@ECHO OFF
IF     "%~1"=="" GOTO Syntax
IF NOT "%~2"=="" GOTO Syntax
ECHO.%~1| FINDSTR.EXE /R /X /I /C:"N[0-9][0-9]*[0-9A-Z]*" >NUL 2>&1 || GOTO Syntax
IF NOT EXIST MASTER.txt  IF NOT EXIST "%~dp0MASTER.txt"  GOTO Download
IF NOT EXIST ACFTREF.txt IF NOT EXIST "%~dp0ACFTREF.txt" GOTO Download

SETLOCAL ENABLEDELAYEDEXPANSION
SET NNumber=%~1
SET NNumber=%NNumber:~1%
IF EXIST MASTER.txt  (SET Master=MASTER.txt)   ELSE (IF EXIST %~dps0MASTER.txt  SET Master=%~dps0MASTER.txt)
IF EXIST ACFTREF.txt (SET AcftRef=ACFTREF.txt) ELSE (IF EXIST %~dps0ACFTREF.txt SET AcftRef=%~dps0ACFTREF.txt)

REM Loop through the MASTER table to find the manufacturer/model code for the specified N-number
FOR /F "tokens=1,3 delims=," %%A IN (%Master%) DO (
	IF %NNumber% EQU %%A (
		REM The N-number is recognized, now loop through the ACFTREF table to convert the manufacturer/model code to meaningful text
		SET Found=1
		FOR /F "tokens=1-3 delims=," %%C IN (%AcftRef%) DO (
			IF %%B EQU %%C (
				SET Aircraft=N%NNumber%
				REM Trim trailing whitespace from manufacturer name
				FOR %%F IN (%%D) DO (
					SET Aircraft=!Aircraft! %%F
				)
				REM Trim trailing whitespace from aircraft model
				FOR %%F IN (%%E) DO (
					SET Aircraft=!Aircraft! %%F
				)
				ECHO.!Aircraft!
				ENDLOCAL
				EXIT /B 0
			)
		)
	)
)
ENDLOCAL

REM This part of the code will only be reached if the aircraft wasn't found, hence returncode 2
EXIT /B 2


:Download
ECHO.
ECHO This script requires the FAA Aircraft Registry's Releasable Aircraft Database files in the current directory.
ECHO Download and unZIP the files and restart this script in the directory where the unZIPed files are located.
ECHO https://www.faa.gov/licenses_certificates/aircraft_certification/aircraft_registry/releasable_aircraft_download/
ECHO.
CHOICE.EXE /C YN /T 5 /D N /M "Do you want to open the download page now"
IF %ErrorLevel% EQU 1 (
	START https://www.faa.gov/licenses_certificates/aircraft_certification/aircraft_registry/releasable_aircraft_download/
	ECHO.
	ECHO Download and unZIP the database file, then restart this
	ECHO script in the directory where the unZIPed files are located.
	ECHO.
)
EXIT /B 3


:Syntax
ECHO.
ECHO AirRegNCmd.cmd,  Version 1.00 for Windows
ECHO Search downloaded FAA registry database files for the specified aircraft
ECHO registration number ^("N-number"^)
ECHO.
ECHO Usage:   AirRegNCmd.cmd  Nxxx
ECHO.
ECHO Where:   Nxxx is a valid aircraft registration "N-number", e.g. N18906
ECHO.
ECHO Example: AirRegNCmd.cmd N18906
ECHO          will return:
ECHO          N18906 LOCKHEED 12A
ECHO.
ECHO Notes:   This script requires the FAA Aircraft Registry's releasable
ECHO          aircraft database files either in the current directory or in this
ECHO          script's parent directory. The database files can be downloaded at:
ECHO          https://www.faa.gov/licenses_certificates/aircraft_certification
ECHO          /aircraft_registry/releasable_aircraft_download/
ECHO          You will be prompted to open the download page if the database
ECHO          files aren't found.
ECHO          Neither this script nor its author are associated with the FAA.
ECHO          This script's return code ^("errorlevel"^) will equal 0 if the
ECHO          specified aircraft registration was found, 2 if it wasn't,
ECHO          3 if the database files weren't found, 1 on command line errors.
ECHO.
ECHO Written by Rob van der Woude
ECHO https://www.robvanderwoude.com
EXIT /B 1