( utility macros )

%INC-X { .Screen/x DEI2 #0008 ADD2 .Screen/x DEO2 } ( -- )
%INC-Y { .Screen/y DEI2 #0008 ADD2 .Screen/y DEO2 } ( -- )

%CENTER-X { .Screen/width DEI2 #01 SFT2 }
%CENTER-Y { .Screen/height DEI2 #01 SFT2 }

%MOD { DIVk MUL SUB }
%MOD2 { DIV2k MUL2 SUB2 }

%2**  { #10 SFT2 } %2// { #01 SFT2 }
%8**  { #30 SFT2 } %8// { #03 SFT2 }
%TOS  { #00 SWP }  %TOB { SWP POP }

%NEXT-TILE { DUP2 #0010 ADD2 }
%GET-USABLE-HEIGHT { .Screen/height DEI2 #0050 SUB2 #03 SFT2 SWP POP }

%RTN { JMP2r }

( devices )

|00 @System     [ &vector $2 &wst      $1 &rst    $1 &pad   $4 &r      $2 &g      $2 &b    $2 &debug  $1 &halt $1 ]
|10 @Console    [ &vector $2 &read     $1 &pad    $5 &write $1 &error  $1 ]
|20 @Screen     [ &vector $2 &width    $2 &height $2 &pad   $2 &x      $2 &y      $2 &addr $2 &pixel  $1 &sprite $1 ]
|30 @Audio0     [ &vector $2 &position $2 &output $1 &pad   $3 &adsr   $2 &length $2 &addr $2 &volume $1 &pitch $1 ]
|40 @Audio1     [ &vector $2 &position $2 &output $1 &pad   $3 &adsr   $2 &length $2 &addr $2 &volume $1 &pitch $1 ]
|50 @Audio2     [ &vector $2 &position $2 &output $1 &pad   $3 &adsr   $2 &length $2 &addr $2 &volume $1 &pitch $1 ]
|60 @Audio3     [ &vector $2 &position $2 &output $1 &pad   $3 &adsr   $2 &length $2 &addr $2 &volume $1 &pitch $1 ]
|80 @Controller [ &vector $2 &button   $1 &key    $1 ]
|90 @Mouse      [ &vector $2 &x        $2 &y      $2 &state $1 &wheel  $1 ]
|a0 @File       [ &vector $2 &success  $2 &offset-hs $2 &offset-ls $2 &name   $2 &length $2 &load $2 &save   $2 ]
|b0 @DateTime   [ &year   $2 &month    $1 &day    $1 &hour  $1 &minute $1 &second $1 &dotw $1 &doty   $2 &isdst $1 ]

( variables )

|0000

@state $1
@ticker $1
@anim-speed $1

@logo-coords [
  &x $2
  &y $2
]

@list-len $2
@list-offset $1
@list-elem-offset $1
@list-top $1
@list-height $1
@select-index $1
@ncarts $1
@btn-state $1
@sb-len $1
@sb-pos $1
@sb-step $1

@cart $32
@realm $32

( program )

|0100 
@init ( -> )

  ( steppewnolf-dark theme ) 
  #02c1 .System/r DEO2 
  #02cd .System/g DEO2 
  #02cb .System/b DEO2

  ( load individual sprites from the main sheet )
  ;spritesheet .File/name DEO2
  #0100 .File/length DEO2

	( logos )
  #0000 .File/offset-ls DEO2
  ;uxn-logo .File/load DEO2
  
  #0200 .File/offset-ls DEO2
  ;xrxs-logo .File/load DEO2

  ( buttons )
  #00c0 .File/length DEO2
  #0400 .File/offset-ls DEO2
  ;yes-btn .File/load DEO2

  #04c0 .File/offset-ls DEO2
  ;yes-btn-active .File/load DEO2

  #0600 .File/offset-ls DEO2
  ;no-btn .File/load DEO2

  #06c0 .File/offset-ls DEO2
  ;no-btn-active .File/load DEO2

  ( scrollbar )
  #0010 .File/length DEO2
  #0800 .File/offset-ls DEO2
  ;scroll-down-btn .File/load DEO2

