use std::collections::BTreeMap;

use color_eyre::Result;
use crossterm::event::{KeyCode, KeyEvent};
use ratatui::layout::{Constraint, Margin};
use ratatui::style::{Modifier, Stylize};
use ratatui::{
    text::Text,
    layout::{Alignment, Rect}, 
    widgets::{
        Block, Cell, Row, Table, TableState, Scrollbar,
        ScrollbarOrientation, ScrollbarState,
    }, 
    Frame
};

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

pub struct Withdrawals {
    is_active: bool,
    palette: StylePalette,
    scroll_state: ScrollbarState,
    table_state: TableState,
    unlockings: BTreeMap<u32, u128>, 
    current_era: u32,
}

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

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

    pub fn new() -> Self {
        Self {
            is_active: false,
            scroll_state: ScrollbarState::new(0),
            table_state: TableState::new(),
            palette: StylePalette::default(),
            unlockings: BTreeMap::new(),
            current_era: 0,
        }
    }

    fn first_row(&mut self) {
        if self.unlockings.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.unlockings.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.unlockings.len() > 0 {
            let last = self.unlockings.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 add_new_unlocking(&mut self, era_index: u32, unlocking: u128) {
        match self.unlockings.get_mut(&era_index) {
            Some(unlck) => *unlck = unlocking,
            None => {
                let _ = self.unlockings.insert(era_index, unlocking);
            },
        }
    }

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

    fn estimate_time(&self, era_index: u32) -> String {
        if era_index > self.current_era {
            format!("{} eras", era_index - self.current_era)
        } else {
            String::from("ready")
        } 
    }
}

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

impl Component for Withdrawals {
    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::SetCurrentEra(current_era) => self.current_era = current_era,
            Action::SetValidatorEraUnlocking(era_index, unlocking) => 
                self.add_new_unlocking(era_index, unlocking),
            _ => {}
        };
        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.unlockings
                .iter()
                .map(|(key, value)| {
                    let mut est_era_text = Text::from(self.estimate_time(*key)).alignment(Alignment::Center);
                    let mut value_text = Text::from(self.prepare_u128(*value)).alignment(Alignment::Right);

                    if *key > self.current_era {
                        est_era_text = est_era_text.add_modifier(Modifier::CROSSED_OUT);
                        value_text = value_text.add_modifier(Modifier::CROSSED_OUT);
                    }

                    Row::new(vec![
                        Cell::from(est_era_text),
                        Cell::from(value_text),
                    ])
                }),
            [
                Constraint::Length(7),
                Constraint::Min(0),
            ],
        )
        .highlight_style(self.palette.create_highlight_style())
        .column_spacing(1)
        .block(Block::bordered()
            .border_style(border_style)
            .border_type(border_type)
            .title_alignment(Alignment::Right)
            .title_style(self.palette.create_title_style(false))
            .title("Withdrawals"));

        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(())
    }
}