// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//! Alacritty - The GPU Enhanced Terminal
#![deny(clippy::all, clippy::if_not_else, clippy::enum_glob_use, clippy::wrong_pub_self_convention)]
#![cfg_attr(feature = "nightly", feature(core_intrinsics))]
#![cfg_attr(all(test, feature = "bench"), feature(test))]

// With the default subsystem, 'console', windows creates an additional console
// window for the program.
// This is silently ignored on non-windows systems.
// See https://msdn.microsoft.com/en-us/library/4cc7ya5b.aspx for more details.
#![windows_subsystem = "windows"]

#[cfg(target_os = "macos")]
use dirs;

#[cfg(windows)]
use winapi::um::wincon::{AttachConsole, FreeConsole, ATTACH_PARENT_PROCESS};

use log::{info, error};

use std::error::Error;
use std::sync::Arc;
use std::io::{self, Write};
use std::fs;

#[cfg(target_os = "macos")]
use std::env;

#[cfg(not(windows))]
use std::os::unix::io::AsRawFd;

#[cfg(target_os = "macos")]
use alacritty::locale;
use alacritty::{cli, event, die};
use alacritty::config::{self, Config, Monitor};
use alacritty::display::Display;
use alacritty::event_loop::{self, EventLoop, Msg};
use alacritty::logging;
use alacritty::panic;
use alacritty::sync::FairMutex;
use alacritty::term::Term;
use alacritty::tty;
use alacritty::util::fmt::Red;
use alacritty::message_bar::MessageBuffer;

fn main() {
    panic::attach_handler();

    // When linked with the windows subsystem windows won't automatically attach
    // to the console of the parent process, so we do it explicitly. This fails
    // silently if the parent has no console.
    #[cfg(windows)]
    unsafe { AttachConsole(ATTACH_PARENT_PROCESS); }

    // Load command line options
    let options = cli::Options::load();

    // Setup storage for message UI
    let message_buffer = MessageBuffer::new();

    // Initialize the logger as soon as possible as to capture output from other subsystems
    let log_file =
        logging::initialize(&options, message_buffer.tx()).expect("Unable to initialize logger");

    // Load configuration file
    // If the file is a command line argument, we won't write a generated default file
    let config_path = options.config_path()
        .or_else(Config::installed_config)
        .or_else(|| Config::write_defaults().ok())
        .map(|path| path.to_path_buf());
    let config = if let Some(path) = config_path {
        Config::load_from(path).update_dynamic_title(&options)
    } else {
        error!("Unable to write the default config");
        Config::default()
    };

    // Switch to home directory
    #[cfg(target_os = "macos")]
    env::set_current_dir(dirs::home_dir().unwrap()).unwrap();
    // Set locale
    #[cfg(target_os = "macos")]
    locale::set_locale_environment();

    // Store if log file should be deleted before moving config
    let persistent_logging = options.persistent_logging || config.persistent_logging();

    // Run alacritty
    if let Err(err) = run(config, &options, message_buffer) {
        die!("Alacritty encountered an unrecoverable error:\n\n\t{}\n", Red(err));
    }

    // Clean up logfile
    if let Some(log_file) = log_file {
        if !persistent_logging && fs::remove_file(&log_file).is_ok() {
            let _ = writeln!(io::stdout(), "Deleted log file at {:?}", log_file);
        }
    }
}

/// Run Alacritty
///
/// Creates a window, the terminal state, pty, I/O event loop, input processor,
/// config change monitor, and runs the main display loop.
fn run(
    mut config: Config,
    options: &cli::Options,
    message_buffer: MessageBuffer,
) -> Result<(), Box<dyn Error>> {
    info!("Welcome to Alacritty");
    if let Some(config_path) = config.path() {
        info!("Configuration loaded from {:?}", config_path.display());
    };

    // Set environment variables
    tty::setup_env(&config);

    // Create a display.
    //
    // The display manages a window and can draw the terminal
    let mut display = Display::new(&config, options)?;

    info!(
        "PTY Dimensions: {:?} x {:?}",
        display.size().lines(),
        display.size().cols()
    );

