/*

File: EntryListController.m

Abstract: Use the PubSub framework to create a simple RSS news reader. 

Version: <1.0>

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*/

#import "EntryListController.h"

#import "FeedListController.h"

#import "ContentFormatting.h"

#import "NewsReaderApp.h"

#import <PubSub/PubSub.h>

#pragma mark -

#pragma mark ENTRYLISTCONTROLLER:

// Time since update until activity level decays to zero

#define kActivityThresholdTime  (2 * 60 * 60)

@implementation EntryListController

static NSFont *kNormalFont, *kBoldFont;

- (void) awakeFromNib

{

    // We're going to swap back and forth between these fonts later, depending upon what's happening

    // with the entry that's being displayed. Save these off.

    kNormalFont = [[[[_table tableColumns] objectAtIndex: 0] dataCell] font];

    kBoldFont = [[NSFontManager sharedFontManager] convertFont: kNormalFont toHaveTrait: NSBoldFontMask];

    // Double clicks in the table view should call openEntryInBrowser:

    [_table setDoubleAction: @selector(openEntryInBrowser:)];

}

// The feed for which entries are currently being displayed

- (PSFeed*) currentFeed

{

    return _currentFeed;

}

// Change the feed for which entries are being displayed

- (void) setCurrentFeed: (PSFeed*)feed

{

    if( feed != _currentFeed ) {

        NSLog(@"EntryListController: Now showing %@",feed);

        // If we're changing our notion of currentFeed, we'll want to remove ourself as observer

        // for its PSFeedEntriesChangedNotification

        if( _currentFeed )

            [[NSNotificationCenter defaultCenter] removeObserver: self

                                                            name: PSFeedEntriesChangedNotification

                                                          object: _currentFeed];

        // Then, remember the new one

        _currentFeed = feed;

        // Reload our table view (using the new feed, or, it'll empty out if the input feed is nil)

        [self reloadEntries];

        // And add ourself as observer of this new feed's PSFeedEntriesChangedNotification

        if( _currentFeed )

            [[NSNotificationCenter defaultCenter] addObserver: self

                                                     selector: @selector(_entriesChanged:)

                                                         name: PSFeedEntriesChangedNotification 

                                                       object: _currentFeed];

    }

}

// Sorts the table view using the columns' sort descriptors

- (void) _sortEntryList

{

    // Remember what's selected at the moment, so that we can restore selection after the sort

    PSEntry *sel = [self selectedEntry];

    _entries = [[_entrySet allObjects] sortedArrayUsingDescriptors: [_table sortDescriptors]];

    [_table reloadData];

    [_table noteNumberOfRowsChanged];

    [_table setNeedsDisplay: YES];

    self.selectedEntry = sel;

}

// Reloads the table view with the PSEntry objects from the currentFeed

- (void) reloadEntries

{

    NSArray *entries = [_currentFeed entries];

    if( ! entries ) {

        if( _currentFeed )

            [gApp fatalError: @"Couldn't get list of entries"];

        entries = [NSArray array];

    }

    _entrySet = [[NSMutableSet alloc] initWithArray: entries];

    [self _sortEntryList];

}

// Apply updates to entries in our mutable set

- (void) updateEntries: (NSArray*)updated

{

    if( [updated count] ) {

        NSSet* updatedSet = [NSSet setWithArray: updated];

        [_entrySet minusSet: updatedSet];      // Replace old copies of entries

        [_entrySet unionSet: updatedSet];      // with new (updated) ones

    }

}

// Called when we receive a PSFeedEntriesChangedNotification

- (void) _entriesChanged: (NSNotification*)n

{

    if( [n object] != _currentFeed ) {

        // Got PSFeedEntriesChangedNotification for wrong feed!

        return;

    }

    NSLog(@"EntryListController: Entries changed in %@",_currentFeed);

    // Information as to what exactly changed is included in the userInfo dictionary

    NSDictionary *info = [n userInfo];

    // If we've removed entries, just call reloadEntries to resync our table view with the PSFeed's entries

    if( [[info objectForKey: PSFeedRemovedEntriesKey] count] )

        [self reloadEntries];

    else {

        // If we've added entries, union them with our existing set of entries

        NSArray *added = [info objectForKey: PSFeedAddedEntriesKey];

        if( added )

            [_entrySet unionSet: [NSSet setWithArray: added]];

        // If it's state changes for existing objects in our set of entries, just update them

        [self updateEntries: [info objectForKey: PSFeedUpdatedEntriesKey]];

        [self updateEntries: [info objectForKey: PSFeedDidChangeEntryFlagsKey]];

    }

    // Resort, to accomodate the changes we've just applied

    [self _sortEntryList];

}

// The currently selected entry

- (PSEntry*) selectedEntry

{

    int row = [_table selectedRow];

    return row>=0 ?[_entries objectAtIndex: row] :nil;

