use crossterm::event::{read, Event, KeyCode};
use tui::{backend::Backend, Frame, layout::Layout};

use crate::{state::GameState, person::Person, entity::Entity};

/**
 * |........................|
 * | Conversations/Selection|
 * |                        |
 * |........................|
 * | Available Options      |
 * |........................|
 */

enum AppStatus {
    Initial,
    GuestSelection,
    TalkToGuest(Option<u32>),
}

pub struct App<'a> {
    state: GameState,
    guest_list: Vec<tui::widgets::ListItem<'a>>,
    guest_list_state: tui::widgets::ListState,
    status: AppStatus,
    conversation: Vec<tui::text::Spans<'a>>,
}

impl<'a> App<'a> {
    pub fn new(state: GameState) -> App<'a> {
        App {
            state: state,
            guest_list: vec![],
            guest_list_state: tui::widgets::ListState::default(),
            status: AppStatus::Initial,
            conversation: Vec::new(),
        }
    }

    pub fn step(&mut self) -> bool {
        match &self.status {
            AppStatus::Initial => {
                // determine guests
                self.guest_list = self.state.guests().iter().map(|guest| {
                    tui::widgets::ListItem::new(guest.name.clone())
                }).collect();
                self.guest_list_state = tui::widgets::ListState::default();
                self.guest_list_state.select(Some(0));
                self.status = AppStatus::GuestSelection;
                true
            },
            AppStatus::GuestSelection => {
                match read() {
                    Ok(Event::Key(event)) => {
                        match event.code {
                            KeyCode::Up => {
                                let selected = self.guest_list_state.selected().unwrap();
                                if selected > 0 {
                                    self.guest_list_state.select(Some(selected - 1));
                                }
                            },
                            KeyCode::Down => {
                                let selected = self.guest_list_state.selected().unwrap();
                                if selected < self.guest_list.len() - 1 {
                                    self.guest_list_state.select(Some(selected + 1));
                                }
                            },
                            KeyCode::Enter => {
                                let selected = self.guest_list_state.selected().unwrap();
                                let guest = &self.state.guests()[selected];
                                self.conversation = Vec::new();
                                self.greet_guest(guest);
                                self.status = AppStatus::TalkToGuest(guest.id());
                            },
                            KeyCode::Char('.') => {
                                self.state.step();
                                self.status = AppStatus::Initial;
                            },
                            KeyCode::Esc => {
                                return false;
                            },
                            _ => {}
                        }
                    },
                    _ => {}
                }
                true
            },
            AppStatus::TalkToGuest(guest) => {
                match read() {
                    Ok(Event::Key(event)) => {
                        match event.code {
                            KeyCode::Esc => {
                                self.status = AppStatus::GuestSelection;
                            },
                            KeyCode::Char('a') => {
                                self.ask_business(*guest);
                            },
                            _ => {}
                        }
                    },
                    _ => {}
                }
                true
            }
        }
    }

    pub fn draw<B: Backend>(&mut self, f: &mut Frame<B>) {
        match &self.status {
            AppStatus::Initial => {
                self.draw_initial(f);
            },
            AppStatus::GuestSelection => {
                self.draw_guest_selection(f);
            },
            AppStatus::TalkToGuest(guest_id) => {
                self.draw_talk_to_guest(f, *guest_id);
            }
        }

    }

    pub fn draw_initial<B: Backend>(&mut self, f: &mut Frame<B>) {}

    pub fn draw_guest_selection<B: Backend>(&mut self, f: &mut Frame<B>) {
        let chunks = Layout::default()
            .direction(tui::layout::Direction::Vertical)
            .constraints(
                [
                    tui::layout::Constraint::Min(3),
                    tui::layout::Constraint::Length(2)
                ]
                .as_ref(),
            )
            .split(f.size());

        let main_window = tui::widgets::List::new(self.guest_list.clone())
            .block(tui::widgets::Block::default().title("Guests").borders(tui::widgets::Borders::ALL))
            .style(tui::style::Style::default().fg(tui::style::Color::White))
            .highlight_style(tui::style::Style::default().add_modifier(tui::style::Modifier::ITALIC))
            .highlight_symbol(">>");

        let key_style = tui::style::Style::default()
            .add_modifier(tui::style::Modifier::BOLD)
            .fg(tui::style::Color::Green)
            .bg(tui::style::Color::Black);
        let control_text = tui::text::Spans::from(vec![
            tui::text::Span::styled("↑↓", key_style),
            tui::text::Span::raw(" select guest"),
            tui::text::Span::raw("    "),
            tui::text::Span::styled("⏎", key_style),
            tui::text::Span::raw(" talk to guest"),
            tui::text::Span::raw("    "),
            tui::text::Span::styled(".", key_style),
            tui::text::Span::raw(" pass one day"),
            tui::text::Span::raw("    "),
            tui::text::Span::styled("Esc", key_style),
            tui::text::Span::raw(" quit"),

        ]);
        let controls = tui::widgets::Paragraph::new(control_text)
            .style(tui::style::Style::default().fg(tui::style::Color::White));

        f.render_stateful_widget(main_window, chunks[0], &mut self.guest_list_state);    
        f.render_widget(controls, chunks[1]);
    }
    fn draw_talk_to_guest<B: Backend>(&self, f: &mut Frame<B>, guest: Option<u32>) {
        let guest = self.state.get_person(guest.unwrap()).unwrap();

        let key_style = tui::style::Style::default()
            .add_modifier(tui::style::Modifier::BOLD)
            .fg(tui::style::Color::Green)
            .bg(tui::style::Color::Black);

        let mut full_text = self.conversation.clone();
        full_text.push(tui::text::Spans::from(vec![
            tui::text::Span::styled("(a) ", key_style),
            tui::text::Span::raw("What's your business?"),
        ]));
        let text = tui::text::Text::from(full_text);

        let main_window = tui::widgets::Paragraph::new(text)
            .block(tui::widgets::Block::default().title(guest.name.clone()).borders(tui::widgets::Borders::ALL))
            .style(tui::style::Style::default().fg(tui::style::Color::White));
        f.render_widget(main_window, f.size());
    }

    /**
     * Conversation
     */
    fn greet_guest(&mut self, guest: &Person) {
        self.conversation.push(
            tui::text::Spans::from(vec![
                tui::text::Span::styled("Greetings traveller?\n", tui::style::Style::default().fg(tui::style::Color::Yellow)),
            ])
        );
        self.conversation.push(
            tui::text::Spans::from(vec![
                tui::text::Span::raw("Hello, I'm "),
                tui::text::Span::styled(guest.name.clone(), tui::style::Style::default().add_modifier(tui::style::Modifier::BOLD)),
                tui::text::Span::raw(".\n"),
            ])
        );
    }

    fn ask_business(&mut self, guest: Option<u32>) {
        let guest = self.state.get_person(guest.unwrap()).unwrap();
        self.conversation.push(
            tui::text::Spans::from(vec![
                tui::text::Span::styled("What's your business?\n", tui::style::Style::default().fg(tui::style::Color::Yellow))
            ])
        );
        self.conversation.push(
            tui::text::Spans::from(vec![
                tui::text::Span::raw(guest.say_agenda(& self.state)),
                tui::text::Span::raw("\n"),
            ])
        );
    }
}