;license:MIT
;(c) 2018 by 4am
;
; Mega Attract Mode - cycle through slideshows and self-running demos
;
; Public functions
; - AttractMode
;
; Public variables
; - gAttractIndex                    ; [byte] numeric index in gAttractModeStore of next Mega-Attract Module
; - gFXIndex                         ; [byte] numeric index in gFXStore of next HGR transition effect
; - gDFXIndex                        ; [byte] numeric index in gDFXStore of next DHGR transition effect

;------------------------------------------------------------------------------
; AttractMode
; main entry point for Mega Attract Mode, which cycles through modules listed
; in ATTRACT.CONF to provide pretty visual effects and snippets of self-running
; self-terminating game demos
;
; in:    gGlobalPrefsStore must be initialized
; out:   exits to caller (note that some attract mode modules never return but
;        instead call |Reenter|, in which case this routine technically never
;        returns)
;        if this routine returns, everything is clobbered (zero page, main
;        memory, unused portions of the stack page, all registers, all flags)
;------------------------------------------------------------------------------
AttractMode
         jsr   LoadFile              ; load attract-mode configuration file at $8000
         !word kAttractModeConfFile
         jsr   ParseKeyValueList     ; parse attract-mode configuration into OKVS data structure at $6000
         !word gAttractModeStore
         !word ldrlo2                ; (ldrlo2) points to last load address, so $8000
         !byte 0

         jsr   okvs_get              ; get next attract-mode module from prefs
         !word gGlobalPrefsStore
         !word kNextAttract
         bcs   @noattract
         +STAY @attract
         jsr   okvs_get
         !word gAttractModeStore
@attract !word $FDFD                 ; SMC
         bcc   +
@noattract
         ldx   #0
+        stx   gAttractIndex

         jsr   okvs_nth              ; get filename of next attract-mode module
         !word gAttractModeStore
gAttractIndex
         !byte 0
         +STAY @key

         lda   gAttractIndex
         sta   gCurrentAttractIndex
         inc   gAttractIndex         ; increment module index for next time
         jsr   okvs_len
         !word gAttractModeStore
         cmp   gAttractIndex
         bne   +
         lda   #0
         sta   gAttractIndex
+
         lda   gAttractIndex
         sta   @nexti
         jsr   okvs_nth              ; get name of next attract-mode module
         !word gAttractModeStore
@nexti   !byte $FD                   ; SMC
         +STAY @nextattract

         jsr   okvs_update           ; save name of next attract-mode module in prefs store
         !word gGlobalPrefsStore
         !word kNextAttract
@nextattract
         !word $FDFD                 ; SMC

         jsr   SaveGlobalPreferences ; write prefs store to disk

         jsr   okvs_get
         !word gAttractModeStore
@key     !word $FDFD                 ; SMC
         +STAY PTR

         jsr   @RunNextAttractModule
         lda   $C000
         bpl   AttractMode
         rts

@RunNextAttractModule
         ldy   #1
         lda   (PTR),y
         and   #$0F
         bne   @Slideshow

; Self-running demos are loaded into main memory and executed.
; Each binary has been patched to quit on any key and jump back
; to the |Reenter| entry point.
; All demos are strictly 48K / main memory. No demo uses the
; language card or auxiliary memory.

         jsr   Home                  ; clear text screen and switch to it during loading
                                     ; to avoid seeing executable code load into the HGR page
         +LOAD_PATH kDemoDirectory
         ldy   gPathname
         sty   ProDOS_prefix
-        lda   gPathname, y
         sta   ProDOS_prefix, y
         dey
         bne   -

         +LOAD_FILE_IMM @key

         jsr   SaveScreenHoles       ; save screen hole contents in case game changes them
         jmp   copy_prelaunch

@Slideshow                           ; HGR or DHGR slideshow
         pha                         ; save module type (1=HGR title, 2=HGR action, 3=DHGR title)

         ; load slideshow configuration file at $4000
         +LOAD_FILE kAttractModeSlideshowDirectory, @key

         jsr   ParseKeyValueList     ; parse slideshow configuration into an OKVS data structure at $0800
         !word gSlideshowStore
         !word ldrlo2                ; (ldrlo2) points to address of last loaded file, so $4000
         !byte 0

         pla                         ; restore module type
         asl
         tax
         lda   @slideshows-2,x
         sta   @jmp+1
         lda   @slideshows-1,x
         sta   @jmp+2
@jmp     jmp   $FDFD                 ; SMC
@slideshows
         !word HGRTitleSlideshow
         !word HGRActionSlideshow
         !word DHGRTitleSlideshow
         !word SHRArtworkSlideshow

kAttractModeConfFile
         !byte @kAttractModeConfFile_e-*-1
         !text "ATTRACT.CONF"
@kAttractModeConfFile_e

;------------------------------------------------------------------------------
; internal functions

;------------------------------------------------------------------------------
; Home
; clear and display text screen
;
; in:    none
; out:   $0106..$011F clobbered
;------------------------------------------------------------------------------
Home
         ldx   #(@end-@start-1)
-        lda   @start,x
         sta   $106,x
         dex
         bpl   -
         jmp   $106
@start
         ; this will be run from main memory
         +READ_ROM_NO_WRITE
         sta   $C00C                 ; get out of DHGR mode
         sta   $C05F                 ; get out of DHGR mode
         jsr   $FB2F                 ; TEXT
         jsr   $FC58                 ; HOME
         +READ_RAM1_WRITE_RAM1
         lda   MachineStatus
         and   #SUPPORTS_SHR
         beq   @noSHR
         lda   $C029
         and   #$7F
         sta   $C029                 ; get out of SHR mode
@noSHR
         rts
@end