/*
 * Created by Martin Carlberg on Juli 18, 2012.
 * Copyright 2012, All rights reserved.
 */

@import <Foundation/CPObject.j>
@import "LOJSKeyedArchiver.j"
@import "LOFetchSpecification.j"
@import "LOObjectStore.j"


@implementation LOLocalDictionaryObjectStore : LOObjectStore {
    CPMutableDictionary     objectFixture @accessors;
}

- (id)init {
    self = [super init];
    if (self) {
        objectFixture = [CPMutableDictionary dictionary];
    }
    return self;
}

- (CPArray) _fetchAndFilterObjects:(LOFetchSpecification) fetchSpecification objectContext:(LOObjectContext)objectContext {
    //print(_cmd + " entity:" + [fetchSpecification entityName] + " oper: " + [fetchSpecification operator] + " qualifier:" + [fetchSpecification qualifier]);
    var fixtureObjects = [objectFixture objectForKey:[fetchSpecification entityName]];
    var predicate = [fetchSpecification qualifier];
    if (predicate) {
        fixtureObjects = [fixtureObjects filteredArrayUsingPredicate:predicate];
    }

    var objects = [];
    var registeredObjects = [CPMutableDictionary dictionary];

    var possibleToOneFaultObjects =[CPMutableArray array];

    for (var i=0; i<[fixtureObjects count]; i++) {
        var object = [fixtureObjects objectAtIndex:i];

        var objectUuid = [object valueForKey:@"key"];
        var objectType = [objectContext typeOfObject:object];
        var newObject = [registeredObjects objectForKey:objectUuid];
        if (!newObject) {
            var newObject = [self newObjectForType:objectType objectContext:objectContext];
            if (newObject) {
                [newObject setValue:objectUuid forKey:@"key"];
                [registeredObjects setObject:newObject forKey:objectUuid];
            }
        }
        if (!newObject) continue;
        [self _populateNewObject:newObject fromReceivedObject:object notePossibleToOneFaults:possibleToOneFaultObjects objectContext:objectContext];
        if (objectType === [fetchSpecification entityName]) {
            [objects addObject:newObject];
        }
    }

    [self _tryResolvePossibleToOneFaults:possibleToOneFaultObjects withAlreadyRegisteredObjects:registeredObjects];
    [self _updateObjectsInContext:objectContext withValuesOfFromFetchedObjects:[registeredObjects allValues]];
    return [self _arrayByReplacingNewObjects:objects withObjectsAlreadyRegisteredInContext:objectContext];
    return objects;
}

- (void)_populateNewObject:(id)newObject fromReceivedObject:(id)theReceivedObject notePossibleToOneFaults:(CPMutableArray)thePossibleToOneFaults objectContext:(LOObjectContext)anObjectContext {
    var type = [self typeOfObject:newObject];
    var attributeKeys = [self attributeKeysForObject:newObject withType:type];
    //print(_cmd + " " + type + " processing attribute keys of new object: " + [attributeKeys description]);
    for (var j=0; j<[attributeKeys count]; j++) {
        var key = [attributeKeys objectAtIndex:j];
        var value = [theReceivedObject valueForKey:key];
        if ([self isForeignKeyAttribute:key forType:type objectContext:anObjectContext]) {    // Handle to one relationship.
            key = [self toOneRelationshipAttributeForForeignKeyAttribute:key forType:type objectContext:anObjectContext]; // Remove "_fk" at end
            if (value) {
                var toOne = [anObjectContext objectForGlobalId:value];
                if (toOne) {
                    value = toOne;
                } else {
                    // Add it to a list and try again after we have registered all objects.
                    // FIXME: should set newObject, right?
                    [thePossibleToOneFaults addObject:{@"object":newObject , @"relationshipKey":key , @"globalId":value}];
                    value = nil;
                }
            }
        }
        //print(_cmd + " setValue: " + value + " for Key: " + key);
        [newObject setValue:value forKey:key];
    }
}

