//
//  Caches.m
//  Geopher Lite
//
//  Created by Branden Russell on 8/30/08.
//  Copyright 2008 Equis International. All rights reserved.
//

#import "Caches.h"
#import "Cache.h"

#define DATABASE_FILE_NAME @"cachesdb.sql"

@implementation Caches
@synthesize caches;

// Open the database connection and retrieve minimal information for all objects.
- (void)initializeDatabase
{
    NSMutableArray *array = [[NSMutableArray alloc] init];
    self.caches = array;
    [array release];
    // The database is stored in the application bundle. 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:DATABASE_FILE_NAME];
    // Open the database. The database was prepared outside the application.
    if (sqlite3_open([path UTF8String], &database) == SQLITE_OK)
    {
        // Get the primary key for all caches.
        const char *sql = "SELECT pk FROM cache";
        sqlite3_stmt *statement;
        // Preparing a statement compiles the SQL query into a byte-code program in the SQLite library.
        // The third parameter is either the length of the SQL string or -1 to read up to the first null terminator.        
        if (sqlite3_prepare_v2(database, sql, -1, &statement, NULL) == SQLITE_OK)
        {
            // We "step" through the results - once for each row.
            while (sqlite3_step(statement) == SQLITE_ROW)
            {
                // The second parameter indicates the column index into the result set.
                int primaryKey = sqlite3_column_int(statement, 0);
                // We avoid the alloc-init-autorelease pattern here because we are in a tight loop and
                // autorelease is slightly more expensive than release. This design choice has nothing to do with
                // actual memory management - at the end of this block of code, all the cache objects allocated
                // here will be in memory regardless of whether we use autorelease or release, because they are
                // retained by the caches array.
                Cache *cache = [[Cache alloc] initWithPrimaryKey:primaryKey database:database];
                [caches addObject:cache];
                [cache release];
            }
        }
        // "Finalize" the statement - releases the resources associated with the statement.
        sqlite3_finalize(statement);
    } else
    {
        // Even though the open failed, call close to properly clean up resources.
        sqlite3_close(database);
        NSAssert1(0, @"Failed to open database with message '%s'.", sqlite3_errmsg(database));
        // Additional error handling, as appropriate...
    }
}

// Removes a cache from the array of caches, and also deletes it from the database. There is no undo.
- (void)removeCache:(Cache *)cache;
{
    // Delete from the database first. The cache knows how to do this (see Cache.m)
    [cache deleteFromDatabase];
    [caches removeObject:cache];
}

// Creates a new cache object with default data. 
- (void)addCache:(Cache *)cache;
{
    // Create a new record in the database and get its automatically generated primary key.
    [cache insertIntoDatabase:database];
    [caches addObject:cache];
}

@end