readonly) BOOL              isReceiving;
@property (nonatomic, retain)   NSURLConnection * connection;
@property (nonatomic, copy)     NSString *        filePath;
@property (nonatomic, retain)   NSOutputStream *  fileStream;

@end

@implementation URLGetController

#pragma mark * Status management

// These methods are used by the core transfer code to update the UI.

- (void)_receiveDidStart
{
    // Clear the current image so that we get a nice visual cue if the receive fails.
    self.imageView.image = [UIImage imageNamed:@"NoImage.png"];
    self.statusLabel.text = @"Receiving";
    self.getOrCancelButton.title = @"Cancel";
    [self.activityIndicator startAnimating];
    [[AppDelegate sharedAppDelegate] didStartNetworking];
}

- (void)_updateStatus:(NSString *)statusString
{
    assert(statusString != nil);
    self.statusLabel.text = statusString;
}

- (void)_receiveDidStopWithStatus:(NSString *)statusString
{
    if (statusString == nil) {
        assert(self.filePath != nil);
        self.imageView.image = [UIImage imageWithContentsOfFile:self.filePath];
        statusString = @"GET succeeded";
    }
    self.statusLabel.text = statusString;
    self.getOrCancelButton.title = @"Get";
    [self.activityIndicator stopAnimating];
    [[AppDelegate sharedAppDelegate] didStopNetworking];
}

#pragma mark * Core transfer code

// This is the code that actually does the networking.

@synthesize connection    = _connection;
@synthesize filePath      = _filePath;
@synthesize fileStream    = _fileStream;

- (BOOL)isReceiving
{
    return (self.connection != nil);
}

- (void)_startReceive
    // Starts a connection to download the current URL.
{
    BOOL                success;
    NSURL *             url;
    NSURLRequest *      request;
    
    assert(self.connection == nil);         // don't tap receive twice in a row!
    assert(self.fileStream == nil);         // ditto
    assert(self.filePath == nil);           // ditto

    // First get and check the URL.
    
    url = [[AppDelegate sharedAppDelegate] smartURLForString:self.urlText.text];
    success = (url != nil);

    // If the URL is bogus, let the user know.  Otherwise kick off the connection.
    
    if ( ! success) {
        self.statusLabel.text = @"Invalid URL";
    } else if ( ! [[AppDelegate sharedAppDelegate] isImageURL:url] ) {
        self.statusLabel.text = @"Can only get images";
    } else {

        // Open a stream for the file we're going to receive into.

        self.filePath = [[AppDelegate sharedAppDelegate] pathForTemporaryFileWithPrefix:@"Get"];
        assert(self.filePath != nil);
        
        self.fileStream = [NSOutputStream outputStreamToFileAtPath:self.filePath append:NO];
        assert(self.fileStream != nil);
        
        [self.fileStream open];

        // Open a connection for the URL.

        request = [NSURLRequest requestWithURL:url];
        assert(request != nil);
        
        self.connection = [NSURLConnection connectionWithRequest:request delegate:self];
        assert(self.connection != nil);

        // Tell the UI we're receiving.
        
        [self _receiveDidStart];
    }
}

- (void)_stopReceiveWithStatus:(NSString *)statusString
    // Shuts down the connection and displays the result (statusString == nil) 
    // or the error status (otherwise).
{
    if (self.connection != nil) {
        [self.connection cancel];
        self.connection = nil;
    }
    if (self.fileStream != nil) {
        [self.fileStream close];
        self.fileStream = nil;
    }
    [self _receiveDidStopWithStatus:statusString];
    self.filePath = nil;
}

- (void)connection:(NSURLConnection *)theConnection didReceiveResponse:(NSURLResponse *)response
    // A delegate method called by the NSURLConnection when the request/response 
    // exchange is complete.
    //
    // For an HTTP request you would check [response statusCode] and [response MIMEType] to 
    // verify that this is acceptable data, but for an FTP request there is no status code 
    // and the type value is derived from the extension so you might as well pre-flight that.
    //
    // You could, use this opportunity to get [response expectedContentLength] and 
    // [response suggestedFilename], but I don't need either of these values for 
    // this sample.
{
    #pragma unused(theConnection)
    #pragma unused(response)