  #0810 .File/offset-ls DEO2
  ;scroll-up-btn .File/load DEO2

  #0820 .File/offset-ls DEO2
  ;scrollbar .File/load DEO2

  #0830 .File/offset-ls DEO2
  ;scrollbar-trough .File/load DEO2

  ( load zz font )
  ;fontsheet .File/name DEO2
  #0000 .File/offset-ls DEO2
  #0300 .File/length DEO2
  ;font .File/load DEO2

  ( initialize state )
  #00 .ticker STZ
  #00 .state STZ
  #00 .select-index STZ
  #20 .anim-speed STZ
  #ff .btn-state STZ
  GET-USABLE-HEIGHT .list-height STZ
  
  CENTER-X .logo-coords/x STZ2
  CENTER-Y .logo-coords/y STZ2
  
  ;on-frame .Screen/vector DEO2
  
BRK

@on-frame ( -> )

  .ticker LDZ #01 ADD
  DUP .anim-speed LDZ EQU ,&next-render JCN
  .ticker STZ
  BRK
  
  &next-render
  POP #00 .ticker STZ
  .state LDZ
  
  ( draw uxn logo )
  DUP #00 NEQ ,&state1 JCN
    ;draw-uxn-logo JSR2
    INC .state STZ
  BRK
  
  ( draw first syllable of xrxs logo )
  &state1 DUP #01 NEQ ,&state2 JCN
    ;draw-xrxs-logo-xr JSR2
    INC .state STZ
  BRK
  
  ( draw second syllable of xrxs logo )
  &state2 DUP #02 NEQ ,&state3 JCN
    ;draw-xrxs-logo-xs JSR2
    
    INC .state STZ
  BRK
  
  ( clear screen )
  &state3
    ;clear-screen JSR2
  
  ( move shove logo into top-left corner )
    DUP #03 NEQ ,&state4 JCN
    #04 .anim-speed STZ
    ;scoot-logos JSR2
    ;draw-uxn-logo JSR2
    ;draw-xrxs-logo-xr JSR2
    ;draw-xrxs-logo-xs JSR2
    .logo-coords/x LDZ2 #0020 GTH2 ,&keep-state JCN
      ;carts-file .File/name DEO2
      #2000 .File/length DEO2
      ;list-buf .File/load DEO2
      .File/success DEI2 .list-len STZ2
      INC .state STZ 
      ;get-select-idx-by-mouse .Mouse/vector DEO2
      ;get-select-idx-by-key .Controller/vector DEO2 BRK
    &keep-state POP
  BRK
  
  ( render the cartridge list interface )
  &state4 DUP #04 NEQ ,&state5 JCN
    ;draw-gray-borders JSR2
    ;draw-bl-scanlines JSR2
    ;draw-tl-scanlines JSR2
    ;draw-tr-scanlines JSR2
    ;draw-br-scanlines JSR2
    ;draw-uxn-logo JSR2
    ;draw-xrxs-logo-xr JSR2
    ;draw-xrxs-logo-xs JSR2
    [ ;title-loadCart
      CENTER-X OVR2 ;strlen JSR2 #20 SFT2 SUB2
      #0010
      #02 ] ;draw-string JSR2
    ;render-cart-list JSR2
    ;draw-scrollbar JSR2
    ;draw-pointer JSR2
    POP
  BRK

