section .data
    health db 100
    dmg db 5

    newline db 0xA,0x0
    com db 'Command? ',0x0
    fullstr db 'You have full health.',0x0
    medstr db 'You have medium health.',0x0
    lowstr db 'You have low health.',0x0
    deadstr db 'You have died!',0x0
    welcome db 'Welcome to my adventure!',0x0
    encounterstr db 'You see a monster.',0x0

section .bss
    input resb 32 ;input buffer

section .text
    global _start

_start:
    call init

    mov rdi,welcome
    call println
    call tellHealth

    jmp exit

init:
    mov r9,health;health
    mov r10,dmg;damage
    ret

tellHealth: ;inform the player of how much health they have
    cmp r9,25
    jz .nohealth
    jle .lowhealth
    cmp r9,50
    jge .medhealth
.fullhealth:
    mov rdi,fullstr
    call println
    ret
.nohealth:
    mov rdi,deadstr
    call println
    jmp exit
.lowhealth:
    mov rdi,lowstr
    call println
    ret
.medhealth:
    cmp r9,100
    je .fullhealth
    mov rdi,medstr
    call println
    ret


encounter: ;monster encounter
    mov rdi,encounterstr
    call println

getCom: ;get command from user
    mov rdi,com
    call print
    call getInput

getInput: ;get input from stdin and store in input buffer
    mov rax,0
    mov rdi,0
    mov rsi,input
    mov rdx,16
    syscall
    ret

print:;print without newline
    push rdi
    call strlen
    mov rdi,1
    pop rsi
    mov rdx,rax
    mov rax,1
    syscall
    ret

println:;print with a newline
    call print
    mov rdi,newline
    call print
    ret

strlen: ;get length of strings that end with 0x0
    xor rax,rax ;zero rax
.strlen_loop:
    cmp BYTE [rdi + rax],0x0
    je .strlen_break
    inc rax
    jmp .strlen_loop
.strlen_break:
    inc rax
    ret

exit:
    mov rax,60
    mov rdi,0
    syscall

errExit:
    mov rax,60
    mov rdi,1
    syscall