use crate::tui::component::{Action, Component};
use crate::tui::editor::Editor;
use crate::tui::explorer::Explorer;
use ratatui::buffer::Buffer;
use ratatui::crossterm::event;
use ratatui::crossterm::event::{Event, KeyCode, KeyEvent, KeyEventKind, KeyModifiers};
use ratatui::layout::{Constraint, Direction, Layout, Rect};
use ratatui::prelude::{Color, Style, Widget};
use ratatui::widgets::{Block, Borders, Padding, Paragraph, Tabs, Wrap};
use ratatui::{DefaultTerminal, symbols};
use std::time::Duration;

pub struct App<'a> {
    explorer: Explorer<'a>,
    editor: Editor,
}

impl<'a> App<'a> {
    pub(crate) fn new(root_path: std::path::PathBuf) -> Self {
        let mut app = Self {
            explorer: Explorer::new(&root_path),
            editor: Editor::new(),
        };
        app.editor
            .set_contents(&root_path.join("src/tui/app.rs"))
            .expect("Failed to set editor contents.");
        app
    }

    fn get_event(&mut self) -> Option<Event> {
        if !event::poll(Duration::from_millis(250)).expect("event poll failed") {
            return None;
        }

        event::read().ok()
    }

    pub fn run(mut self, mut terminal: DefaultTerminal) -> anyhow::Result<()> {
        loop {
            // TODO: Handle events based on which component is active.
            terminal.draw(|f| {
                f.render_widget(&mut self, f.area());
            })?;

            if let Some(event) = self.get_event() {
                match self.handle_event(event) {
                    Action::Quit => break,
                    Action::Handled => {}
                    _ => {
                        // panic!("Unhandled event: {:?}", event);
                    }
                }
            }
        }
        Ok(())
    }

    fn draw_status(&self, area: Rect, buf: &mut Buffer) {
        // TODO: Status bar should have drop down menus
        Tabs::new(["File", "Edit", "View", "Help"])
            .style(Style::default())
            .block(Block::default().borders(Borders::ALL))
            .render(area, buf);
    }

    fn draw_tabs(&self, area: Rect, buf: &mut Buffer) {
        // TODO: Tabs should be opened from file explorer
        Tabs::new(["file.md", "file.cpp"])
            .divider(symbols::DOT)
            .block(
                Block::default()
                    .borders(Borders::NONE)
                    .padding(Padding::new(0, 0, 0, 0)),
            )
            .highlight_style(Style::default().fg(Color::LightRed))
            .render(area, buf);
    }

    fn draw_terminal(&self, area: Rect, buf: &mut Buffer) {
        // TODO: Title should be detected shell name
        // TODO: Contents should be shell output
        Paragraph::new("shaun@pc:~/Code/clide$ ")
            .style(Style::default())
            .block(
                Block::default()
                    .title("Bash")
                    .title_style(Style::default().fg(Color::DarkGray))
                    .borders(Borders::ALL),
            )
            .wrap(Wrap { trim: false })
            .render(area, buf);
    }
}

// TODO: Separate complex components into their own widgets.
impl<'a> Widget for &mut App<'a> {
    fn render(self, area: Rect, buf: &mut Buffer)
    where
        Self: Sized,
    {
        let vertical = Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Length(3),      // status bar
                Constraint::Percentage(70), // horizontal layout
                Constraint::Percentage(30), // terminal
            ])
            .split(area);

        let horizontal = Layout::default()
            .direction(Direction::Horizontal)
            .constraints([
                Constraint::Max(30), // File explorer with a max width of 30 characters.
                Constraint::Fill(1), // Editor fills the remaining space.
            ])
            .split(vertical[1]);

        let editor_layout = Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Length(1), // Editor tabs.
                Constraint::Fill(1),   // Editor contents.
            ])
            .split(horizontal[1]);

        self.draw_status(vertical[0], buf);
        self.draw_terminal(vertical[2], buf);

        self.explorer.render(horizontal[0], buf);

        self.draw_tabs(editor_layout[0], buf);
        self.editor.render(editor_layout[1], buf);
    }
}

impl<'a> Component for App<'a> {
    fn id(&self) -> &str {
        "app"
    }

    /// TODO: Get active widget with some Component trait function helper?
    /// trait Component { fn get_state() -> ComponentState; }
    /// if component.get_state() = ComponentState::Active { component.handle_event(); }
    ///
    /// App could then provide helpers for altering Component state based on TUI grouping..
    ///    (such as editor tabs, file explorer, status bars, etc..)
    fn handle_event(&mut self, event: Event) -> Action {
        // Handle events in the primary application.
        if let Some(key_event) = event.as_key_event() {
            match self.handle_key_events(key_event) {
                Action::Quit => return Action::Quit,
                Action::Handled => {
                    dbg!(format!("Handled event: {:?}", self.id()));
                    return Action::Handled;
                }
                _ => {}
            }
        }
        self.editor.handle_event(event);

        // Handle events for all components.
        // for component in &mut self.components {
        //     dbg!(format!("Handling event: {:?}", component.id()));
        //     // Actions returned here abort the input handling iteration.
        //     match component.handle_event(event.clone()) {
        //         Action::Quit => return Action::Quit,
        //         Action::Handled => return Action::Handled,
        //         _ => continue,
        //     }
        // }
        Action::Noop
    }

    fn handle_key_events(&mut self, key: KeyEvent) -> Action {
        match key {
            KeyEvent {
                code: KeyCode::Char('c'),
                modifiers: KeyModifiers::CONTROL,
                kind: KeyEventKind::Press,
                state: _state,
            } => Action::Quit,
            key_event => {
                // Pass the key event to each component that can handle it.
                self.explorer.handle_key_events(key_event)
            }
        }
    }
}