  ( confirm the selected cartridge )
  &state5 DUP #05 NEQ ,&state6 JCN
    ;draw-gray-borders JSR2
        ;draw-bl-scanlines JSR2
        ;draw-tl-scanlines JSR2
        ;draw-tr-scanlines JSR2
        ;draw-br-scanlines JSR2
        ;draw-uxn-logo JSR2
        ;draw-xrxs-logo-xr JSR2
        ;draw-xrxs-logo-xs JSR2
        [ ;title-confirmCart
          CENTER-X OVR2 ;strlen JSR2 #20 SFT2 SUB2
          #0010
          #02 ] ;draw-string JSR2
        ;render-cart-list JSR2
        ;draw-scrollbar JSR2
        ;draw-confirm-buttons JSR2
        ;draw-pointer JSR2
        POP
      BRK
  &state6 POP
  
BRK

@clear-screen ( -> )
 
  .Screen/width DEI2 #0000 &whilex EQU2k ,&endx JCN
    DUP2 ,&x STR2
    .Screen/height DEI2 #0000 &whiley EQU2k ,&endy JCN
      DUP2 ,&y STR2
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      ;blank .Screen/addr DEO2
      #10 .Screen/sprite DEO
      #40 .Screen/sprite DEO
    #0008 ADD2 ,&whiley JMP &endy POP2 POP2
  #0008 ADD2 ,&whilex JMP &endx POP2 POP2
  
RTN
&x $2
&y $2

@scoot-logos ( -> )

  .logo-coords/x LDZ2 #0021 LTH2 ,&no-scoot-x JCN
    .logo-coords/x LDZ2 #01 SFT2
    .logo-coords/x STZ2
  &no-scoot-x
  
  .logo-coords/y LDZ2 #0021 LTH2 ,&no-scoot-y JCN
    .logo-coords/y LDZ2 #01 SFT2
    .logo-coords/y STZ2
  &no-scoot-y

RTN

@draw-uxn-logo ( -> )

  .logo-coords/x LDZ2 #0020 SUB2 .Screen/x DEO2
  .logo-coords/y LDZ2 #0010 SUB2 .Screen/y DEO2
  
  #0100 #0000 &while EQU2k ,&end JCN
    DUP2 ;uxn-logo ADD2 .Screen/addr DEO2
    #c1 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0030 AND2 #0000 NEQ2 ,&no-inc-y JCN
      .logo-coords/x LDZ2 #0020 SUB2 .Screen/x DEO2
      INC-Y
    &no-inc-y
  #0010 ADD2 ,&while JMP &end POP2 POP2
  
RTN

@draw-xrxs-logo-xr ( -> )

  .logo-coords/x LDZ2 .Screen/x DEO2
  .logo-coords/y LDZ2 #0010 SUB2 .Screen/y DEO2
  
  #0080 #0000 &while EQU2k ,&end JCN
    DUP2 ;xrxs-logo ADD2 .Screen/addr DEO2
    #c1 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0030 AND2 #0000 NEQ2 ,&no-inc-y JCN
      .logo-coords/x LDZ2 .Screen/x DEO2
      INC-Y
    &no-inc-y
  #0010 ADD2 ,&while JMP &end POP2 POP2
  
RTN

@draw-xrxs-logo-xs ( -> )

  .logo-coords/x LDZ2 .Screen/x DEO2
  .logo-coords/y LDZ2 .Screen/y DEO2
  
  #0100 #0080 &while EQU2k ,&end JCN
    DUP2 ;xrxs-logo ADD2 .Screen/addr DEO2
    #c1 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0030 AND2 #0000 NEQ2 ,&no-inc-y JCN
      .logo-coords/x LDZ2 .Screen/x DEO2
      INC-Y
    &no-inc-y
  #0010 ADD2 ,&while JMP &end POP2 POP2
  
RTN

@draw-gray-borders ( -> )

  ;blank .Screen/addr DEO2
  #0028 #0000 &whilemtop EQU2k ,&endmtop JCN
    DUP2 .Screen/y DEO2
    .Screen/width DEI2 #0000 &whiletop EQU2k ,&endtop JCN
      DUP2 .Screen/x DEO2
      #84 .Screen/sprite DEO
    #0008 ADD2 ,&whiletop JMP &endtop POP2 POP2
  #0008 ADD2 ,&whilemtop JMP &endmtop POP2 POP2
  
