;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
;    FTPS
;    FTP Server
;
;    Compile with FASM for Menuet
;

; note: telnet == 23, ftp cmd == 21, data on 20

use32

    org     0x0

    db      'MENUET00'              ; 8 byte id
    dd      38                      ; required os
    dd      START                   ; program start
    dd      I_END                   ; program image size
    dd      0x170000                ; required amount of memory
                                    ; esp = 0x7FFF0
    dd      0x00000000              ; reserved=no extended header


; Various states of client connection
USER_NONE       equ 0   ; Awaiting a connection
USER_CONNECTED  equ 1   ; User just connected, prompt given
USER_USERNAME   equ 2   ; User given username
USER_LOGGED_IN  equ 3   ; User given password





START:                          ; start of execution
    ; Clear the screen memory
    mov     eax, '    '
    mov     edi,text
    mov     ecx,80*30 /4
    cld
    rep     stosd

    call    draw_window

    ; init the receive buffer pointer
    mov     eax, buff
    mov     [buffptr], eax

    ; Init FTP server state machine
    mov     al, USER_NONE
    mov     [state], al

    ; Open the listening socket
    call    connect

still:
    ; check connection status
    mov     eax,53
    mov     ebx,6               ; Get socket status
    mov     ecx,[CmdSocket]
    int     0x40

    mov     ebx, [CmdSocketStatus]
    mov     [CmdSocketStatus], eax

    cmp     eax, ebx
    je      waitev

    ; If the socket closed by remote host, open it again.
    cmp     eax, 7
    je      con
    
    ; If socket closed by Reset, open it again
    cmp     eax, 11
    je      con

    ; If a user has just connected, start by outputting welcome msg
    cmp     eax, 4
    jne     noc

    mov     esi, loginStr0
    mov     edx, loginStr0_end - loginStr0
    call    outputStr

    mov     al, USER_CONNECTED
    mov     [state], al
    jmp     noc


con:
    ; Need to call disconnect, since a remote close does not fully
    ; close the socket
    call    disconnect
    call    connect
    jmp     noc

noc:
    ; Display the changed connected status
    call    draw_window

waitev:
    mov     eax,23                 ; wait here for event
    mov     ebx,1                 ; Delay for up to 1s
    int     0x40

    cmp     eax,1                  ; redraw request ?
    je      red
    cmp     eax,2                  ; key in buffer ?
    je      key
    cmp     eax,3                  ; button in buffer ?
    je      button

    ; any data from the socket?

    mov     eax, 53
    mov     ebx, 2                  ; Get # of bytes in input queue
    mov     ecx, [CmdSocket]
    int     0x40
    cmp     eax, 0
    jne     read_input

    jmp     still

read_input:
    mov     eax, 53
    mov     ebx, 3                  ; Get a byte from socket in bl
    mov     ecx, [CmdSocket]
    int     0x40

    call    ftpRxCmdData            ; process incoming ftp command

    ; Keep processing data until there is no more to process
    mov     eax, 53
    mov     ebx, 2                  ; Get # of bytes in input queue
    mov     ecx, [CmdSocket]
    int     0x40
    cmp     eax, 0
    jne     read_input

    ; Now redraw the text text field.
    ; Probably not required, since ftp requires no
    ; console i/o.
    ; Leave in for now, for debugging.
    call    draw_text
    jmp     still

red:                          ; REDRAW WINDOW
    call    draw_window
    jmp     still

key:                          ; KEY
    mov     eax,2                  ; get but ignore
    int     0x40
    jmp     still

button:
    mov     eax,17
    int     0x40
    cmp     ah,1
    jne     still

    ; Exit button pressed, so close socket and quit
    mov     eax,53
    mov     ebx,8
    mov     ecx,[CmdSocket]
    int     0x40

