vas.v

module main

import os
import flag
import lexer
import encoder
import elf
import macho
import pe

fn file_name_without_ext(file_name string) string {
	ext_len := os.file_ext(file_name).len
	bytes := file_name.bytes()
	return if file_name == '-' {
		'main'
	} else {
		bytes[..bytes.len - ext_len].bytestr()
	}
}

fn main() {
	mut fp := flag.new_flag_parser(os.args)
	fp.application('vas')
	fp.version('v0.0.0')
	fp.skip_executable()
	mut out_file  := fp.string('o', `o`, 'out_file_none', 'set output file name')
	keep_locals   := fp.bool('keep-locals', 0, false, 'keeps local symbols (e.g., those starting with `.L`)')
	format_flag   := fp.string('format', `f`, 'auto', 'output format: elf or macho (default: auto-detect from OS)')

	additional_args := fp.finalize() or {
		println(fp.usage())
		return
	}

	if additional_args.len < 1 {
		println(fp.usage())
		return
	}

	file_name := additional_args[0]

	if out_file == 'out_file_none' {
		out_file = file_name_without_ext(file_name) + '.o'
	}

	program := if file_name == '-' {
		os.get_raw_lines_joined()
	} else {
		os.read_file(file_name) or {
			eprintln('error: reading file `${file_name}`')
			exit(1)
		}
	}

	effective_format := if format_flag == 'auto' {
		if os.user_os() == 'macos' { 'macho' } else if os.user_os() == 'windows' { 'pe' } else { 'elf' }
	} else {
		format_flag
	}

	valid_formats := ['elf', 'macho', 'pe']
	if effective_format !in valid_formats {
		eprintln('error: unknown format `${effective_format}` — valid values: ${valid_formats.join(', ')}')
		exit(1)
	}

	mut l := lexer.new(file_name, program)
	mut en := encoder.new(mut l, file_name)
	en.encode()
	en.assign_addresses()

	if effective_format == 'macho' {
		mut m := macho.new(out_file, keep_locals, en.rela_text_users, en.user_defined_sections, en.user_defined_symbols)
		m.collect_rela_symbols()
		m.build_symtab_strtab()
		m.build_relocations()
		m.write_macho()
	} else if effective_format == 'pe' {
		mut p := pe.new(out_file, keep_locals, en.rela_text_users, en.user_defined_sections, en.user_defined_symbols)
		p.collect_rela_symbols()
		p.build_symtab_strtab()
		p.build_relocations()
		p.write_pe()
	} else {
		mut e := elf.new(out_file, keep_locals, en.rela_text_users, en.user_defined_sections, en.user_defined_symbols)
		e.collect_rela_symbols()
		e.build_symtab_strtab()
		e.rela_text_users()
		e.build_shstrtab()
		e.build_headers()
		e.write_elf()
	}
}