use color_eyre::Result;
use crossterm::event::{KeyCode, KeyEvent};
use ratatui::layout::{Constraint, Margin};
use ratatui::{
    text::Text,
    layout::{Alignment, Rect}, 
    widgets::{
        Block, Cell, Row, Table, TableState, Scrollbar, Padding,
        ScrollbarOrientation, ScrollbarState,
    }, 
    Frame
};
use tokio::sync::mpsc::UnboundedSender;

use super::{PartialComponent, Component, CurrentTab};
use crate::types::Nominator;
use crate::{
    action::Action, 
    config::Config, 
    palette::StylePalette, 
};

pub struct NominatorsByValidator {
    is_active: bool,
    action_tx: Option<UnboundedSender<Action>>,
    palette: StylePalette,
    scroll_state: ScrollbarState,
    table_state: TableState,
    nominators: Vec<Nominator>,
}

impl Default for NominatorsByValidator {
    fn default() -> Self {
        Self::new()
    }
}

impl NominatorsByValidator {
    const TICKER: &str = " CSPR";
    const DECIMALS: usize = 5;

    pub fn new() -> Self {
        Self {
            is_active: false,
            action_tx: None,
            scroll_state: ScrollbarState::new(0),
            table_state: TableState::new(),
            nominators: Vec::new(),
            palette: StylePalette::default(),
        }
    }

    fn update_nominators(&mut self, nominators: Vec<Nominator>) {
        if self.nominators.len() > nominators.len() {
            if let Some(_) = self.table_state.selected() {
                self.last_row();
            }
        }
        self.nominators = nominators;
    }

    fn first_row(&mut self) {
        if self.nominators.len() > 0 {
            self.table_state.select(Some(0));
            self.scroll_state = self.scroll_state.position(0);
        }
    }

    fn next_row(&mut self) {
        let i = match self.table_state.selected() {
            Some(i) => {
                if i >= self.nominators.len() - 1 {
                    i
                } else {
                    i + 1
                }
            },
            None => 0,
        };
        self.table_state.select(Some(i));
        self.scroll_state = self.scroll_state.position(i);
    }

    fn last_row(&mut self) {
        if self.nominators.len() > 0 {
            let last = self.nominators.len() - 1;
            self.table_state.select(Some(last));
            self.scroll_state = self.scroll_state.position(last);
        }
    }

    fn previous_row(&mut self) {
        let i = match self.table_state.selected() {
            Some(i) => {
                if i == 0 {
                    0
                } else {
                    i - 1
                }
            },
            None => 0
        };
        self.table_state.select(Some(i));
        self.scroll_state = self.scroll_state.position(i);
    }

    fn prepare_u128(&self, value: u128) -> String {
        let value = value as f64 / 10f64.powi(18);
        let after = Self::DECIMALS;
        format!("{:.after$}{}", value, Self::TICKER)
    }
}

impl PartialComponent for NominatorsByValidator {
    fn set_active(&mut self, current_tab: CurrentTab) {
        match current_tab {
            CurrentTab::NominatorsByValidator => self.is_active = true,
            _ => {
                self.is_active = false;
                self.table_state.select(None);
                self.scroll_state = self.scroll_state.position(0);
            }
        }
    }
}

impl Component for NominatorsByValidator {
    fn register_action_handler(&mut self, tx: UnboundedSender<Action>) -> Result<()> {
        self.action_tx = Some(tx);
        Ok(())
    }

    fn register_config_handler(&mut self, config: Config) -> Result<()> {
        if let Some(style) = config.styles.get(&crate::app::Mode::Validator) {
            self.palette.with_normal_style(style.get("normal_style").copied());
            self.palette.with_hover_style(style.get("hover_style").copied());
            self.palette.with_normal_border_style(style.get("normal_border_style").copied());
            self.palette.with_hover_border_style(style.get("hover_border_style").copied());
            self.palette.with_normal_title_style(style.get("normal_title_style").copied());
            self.palette.with_hover_title_style(style.get("hover_title_style").copied());
            self.palette.with_highlight_style(style.get("highlight_style").copied());
            self.palette.with_scrollbar_style(style.get("scrollbar_style").copied());
        }
        Ok(())
    }

    fn update(&mut self, action: Action) -> Result<Option<Action>> {
        match action {
            Action::SetNominatorsByValidator(nominators) => self.update_nominators(nominators),
            _ => {}
        };
        Ok(None)
    }

    fn handle_key_event(&mut self, key: KeyEvent) -> Result<Option<Action>> {
        if self.is_active {
            match key.code {
                KeyCode::Up | KeyCode::Char('k') => self.previous_row(), 
                KeyCode::Down | KeyCode::Char('j') => self.next_row(), 
                KeyCode::Char('g') => self.first_row(),
                KeyCode::Char('G') => self.last_row(),
                _ => {},
            };
        }
        Ok(None)
    }

    fn draw(&mut self, frame: &mut Frame, area: Rect) -> Result<()> {
        let [place, _, _] = super::validator_statistics_layout(area);
        let (border_style, border_type) = self.palette.create_border_style(self.is_active);
        let table = Table::new(
            self.nominators
                .iter()
                .map(|info| {
                    Row::new(vec![
                        Cell::from(Text::from(info.who.clone()).alignment(Alignment::Left)),
                        Cell::from(Text::from(self.prepare_u128(info.value)).alignment(Alignment::Right)), 
                    ])
                }),
            [
                Constraint::Min(0),
                Constraint::Min(11),
            ],
        )
        .highlight_style(self.palette.create_highlight_style())
        .column_spacing(1)
        .block(Block::bordered()
            .border_style(border_style)
            .border_type(border_type)
            .padding(Padding::right(2))
            .title_alignment(Alignment::Right)
            .title_style(self.palette.create_title_style(false))
            .title("My Nominators"));

        let scrollbar = Scrollbar::default()
            .orientation(ScrollbarOrientation::VerticalRight)
            .begin_symbol(None)
            .end_symbol(None)
            .style(self.palette.create_scrollbar_style());

        frame.render_stateful_widget(table, place, &mut self.table_state);
        frame.render_stateful_widget(
            scrollbar,
            place.inner(Margin { vertical: 1, horizontal: 1 }),
            &mut self.scroll_state,
        );

        Ok(())
    }
}