}

// Sets the current entry selection, or deselects all if the requested entry isn't present 

// in the table view

- (void) setSelectedEntry: (PSEntry*)entry

{

    NSUInteger row = entry ?[_entries indexOfObject: entry] :NSNotFound;

    if( row != NSNotFound ) {

        [_table selectRow: row byExtendingSelection: NO];

        [_table scrollRowToVisible: row];

    } else {

        [_table deselectAll: self];

    }

}

// Open the current entry's alternateURL in the user's default web browser

-  (IBAction) openEntryInBrowser: (id)sender

{

    NSURL *url = [[self selectedEntry] alternateURL];

    if( ! url || ! [[NSWorkspace sharedWorkspace] openURL: url] )

        NSBeep();

}

#pragma mark -

#pragma mark REDRAWING:

// If we don't already have a pending scheduled redraw, schedule a call to

// _redrawTable in 60 seconds.

- (void) _scheduleTableRedraw

{

    if( ! _scheduledTableRedraw ) {

        [self performSelector: @selector(_redrawTable)

                   withObject: nil

                   afterDelay: 60.0];

        _scheduledTableRedraw = YES;

    }

}

// Redraw our table view

- (void) _redrawTable

{

    _scheduledTableRedraw = NO;

    [_table setNeedsDisplay: YES];

}

#pragma mark -

#pragma mark TABLE VIEW DATA SOURCE:

// NSTableView datasource protocol

// We have as many rows as we have entries

- (int)numberOfRowsInTableView:(NSTableView *)tableView

{

    return [_entries count];

}

// Our table uses KVC (key-value coding) to obtain values for itself. We use this method

// to modify those values, if desired, e.g. to change the formating of a date string,

// or provide a "look" for a boolean value.

- (id)tableView:(NSTableView *)tableView objectValueForTableColumn:(NSTableColumn *)tableColumn

            row:(int)row

{

    PSEntry *entry = [_entries objectAtIndex: row];

    NSString *ident = [tableColumn identifier];

    id value = [entry valueForKey: ident];              // Use KVC to get property value

    if( [ident isEqualToString: @"isRead"] ) {

        if( [value boolValue]==NO )

            value = @"*";

        else if( [entry isFlagged] )

            value = @"F";

        else

            value = @"";

    } else if( [value isKindOfClass: [NSDate class]] ) {

        value = ShortDateTimeString(value);

    }

    return value;

}

// When a titleForDisplay cell in our table is going to be displayed, we'd like to bold its font if the entry

// is unread. The newest items also are color-coded.

- (void)tableView:(NSTableView *)tableView willDisplayCell:(id)cell forTableColumn:(NSTableColumn *)tableColumn row:(int)row;

{

    PSEntry *entry = [_entries objectAtIndex: row];

    NSString *ident = [tableColumn identifier];

    if( [ident isEqualToString: @"titleForDisplay"] ) {

        NSFont *font;

        NSColor *color;

        if( [entry isRead] ) {

            font = kNormalFont;

            color = nil;

        } else {

            font = kBoldFont;

            color = ActivityColorForDate([entry localDateCreated]);

        }

        [cell setFont: font];

        if( color ) {

            [cell setTextColor: color];

            // Redraw the table in a minute so the color fades

            [self _scheduleTableRedraw];

        } else {

            [cell setTextColor: [NSColor controlTextColor]];

        }

    } else if( [ident isEqualToString: @"dateForDisplay"] ) {

        // Dates that aren't from the feed should be grayed-out

        // (If the XML feed contained no date information, we'll use the date PubSub downloaded and stored

        // the entry into its database.)

        BOOL hasRealDate = [entry datePublished] != nil;

        [cell setTextColor: (hasRealDate ?[NSColor controlTextColor] :[NSColor disabledControlTextColor])];

    }

}

// The table view is telling us that we might want to resort by calling this. We do.

- (void)tableView:(NSTableView *)tableView sortDescriptorsDidChange:(NSArray *)oldDescriptors

{

    [self _sortEntryList];

}

// When we're notified that the table view's selection has changed, we tell our application that

// its selected entry has been set to the new selection's value.

- (void) tableViewSelectionDidChange: (NSTableView*)tableView

{

    [gApp setSelectedEntry: [self selectedEntry]];

}

@end

// Different colors indicate the newness of an entry, to convey urgency or freshness for the newest.

NSColor* ActivityColorForDate( NSDate *updatedDate )

{

    if( updatedDate ) {

        float activityLevel = 1.0 - (-[updatedDate timeIntervalSinceNow]) / kActivityThresholdTime;

        if( activityLevel > 0.0 ) {

            activityLevel =  MIN(1.0, activityLevel);

            return [NSColor colorWithCalibratedHue: 0.0 // red (green is 0.333, blue is 0.666)

                                        saturation: 1.0 

                                        brightness: activityLevel

                                             alpha: 1.0];

        }

    }

    return nil;

}