    // Create the terminal
    //
    // This object contains all of the state about what's being displayed. It's
    // wrapped in a clonable mutex since both the I/O loop and display need to
    // access it.
    let terminal = Term::new(&config, display.size().to_owned(), message_buffer);
    let terminal = Arc::new(FairMutex::new(terminal));

    // Find the window ID for setting $WINDOWID
    let window_id = display.get_window_id();

    // Create the pty
    //
    // The pty forks a process to run the shell on the slave side of the
    // pseudoterminal. A file descriptor for the master side is retained for
    // reading/writing to the shell.
    let pty = tty::new(&config, options, &display.size(), window_id);

    // Get a reference to something that we can resize
    //
    // This exists because rust doesn't know the interface is thread-safe
    // and we need to be able to resize the PTY from the main thread while the IO
    // thread owns the EventedRW object.
    #[cfg(windows)]
    let mut resize_handle = pty.resize_handle();
    #[cfg(not(windows))]
    let mut resize_handle = pty.fd.as_raw_fd();

    // Create the pseudoterminal I/O loop
    //
    // pty I/O is ran on another thread as to not occupy cycles used by the
    // renderer and input processing. Note that access to the terminal state is
    // synchronized since the I/O loop updates the state, and the display
    // consumes it periodically.
    let event_loop = EventLoop::new(
        Arc::clone(&terminal),
        display.notifier(),
        pty,
        options.ref_test,
    );

    // The event loop channel allows write requests from the event processor
    // to be sent to the loop and ultimately written to the pty.
    let loop_tx = event_loop.channel();

    // Event processor
    //
    // Need the Rc<RefCell<_>> here since a ref is shared in the resize callback
    let mut processor = event::Processor::new(
        event_loop::Notifier(event_loop.channel()),
        display.resize_channel(),
        options,
        &config,
        options.ref_test,
        display.size().to_owned(),
    );

    // Create a config monitor when config was loaded from path
    //
    // The monitor watches the config file for changes and reloads it. Pending
    // config changes are processed in the main loop.
    let config_monitor = match (options.live_config_reload, config.live_config_reload()) {
        // Start monitor if CLI flag says yes
        (Some(true), _) |
        // Or if no CLI flag was passed and the config says yes
        (None, true) => config.path()
                .map(|path| config::Monitor::new(path, display.notifier())),
        // Otherwise, don't start the monitor
        _ => None,
    };

    // Kick off the I/O thread
    let _io_thread = event_loop.spawn(None);

    info!("Initialisation complete");

    // Main display loop
    loop {
        // Process input and window events
        let mut terminal_lock = processor.process_events(&terminal, display.window());

        // Handle config reloads
        if let Some(ref path) = config_monitor.as_ref().and_then(Monitor::pending) {
            // Clear old config messages from bar
            terminal_lock.message_buffer_mut().remove_topic(config::SOURCE_FILE_PATH);

            if let Ok(new_config) = Config::reload_from(path) {
                config = new_config.update_dynamic_title(options);
                display.update_config(&config);
                processor.update_config(&config);
                terminal_lock.update_config(&config);
            }

            terminal_lock.dirty = true;
        }

        // Begin shutdown if the flag was raised
        if terminal_lock.should_exit() || tty::process_should_exit() {
            break;
        }

        // Maybe draw the terminal
        if terminal_lock.needs_draw() {
            // Try to update the position of the input method editor
            #[cfg(not(windows))]
            display.update_ime_position(&terminal_lock);

            // Handle pending resize events
            //
            // The second argument is a list of types that want to be notified
            // of display size changes.
            display.handle_resize(&mut terminal_lock, &config, &mut resize_handle, &mut processor);

            drop(terminal_lock);

            // Draw the current state of the terminal
            display.draw(&terminal, &config);
        }
    }

    loop_tx
        .send(Msg::Shutdown)
        .expect("Error sending shutdown to event loop");

    // FIXME patch notify library to have a shutdown method
    // config_reloader.join().ok();

    // Without explicitly detaching the console cmd won't redraw it's prompt
    #[cfg(windows)]
    unsafe { FreeConsole(); }

    info!("Goodbye");

    Ok(())
}