//! Sensors and coverage (spec/basement-map.md).
//!
//! A sensor covers a radius around its position; the player's vision is the
//! union of the sensors they control. Uncontrolled sensors belong to the
//! facility (dock camera, corridor nodes) and render as fog until claimed.

use std::collections::HashSet;

use crate::map::GameMap;

#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub struct Sensor {
    pub name: String,
    pub x: i32,
    pub y: i32,
    pub radius: i32,
    pub controlled: bool,
}

impl Sensor {
    pub fn new(name: impl Into<String>, x: i32, y: i32, radius: i32, controlled: bool) -> Self {
        Self {
            name: name.into(),
            x,
            y,
            radius,
            controlled,
        }
    }

    /// Insert every tile within radius (Chebyshev) that isn't blocked by a
    /// wall on the straight line — simple radial reveal, no full raycast.
    pub fn cover_into(&self, out: &mut HashSet<(i32, i32)>, map: &GameMap) {
        for dy in -self.radius..=self.radius {
            for dx in -self.radius..=self.radius {
                let (tx, ty) = (self.x + dx, self.y + dy);
                if !map.in_bounds(tx, ty) {
                    continue;
                }
                if dx * dx + dy * dy > self.radius * self.radius {
                    continue;
                }
                out.insert((tx, ty));
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn coverage_is_a_disc() {
        let map = GameMap::new(0, 0);
        let s = Sensor::new("cam", 20, 15, 3, true);
        let mut set = HashSet::new();
        s.cover_into(&mut set, &map);
        assert!(set.contains(&(20, 15)));
        assert!(set.contains(&(22, 15)));
        assert!(!set.contains(&(25, 15)), "outside radius");
    }
}