global _start

; constants
SYS_READ        equ 0
SYS_WRITE       equ 1
SYS_POLL        equ 7
SYS_SENDFILE    equ 40
SYS_SOCKET      equ 41
SYS_ACCEPT      equ 43
SYS_BIND        equ 49
SYS_LISTEN      equ 50
SYS_EXIT        equ 60
SYS_FCNTL       equ 72
SYS_UNLINK      equ 87
STDOUT          equ 1
AF_UNIX         equ 1
SOCK_STREAM     equ 1
F_GETFL         equ 3
F_SETFL         equ 4
O_NONBLOCK      equ 2048
POLLIN          equ 1
POLLOUT         equ 4

pollfd_size equ 4 + 2 + 2  ; $ man 2 poll
pollfds_capacity equ 100

SECTION .data
server_path     db "server.sock", 0x00
server_path_len equ $ - server_path
sockaddr_size   equ 2 + 108  ; $ man 7 unix

SECTION .bss
sockaddr    resb sockaddr_size
pollfds     resb pollfd_size * pollfds_capacity

SECTION .text

%include "server.s"

_start:
    call make_server
    mov rbx, 0  ; pollfd array length
    mov ebp, eax  ; server fd

    mov rax, rbx
    mov edi, ebp
    mov si, POLLIN
    call pollfds__append
    mov rbx, rax

poll:
    mov rax, SYS_POLL
    mov rdi, pollfds
    mov rsi, rbx
    mov rdx, 5000
    syscall
    cmp rax, 0
    je poll
    jl exit

exit:
    mov rax, SYS_EXIT
    mov rdi, 0
    syscall

accept:
    mov rdi, rax
    mov rax, SYS_ACCEPT
    mov rsi, 0
    mov rdx, 0
    syscall
    ret

; rax - array length
; edi - fd
; si - events
; Returns new array length in rax
pollfds__append:
    mov [pollfds + rax], edi
    mov [pollfds + rax + 4], si
    add rax, 1
    ret

; Returns new array length in rax
; rax - array length
; edi - fd
pollfds__remove:
    mov r10d, edi
    mov rdi, 0

; Variables:
; rax - array length
; rdi - array index
; r10d - fd
; r11d - pollfds[rdi].fd
pollfds__remove__loop:
    cmp rdi, rax
    jge return  ; fd was not found
    mov r11d, [pollfds + rdi * pollfd_size]
    add rdi, 1
    cmp r11d, r10d
    jne pollfds__remove__loop
    sub rdi, 1

; Returns new array length in rax
; rax - array length
; rdi - array index to remove
pollfds__remove_index:
    cmp rax, 1
    jle pollfds__clear
    mov r10d, [pollfds + (rax - 1) * pollfd_size]
    mov [pollfds + rdi * pollfd_size], r10d
    sub rax, 1
    ret

; Returns new array length in rax
; rax - array length
pollfds__clear:
    mov rax, 0
    ret

return:
    ret