// This file is part of Deja-vu.
//
// Deja-vu is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Deja-vu is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Deja-vu. If not, see <https://www.gnu.org/licenses/>.
//
use std::collections::{hash_map, HashMap};

use ratatui::widgets::ListState;

#[derive(Default, Debug, Clone, PartialEq)]
pub struct StatefulList<T> {
    pub state: ListState,
    pub items: Vec<T>,
    pub last_selected: Option<usize>,
    pub selected: HashMap<usize, bool>,
}

impl<T: Clone> StatefulList<T> {
    #[must_use]
    pub fn new() -> StatefulList<T> {
        StatefulList {
            state: ListState::default(),
            items: Vec::new(),
            last_selected: None,
            selected: HashMap::new(),
        }
    }

    pub fn clear_items(&mut self) {
        // Clear list and rebuild with provided items
        self.items.clear();
    }

    #[must_use]
    pub fn get_selected(&self) -> Option<&T> {
        if let Some(i) = self.state.selected() {
            self.items.get(i)
        } else {
            None
        }
    }

    pub fn pop_selected(&mut self) -> Option<T> {
        if let Some(i) = self.state.selected() {
            Some(self.items[i].clone())
        } else {
            None
        }
    }

    fn select_first_item(&mut self) {
        if self.items.is_empty() {
            self.state.select(None);
        } else {
            self.state.select(Some(0));
        }
        self.last_selected = None;
    }

    pub fn set_items(&mut self, items: Vec<T>) {
        // Clear list and rebuild with provided items
        self.clear_items();
        for item in items {
            self.items.push(item);
        }

        // Reset state and select first item (if available)
        self.state = ListState::default();
        self.select_first_item();
    }

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

    pub fn previous(&mut self) {
        if self.items.is_empty() {
            return;
        }
        let i = match self.state.selected() {
            Some(i) => {
                if i == 0 {
                    self.items.len() - 1
                } else {
                    i - 1
                }
            }
            None => self.last_selected.unwrap_or(0),
        };
        self.state.select(Some(i));
    }
    pub fn toggle_selected(&mut self) {
        if let Some(i) = self.state.selected() {
            if let hash_map::Entry::Vacant(e) = self.selected.entry(i) {
                // Was NOT selected, WILL be shortly
                self.last_selected = Some(i);
                e.insert(true);
            } else {
                // WAS selected, will NOT be shortly
                self.last_selected = None;
                self.selected.remove(&i);
            }
        }
    }
}