extern crate num as num_renamed;

use std::io;
use std::time::{Duration, Instant};

use crossterm::event;
use crossterm::event::{Event, KeyCode};
use tui::backend::Backend;
use tui::layout::{Constraint, Direction, Layout, Margin};
use tui::style::{Color, Style};
use tui::widgets::*;
use tui::{Frame, Terminal};

use sea_battle_backend::data::GameRules;

use crate::constants::TICK_RATE;
use crate::ui_screens::utils::centered_rect_size;
use crate::ui_screens::ScreenResult;
use crate::ui_widgets::button_widget::ButtonWidget;
use crate::ui_widgets::checkbox_widget::CheckboxWidget;
use crate::ui_widgets::text_editor_widget::TextEditorWidget;

#[derive(num_derive::FromPrimitive, num_derive::ToPrimitive, Eq, PartialEq)]
enum EditingField {
    MapWidth = 0,
    MapHeight,
    BoatsList,
    BoatsCanTouch,
    PlayerContinueOnHit,
    Cancel,
    OK,
}

struct GameRulesConfigurationScreen {
    rules: GameRules,
    curr_field: EditingField,
}

pub fn configure_play_rules<B: Backend>(
    rules: GameRules,
    terminal: &mut Terminal<B>,
) -> io::Result<ScreenResult<GameRules>> {
    let mut model = GameRulesConfigurationScreen {
        rules,
        curr_field: EditingField::OK,
    };

    let mut last_tick = Instant::now();
    loop {
        terminal.draw(|f| ui(f, &mut model))?;

        let timeout = TICK_RATE
            .checked_sub(last_tick.elapsed())
            .unwrap_or_else(|| Duration::from_secs(0));

        if crossterm::event::poll(timeout)? {
            let mut cursor_pos = model.curr_field as i32;

            if let Event::Key(key) = event::read()? {
                match key.code {
                    // Quit app
                    KeyCode::Char('q') => return Ok(ScreenResult::Canceled),

                    // Navigate between fields
                    KeyCode::Up | KeyCode::Left => cursor_pos -= 1,
                    KeyCode::Down | KeyCode::Right | KeyCode::Tab => cursor_pos += 1,

                    // Submit results
                    KeyCode::Enter => {
                        if model.curr_field == EditingField::Cancel {
                            return Ok(ScreenResult::Canceled);
                        }

                        if model.curr_field == EditingField::OK && model.rules.is_valid() {
                            return Ok(ScreenResult::Ok(model.rules));
                        }
                    }

                    KeyCode::Char(' ') => {
                        if model.curr_field == EditingField::BoatsCanTouch {
                            model.rules.boats_can_touch = !model.rules.boats_can_touch;
                        }

                        if model.curr_field == EditingField::PlayerContinueOnHit {
                            model.rules.player_continue_on_hit =
                                !model.rules.player_continue_on_hit;
                        }
                    }

                    KeyCode::Backspace => {
                        if model.curr_field == EditingField::MapWidth {
                            model.rules.map_width /= 10;
                        }

                        if model.curr_field == EditingField::MapHeight {
                            model.rules.map_height /= 10;
                        }

                        if model.curr_field == EditingField::BoatsList
                            && !model.rules.boats_list().is_empty()
                        {
                            model.rules.remove_last_boat();
                        }
                    }

                    KeyCode::Char(c) if ('0'..='9').contains(&c) => {
                        let val = c.to_string().parse::<usize>().unwrap_or_default();

                        if model.curr_field == EditingField::MapWidth {
                            model.rules.map_width *= 10;
                            model.rules.map_width += val;
                        }

                        if model.curr_field == EditingField::MapHeight {
                            model.rules.map_height *= 10;
                            model.rules.map_height += val;
                        }

                        if model.curr_field == EditingField::BoatsList {
                            model.rules.add_boat(val);
                        }
                    }

                    _ => {}
                }
            }

            // Apply new cursor position
            model.curr_field = if cursor_pos < 0 {
                EditingField::OK
            } else {
                num_renamed::FromPrimitive::from_u64(cursor_pos as u64)
                    .unwrap_or(EditingField::MapWidth)
            }
        }
        if last_tick.elapsed() >= TICK_RATE {
            last_tick = Instant::now();
        }
    }
}

fn ui<B: Backend>(f: &mut Frame<B>, model: &mut GameRulesConfigurationScreen) {
    let area = centered_rect_size(50, 16, &f.size());

    let block = Block::default().title("Game rules").borders(Borders::ALL);
    f.render_widget(block, area);

    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Length(3),
            Constraint::Length(3),
            Constraint::Length(3),
            Constraint::Length(1),
            Constraint::Length(1),
            Constraint::Length(1),
            Constraint::Length(1), // Buttons
            Constraint::Length(1), // Error message (if any)
        ])
        .split(area.inner(&Margin {
            horizontal: 2,
            vertical: 1,
        }));

    let editor = TextEditorWidget::new(
        "Map width",
        &model.rules.map_width.to_string(),
        model.curr_field == EditingField::MapWidth,
    );
    f.render_widget(editor, chunks[EditingField::MapWidth as usize]);

    let editor = TextEditorWidget::new(
        "Map height",
        &model.rules.map_height.to_string(),
        model.curr_field == EditingField::MapHeight,
    );
    f.render_widget(editor, chunks[EditingField::MapHeight as usize]);

    let editor = TextEditorWidget::new(
        "Boats list",
        &model
            .rules
            .boats_list()
            .iter()
            .map(usize::to_string)
            .collect::<Vec<_>>()
            .join("; "),
        model.curr_field == EditingField::BoatsList,
    );
    f.render_widget(editor, chunks[EditingField::BoatsList as usize]);

    let editor = CheckboxWidget::new(
        "Boats can touch",
        model.rules.boats_can_touch,
        model.curr_field == EditingField::BoatsCanTouch,
    );
    f.render_widget(editor, chunks[EditingField::BoatsCanTouch as usize]);

    let editor = CheckboxWidget::new(
        "Player continue on hit",
        model.rules.player_continue_on_hit,
        model.curr_field == EditingField::PlayerContinueOnHit,
    );
    f.render_widget(editor, chunks[EditingField::PlayerContinueOnHit as usize]);

    // Buttons
    let buttons_chunk = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([Constraint::Percentage(50), Constraint::Percentage(50)])
        .split(chunks[EditingField::OK as usize]);

    let button = ButtonWidget::new("Cancel", model.curr_field == EditingField::Cancel);
    f.render_widget(button, buttons_chunk[0]);

    let button = ButtonWidget::new("OK", model.curr_field == EditingField::OK)
        .set_disabled(!model.rules.is_valid());
    f.render_widget(button, buttons_chunk[1]);

    // Error message (if any)
    if let Some(msg) = model.rules.get_errors().first() {
        let area = centered_rect_size(msg.len() as u16, 1, chunks.last().unwrap());
        let err = Paragraph::new(*msg).style(Style::default().fg(Color::Red));
        f.render_widget(err, area);
    }
}