use ratatui::{
    crossterm::event::{KeyCode, KeyEvent},
    layout::Rect,
    text::{ToLine, ToSpan},
    widgets::{Paragraph, Widget},
};
use tree_sitter_highlight::HighlightConfiguration;

use crate::{config::keymap::EditorKeyMap, lua};
use crate::{
    config::{theme::editor::bar::EditorBarTheme, GlobalConfig},
    state::{editor::bar::EditorBarState, GlobalState},
    tuicursor::TuiCursor,
};

use super::statusbar::StatusBar;

pub mod theme;
pub mod treesitter;

pub struct LuaEditor {
    bar: StatusBar,
    scroll: usize,
    highlight_config: HighlightConfiguration,
}

impl LuaEditor {
    pub fn new() -> Self {
        Self {
            bar: StatusBar::new(),
            scroll: 0,
            highlight_config: treesitter::new_highlight_configuration(),
        }
    }

    pub fn handle_key_event(&mut self, event: KeyEvent) {
        let r = EditorKeyMap::handle(event);

        if r.unwrap_or(true) {
            match event.code {
                KeyCode::Char(c) => GlobalState::instance_mut().editor.buffer.insert(c),
                KeyCode::Backspace => {
                    GlobalState::instance_mut().editor.buffer.delete();
                }
                KeyCode::Enter => {
                    GlobalState::instance_mut().editor.buffer.insert('\n');
                }
                _ => {}
            }
        }
    }

    pub fn render_cursor(&self) -> Option<TuiCursor> {
        let state = GlobalState::instance();
        let buffer = &state.editor.buffer;
        let nr_width = (buffer.lines().len().to_string().len() + 1).max(4) as u16;

        Some(TuiCursor {
            position: (
                buffer.cursor().y() as u16,
                buffer.cursor().x() as u16 + nr_width,
            ),
            style: ratatui::crossterm::cursor::SetCursorStyle::SteadyBar,
        })
    }
}

impl Widget for &mut LuaEditor {
    fn render(self, area: ratatui::prelude::Rect, buf: &mut ratatui::prelude::Buffer)
    where
        Self: Sized,
    {
        {
            let state = GlobalState::instance();
            let buffer = &state.editor.buffer;

            let config = GlobalConfig::instance();
            let theme = &config.theme.editor;

            let inner_area = self.bar.area(area);

            let text = buffer.as_string();
            let highlights = treesitter::highlighter_split(text.as_bytes(), &self.highlight_config);

            let nr_width = (buffer.lines().len().to_string().len() + 1).max(4) as u16;
            let mut text_area = inner_area;
            text_area.x += nr_width;

            let mut span_area = text_area;
            let mut current_line = 0;

            theme
                .background
                .get((), &lua::get())
                .unwrap_or_default()
                .apply(Paragraph::default())
                .render(area, buf);

            theme
                .cursor_line
                .get((), &lua::get())
                .unwrap_or_default()
                .apply(Paragraph::default())
                .render(
                    Rect::new(
                        text_area.x,
                        text_area.y + buffer.cursor().y() as u16,
                        text_area.width,
                        1,
                    ),
                    buf,
                );

            for (hl, group) in highlights.iter() {
                if *group == "\n" {
                    if current_line >= self.scroll {
                        span_area.y += 1;
                        span_area.x = text_area.x;
                    }

                    current_line += 1;
                } else if current_line >= self.scroll {
                    let group = group.replace('\t', "  ");
                    let span = group.to_span();

                    if inner_area.contains(span_area.into()) {
                        theme.highlight.highlight(*hl, span).render(span_area, buf);
                    }

                    span_area.x += group.len() as u16;
                }
            }

            for i in self.scroll..buffer.lines().len() {
                let mut nr_area = span_area;
                nr_area.x = inner_area.x;
                nr_area.width = nr_width;
                nr_area.y = inner_area.y + (i - self.scroll) as u16;
                nr_area.height = 1;

                if !inner_area.contains(nr_area.into()) {
                    break;
                }

                if buffer.cursor().y() == i {
                    theme
                        .active_line_number
                        .get((), &lua::get())
                        .unwrap_or_default()
                } else {
                    theme.line_number.get((), &lua::get()).unwrap_or_default()
                }
                .apply(((i + 1).to_string() + " ").to_line())
                .right_aligned()
                .render(nr_area, buf);
            }
        }

        EditorBarState::apply(&mut self.bar, (), &lua::get());
        EditorBarTheme::apply(&mut self.bar, (), &lua::get());
        self.bar.render(area, buf);
    }
}

impl Default for LuaEditor {
    fn default() -> Self {
        Self {
            highlight_config: treesitter::new_highlight_configuration(),
            bar: StatusBar::default(),
            scroll: 0,
        }
    }
}