use std::collections::VecDeque;

use crate::tokenizer::{Token, TokenType};

pub fn generate(tokens: Vec<Token>) -> String {
    let mut output = String::new();

    // reserving mem
    output.push_str(
        "section .bss\n\
		data: resb 65536\n",
    );

    // global start label
    output.push_str(
        "global _start\n\
		section .text\n\
		_start:\n",
    );

    // create the pointer for our data
    output.push_str("mov rdx, data\n");

    let mut loops = 0;
    let mut stack: VecDeque<usize> = VecDeque::new();
    for token in tokens {
        match token.r#type {
            TokenType::Plus(x) => {
                output.push_str(&format!("add byte[rdx], {x}\n"));
            }
            TokenType::Minus(x) => {
                output.push_str(&format!("sub byte[rdx], {x}\n"));
            }
            TokenType::MoveRight(x) => {
                output.push_str(&format!("add rdx, {x}\n"));
            }
            TokenType::MoveLeft(x) => {
                output.push_str(&format!("sub rdx, {x}\n"));
            }
            TokenType::Output => {
                output.push_str(
                    "push rdx\n\
					mov rax, 1\n\
					mov rdi, 1\n\
					mov rsi, rdx\n\
					mov rdx, 1\n\
					syscall\n\
					pop rdx\n",
                );
            }
            TokenType::Input => {
                output.push_str(
                    "push rdx\n\
					mov rax, 0\n\
					mov rdi, 0\n\
					mov rsi, rdx\n\
					mov rdx, 1\n\
					syscall\n\
					pop rdx\n",
                );
            }
            TokenType::BracketOpen => {
                output.push_str(&format!(
                    ".loop_{loops}_start:\n\
					cmp byte[rdx], 0\n\
					je .loop_{loops}_end\n"
                ));
                stack.push_back(loops);
                loops += 1;
            }
            TokenType::BracketClose => {
                let current_loop = stack.pop_back().unwrap();
                output.push_str(&format!(
                    "cmp byte[rdx], 0\n\
					jne .loop_{current_loop}_start\n\
					.loop_{current_loop}_end:\n",
                ));
            }
        }
    }

    // exit syscall
    output.push_str(
        "mov rax, 60\n\
		mov rdi, 0\n\
		syscall\n",
    );

    output
}