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

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

#[derive(Debug, Default)]
struct LogDetails {
    time: chrono::DateTime<chrono::Local>,
    level: ActionLevel,
    message: String,
}

#[derive(Debug, Default)]
pub struct EventLogs {
    is_active: bool,
    scroll_state: ScrollbarState,
    table_state: TableState,
    logs: std::collections::VecDeque<LogDetails>,
    palette: StylePalette
}

impl EventLogs {
    const MAX_LOGS: usize = 50;

    fn add_new_log(&mut self, message: String, level: ActionLevel) {
        self.logs.push_front(LogDetails {
            time: chrono::Local::now(),
            level,
            message,
        });

        if self.logs.len() > Self::MAX_LOGS {
            let _ = self.logs.pop_back();
        }
    }

    fn first_row(&mut self) {
        if self.logs.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.logs.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.logs.len() > 0 {
            let last = self.logs.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);
    }
}

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

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

    fn update(&mut self, action: Action) -> Result<Option<Action>> {
        match action {
            Action::EventLog(message, level, target) if target == ActionTarget::ValidatorLog => 
                self.add_new_log(message, level),
            _ => {}
        };
        Ok(None)
    }

    fn draw(&mut self, frame: &mut Frame, area: Rect) -> Result<()> {
        let [_, _, _, place] = super::validator_layout(area);

        let (border_style, border_type) = self.palette.create_border_style(self.is_active);
        let error_style = Style::new().fg(Color::Red);
        let warn_style = Style::new().fg(Color::Yellow);
        let info_style = Style::new().fg(Color::Green);

        let table = Table::new(
            self.logs
                .iter()
                .map(|log| {
                    let style = match log.level {
                        ActionLevel::Info => info_style,
                        ActionLevel::Warn => warn_style,
                        ActionLevel::Error => error_style,
                    };
                    Row::new(vec![
                        Cell::from(Text::from(log.time.format("%H:%M:%S").to_string()).style(style).alignment(Alignment::Left)),
                        Cell::from(Text::from(log.message.clone()).style(style).alignment(Alignment::Left)),
                    ])
                }),
            [
                Constraint::Max(8),
                Constraint::Min(0),
            ],
        )
        .column_spacing(1)
        .highlight_style(self.palette.create_highlight_style())
        .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("Action Logs"));

        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(())
    }
}