  #0040 #0000 &whilemleft EQU2k ,&endmleft JCN
    DUP2 .Screen/x DEO2
    .Screen/height DEI2 #0028 SUB2 #0028 &whileleft EQU2k ,&endleft JCN
      DUP2 .Screen/y DEO2
      #84 .Screen/sprite DEO
    #0008 ADD2 ,&whileleft JMP &endleft POP2 POP2
  #0008 ADD2 ,&whilemleft JMP &endmleft POP2 POP2
  
  .Screen/width DEI2 DUP2 #0040 SUB2 &whilemright EQU2k ,&endmright JCN
    DUP2 .Screen/x DEO2
    .Screen/height DEI2 #0028 SUB2 #0028 &whileright EQU2k ,&endright JCN
      DUP2 .Screen/y DEO2
      #84 .Screen/sprite DEO
    #0008 ADD2 ,&whileright JMP &endright POP2 POP2
  #0008 ADD2 ,&whilemright JMP &endmright POP2 POP2
  
  .Screen/height DEI2 DUP2 #0028 SUB2 &whilembottom EQU2k ,&endmbottom JCN
    DUP2 .Screen/y DEO2
    .Screen/width DEI2 #0000 &whilebottom EQU2k ,&endbottom JCN
      DUP2 .Screen/x DEO2
      #84 .Screen/sprite DEO
    #0008 ADD2 ,&whilebottom JMP &endbottom POP2 POP2
  #0008 ADD2 ,&whilembottom JMP &endmbottom POP2 POP2
  
RTN
    

( come up with a more elegant way to draw these )

@draw-bl-scanlines ( -> )
  CENTER-Y ,&y STR2
  #0008 ,&x STR2
  
  &whileld
  ,&y LDR2 CENTER-Y SUB2 #04 SFT2 DUP2 ADD2 #0008 ADD2 ,&x STR2
  .Screen/height DEI2 #0028 SUB2 ,&y LDR2  LTH2 ,&endld JCN 
    &dlscan #0040 ,&x LDR2 EQU2 ,&enddlscan JCN
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      #03 .Screen/pixel DEO
    ,&x LDR2 #0001 ADD2 ,&x STR2 ,&dlscan JMP &enddlscan
  ,&y LDR2 #0004 ADD2 ,&y STR2 ,&whileld JMP &endld

RTN
&x $2
&y $2

@draw-tl-scanlines
  #0028 ,&y STR2
  #0008 ,&x STR2
  
  &whilelu
  CENTER-Y ,&y LDR2 SUB2 #04 SFT2 DUP2 ADD2 #0008 ADD2 ,&x STR2
  CENTER-Y ,&y LDR2  LTH2 ,&endlu JCN 
    &ulscan #0040 ,&x LDR2 EQU2 ,&endulscan JCN
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      #03 .Screen/pixel DEO
    ,&x LDR2 #0001 ADD2 ,&x STR2 ,&ulscan JMP &endulscan
  ,&y LDR2 #0004 ADD2 ,&y STR2 ,&whilelu JMP &endlu

RTN
&x $2
&y $2
  
@draw-br-scanlines ( -> )
  CENTER-Y ,&y STR2
  .Screen/width DEI2 #0008 SUB2 ,&x STR2
  
  &whilerd
  .Screen/width DEI2 #0040 SUB2 ,&x STR2
  .Screen/height DEI2 #0028 SUB2 ,&y LDR2  LTH2 ,&endrd JCN 
    &drscan .Screen/width DEI2 #0008 SUB2 ,&y LDR2 CENTER-Y SUB2 #04 SFT2 DUP2 ADD2 SUB2 ,&x LDR2 EQU2 ,&enddrscan JCN
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      #03 .Screen/pixel DEO
    ,&x LDR2 #0001 ADD2 ,&x STR2 ,&drscan JMP &enddrscan
  ,&y LDR2 #0004 ADD2 ,&y STR2 ,&whilerd JMP &endrd
RTN
&x $2
&y $2

