// hide console in release mode
#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]

use std::{path::PathBuf, process, time::SystemTime};

use anyhow::{Result, bail};
use app::Application;
use clap::Parser;
use emulator::EmulatorBuilder;
use thread_priority::{ThreadBuilder, ThreadPriority};
use tracing::error;
use tracing_subscriber::{EnvFilter, Layer, layer::SubscriberExt, util::SubscriberInitExt};
use winit::event_loop::{ControlFlow, EventLoop};

mod app;
mod audio;
mod controller;
mod emulator;
mod gdbserver;
mod graphics;
mod images;
mod input;
mod memory;
mod persistence;
mod profiler;
mod window;

#[derive(Parser)]
struct Args {
    /// The path to a virtual boy ROM to run.
    rom: Option<PathBuf>,
    /// Start a GDB/LLDB debug server on this port.
    #[arg(short, long)]
    debug_port: Option<u16>,
    /// Enable profiling a game
    #[arg(short, long)]
    profile: bool,
}

fn init_logger() {
    let directives = std::env::var("RUST_LOG").unwrap_or("error,lemur=info".into());
    let filter = EnvFilter::builder().parse_lossy(directives);
    let layer = tracing_subscriber::fmt::layer().with_filter(filter);
    tracing_subscriber::registry().with(layer).init();
}

fn set_panic_handler() {
    std::panic::set_hook(Box::new(|info| {
        let mut message = String::new();
        if let Some(msg) = info.payload().downcast_ref::<&str>() {
            message += &format!("{msg}\n");
        } else if let Some(msg) = info.payload().downcast_ref::<String>() {
            message += &format!("{msg}\n");
        }
        if let Some(location) = info.location() {
            message += &format!(
                "    in file '{}' at line {}\n",
                location.file(),
                location.line()
            );
        }
        let backtrace = std::backtrace::Backtrace::force_capture();
        message += &format!("stack trace:\n{backtrace:#}\n");

        eprint!("{message}");

        let Some(project_dirs) = directories::ProjectDirs::from("com", "virtual-boy", "Lemur")
        else {
            return;
        };
        let data_dir = project_dirs.data_dir();
        if std::fs::create_dir_all(data_dir).is_err() {
            return;
        }
        let timestamp = SystemTime::now()
            .duration_since(SystemTime::UNIX_EPOCH)
            .unwrap()
            .as_millis();
        let logfile_name = format!("crash-{timestamp}.txt");
        let _ = std::fs::write(data_dir.join(logfile_name), message);
    }));
}

#[cfg(windows)]
fn set_process_priority_to_high() -> Result<()> {
    use windows::Win32::{Foundation, System::Threading};
    let process = unsafe { Threading::GetCurrentProcess() };
    unsafe { Threading::SetPriorityClass(process, Threading::HIGH_PRIORITY_CLASS)? };
    unsafe { Foundation::CloseHandle(process)? };
    Ok(())
}

fn main() -> Result<()> {
    init_logger();

    set_panic_handler();

    #[cfg(windows)]
    set_process_priority_to_high()?;

    let args = Args::parse();

    let (mut builder, client) = EmulatorBuilder::new();
    if let Some(path) = &args.rom {
        builder = builder.with_rom(path);
    }
    if args.debug_port.is_some() {
        if args.rom.is_none() {
            bail!("to start debugging, please select a game.");
        }
        builder = builder.start_paused(true);
    }
    if args.profile {
        builder = builder.start_paused(true)
    }

    ThreadBuilder::default()
        .name("Emulator".to_owned())
        .priority(ThreadPriority::Max)
        .spawn_careless(move || {
            let mut emulator = match builder.build() {
                Ok(e) => e,
                Err(error) => {
                    error!(%error, "Error initializing emulator");
                    process::exit(1);
                }
            };
            emulator.run();
        })?;

    let event_loop = EventLoop::with_user_event().build().unwrap();
    event_loop.set_control_flow(ControlFlow::Poll);
    let proxy = event_loop.create_proxy();
    event_loop.run_app(&mut Application::new(
        client,
        proxy,
        args.debug_port,
        args.profile,
    ))?;
    Ok(())
}