%include "simple_io.inc"

global asm_main

section .data

err1: db "incorrect number of command line arguments",10,0
err2: db "incorrect length of the argument",10,0
err3: db "inccorect first letter of the argument (should be an upper case letter)",10,0
err4: db "inccorect second letter of the argument (should be 3 or 5 or 7 or 9)",10,0

section .bss

section .text

len:
    push    rbx
    mov     rcx,0
    dec     rbx
    count:
        inc     rcx
        inc     rbx
        cmp     byte[rbx],0
        jnz     count
    dec     rcx
    pop     rbx
    ret

display_line:
    enter   0,0
    saveregs

    mov	    r12, qword [rbp+16] ;; char
    mov     r13, qword [rbp+24] ;; q
    mov     r14, qword [rbp+32] ;; p

    mov     rcx, r13

    cmp     r13, 0
    je      skip_spaces
    display_spaces:
        mov     rax, ' '
        call    print_char
        loop    display_spaces

    skip_spaces:

    mov     rcx, r14
    cmp     r14, 0
    je      skip_chars
    display_chars:
        mov     rax, r12
        call    print_char
        loop display_chars

    skip_chars:

    restoregs
    leave
    ret

display_shape:
    enter   0,0
    saveregs

    mov	    r15, qword [rbp+24] ;; size
    mov     r13, qword [rbp+32] ;; char

    mov     rdx, 0
    mov     r12, 2
    div     r12

    mov     r14, rax ;;q

    mov     rax, r15
    sub     rax, r14
    mov     r12, rax ;;p
    mov     rcx, r14 ;;q for counter
    mov     rbx, r12
    inc     rcx
    print_lines:
        push    rbx ;;p
        dec     rcx
        push    rcx ;;q
        push    r13 ;;char
        call    display_line
        add     rsp, 24
        call    print_nl
        inc     rbx
        inc     rcx
        loop print_lines

    restoregs
    leave
    ret

asm_main:
    ;;Saving regs
    enter 0,0
    saveregs

    ;;Checking number of params
    cmp     rdi, qword 2
    jne     ERR1

    ;;Checking first param length
    mov     rbx, qword [rsi+8]
    call    len
    cmp     rcx, 2
    jne     ERR2

    ;;Checking If first byte is a Upper case letter
    mov     rbx, qword [rsi+8]
    cmp     byte[rbx], 'A'
    jb      ERR3

    cmp     byte[rbx], 'Z'
    ja      ERR3

    ;;Checking If second byte is a nubmer
    cmp     byte[rbx+1], '0'
    jb      ERR4

    cmp     byte[rbx+1], '9'
    ja      ERR4

    ;;Converting from string to integer
    movzx   rax, byte[rbx+1]
    sub     rax, '0'

    ;;Checking if number is odd
    push    rax
    mov     rdx, 0
    mov     rcx, 2
    div     rcx
    cmp     rdx, 1
    jne     ERR4
    pop     rax

    ;;Removing 1 from case of odd numbers
    cmp     rax, 1
    je      ERR4

    ;;Moving char and digits
    movzx   rdx, byte[rbx]
    mov     rbx, rax

    ;;Pushing parameters for display_shape
    push    rdx
    push 	rbx
    sub     rsp, 8
    call    display_shape
    add	    rsp, 24

    jmp     asm_main_end

ERR1:
    mov     rax, err1
    call    print_string
    jmp     asm_main_end

ERR2:
    mov     rax, err2
    call    print_string
    jmp     asm_main_end

ERR3:
    mov     rax, err3
    call    print_string
    jmp     asm_main_end

ERR4:
    mov     rax, err4
    call    print_string
    jmp     asm_main_end

asm_main_end:
    restoregs
    leave
    ret