@draw-tr-scanlines
  #0028 ,&y STR2
  .Screen/width DEI2 #0008 SUB2 ,&x STR2
  
  &whileru
  .Screen/width DEI2 #0040 SUB2 ,&x STR2
  CENTER-Y ,&y LDR2 LTH2 ,&endru JCN 
    &urscan .Screen/width DEI2 #0008 SUB2 CENTER-Y ,&y LDR2  SUB2 #04 SFT2 DUP2 ADD2 SUB2 ,&x LDR2 EQU2 ,&endurscan JCN
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      #03 .Screen/pixel DEO
    ,&x LDR2 #0001 ADD2 ,&x STR2 ,&urscan JMP &endurscan
  ,&y LDR2 #0004 ADD2 ,&y STR2 ,&whileru JMP &endru

RTN
&x $2
&y $2


@draw-pointer ( -> )

  ;cursor .Screen/addr DEO2

  .Mouse/x DEI2 .Screen/x DEO2
  .Mouse/y DEI2 .Screen/y DEO2

  #4a .Screen/sprite DEO
  
RTN  

@draw-string ( addr x y color -- )
	
	STH ( save color )
	.Screen/y DEO2 ( set y )
	.Screen/x DEO2 ( set x )

  ( now the string address is at the top of the stack )
  &loop
    LDAk DUP #00 NEQ #20 MUL SUB TOS 8** ;font ADD2 .Screen/addr DEO2 
    STHkr .Screen/sprite DEO
    INC-X
    INC2
    LDAk #00 NEQ ,&loop JCN
  POP2
  POPr

RTN

@strlen ( addr -- len )

  DUP2
  &loop
    INC2 LDAk ,&loop JCN
  SWP2 SUB2
  
RTN

@store-char ( char -- char )

  #00 .list-elem-offset LDZ ;word ADD2 STA
  .list-elem-offset LDZ INC .list-elem-offset STZ

RTN

@shouldnt-draw-word ( -- flag )

  .list-offset LDZ .list-top LDZ LTH ,&no JCN
  .list-offset LDZ .list-top LDZ .list-height LDZ ADD #01 SUB GTH ,&no JCN
  #00 RTN 

  &no
  #01
RTN

@finish-line ( -> )

  ;get-entry-color JSR2 #02 EQU ,&end JCN
  
  &while
  .Screen/x DEI2
  .Screen/width DEI2 #0048 SUB2
  
  EQU2 ,&end JCN
    #0c .Screen/sprite DEO
    INC-X
    
  ,&while JMP &end

RTN
    
  

@render-cart-list ( -> )

  #0040 .Screen/x DEO2
  #0028 .Screen/y DEO2

  #00 .list-offset STZ
  .list-len LDZ2 #0000 &while EQU2k ,&end JCN
    ( get a character from the list )
    DUP2 ;list-buf ADD2 LDA
    
    ( if null byte, terminate loop )
    DUP #00 EQU ,&end JCN
    
    ( if not newline, store the character and increment the offsets )
    DUP #0a EQU ,&inc-line JCN
      ;store-char JSR2
    ,&continue JMP ( continue looping )
    
    ( if newline, print the word, increment x, reset y )
    ( clear the word and word offsets, increment the buffer offset )
    &inc-line
      #00 .list-elem-offset LDZ ;word ADD2 STA
      ( if the word isn't in the scroll window, don't draw it )
      ;shouldnt-draw-word JSR2 ,&no-draw JCN
      [ ;word
        .Screen/x DEI2
        .Screen/y DEI2
        ;get-entry-color JSR2 ] ;draw-string JSR2
      ;finish-line JSR2
      #0040 .Screen/x DEO2
      INC-Y
      &no-draw
      .list-offset LDZ INC .list-offset STZ
      
