use crossterm::event::{Event, self, KeyCode};
use ratatui::widgets::ListState;

use crate::uis::history::HistoryState;
use crate::uis::new_transaction::NewTransactionTabState;
use crate::uis::navigation_frame::NavigationState;

pub type AppResult<T> = std::result::Result<T, Box<dyn std::error::Error>>;

pub struct StatefulList<T> {
    pub state: ListState,
    pub items: Vec<T>,
}

impl<T> StatefulList<T> {
    pub fn with_items(items: Vec<T>) -> StatefulList<T> {
        StatefulList {
            state: ListState::default(),
            items,
        }
    }

    pub fn next(&mut self) {
        let i = match self.state.selected() {
            Some(i) => {
                if i >= self.items.len() - 1 {
                    0
                } else {
                    i + 1
                }
            }
            None => 0,
        };
        self.state.select(Some(i));
    }

    pub fn previous(&mut self) {
        let i = match self.state.selected() {
            Some(i) => {
                if i == 0 {
                    self.items.len() - 1
                } else {
                    i - 1
                }
            }
            None => 0,
        };
        self.state.select(Some(i));
    }

    pub fn unselect(&mut self) {
        self.state.select(None);
    }
}

pub enum InputMode {
    Insert,
    Normal,
}

pub struct App<'a> {
    pub running: bool,

    pub states: States<'a>,

    pub input_mode: InputMode,
}

impl<'a> App<'a> {
    pub fn new() -> App<'a> {
        App {
            running: true,
            states: States::new(),
            input_mode: InputMode::Normal,
        }
    }

    pub fn poll_events(&mut self) -> AppResult<()> {
        if let Event::Key(key) = event::read()? {
            // 'q' needs to be handled at the top level so it can't be
            // accidentally handed to a dead end
            if let KeyCode::Char('q') = key.code {
                if let Some(_) = self.states.nav_state.message.clone() {
                    self.states.nav_state.message = None;
                } else {
                    if let ActiveFrame::Navigation = self.states.active_frame {
                        self.running = false;
                    } else {
                        self.states.active_frame = ActiveFrame::Navigation;
                    }
                }
            }
            match self.states.active_frame {
                ActiveFrame::Navigation => {
                    NavigationState::handle_event(key, self);
                }
                ActiveFrame::History => {
                    HistoryState::handle_event(key, self);
                }
                ActiveFrame::NewTransaction => {
                    NewTransactionTabState::handle_event(key, self);
                }
            }
        }
        return Ok(())
    }
}

pub enum ActiveFrame {
    Navigation,
    NewTransaction,
    History,
}

pub struct States<'a> {
    pub nav_state: NavigationState<'a>,
    pub transactions: NewTransactionTabState<'a>,
    pub history: HistoryState,

    pub active_frame: ActiveFrame,
}

impl<'a> States<'a> {
    pub fn new() -> States<'a> {
        States {
            nav_state: NavigationState::new(),
            transactions: NewTransactionTabState::new(),
            history: HistoryState::new(),

            active_frame: ActiveFrame::Navigation,
        }
    }
}