//
//  NBGeocoderMetadataHelper.m
//  libPhoneNumberiOS
//
//  Created by Rastaar Haghi on 6/12/20.
//  Copyright © 2020 Google LLC. All rights reserved.
//

#import "NBGeocoderMetadataHelper.h"
#import "NBPhoneNumber.h"

@implementation NBGeocoderMetadataHelper {
 @private
  NSString *_databasePath;
  sqlite3 *_database;
  sqlite3_stmt *_selectStatement;
  NSString *_language;
  NSNumber *_countryCode;
}

NSString *const preparedStatement = @"WITH recursive count(x)"
                                            @"AS"
                                                @"( "
                                                    @"SELECT 1 "
                                                    @"UNION ALL "
                                                    @"SELECT x+1 "
                                                    @"FROM   count "
                                                    @"LIMIT  length(?)), tosearch "
                                            @"AS "
                                                @"( "
                                                    @"SELECT substr(?, 1, x) AS indata "
                                                    @"FROM   count) "
                                                @"SELECT   nationalnumber, "
                                                    @"description, "
                                                    @"length(nationalnumber) AS nationalnumberlength "
                                                @"FROM     geocodingpairs%@ "
                                                @"WHERE    nationalnumber IN tosearch "
                                                @"ORDER BY nationalnumberlength DESC "
                                                @"LIMIT    1";

- (instancetype)initWithCountryCode:(NSNumber *)countryCode withLanguage:(NSString *)language {
  self = [super init];
    if (self != nil) {
        _countryCode = countryCode;
        _language = language;
        
        NSBundle *bundle = [NSBundle bundleForClass:self.classForCoder];
        NSURL *bundleURL = [[bundle resourceURL] URLByAppendingPathComponent:@"Resources.bundle"];
        NSString *databasePath = [NSString stringWithFormat:@"%@%@.db", bundleURL, _language];
        _databasePath = databasePath;

        sqlite3_open([databasePath UTF8String], &_database);

        sqlite3_prepare_v2(
            _database,
            [[NSString stringWithFormat: preparedStatement, countryCode] UTF8String], -1, &_selectStatement, NULL);
    }
  return self;
}

- (void)dealloc {
  sqlite3_finalize(_selectStatement);
  sqlite3_close_v2(_database);
}

- (int)createSelectStatement:(NBPhoneNumber *)phoneNumber {
  int sqliteResultCode;
  @autoreleasepool {
    sqliteResultCode = sqlite3_reset(_selectStatement);
    sqlite3_clear_bindings(_selectStatement);
    if (sqliteResultCode == SQLITE_OK) {
      const char *completePhoneNumber =
          [[NSString stringWithFormat:@"%@%@", phoneNumber.countryCode, phoneNumber.nationalNumber]
              UTF8String];
      sqlite3_bind_text(_selectStatement, 1, completePhoneNumber, -1, SQLITE_TRANSIENT);
      sqlite3_bind_text(_selectStatement, 2, completePhoneNumber, -1, SQLITE_TRANSIENT);
    } else {
      NSLog(@"The prepare statement result code was: %d", sqliteResultCode);
    }
  }
  return sqliteResultCode;
}

- (NSString *)searchPhoneNumber:(NBPhoneNumber *)phoneNumber {
    if (![phoneNumber.countryCode isEqualToNumber: _countryCode]) {
      _countryCode = phoneNumber.countryCode;
      sqlite3_prepare_v2(
          self->_database,
          [[NSString
            stringWithFormat: preparedStatement, _countryCode] UTF8String],
          -1, &_selectStatement, NULL);
    }

    int sqlCommandResults = [self createSelectStatement:phoneNumber];

    if (sqlCommandResults != SQLITE_OK) {
      NSLog(@"Error with preparing statement");
      return @"";
    }
    int step = sqlite3_step(_selectStatement);
    if (step == SQLITE_ROW) {
      return @((const char *)sqlite3_column_text(_selectStatement, 1));
    } else {
        return nil;
    }
}

@end