use std::{error, collections::HashMap};
use ratatui::widgets::ListState;
use wad::{Wad, load_wad_file};

use crate::lumps::{LumpInfo, get_lumps, LumpType};

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

/// Application.

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

impl<T> StatefulList<T> {
    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 struct App {
    pub wad:Wad,
    pub lumps:StatefulList<LumpInfo>,
    pub sizes: HashMap<Option<LumpType>, usize>,
    pub running:bool,
}

impl App {
    fn from_wad(wad_path:&str) -> Self {
        let wad = load_wad_file(wad_path).unwrap();
        let lumps = get_lumps(&wad);
        let mut sizes = HashMap::new();
        for lump in lumps.iter() {
            if let Some(LumpType::Marker(_, _)) = lump.lump_type {
                continue;
            }
            sizes.insert(lump.lump_type.clone(), sizes.get(&lump.lump_type).unwrap_or(&0) + lump.size);
        }
        Self {
            wad: wad,
            lumps: StatefulList::with_items(lumps),
            sizes: sizes,
            running: true
        }
    }
}

impl App {
    /// Constructs a new instance of [`App`].
    pub fn new(wad_path:&str) -> Self {
        Self::from_wad(wad_path)
    }

    /// Handles the tick event of the terminal.
    pub fn tick(&self) {}

    /// Set running to false to quit the application.
    pub fn quit(&mut self) {
        self.running = false;
    }

}