; The OS/K Team licenses this file to you under the MIT license.
; See the LICENSE file in the project root for more information.

N := 11

builtins.dir:
    push rbp
    mov rbp, rsp

    push r12
    push r13

    mov r12, zero        # no. of files found

    call print, .dirmsg

.first:
    mov rax, Sys.FindFirst
    mov ax0, .buf
    mov ax1, FNAME_MAX
    trap 0

    jmp .list

.next:
    mov rax, Sys.FindNext
    mov ax0, .buf
    mov ax1, FNAME_MAX
    trap 0

.list:
    mov r13, rcx        # file size

    jmp.axz .end

    ; found something
    inc r12, 1

    ; directory?
    jmp.dxnz .is_dir

    ; separate extension from file name
    mov rcx, FNAME_MAX
    mov rsi, .buf
    mov rdi, rsi
    scasb.rep.nz rsi, '.'

    ; print file name
    sub rcx, rsi, rdi
    prns.rep rdi

    ; calculate where to put extension
    sub rdi, rsi, .buf
    dec rdi, 1

.ext_pad:
    ; print at least N non-space characters before extension
    b.ae rdi, N, .print_ext
    prn ' '
    inc rdi, 1
    jmp .ext_pad

.print_ext:
    ; here we print at least 4 characters excluding '.'
    mov rcx, 4
    prn ' '

    cmp b[rsi], '.'
    inc.z rsi, 1

.print_ext.1:
    b.z b[rsi], 0, .print_ext.2

    ; print and decrease rcx, unless it's already 0
    prn b[rsi]
    inc rsi, 1
    dec.cxnz rcx, 1

    jmp .print_ext.1

.print_ext.2:
    ; did we print at least 4 bytes?
    jmp.cxz .print_bytes    ; yes, carry on

    prn.rep ' '

.print_bytes:
    ; print file size in bytes
    mov rcx, 3
    prn.rep ' '

    shr rax, r13, 10
    and r13, r13, 1023

    push r13
    push rax
    call printf, .bytesstr
    inc rsp, 16

.prepare_next:
    ; go find next entry
    prn 10
    jmp .next

.end:
    push r12
    call printf, .endstr1
    inc rsp, 8

    call print, .endstr2

    pop r13
    pop r12

    leave
    ret

    ; special case: direcory
.is_dir:
    mov rcx, STRLEN_MAX
    mov rdx, .buf
    prns.rep.nz rdx

    sub rcx, STRLEN_MAX, rcx
    b.ae rcx, N, .is_dir.print_ext
    sub rcx, N, rcx
    prn.rep ' '

.is_dir.print_ext:
    call print, .dir_ext

    jmp .print_bytes

.buf = [FNAME_MAX]
.dir_ext = " <DIR>"
.endstr1 = "             %d file(s)\n"
.endstr2 = "             0 dir(s)\n"
.dirmsg = "Directory of C:\\\n\n"
.bytesstr = "%d kilobytes + %d bytes"