    ; ... terminate program
    mov     eax,-1
    int     0x40
    jmp     still



;   *********************************************
;   *******  WINDOW DEFINITIONS AND DRAW ********
;   *********************************************
draw_window:
    pusha

    mov  eax,12
    mov  ebx,1
    int  0x40

    mov  eax,0                     ; DRAW WINDOW
    mov  ebx,100*65536+491 + 8 +15
    mov  ecx,100*65536+270 + 20     ; 20 for status bar
    mov  edx,[wcolor]
    add  edx,0x02000000
    mov  esi,0x80557799
    mov  edi,0x00557799
    int  0x40

    mov  eax,4                     ; WINDOW LABEL
    mov  ebx,8*65536+8
    mov  ecx,0x00ffffff
    mov  edx,labelt
    mov  esi,labellen-labelt
    int  0x40


    mov  eax,8                     ; CLOSE BUTTON
     mov  ebx,(491 + 20 -19)*65536+12

    mov  ecx,5*65536+12
    mov  edx,1
    mov  esi,0x557799
    int  0x40

    ; draw status bar
    mov     eax, 13
    mov     ebx, 4*65536+484 + 8 +15
    mov     ecx, 270*65536 + 3
    mov     edx, 0x00557799
    int     0x40


    mov  esi,contlen-contt          ; display connected status
    mov     edx, contt
    mov     eax, [CmdSocketStatus]
    cmp     eax, 4                  ; 4 is connected
    je      pcon
    mov     esi,discontlen-discontt
    mov     edx, discontt
pcon:

    mov  eax,4                      ; status text
    mov  ebx,380*65536+276
    mov  ecx,0x00ffffff
    int  0x40

    ; Draw the text on the screen, clearing it first
    ; This can go when we loose debuggin info.
    xor  eax,eax
    mov  edi,text+80*30
    mov  ecx,80*30 /4
    cld
    rep  stosd

    call draw_text

    mov  eax,12
    mov  ebx,2
    int  0x40

    popa

    ret


;***************************************************************************
;   Function
;      draw_text
;
;   Description
;       Updates the text on the screen. This is part of the debugging code
;
;   Inputs
;       Character to add in bl
;
;***************************************************************************
draw_text:

    pusha

    mov  esi,text
    mov  eax,0
    mov  ebx,0
  newletter:
    mov  cl,[esi]
    cmp  cl,[esi+30*80]
    jne  yesletter
    jmp  noletter
  yesletter:
    mov  [esi+30*80],cl

    ; erase character

    pusha
    mov     edx, 0                  ; bg colour
    mov     ecx, ebx
    add     ecx, 26
    shl     ecx, 16
    mov     cx, 9
    mov     ebx, eax
    add     ebx, 6
    shl     ebx, 16
    mov     bx, 6
    mov     eax, 13
    int     0x40
    popa

    ; draw character

    pusha
    mov     ecx, 0x00ffffff
    push bx
    mov  ebx,eax
    add  ebx,6
    shl  ebx,16
    pop  bx
    add  bx,26
    mov  eax,4
    mov  edx,esi
    mov  esi,1
    int  0x40
    popa

  noletter:

    add  esi,1
    add  eax,6
    cmp  eax,80*6
    jb   newletter
    mov  eax,0
    add  ebx,10
    cmp  ebx,24*10
    jb   newletter

    popa
    ret



;***************************************************************************
;   Function
;      ftpRxCmdData
;
;   Description
;       Prcoesses incoming command data, calling a handler for each command.
;       Commands are built up in buff before being processed.
;
;   Inputs
;       Character to add in bl
;
;***************************************************************************
ftpRxCmdData:
    ; Quit if we are not connected
    ;( This case shouldn't be necessary, but be safe )
    mov     al, [state]
    cmp     al, USER_NONE
    je      frcd_exit

    ; Store the incoming character
    mov     esi, [buffptr]
    mov     [esi], bl
    inc     esi
    mov     [buffptr], esi

    ; For debugging, show the data coming in
    pusha
    call    printChar
    popa

    ; Do we have an end of line? (LF)
    ; if not, just exit
    cmp     bl, 0x0a
    jne     frcd_exit

    ; OK we have a complete command.
    ; Process, and send response

    ; There are a number of states involved in ftp,
    ; to do with logging in.

