use anyhow::Result;
use crossterm::{
    event::{self, DisableMouseCapture, Event},
    execute,
    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
};
use parking_lot::Mutex;
use std::{
    io::{self, Stdout, Write},
    sync::{atomic::Ordering, Arc},
};
use std::{sync::atomic::AtomicBool, time::Instant};
use tokio::sync::mpsc::Sender;
use tracing::error;
use tui::{
    backend::{Backend, CrosstermBackend},
    layout::{Constraint, Direction, Layout},
    Frame, Terminal,
};

mod color_match;
mod draw_blocks;
mod gui_state;

pub use self::color_match::*;
pub use self::gui_state::{GuiState, SelectablePanel, Status};
use crate::{
    app_data::AppData, app_error::AppError, docker_data::DockerMessage,
    input_handler::InputMessages,
};

pub struct Ui {
    app_data: Arc<Mutex<AppData>>,
    docker_sx: Sender<DockerMessage>,
    gui_state: Arc<Mutex<GuiState>>,
    is_running: Arc<AtomicBool>,
    now: Instant,
    sender: Sender<InputMessages>,
    terminal: Terminal<CrosstermBackend<Stdout>>,
}

/// Enable moust capture, but don't enable all the mouse movements, which improves performance, and fixes the weird mouse event output bug
pub fn enable_mouse_capture() {
    io::stdout()
        .write_all(
            concat!(
                crossterm::csi!("?1000h"),
                crossterm::csi!("?1015h"),
                crossterm::csi!("?1006h"),
            )
            .as_bytes(),
        )
        .unwrap_or(());
}

impl Ui {
    /// Create a new Ui struct, and execute the drawing loop
    pub async fn create(
        app_data: Arc<Mutex<AppData>>,
        docker_sx: Sender<DockerMessage>,
        gui_state: Arc<Mutex<GuiState>>,
        is_running: Arc<AtomicBool>,
        sender: Sender<InputMessages>,
    ) {
        if let Ok(terminal) = Self::setup_terminal() {
            let mut ui = Self {
                app_data,
                docker_sx,
                gui_state,
                is_running,
                now: Instant::now(),
                sender,
                terminal,
            };
            if let Err(e) = ui.draw_ui().await {
                error!("{e}");
            }
            if let Err(e) = ui.reset_terminal() {
                error!("{e}");
            };
        } else {
            error!("Terminal Error");
        }
    }

    /// Setup the terminal for full-screen drawing mode, with mouse capture
    fn setup_terminal() -> io::Result<Terminal<CrosstermBackend<Stdout>>> {
        enable_raw_mode()?;
        let mut stdout = io::stdout();
        execute!(stdout, EnterAlternateScreen)?;
        enable_mouse_capture();
        let backend = CrosstermBackend::new(stdout);
        Terminal::new(backend)
    }

    /// reset the terminal back to default settings
    pub fn reset_terminal(&mut self) -> Result<()> {
        self.terminal.clear()?;

        disable_raw_mode()?;
        execute!(
            self.terminal.backend_mut(),
            LeaveAlternateScreen,
            DisableMouseCapture
        )?;
        self.terminal.show_cursor()?;
        Ok(())
    }

    /// Draw the the error message ui, for 5 seconds, with a countdown
    fn err_loop(&mut self) -> Result<(), AppError> {
        let mut seconds = 5;
        loop {
            if self.now.elapsed() >= std::time::Duration::from_secs(1) {
                seconds -= 1;
                self.now = Instant::now();
            }

            if seconds < 1 {
                break;
            }

            if self
                .terminal
                .draw(|f| draw_blocks::error(f, AppError::DockerConnect, Some(seconds)))
                .is_err()
            {
                return Err(AppError::Terminal);
            }
        }
        Ok(())
    }