- (void)_tryResolvePossibleToOneFaults:(CPArray)theCandidates withAlreadyRegisteredObjects:(CPDictionary)theRegisteredObjects {
    var size = [theCandidates count];
    for (var i = 0; i < size; i++) {
        var aCandidate = [theCandidates objectAtIndex:i];
        var toOne = [theRegisteredObjects objectForKey:aCandidate.globalId];
        if (toOne) {
            [aCandidate.object setValue:toOne forKey:aCandidate.relationshipKey];
        } else {
            //console.log([self className] + " " + _cmd + " Can't find object for toOne relationship '" + aCandidate.relationshipKey + "' (" + toOne + ") on object " + aCandidate.object);
            //print([self className] + " " + _cmd + " Can't find object for toOne relationship '" + aCandidate.relationshipKey + "' (" + toOne + ") on object " + aCandidate.object);
        }
    }
}

- (void)_updateObjectsInContext:(LOObjectContext)anObjectContext withValuesOfFromFetchedObjects:(CPArray)theNewObjects {
    var newObjectsCount = [theNewObjects count];
    for (var i = 0; i < newObjectsCount; i++) {
        var newObject = [theNewObjects objectAtIndex:i];
        if (![anObjectContext isObjectRegistered:newObject]) continue;

        // If we already got the object transfer all attributes to the old object
        //CPLog.trace(@"tracing: " + _cmd + ": Object already in objectContext: " + newObject);
        var type = [self typeOfObject:newObject];
        [anObjectContext setDoNotObserveValues:YES];

        var oldObject = [anObjectContext objectForGlobalId:[self globalIdForObject:newObject]];
        var columns = [self attributeKeysForObject:newObject withType:type];
        var columnsCount = [columns count];
        for (var j = 0; j < columnsCount; j++) {
            var columnKey = [columns objectAtIndex:j];
            if ([self isForeignKeyAttribute:columnKey forType:type objectContext:anObjectContext]) {    // Handle to one relationship.
                columnKey = [self toOneRelationshipAttributeForForeignKeyAttribute:columnKey forType:type objectContext:anObjectContext]; // Remove "_fk" at end
            }
            var newValue = [newObject valueForKey:columnKey];
            var oldValue = [oldObject valueForKey:columnKey];
            if (newValue !== oldValue) {
                [oldObject setValue:newValue forKey:columnKey];
            }
        }
        [anObjectContext setDoNotObserveValues:NO];
    }
}

- (CPArray)_arrayByReplacingNewObjects:(CPArray)newObjects withObjectsAlreadyRegisteredInContext:(LOObjectContext)anObjectContext {
    var result = [CPMutableArray array];

    var newObjectsCount = [newObjects count];
    for (var i = 0; i < newObjectsCount; i++) {
        var anObject = [newObjects objectAtIndex:i];
        if ([anObjectContext isObjectRegistered:anObject]) {
            anObject = [anObjectContext objectForGlobalId:[self globalIdForObject:anObject]];
        }
        [result addObject:anObject];
    }

    return result;
}

/*!
 * Must call [objectContext objectsReceived: withFetchSpecification:] when objects are received
 */
- (CPArray)requestObjectsWithFetchSpecification:(LOFetchSpecification) fetchSpecification objectContext:(LOObjectContext)objectContext withCompletionHandler:(Function)aCompletionBlock {
    var objects = [self _fetchAndFilterObjects:fetchSpecification objectContext:objectContext];
    [objectContext objectsReceived:objects allReceivedObjects:objects withFetchSpecification:fetchSpecification withCompletionBlocks:aCompletionBlock ? [aCompletionBlock] : nil];
}

