//
//  History.m
//  RemoteR
//
//  Created by Simon Urbanek on 2/14/11.
//  Copyright 2011 Simon Urbanek. All rights reserved.
//

#import "History.h"

/** implements a history with one dirty entry (i.e. an entry which is still being edited but not committed yet) */
@implementation History

- (id) init
{
    self = [super init];
    if (self != nil) {
	hist = [[NSMutableArray alloc] initWithCapacity: 128];
	dirtyEntry = nil;
	pos = 0;	
    }
    return self;
}


- (void) setHist: (NSArray *) entries
{
    if (hist) 
	[self resetAll];
    [hist addObjectsFromArray: entries];
    pos = [hist count];
}

- (void) dealloc {
    [self resetAll];
    [hist release];
    [super dealloc];
}

- (void) commit: (NSString*) entry {
    if (dirtyEntry != nil)
	[dirtyEntry release];
    dirtyEntry = nil;
    [hist addObject:entry];
    pos = [hist count];
}

/** moves to the next entry; if out of the history, returns the dirty entry */
- (NSString*) next {
    NSInteger ac = [hist count];
    if (pos < ac && ++pos < ac)
	return (NSString*) [hist objectAtIndex: pos];
    // we're past the history, always return the dirty entry
    return dirtyEntry;
}

/** moves to the previous entry; if past the beginning, returns nil */
- (NSString*) prev {
    if (pos > 0) {
	pos--;
	return (NSString*) [hist objectAtIndex: pos];
    }
    return nil;
}

/** returns the current entry (can be the dirty entry, too) */
- (NSString*) current {
    NSInteger ac = [hist count];
    if (pos < ac)
	return (NSString*) [hist objectAtIndex: pos];
    return dirtyEntry;
}

/** returns YES if the current position is in the dirty entry */
- (BOOL) isDirty {
    return (pos == [hist count]) ? YES : NO;
}

/** updates the dirty entry with the arg, if we're currently in the dirty position */
- (void) updateDirty: (NSString*) entry {
    if (pos == [hist count]) {
        if (entry == dirtyEntry) return;
        if (dirtyEntry != nil)
	    [dirtyEntry release];
        dirtyEntry = entry ? [entry retain] : nil;
    }
}

/** resets the entire history, position and ditry entry */
- (void) resetAll {
    [hist removeAllObjects];
    if (dirtyEntry != nil)
	[dirtyEntry release];
    pos = 0;
}

/** removes selected entry entry */
- (void) deleteEntry:(unsigned)index {
    [hist removeObjectAtIndex: index];
    if (dirtyEntry != nil)
	[dirtyEntry release];
    dirtyEntry = nil;
    pos = [hist count];
}

/** returns a snapshot of the current histroy (w/o the dirty entry). */
- (NSArray*) entries {
    return [NSArray arrayWithArray: hist];
}

/** encode dirty, position and history */
- (void) encodeWithCoder:(NSCoder *)coder{
    [coder encodeObject:dirtyEntry];
    [coder encodeObject:[NSNumber numberWithInt:pos]];
    [coder encodeObject:hist];
}

/** decoder init */
- (id) initWithCoder:(NSCoder *)coder{
    if ((self = [self init])) {
	dirtyEntry = [coder decodeObject];
	if (dirtyEntry)
	    [dirtyEntry retain];
	pos = [[coder decodeObject] intValue];
	hist = [[NSMutableArray alloc] initWithCoder:coder];
    }
    return self;
}

@end