    /// The loop for drawing the main UI to the terminal
    async fn gui_loop(&mut self) -> Result<(), AppError> {
        let input_poll_rate = std::time::Duration::from_millis(100);
        let update_duration =
            std::time::Duration::from_millis(u64::from(self.app_data.lock().args.docker_interval));

        while self.is_running.load(Ordering::SeqCst) {
            if self
                .terminal
                .draw(|frame| draw_frame(frame, &self.app_data, &self.gui_state))
                .is_err()
            {
                return Err(AppError::Terminal);
            }
            if crossterm::event::poll(input_poll_rate).unwrap_or(false) {
                if let Ok(event) = event::read() {
                    if let Event::Key(key) = event {
                        self.sender
                            .send(InputMessages::ButtonPress(key.code))
                            .await
                            .unwrap_or(());
                    } else if let Event::Mouse(m) = event {
                        self.sender
                            .send(InputMessages::MouseEvent(m))
                            .await
                            .unwrap_or(());
                    } else if let Event::Resize(_, _) = event {
                        self.gui_state.lock().clear_area_map();
                        self.terminal.autoresize().unwrap_or(());
                    }
                }
            }

            if self.now.elapsed() >= update_duration {
                self.docker_sx
                    .send(DockerMessage::Update)
                    .await
                    .unwrap_or(());
                self.now = Instant::now();
            }
        }
        Ok(())
    }

    /// Draw either the Error, or main oxker ui, to the terminal
    async fn draw_ui(&mut self) -> Result<(), AppError> {
        let status_dockerconnect = self
            .gui_state
            .lock()
            .status_contains(&[Status::DockerConnect]);
        if status_dockerconnect {
            self.err_loop()?;
        } else {
            self.gui_loop().await?;
        }

        Ok(())
    }
}

/// Draw the main ui to a frame of the terminal
fn draw_frame<B: Backend>(
    f: &mut Frame<'_, B>,
    app_data: &Arc<Mutex<AppData>>,
    gui_state: &Arc<Mutex<GuiState>>,
) {
    // set max height for container section, needs +4 to deal with docker commands list and borders
    let height = app_data.lock().get_container_len();
    let height = if height < 12 { height + 4 } else { 12 };

    let column_widths = app_data.lock().get_width();
    let has_containers = app_data.lock().get_container_len() > 0;
    let has_error = app_data.lock().get_error();
    let sorted_by = app_data.lock().get_sorted();

    let show_help = gui_state.lock().status_contains(&[Status::Help]);
    let info_text = gui_state.lock().info_box_text.clone();
    let loading_icon = gui_state.lock().get_loading();

    let whole_layout = Layout::default()
        .direction(Direction::Vertical)
        .constraints([Constraint::Min(1), Constraint::Min(100)].as_ref())
        .split(f.size());

    // Split into 3, containers+controls, logs, then graphs
    let upper_main = Layout::default()
        .direction(Direction::Vertical)
        .constraints(
            [
                Constraint::Max(height.try_into().unwrap_or_default()),
                Constraint::Percentage(50),
            ]
            .as_ref(),
        )
        .split(whole_layout[1]);

    let top_split = if has_containers {
        vec![Constraint::Percentage(90), Constraint::Percentage(10)]
    } else {
        vec![Constraint::Percentage(100)]
    };
    // Containers + docker commands
    let top_panel = Layout::default()
        .direction(Direction::Horizontal)
        .constraints(top_split.as_ref())
        .split(upper_main[0]);

    let lower_split = if has_containers {
        vec![Constraint::Percentage(75), Constraint::Percentage(25)]
    } else {
        vec![Constraint::Percentage(100)]
    };

    // Split into 2, logs, and optional charts
    let lower_main = Layout::default()
        .direction(Direction::Vertical)
        .constraints(lower_split.as_ref())
        .split(upper_main[1]);

    draw_blocks::containers(app_data, top_panel[0], f, gui_state, &column_widths);

    if has_containers {
        draw_blocks::commands(app_data, top_panel[1], f, gui_state);
    }

    draw_blocks::logs(app_data, lower_main[0], f, gui_state, &loading_icon);

    draw_blocks::heading_bar(
        whole_layout[0],
        &column_widths,
        f,
        has_containers,
        &loading_icon,
        sorted_by,
        gui_state,
    );

    // only draw charts if there are containers
    if has_containers {
        draw_blocks::chart(f, lower_main[1], app_data);
    }

    if let Some(info) = info_text {
        draw_blocks::info(f, info);
    }

    // Check if error, and show popup if so
    if show_help {
        draw_blocks::help_box(f);
    }

    if let Some(error) = has_error {
        draw_blocks::error(f, error, None);
    }
}