extern crate cc;

use std::fs::File;
use std::io::{Result, Write};

fn main() {
	println!("cargo:rerun-if-env-changed=LOG");
	println!("cargo:rerun-if-env-changed=BOARD");
	println!("cargo:rerun-if-env-changed=SFSIMG");

	let arch: String = std::env::var("ARCH").unwrap();
	let board: String = std::env::var("BOARD").unwrap();
	match arch.as_str() {
		"x86_64" => {
			gen_vector_asm().unwrap();
		}
		"riscv32" => {
		}
		"riscv64" => {
		}
		"mipsel" => {
			gen_dtb_asm().unwrap();
		}
		"aarch64" => {
		}
		_ => panic!("Unknown arch {}", arch),
	}
}

fn gen_vector_asm() -> Result<()> {
	let mut f = File::create("src/arch/x86_64/interrupt/vector.asm").unwrap();

	writeln!(f, "# generated by build.rs - do not edit")?;
	writeln!(f, ".section .text")?;
	writeln!(f, ".intel_syntax noprefix")?;
	for i in 0..256 {
		writeln!(f, "vector{}:", i)?;
		if !(i == 8 || (i >= 10 && i <= 14) || i == 17) {
			writeln!(f, "\tpush 0")?;
		}
		writeln!(f, "\tpush {}", i)?;
		writeln!(f, "\tjmp __alltraps")?;
	}

	writeln!(f, "\n.section .rodata")?;
	writeln!(f, ".global __vectors")?;
	writeln!(f, "__vectors:")?;
	for i in 0..256 {
		writeln!(f, "\t.quad vector{}", i)?;
	}
	Ok(())
}


fn gen_dtb_asm() -> Result<()> {
	let arch = std::env::var("ARCH").unwrap();
    let dtb = std::env::var("DTB").unwrap();
	let board = std::env::var("BOARD").unwrap();

    if !Path::new(&dtb).is_file() {
        panic!("DTB `{}` not found", dtb)
    }

	let mut f = File::create(format!("src/arch/{}/boot/dtb.S", arch)).unwrap();

    println!("cargo:rerun-if-changed={}", dtb);
    println!("cargo:rerun-if-env-changed=DTB");

	writeln!(f, "# generated by build.rs - do not edit")?;
	writeln!(f, ".intel_syntax noprefix")?;
	write!(f, r#"
    .section .dtb,"a"
    .align 12
    .global _dtb_start, _dtb_end
_dtb_start:
    .incbin "{}"
_dtb_end:
    "#, dtb)?;

    Ok(())
}