;;; ============================================================
;;; RUN.BASIC.HERE - Desk Accessory
;;;
;;; Launches BASIC.SYSTEM with PREFIX set to the path of the
;;; current window. BYE will return to DeskTop. Looks for
;;; BASIC.SYSTEM up the directory tree from DeskTop itself.
;;; ============================================================

        .setcpu "6502"

        .include "apple2.inc"
        .include "../inc/apple2.inc"
        .include "../inc/prodos.inc"
        .include "../mgtk.inc"
        .include "../desktop.inc"
        .include "../macros.inc"

;;; ============================================================

        .org $800

;;; ============================================================

        jmp     start

;;; ============================================================

bs_path:        .res    65, 0
prefix_path:    .res    65, 0

        DEFINE_GET_FILE_INFO_PARAMS get_file_info_params, bs_path
        DEFINE_OPEN_PARAMS open_params, bs_path, $C00
        DEFINE_READ_PARAMS read_params, $2000, $BF00-$2000
        DEFINE_CLOSE_PARAMS close_params
        DEFINE_SET_PREFIX_PARAMS set_prefix_params, prefix_path
        DEFINE_QUIT_PARAMS quit_params

;;; ============================================================

        ;; Early errors - show alert and return to DeskTop
fail:   jsr JUMP_TABLE_ALERT_X
        rts

start:
        ;; Get active window's path
        jsr     get_win_path
        beq     :+
        lda     #$FA            ; "This file cannot be run" - not perfect
        bne     fail

        ;; Find BASIC.SYSTEM
:       jsr     check_basic_system
        beq     :+
        lda     #$FE            ; "BASIC.SYSTEM not found"
        bne     fail

        ;; Restore devices DeskTop may have removed
:       jsr     restore_device_list

        jsr     JUMP_TABLE_COLOR_MODE

        ;; Restore to normal state
        sta     ALTZPOFF
        lda     ROMIN2
        jsr     SETVID
        jsr     SETKBD
        jsr     INIT
        jsr     HOME
        sta     TXTSET
        sta     LOWSCR
        sta     LORES
        sta     MIXCLR
        sta     DHIRESOFF
        sta     CLRALTCHAR
        sta     CLR80VID
        sta     CLR80COL

        ;; Reformat /RAM if it was restored
        jsr     maybe_reformat_ram

        ;; Load BS
        MLI_CALL OPEN, open_params
        bcs     quit
        lda     open_params::ref_num
        sta     read_params::ref_num
        sta     close_params::ref_num

        MLI_CALL READ, read_params
        bcs     quit

        MLI_CALL CLOSE, close_params
        bcs     quit

        ;; Set PREFIX. Do this last; see:
        ;; https://github.com/inexorabletash/a2d/issues/95
        MLI_CALL SET_PREFIX, set_prefix_params
        bcs     quit

        ;; Launch
        jmp     $2000

        ;; Late errors - QUIT, which should relaunch DeskTop
quit:   MLI_CALL QUIT, quit_params


;;; ============================================================

        DEFINE_GET_PREFIX_PARAMS get_prefix_params, bs_path

.proc check_basic_system
        ;; Was DeskTop copied to a RAM Card?
        jsr     get_copied_to_ramcard_flag
        bpl     get_current_prefix ; nope

        ;; Use original location, since BASIC.SYSTEM was unlikely
        ;; to be copied.
        addr_call copy_desktop_orig_prefix, bs_path
        jmp     got_prefix

get_current_prefix:
        axy_call JUMP_TABLE_MLI, GET_PREFIX, get_prefix_params
        bne     no_bs

got_prefix:
        lda     bs_path
        sta     path_length

        ;; Append BASIC.SYSTEM to path and check for file.
loop:   ldx     path_length
        ldy     #0
:       inx
        iny
        copy    str_basic_system,y, bs_path,x
        cpy     str_basic_system
        bne     :-
        stx     bs_path

        axy_call JUMP_TABLE_MLI, GET_FILE_INFO, get_file_info_params
        bne     not_found
        rts

        ;; Pop off a path segment and try again.
not_found:
        ldx     path_length
        dex
:       lda     bs_path,x
        cmp     #'/'
        beq     found_slash
        dex
        bne     :-

found_slash:
        cpx     #1
        beq     no_bs
        stx     path_length
        jmp     loop

no_bs:  return  #1

        ;; length of directory path e.g. "/VOL/DIR/"
path_length:
        .byte   0

str_basic_system:
        PASCAL_STRING "BASIC.SYSTEM"
.endproc

;;; ============================================================

.proc get_win_path
        ptr := $06

        yax_call JUMP_TABLE_MGTK_RELAY, MGTK::FrontWindow, ptr
        lda     ptr             ; any window open?
        beq     fail
        cmp     #9              ; windows are 1-8
        bcs     fail

        asl     a               ; window index * 2
        tay
        copy16  path_table,y, ptr

        ldy     #0
        lda     (ptr),y
        tay
:       copy    (ptr),y, prefix_path,y
        dey
        bpl     :-
        return  #0

fail:   return  #1

.endproc

;;; ============================================================

.proc get_copied_to_ramcard_flag
        sta     ALTZPOFF
        lda     LCBANK2
        lda     LCBANK2
        lda     copied_to_ramcard_flag
        tax
        sta     ALTZPON
        lda     LCBANK1
        lda     LCBANK1
        txa
        rts
.endproc

.proc copy_desktop_orig_prefix
        stax    @destptr
        sta     ALTZPOFF
        lda     LCBANK2
        lda     LCBANK2

        ldx     desktop_orig_prefix
:       lda     desktop_orig_prefix,x
        @destptr := *+1
        sta     $1234,x
        dex
        bpl     :-

        sta     ALTZPON
        lda     LCBANK1
        lda     LCBANK1
        rts
.endproc

;;; ============================================================

.proc restore_device_list
        ldx     devlst_backup
        inx
:       copy    devlst_backup,x, DEVLST-1,x
        dex
        bpl     :-
        rts
.endproc

;;; ============================================================

.proc maybe_reformat_ram
        ram_unit_number = (1<<7 | 3<<4 | DT_RAM)

        ;; Search DEVLST to see if S3D2 RAM was restored
        ldx     DEVCNT
:       lda     DEVLST,x
        cmp     #ram_unit_number
        beq     format
        dex
        bpl     :-
        rts

        ;; NOTE: Assumes driver (in DEVADR) was not modified
        ;; when detached.

        ;; /RAM FORMAT call; see ProDOS 8 TRM 5.2.2.4 for details
format: copy    #DRIVER_COMMAND_FORMAT, DRIVER_COMMAND
        copy    #ram_unit_number, DRIVER_UNIT_NUMBER
        copy16  #$2000, DRIVER_BUFFER
        lda     LCBANK1
        lda     LCBANK1
        jsr     driver
        sta     ROMIN2
        rts

RAMSLOT := DEVADR + $16         ; Slot 3, Drive 2

driver: jmp     (RAMSLOT)
.endproc