/*!
 * Must call [objectContext faultReceived:(CPArray)objectList withFetchSpecification:(LOFetchSpecification)fetchSpecification faultArray:(LOFaultArray)faultArray] when fault objects are received
 */
- (CPArray)requestFaultArray:(LOFaultArray)faultArray withFetchSpecification:(LOFetchSpecification)fetchSpecification objectContext:(LOObjectContext) objectContext withCompletionHandler:(Function)aCompletionBlock {
    var objects = [self _fetchAndFilterObjects:fetchSpecification objectContext:objectContext];
    [objectContext faultReceived:objects withFetchSpecification:fetchSpecification withCompletionBlocks:aCompletionBlock ? [aCompletionBlock] : nil faults:[faultArray]];
}

/*!
 * This method should save all changes to the backend.
 * The ObjectContext has a list of LOModifyRecord that contains all changes.
 * Must call [objectContext saveChangesDidComplete] when done
 */
- (void)saveChangesWithObjectContext:(LOObjectContext)objectContext withCompletionHandler:(Function)aCompletionBlock {
    [objectContext saveChangesDidComplete];
}

/*!
 * Must return an array with keys for all attributes for this object.
 * The objectContext will observe all these attributes for changes and record them.
 */
- (CPArray)attributeKeysForObject:(id) theObject withType:(CPString)entityName {
    // Maybe not the cleanest way of doing this but it works for now.
    // The dictionary (theObject) might just have the attribute "key" and "entity" so we need to find a
    // complete dictionary in the fixture to find all attributes.

    var fixtureObjects = [objectFixture objectForKey:[theObject valueForKey:@"entity"]];
    if ([fixtureObjects count] > 0) {
        return [[fixtureObjects objectAtIndex:0] allKeys];
    } else {
        return [CPArray array];
    }
}

/*!
 * Returns the type of the object
 */
- (CPString)typeOfObject:(id)theObject {
    return [theObject objectForKey:@"entity"];
}

/*!
 * Returns a unique id for the object
 */
- (CPString)globalIdForObject:(id)theObject {
    return [theObject UID];
}

/*!
 * Returns the type for the raw row.
 */
- (CPString)typeForRawRow:(id)row objectContext:(LOObjectContext)objectContext fetchSpecification:(LOFetchSpecification)fetchSpecification {
    return row._type;
}

/*!
 * Returns the primary key attribute for the raw row.
 */
- (CPString)primaryKeyAttributeForType:(CPString)aType objectContext:(LOObjectContext)objectContext {
        return @"key";
}

/*!
 * Returns true if the attribute is a foreign key for the raw row.
 */
- (BOOL)isForeignKeyAttribute:(CPString)attribute forType:(CPString)aType objectContext:(LOObjectContext)objectContext {
    return [attribute hasSuffix:@"_fk"];
}

/*!
 * Returns to one relationship attribute that correspond to the foreign key attribute for the type
 */
- (CPString)toOneRelationshipAttributeForForeignKeyAttribute:(CPString)attribute forType:(CPString)aType objectContext:(LOObjectContext)objectContext {
    return [attribute substringToIndex:[attribute length] - 3]; // Remove "_fk" at end of attribute
}

/*!
 * Returns foreign key attribute that correspond to the to one relationship attribute for the type
 */
- (CPString)foreignKeyAttributeForToOneRelationshipAttribute:(CPString)attribute forType:(CPString)aType {
    return attribute + @"_fk";
}

/*!
 * Returns the primary key for the raw row with type aType.
 */
- (CPString)primaryKeyForRawRow:(id)row type:(CPString)aType objectContext:(LOObjectContext)objectContext {
    var primaryKeyAttribute = [self primaryKeyAttributeForType:aType objectContext:objectContext];
    return row[primaryKeyAttribute];
}

- (CPString)foreignKeyAttributeForInversRelationshipWithRelationshipAttribute:(CPString)relationshipKey withEntityNamed:(CPString)entityName {
    return [self foreignKeyAttributeForToOneRelationshipAttribute:entityName forType:[relationshipKey substringToIndex:[relationshipKey length] - 1]];
}

- (CPString)destinationEntityNameForRelationshipKey:(CPString)attributeName withEntityNamed:(CPString)entityName {
    return [attributeName substringToIndex:[attributeName length] - 1];
}

@end