      #20 #00 &word_clr EQUk ,&end-clr JCN
        #00 OVR SWP DUP ROT ;word ADD2 STA
      INC ,&word_clr JMP &end-clr POP2
      #00 .list-elem-offset STZ
    &continue INC2 ,&while JMP
  &end .list-offset LDZ #01 SUB .ncarts STZ POP2 POP2
  
RTN

@get-entry-color ( -- colorByte )

  .list-offset LDZ
  .select-index LDZ

  NEQ ,&normal JCN

  ( selected )
    #0c RTN
  &normal
    #02

RTN

@draw-scrollbar ( -> )

  .Screen/width DEI2 #0048 SUB2 .Screen/x DEO2
  #0028 .Screen/y DEO2

  ( draw the trough no matter what )
  ;scrollbar-trough .Screen/addr DEO2
  .list-height LDZ #00
  &while-trough EQUk ,&end-trough JCN
    #81 .Screen/sprite DEO
    INC-Y
  INC ,&while-trough JMP &end-trough POP2

  ( stop here if there is no overflow )
  .ncarts LDZ .list-height LDZ LTH ,&no-handle JCN
  ,&draw-handle JMP
  
  &no-handle
  RTN

  ( if there are more carts than will fit in the view area, draw the handle )
  &draw-handle
  #0028 .Screen/y DEO2
  ( store the number of carts per tile of the scrollbar )
  .ncarts LDZ .list-height LDZ DIV .sb-step STZ

  ( set the length of the scrollbar )
  .list-height LDZ .ncarts LDZ .list-height LDZ SUB .sb-step LDZ DIV SUB .sb-len STZ

  ;scrollbar .Screen/addr DEO2
  #0028 .sb-pos LDZ #30 SFT TOS ADD2 .Screen/y DEO2
  .sb-len LDZ #00 &while-handle EQUk ,&end-handle JCN
    .Screen/y DEI2 .Screen/height DEI2 #0028 SUB2 EQU2 ,&end-handle JCN
    #81 .Screen/sprite DEO
  INC INC-Y ,&while-handle JMP &end-handle POP2
  
RTN

@get-select-idx-by-mouse ( -> )

  .Mouse/wheel DEI #00 EQU ,&no-scroll JCN
  .Mouse/wheel DEI #01 NEQ ,&scroll-down JCN
  ( scroll-up )
  ;try-scroll-up-mouse JSR2
  ,&no-scroll JMP
  
  &scroll-down
  ;try-scroll-down-mouse JSR2
  
  &no-scroll
  .Mouse/x DEI2 #0040 LTH2 ,&done JCN
  .Mouse/x DEI2 .Screen/width DEI2 #0048 SUB2 GTH2 ,&done JCN

  .Mouse/y DEI2 #0028 LTH2 ,&done JCN
  .Mouse/y DEI2 .Screen/height DEI2 #0028 SUB2 GTH2 ,&done JCN
  
  .Mouse/y DEI2 #0028 SUB2 8// TOB .list-top LDZ ADD .select-index STZ

  .Mouse/state DEI #00 EQU ,&no-click JCN
    .select-index LDZ .ncarts GTH ,&no-click JCN
    .state LDZ INC .state STZ
    ;set-button-state-by-key .Controller/vector DEO2
    ;set-button-state-by-mouse .Mouse/vector DEO2
  &no-click
  BRK
  
  &done
  #ff .select-index STZ
  
BRK

@try-scroll-up-mouse ( -> )
  .ncarts LDZ .list-height LDZ LTH ,&no-scroll-up JCN
  .list-top LDZ #00 EQU ,&no-scroll-up JCN
    .list-top LDZ #01 SUB .list-top STZ
  &no-scroll-up
  ;update-sb-pos JSR2
RTN

