// This file is part of Deja-vu.
//
// Deja-vu is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Deja-vu is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Deja-vu. If not, see <https://www.gnu.org/licenses/>.
//
use color_eyre::Result;
use crossterm::event::KeyEvent;
use ratatui::{
    prelude::*,
    widgets::{Block, Borders, Padding, Paragraph, Wrap},
};
use tokio::sync::mpsc::UnboundedSender;

use super::{state::StatefulList, Component};
use crate::{action::Action, config::Config, line::DVLine};

#[derive(Default)]
pub struct Right {
    command_tx: Option<UnboundedSender<Action>>,
    config: Config,
    list_header: Vec<DVLine>,
    list_labels: Vec<Vec<DVLine>>,
    list: StatefulList<Vec<DVLine>>,
    selections: Vec<Option<usize>>,
    selections_saved: Vec<Option<usize>>,
    title: String,
}

impl Right {
    pub fn new() -> Self {
        Self {
            selections: vec![None, None],
            selections_saved: vec![None, None],
            title: String::from("Info"),
            ..Default::default()
        }
    }

    fn get_first(&self) -> Option<usize> {
        if self.selections_saved[0].is_some() {
            self.selections_saved[0]
        } else if self.selections[0].is_some() {
            self.selections[0]
        } else {
            self.list.selected()
        }
    }

    fn get_second(&self) -> Option<usize> {
        if self.selections_saved[1].is_some() {
            self.selections_saved[1]
        } else if self.selections[1].is_some() {
            self.selections[1]
        } else if self.selections[0].is_some() && self.selections[0] != self.list.selected() {
            self.list.selected()
        } else {
            None
        }
    }

    fn set_highlight(&mut self, index: usize) {
        self.list.select(index);
    }
}

impl Component for Right {
    fn handle_key_event(&mut self, key: KeyEvent) -> Result<Option<Action>> {
        let _ = key; // to appease clippy
        Ok(None)
    }

    fn register_action_handler(&mut self, tx: UnboundedSender<Action>) -> Result<()> {
        self.command_tx = Some(tx);
        Ok(())
    }

    fn register_config_handler(&mut self, config: Config) -> Result<()> {
        self.config = config;
        Ok(())
    }

    fn update(&mut self, action: Action) -> Result<Option<Action>> {
        match action {
            Action::Highlight(index) => self.set_highlight(index),
            Action::KeyUp => self.list.previous(),
            Action::KeyDown => self.list.next(),
            Action::Select(one, two) => {
                self.selections[0] = one;
                self.selections[1] = two;
                if self.selections_saved[1].is_none() {
                    // Update selections_saved
                    // Conversely, if both selections set then preserve previous choices
                    self.selections_saved[0] = one;
                    self.selections_saved[1] = two;
                }
            }
            Action::SelectRight(one, two) => {
                self.selections_saved[0] = one;
                self.selections_saved[1] = two;
            }
            Action::SetMode(_) => {
                self.selections[0] = None;
                self.selections[1] = None;
                self.selections_saved[0] = None;
                self.selections_saved[1] = None;
            }
            Action::UpdateRight(labels, start_index, list) => {
                self.list_header = list[..start_index].iter().flatten().cloned().collect();
                self.list_labels = labels;
                self.list.set_items(list[start_index..].to_vec());
            }
            _ => {}
        }
        Ok(None)
    }

    fn draw(&mut self, frame: &mut Frame, area: Rect) -> Result<()> {
        let [title_area, body_area] = Layout::default()
            .direction(Direction::Vertical)
            .constraints([Constraint::Length(1), Constraint::Min(1)])
            .areas(area);

        // Title
        let title = Paragraph::new(Line::from(self.title.as_str()).centered())
            .block(Block::default().borders(Borders::NONE));
        frame.render_widget(title, title_area);

        // Body
        let mut body_text: Vec<Line> = Vec::new();
        if !self.list_header.is_empty() {
            // Static Header
            self.list_header
                .iter()
                .for_each(|dv| body_text.push(dv.as_line()));
            body_text.push(Line::from(""));
            body_text.push(Line::from(str::repeat("─", (body_area.width - 4) as usize)));
            body_text.push(Line::from(""));
        }

        // First selection
        if let Some(first_index) = self.get_first() {
            if let Some(first_desc) = self.list.get(first_index) {
                if let Some(label) = self.list_labels.get(0) {
                    label
                        .iter()
                        .for_each(|dv| body_text.push(dv.as_line().bold()));
                }
                body_text.push(Line::from(""));
                first_desc
                    .iter()
                    .for_each(|dv| body_text.push(dv.as_line()));
            }
        }

        // Second selection
        if let Some(second_index) = self.get_second() {
            if let Some(second_desc) = self.list.get(second_index) {
                // Divider
                body_text.push(Line::from(""));
                body_text.push(Line::from(str::repeat("─", (body_area.width - 4) as usize)));
                body_text.push(Line::from(""));
                if let Some(label) = self.list_labels.get(1) {
                    label
                        .iter()
                        .for_each(|dv| body_text.push(dv.as_line().bold()));
                }
                body_text.push(Line::from(""));
                second_desc
                    .iter()
                    .for_each(|dv| body_text.push(dv.as_line()));
            }
        }

        // Build Paragraph
        let body = Paragraph::new(body_text)
            .style(Style::default().fg(Color::Gray))
            .wrap(Wrap { trim: false })
            .block(
                Block::default()
                    .borders(Borders::ALL)
                    .padding(Padding::new(1, 1, 1, 1)),
            );
        frame.render_widget(body, body_area);

        // Done
        Ok(())
    }
}