.686p
.model flat, stdcall
.stack 4096
ExitProcess PROTO, dwExitCode : DWORD
include Irvine32.inc
.data
	passPrompt BYTE "Please Enter Your Passcode: ", 0
	successPrompt BYTE "Door is now open", 0
	failPrompt BYTE "Intruder or new resident", 0
	useNewPrompt BYTE "Would you like to use this code for another apartment? (Y/N) ", 0
	dontSetPrompt BYTE "Well then get off my lawn!", 0
	apartmentPrompt BYTE "Please Enter the Apartment Number: ", 0
	apartErrorPrompt BYTE "ERROR: Invalid apartment number entered. ", 0
	apartSuccessPrompt BYTE "Successfully updated passcode: ", 0
	currentCodesPrompt BYTE "Current Codes: ", 0
	err_msg BYTE "ERROR: Invalid input!", 0
	comma BYTE ", ", 0

	numOfApts = 17
	codeArr WORD numOfApts DUP(?) ; will be filled later
.code
FindCode PROTO inkey:WORD

main PROC
	; fill array with default values
	push OFFSET codeArr
	push numOfApts
	call FillPasscodes
	mov edx, OFFSET currentCodesPrompt
	call WriteString
	call CRLF
	call PrintArray				 ; Show the array so people can

	mov edx, OFFSET passPrompt
	call WriteString			 ; prompt the user for passcode

	call ReadDec
	call CRLF
	jc INPUT_ERROR				 ; If CF = 1, error in input

	.IF ax > 999 && ax < 9999
		INVOKE FindCode, ax
	.ELSE
		jmp INPUT_ERROR
	.ENDIF

	.IF edx == 1
		mov edx, OFFSET successPrompt
		call WriteString
		call CRLF
		INVOKE ExitProcess, 0
	.ELSE
		mov edx, OFFSET failPrompt
		call WriteString
		call CRLF
		push ax						; Push their entered passcode for later use
		jmp AskNewCode
	.ENDIF

	INPUT_ERROR: ; The program has experienced an error
		mov edx, OFFSET err_msg
		call WriteString
		call CRLF
		INVOKE ExitProcess, 1

	AskNewCode:
		; This only works before Windows XP...
		mov eax, 10000
		INVOKE Delay		; Pause for 10 seconds
		mov edx, OFFSET useNewPrompt
		call WriteString
		call ReadChar
		call CRLF

		.IF al == 89 || al == 121	; 'y' or 'Y'
			jmp SetNewCode
		.ELSE
			mov edx, OFFSET dontSetPrompt
			call WriteString
			call CRLF
			INVOKE ExitProcess, 0
		.ENDIF

	SetNewCode:
		mov edx, OFFSET apartmentPrompt
		call WriteString
		call ReadDec
		call CRLF
		jc INPUT_ERROR

		.IF ax < 1 || ax > 17
			mov edx, OFFSET apartErrorPrompt
			call WriteString
			call CRLF
			INVOKE ExitProcess, 1
		.ELSE
			pop bx
			call SetCode
			mov edx, OFFSET apartSuccessPrompt
			call WriteString
			call PrintArray
		.ENDIF

	INVOKE ExitProcess, 0
main ENDP

SetCode PROC

	mov esi, OFFSET codeArr
	mov ecx, 2
	mul ecx					; EAX = EAX * the size of a word (2)

	add esi, eax			; go to the appropriate array index
	mov [esi], bx			; set the code entered into the appropriate place

	ret

SetCode ENDP

;----------------------------------------
;	Find the given key in the codeArr
;	RETURNS: 1 if found, 0 if not found
;----------------------------------------
FindCode PROC, inkey:WORD

	mov esi, OFFSET codeArr
	mov ecx, LENGTHOF codeArr
	mov ax, inkey

	Search:
		cmp ax, [esi]
		JZ Found
		add esi, TYPE codeArr
		LOOP Search
	mov edx, 0					; Not found (0)
	ret

	Found:
		mov edx, 1				; Found (1)
		ret
FindCode ENDP

;--------------------------------------------------------
;	Fills the codeArr array with random 4-digit integers
;   to be used as the default passcodes
;--------------------------------------------------------
FillPasscodes PROC

	push ebp
	mov ebp, esp
	mov esi, [ebp+12] ; get the array offset
	mov ecx, [ebp+8]  ; get the size of the array
	call Randomize

	FillLoop:
		mov eax, 4000  ; Top range or random number generation
		call RandomRange
		mov ebx, eax
		mov eax, 4000
		call RandomRange
		add ebx, eax
		add ebx, 1000  ; make sure numbers are at least above 1000
		mov [esi], ebx
		add esi, TYPE codeArr
		loop FillLoop

	pop ebp
	ret
FillPasscodes ENDP

;---------------------------
;	Print the codeArr array
;---------------------------
PrintArray PROC

	mov esi, OFFSET codeArr
	mov ecx, LENGTHOF codeArr
	mov edx, OFFSET comma
	mov eax, 0

	L1:
		mov ax, [esi]
		call WriteDec
		call WriteString
		add esi, TYPE codeArr
		loop L1
	call CRLF
	ret
PrintArray ENDP

END main