    assert(theConnection == self.connection);
    assert(response != nil);
}

- (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)data
    // A delegate method called by the NSURLConnection as data arrives.  We just 
    // write the data to the file.
{
    #pragma unused(theConnection)
    NSInteger       dataLength;
    const uint8_t * dataBytes;
    NSInteger       bytesWritten;
    NSInteger       bytesWrittenSoFar;

    assert(theConnection == self.connection);
    
    dataLength = [data length];
    dataBytes  = [data bytes];

    bytesWrittenSoFar = 0;
    do {
        bytesWritten = [self.fileStream write:&dataBytes[bytesWrittenSoFar] maxLength:dataLength - bytesWrittenSoFar];
        assert(bytesWritten != 0);
        if (bytesWritten == -1) {
            [self _stopReceiveWithStatus:@"File write error"];
            break;
        } else {
            bytesWrittenSoFar += bytesWritten;
        }
    } while (bytesWrittenSoFar != dataLength);
}

- (void)connection:(NSURLConnection *)theConnection didFailWithError:(NSError *)error
    // A delegate method called by the NSURLConnection if the connection fails. 
    // We shut down the connection and display the failure.  Production quality code 
    // would either display or log the actual error.
{
    #pragma unused(theConnection)
    #pragma unused(error)
    assert(theConnection == self.connection);
    
    [self _stopReceiveWithStatus:@"Connection failed"];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)theConnection
    // A delegate method called by the NSURLConnection when the connection has been 
    // done successfully.  We shut down the connection with a nil status, which 
    // causes the image to be displayed.
{
    #pragma unused(theConnection)
    assert(theConnection == self.connection);
    
    [self _stopReceiveWithStatus:nil];
}

#pragma mark * UI Actions

- (IBAction)getOrCancelAction:(id)sender
{
    #pragma unused(sender)
    if (self.isReceiving) {
        [self _stopReceiveWithStatus:@"Cancelled"];
    } else {
        [self _startReceive];
    }
}

- (void)textFieldDidEndEditing:(UITextField *)textField
    // A delegate method called by the URL text field when the editing is complete. 
    // We save the current value of the field in our settings.
{
    #pragma unused(textField)
    NSString *  newValue;
    NSString *  oldValue;
    
    assert(textField == self.urlText);

    newValue = self.urlText.text;
    oldValue = [[NSUserDefaults standardUserDefaults] stringForKey:@"URLGetURLText"];

    // Save the URL text if it's changed.
    
    assert(newValue != nil);        // what is UITextField thinking!?!
    assert(oldValue != nil);        // because we registered a default
    
    if ( ! [newValue isEqual:oldValue] ) {
        [[NSUserDefaults standardUserDefaults] setObject:newValue forKey:@"URLGetURLText"];
    }
}

- (BOOL)textFieldShouldReturn:(UITextField *)textField
    // A delegate method called by the URL text field when the user taps the Return 
    // key.  We just dismiss the keyboard.
{
    #pragma unused(textField)
    assert(textField == self.urlText);
    [self.urlText resignFirstResponder];
    return NO;
}

#pragma mark * View controller boilerplate

@synthesize urlText           = _urlText;
@synthesize imageView         = _imageView;
@synthesize statusLabel       = _statusLabel;
@synthesize activityIndicator = _activityIndicator;
@synthesize getOrCancelButton = _getOrCancelButton;

- (void)viewDidLoad
{
    [super viewDidLoad];

    assert(self.urlText != nil);
    assert(self.imageView != nil);
    assert(self.statusLabel != nil);
    assert(self.activityIndicator != nil);
    assert(self.getOrCancelButton != nil);
    
    self.getOrCancelButton.possibleTitles = [NSSet setWithObjects:@"Get", @"Cancel", nil];

    self.urlText.text = [[NSUserDefaults standardUserDefaults] stringForKey:@"URLGetURLText"];
    
    self.activityIndicator.hidden = YES;
    self.statusLabel.text = @"Tap Get to start getting";
}

- (void)viewDidUnload
{
    [super viewDidUnload];

    self.urlText = nil;
    self.imageView = nil;
    self.statusLabel = nil;
    self.activityIndicator = nil;
    self.getOrCancelButton = nil;
}

- (void)dealloc
{
    [self _stopReceiveWithStatus:@"Stopped"];

    [self->_urlText release];
    [self->_imageView release];
    [self->_statusLabel release];
    [self->_activityIndicator release];
    [self->_getOrCancelButton release];

    [super dealloc];
}

@end