@try-scroll-down-mouse ( -> )
  .ncarts LDZ .list-height LDZ LTH ,&no-scroll-down JCN
  .list-top LDZ .list-height LDZ ADD .ncarts LDZ #01 ADD EQU ,&no-scroll-down JCN
    .list-top LDZ INC .list-top STZ
  &no-scroll-down
  ;update-sb-pos JSR2
RTN


@try-scroll-up ( -> )
  .select-index LDZ
  DUP .list-top LDZ NEQ ,&no-scroll-up JCN
  .list-top LDZ #00 EQU ,&no-scroll-up JCN
    .list-top LDZ #01 SUB .list-top STZ
  &no-scroll-up
  ;update-sb-pos JSR2
RTN

@try-scroll-down ( -> )
  .select-index LDZ
  DUP .list-top LDZ .list-height LDZ ADD #01 SUB NEQ ,&no-scroll-down JCN
  .list-top LDZ .list-height LDZ ADD .ncarts LDZ #01 ADD EQU ,&no-scroll-down JCN
    .list-top LDZ INC .list-top STZ
  &no-scroll-down
  ;update-sb-pos JSR2
RTN

@update-sb-pos ( -> )

  .list-top LDZ .sb-step LDZ DIV .sb-pos STZ

RTN

@get-select-idx-by-key ( -> )

  .Controller/button DEI
  
  DUP #10 NEQ ,&no-up JCN
    ;try-scroll-up JSR2
    DUP #00 EQU ,&no-dec JCN
      #01 SUB .select-index STZ
      ,&no-up JMP
    &no-dec
      POP
  &no-up
  
  DUP #20 NEQ ,&no-down JCN
    ;try-scroll-down JSR2
    DUP .ncarts LDZ EQU ,&no-inc JCN
      INC .select-index STZ
      ,&no-down JMP
    &no-inc
      POP
  &no-down

  DUP #01 NEQ ,&no-a-btn JCN
    .state LDZ INC .state STZ
    ;set-button-state-by-key .Controller/vector DEO2
    ;set-button-state-by-mouse .Mouse/vector DEO2
  &no-a-btn
  POP

BRK

@set-button-state-by-key ( -> )

  .btn-state LDZ #ff EQU ,&from-null JCN
  .btn-state LDZ #00 EQU ,&from-no JCN
  ( from yes )
    .Controller/button DEI #80 NEQ ,&check-action JCN
    #00 .btn-state STZ
    BRK
  
  &from-no
    .Controller/button DEI #40 NEQ ,&check-action JCN
    #01 .btn-state STZ
    BRK
    
  &from-null
    ( in from left )
    .Controller/button DEI #80 NEQ ,&in-from-right JCN
      #01 .btn-state STZ
      BRK
    &in-from-right
    .Controller/button DEI #40 NEQ ,&check-action JCN
      #00 .btn-state STZ
      BRK
      
  &check-action
    .Controller/button DEI #00 EQU ,&no-action JCN
      ( check A button )
      .Controller/button DEI #01 NEQ ,&check-b-button JCN
        ( A on yes )
        .btn-state LDZ #01 NEQ ,&a-on-no JCN
          ;capture-input JSR2
          #06 .state STZ
          BRK
        &a-on-no
        .btn-state LDZ #00 NEQ ,&no-action JCN
          ;get-select-idx-by-mouse .Mouse/vector DEO2
          ;get-select-idx-by-key .Controller/vector DEO2
          #04 .state STZ
          BRK
        
      &check-b-button
      .Controller/button DEI #02 NEQ ,&no-action JCN
        ;get-select-idx-by-mouse .Mouse/vector DEO2
        ;get-select-idx-by-key .Controller/vector DEO2
        #04 .state STZ
  &no-action

BRK

@set-button-state-by-mouse ( -> )

  ( if not in the vertical range of the buttons, quit early )
  .Mouse/y DEI2 .Screen/height DEI2 #001c SUB2 LTH2 ,&not-no JCN
  .Mouse/y DEI2 .Screen/height DEI2 #000c SUB2 GTH2 ,&not-no JCN
  