    mov     al, [state]
    cmp     al, USER_CONNECTED
    jne     fs001

    ; This should be the username

    ; TODO validate username

    ; OK, username accepted - ask for password
    mov     esi, loginStr1
    mov     edx, loginStr1_end - loginStr1
    call    outputStr

    mov     al, USER_USERNAME
    mov     [state], al

    ; init the receive buffer pointer
    mov     eax, buff
    mov     [buffptr], eax

    jmp     frcd_exit

fs001:
    cmp     al, USER_USERNAME
    jne     fs002

    ; This should be the password

    ; TODO validate password

    ; OK, password accepted - show they are logged in
    mov     esi, loginStr2
    mov     edx, loginStr2_end - loginStr2
    call    outputStr

    mov     al, USER_LOGGED_IN
    mov     [state], al

    ; init the receive buffer pointer
    mov     eax, buff
    mov     [buffptr], eax

    jmp     frcd_exit

fs002:
    cmp     al, USER_LOGGED_IN
    jne     fs003

    ; This should be a cmd
    call    findCmd
    mov     eax, [cmdPtr]
    cmp     eax, 0

    je      fs002b

    call    [cmdPtr]

fs002a:
    ; init the receive buffer pointer
    mov     eax, buff
    mov     [buffptr], eax

    jmp     frcd_exit

fs002b:
    ; an unsupported command was entered.
    ; Tell user that the command is not supported

    mov     esi, unsupStr
    mov     edx, unsupStr_end - unsupStr
    call    outputStr

    jmp     fs002a

fs003:
frcd_exit:
    ret



;***************************************************************************
;   Function
;      outputStr
;
;   Description
;       Sends a string over the 'Command' socket
;
;   Inputs
;       String in esi
;       Length in edx
;
;***************************************************************************
outputStr:
    push    esi
    push    edx
    mov     eax,53
    mov     ebx,7
    mov     ecx,[CmdSocket]
    int     0x40
    pop     edx
    pop     esi
    
    cmp     eax, 0
    je      os_exit
    
    ; The TCP/IP transmit queue is full; Wait a bit, then retry 
    pusha
    mov     eax,5
    mov     ebx,1                 ; Delay for up 100ms
    int     0x40
    popa
    jmp     outputStr        
os_exit:
    ret



;***************************************************************************
;   Function
;      outputDataStr
;
;   Description
;       Sends a string over the 'Data' socket
;
;   Inputs
;       String in esi
;       Length in edx
;
;***************************************************************************
outputDataStr:
    push    esi
    push    edx
    mov     eax,53
    mov     ebx,7
    mov     ecx,[DataSocket]
    int     0x40
    pop     edx
    pop     esi

    cmp     eax, 0
    je      ods_exit

    ; The TCP/IP transmit queue is full; Wait a bit, then retry 
    pusha
    mov     eax,5
    mov     ebx,2            ; Delay for upto 20ms
    int     0x40
    popa
    jmp     outputDataStr        
ods_exit:
    ret



;***************************************************************************
;   Function
;      printChar
;
;   Description
;       Writes a character to the screen; Used to display the data coming
;       in from the user. Really only useful for debugging.
;
;   Inputs
;       Character in bl
;
;***************************************************************************
printChar:
    cmp     bl,13                          ; BEGINNING OF LINE
    jne     nobol
    mov     ecx,[pos]
    add     ecx,1
boll1:
    sub     ecx,1
    mov     eax,ecx
    xor     edx,edx
    mov     ebx,80
    div     ebx
    cmp     edx,0
    jne     boll1
    mov     [pos],ecx
    jmp     newdata
nobol:

    cmp     bl,10                            ; LINE DOWN
    jne     nolf
addx1:
    add     [pos],dword 1
    mov     eax,[pos]
    xor     edx,edx
    mov     ecx,80
    div     ecx
    cmp     edx,0
    jnz     addx1
    mov     eax,[pos]
    jmp     cm1
nolf:

    cmp     bl,8                            ; BACKSPACE
    jne     nobasp
    mov     eax,[pos]
    dec     eax
    mov     [pos],eax
    mov     [eax+text],byte 32
    mov     [eax+text+60*80],byte 0
    jmp     newdata
nobasp:

    cmp     bl,15                           ; CHARACTER
    jbe     newdata
putcha:
    mov     eax,[pos]
    mov     [eax+text],bl
    mov     eax,[pos]
    add     eax,1