; Input Module
; ---------------------------------------------------------------------------

    INCDIR  "c:/Users/capitano/Documents/giochino/"
    INCLUDE "custom.i"

    ; XDEF    ReadInput
    ; XDEF    LastKey

    ; SECTION Code,CODE_C

; ReadInput
; Returns: d0 = Raw Keycode (or 0 if no key)
; Preserves: d1-a6
ReadInput:
    movem.l d1-d2/a0,-(sp)
    
    ; Check if LastKey is still pending (not yet processed)
    move.b  LastKey,d0
    cmp.b   #0,d0
    bne.s   .done           ; Still has unprocessed key, don't read new one
    
    ; Simple keyboard matrix scan for keys '1' and '2'
    ; Key '1' = Row 0, Column 1 (raw code $01)
    ; Key '2' = Row 0, Column 2 (raw code $02)
    
    lea     $bfe001,a0      ; CIAA base
    
    ; Set all rows to output, columns to input
    move.b  #$ff,$bfe201    ; CIAA DDRA (all output)
    move.b  #$00,$bfe301    ; CIAA DDRB (all input)
    
    ; Scan Row 0 (contains keys 1 and 2)
    move.b  #$fe,$bfe001    ; Set row 0 low (active), others high
    nop
    nop                     ; Small delay for signal to settle
    
    move.b  $bfe101,d1      ; Read columns from Port B
    not.b   d1              ; Invert (pressed = 1)
    
    ; Check column 1 (key '1')
    btst    #1,d1
    bne.s   .key1
    
    ; Check column 2 (key '2')  
    btst    #2,d1
    bne.s   .key2
    
    ; No key pressed
    moveq   #0,d0
    bra.s   .done
    
.key1:
    move.b  #$01,d0
    move.b  d0,LastKey
    bra.s   .done
    
.key2:
    move.b  #$02,d0
    move.b  d0,LastKey
    
.done:
    movem.l (sp)+,d1-d2/a0
    rts
    
    ; TODO: Implement proper keyboard reading later
    ; The keyboard reading via CIA is complex and error-prone

    ; SECTION Data,DATA_C

LastKey:    dc.b    0