use clap::{ColorChoice, Parser};
use std::{path::PathBuf, process::ExitCode, rc::Rc};
use talc_lang::{
	compiler::compile,
	lstring::LString,
	optimize::optimize,
	parser,
	prelude::*,
	serial,
	symbol::Symbol,
	value::{function::disasm_recursive, Value},
	vm::Vm,
};

mod helper;
mod repl;

#[derive(Parser, Debug)]
#[command(version, about, long_about = None)]
struct Args {
	/// Start the repl
	#[arg(short, long)]
	repl: bool,

	/// Show disassembled bytecode
	#[arg(short, long)]
	disasm: bool,

	/// Show generated AST
	#[arg(short = 'a', long)]
	show_ast: bool,

	/// Compile to a bytecode file
	#[arg(short, long)]
	compile: Option<PathBuf>,

	/// Don't apply optimizations
	#[arg(long)]
	no_opt: bool,

	/// Set history file
	#[arg(short = 'H', long)]
	histfile: Option<PathBuf>,

	/// enable or disable color
	#[arg(short, long, default_value = "auto")]
	color: ColorChoice,

	// file to run and arguments to pass
	#[arg()]
	args: Vec<LString>,
}

fn exec(name: Symbol, src: &str, args: &Args) -> ExitCode {
	let mut vm = Vm::new(256, args.args.clone());
	talc_std::load_all(&mut vm);

	let mut ex = match parser::parse(src) {
		Ok(ex) => ex,
		Err(e) => {
			eprintln!("Error: {e}");
			return ExitCode::FAILURE
		}
	};

	if !args.no_opt {
		optimize(&mut ex);
	}

	if args.show_ast {
		eprintln!("{}", ex);
	}

	let func = match compile(&ex, Some(name)) {
		Ok(f) => Rc::new(f),
		Err(e) => {
			eprintln!("Error: {e}");
			return ExitCode::FAILURE
		}
	};

	if args.disasm {
		if let Err(e) = disasm_recursive(&func, &mut std::io::stderr()) {
			eprintln!("Error: {e}");
			return ExitCode::FAILURE
		}
	}

	if let Some(path) = &args.compile {
		let f = std::fs::File::options()
			.write(true)
			.truncate(true)
			.create(true)
			.open(path);
		let mut w = match f {
			Ok(f) => f,
			Err(e) => {
				eprintln!("Error opening output file: {e}");
				return ExitCode::FAILURE
			}
		};
		if let Err(e) = serial::write_program(&mut w, &func) {
			eprintln!("Error writing bytecode: {e}");
			return ExitCode::FAILURE
		}
		return ExitCode::SUCCESS
	}

	let res = vm.run_function(func.clone(), vec![func.into()]);

	match res {
		Err(e) => {
			eprintln!("{e}");
			ExitCode::FAILURE
		}
		Ok(Value::Bool(false)) => ExitCode::FAILURE,
		Ok(Value::Int(n)) => ExitCode::from(n.to_u64().unwrap_or(1) as u8),
		_ => ExitCode::SUCCESS,
	}
}

fn main() -> ExitCode {
	let args = Args::parse();

	if args.repl || args.args.is_empty() {
		if args.compile.is_some() {
			eprintln!("Error: cannot compile in REPL mode");
			return ExitCode::FAILURE
		}
		return repl::repl(&args)
	}

	let file = args.args[0].as_ref();

	match std::fs::read_to_string(file.to_os_str()) {
		Ok(s) => exec(Symbol::get(file), &s, &args),
		Err(e) => {
			eprintln!("Error opening source file: {e}");
			ExitCode::FAILURE
		}
	}
}