  .Mouse/x DEI2 CENTER-X #0030 SUB2 LTH2 ,&not-yes JCN
  .Mouse/x DEI2 CENTER-X GTH2 ,&not-yes JCN
  #01 .btn-state STZ
  ,&check-click JMP
  
  &not-yes

  .Mouse/x DEI2 CENTER-X LTH2 ,&not-no JCN
  .Mouse/x DEI2 CENTER-X #0030 ADD2 GTH2 ,&not-no JCN
  #00 .btn-state STZ
  ,&check-click JMP

  &not-no
  #ff .btn-state STZ BRK

  &check-click
  .Mouse/state DEI #00 EQU ,&no-click JCN
    .btn-state LDZ #00 NEQ ,&state-load JCN
      ;get-select-idx-by-mouse .Mouse/vector DEO2
      ;get-select-idx-by-key .Controller/vector DEO2
      #04 .state STZ
      BRK
    &state-load
      ;capture-input JSR2
      #06 .state STZ
  &no-click

BRK

@button-color ( bit -- sprite )

  ,&get-color-yes JCN

  ( get color no )
  .btn-state LDZ #ff EQU ,&no-inactive JCN
  .btn-state LDZ #01 EQU ,&no-inactive JCN
  ( active )
    ;no-btn-active RTN

  &no-inactive
    ;no-btn RTN
  
  
  &get-color-yes
  .btn-state LDZ #ff EQU ,&yes-inactive JCN
  .btn-state LDZ #00 EQU ,&yes-inactive JCN
    ( active )
    ;yes-btn-active RTN

  &yes-inactive
    ;yes-btn 

RTN

@draw-confirm-buttons ( -> )

  ( yes )
  .Screen/height DEI2 #001c SUB2 .Screen/y DEO2
  CENTER-X #0030 SUB2 .Screen/x DEO2

  #00c0 #0000 &while-yes EQU2k ,&end-yes JCN
    DUP2 [ #01 ;button-color JSR2 ] ADD2 .Screen/addr DEO2
    #81 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0060 NEQ2 ,&no-inc-y JCN
      CENTER-X #0030 SUB2 .Screen/x DEO2
      INC-Y
    &no-inc-y
  #0010 ADD2 ,&while-yes JMP &end-yes POP2 POP2
  
  ( no )
  .Screen/height DEI2 #001c SUB2 .Screen/y DEO2
  CENTER-X .Screen/x DEO2

  #00c0 #0000 &while-no EQU2k ,&end-no JCN
    DUP2 [ #00 ;button-color JSR2 ] ADD2 .Screen/addr DEO2
    #81 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0060 NEQ2 ,&no-inc-y-no JCN
      CENTER-X .Screen/x DEO2
      INC-Y
    &no-inc-y-no
  #0010 ADD2 ,&while-no JMP &end-no POP2 POP2

RTN

@capture-input ( -> )

  ;no-instr .Mouse/vector DEO2
  ;no-instr .Controller/vector DEO2

RTN

@no-instr BRK

( constants )
@spritesheet "xrxs.chr 00
@fontsheet "zz.chr 00
@carts-file "n/carts 00
@title-loadCart "Select 20 "A 20 "Cartridge 00
@title-confirmCart "Load 20 "This 20 "Cartridge? 00

( sprites )
@blank $16
@uxn-logo $256
@xrxs-logo $256
@yes-btn $192
@no-btn $192
@yes-btn-active $192
@no-btn-active $192
@scroll-up-btn $16
@scroll-down-btn $16
@scrollbar $16
@scrollbar-trough $16
@cursor [ 80c0 e0f0 f8e0 1000 ]
@font $768

( big data )
@word [ #0000 #0000 #0000 #0000
        #0000 #0000 #0000 #0000
        #0000 #0000 #0000 #0000
        #0000 #0000 #0000 #0000 ]
@list-buf $8192