// -*- coding: utf-8 -*-
//
// Copyright 2021 Michael Büsch <m@bues.ch>
//
// Derived from https://github.com/mlochen/dungeon.git
// Copyright (C) 2020 Marco Lochen
//
// This program 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 2 of the License, or
// (at your option) any later version.
//
// This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
//

use crate::player::Player;
use crate::vec2d::Vec2D;
use crate::world::World;

pub struct Wall {
    dir: Vec2D,
    pos: Vec2D,
    p1: Vec2D,
    p2: Vec2D,
}

impl Wall {
    pub fn new(dir: Vec2D, pos: Vec2D) -> Wall {
        let p1 = pos - (dir * 0.5);
        let p2 = pos + (dir * 0.5);
        Wall { dir, pos, p1, p2 }
    }

    #[inline]
    pub fn get_dir(&self) -> Vec2D {
        self.dir
    }

    #[inline]
    pub fn get_pos(&self) -> Vec2D {
        self.pos
    }

    #[inline]
    pub fn get_p1(&self) -> Vec2D {
        self.p1
    }

    #[inline]
    pub fn get_p2(&self) -> Vec2D {
        self.p2
    }
}

pub struct VisibleWallsIter<'a> {
    world: &'a World,
    player: &'a Player,
    index: usize,
}

impl<'a> VisibleWallsIter<'a> {
    pub fn new(world: &'a World, player: &'a Player) -> VisibleWallsIter<'a> {
        VisibleWallsIter {
            world,
            player,
            index: 0,
        }
    }

    pub fn sorted_by_distance(&mut self, ascending: bool) -> Vec<&'a Wall> {
        let player_pos = self.player.get_pos();
        let mut walls: Vec<&Wall> = self.collect();
        walls.sort_unstable_by(|a, b| {
            let alen = (player_pos - a.get_pos()).len();
            let blen = (player_pos - b.get_pos()).len();
            if ascending {
                alen.partial_cmp(&blen).unwrap()
            } else {
                blen.partial_cmp(&alen).unwrap()
            }
        });
        walls
    }
}

impl<'a> Iterator for VisibleWallsIter<'a> {
    type Item = &'a Wall;

    fn next(&mut self) -> Option<Self::Item> {
        let walls = self.world.get_walls();
        while self.index < walls.len() {
            let wall = &walls[self.index];
            self.index += 1;
            if self.player.wall_is_in_fov(wall) {
                return Some(wall);
            }
        }
        None
    }
}

// vim: ts=4 sw=4 expandtab