initial commit

src/algorithm.rs

@@ -0,0 +1,170 @@
+//! ## Algorithm
+//!
+//! This module contains the definition of the [`Algorithm`] trait, implemented by [`Maze`] resolution strategies.
+//! Already existing implementations of that trait can be found in the [`crate::implementations`] module.
+//!
+
+use std::{
+    collections::{HashMap, HashSet},
+    thread,
+    time::Duration,
+};
+
+use crate::{Maze, Pos};
+
+/// A guess to pass to the current [`Executor`] at the end of every `progress` call.
+pub struct Guess(Vec<Pos>);
+
+/// An insight given to the [`Algorithm`] on every `progress` call.
+/// On the first time about the starting point and every consecutive call about the tail of the previous guess.
+pub struct Insight<'p> {
+    position: Pos,
+    paths: &'p [Pos],
+}
+
+impl<'p> Insight<'p> {
+    fn new(position: Pos, paths: &'p [Pos]) -> Self {
+        Self { paths, position }
+    }
+
+    fn from_position(position: Pos, maze: &'p Maze) -> Self {
+        let paths = maze.paths_from(position);
+        Self::new(position, paths)
+    }
+
+    /// The position of the insight.
+    pub fn position(&self) -> Pos {
+        self.position
+    }
+
+    /// the paths from that position.
+    pub fn paths(&self) -> &[Pos] {
+        self.paths
+    }
+}
+
+/// A context given to the [`Algorithm`] on every `progress` call, provide informations about the maze and method to create a [`Guess`].
+pub struct Context<'m> {
+    maze: &'m Maze,
+}
+
+impl<'m> Context<'m> {
+    fn new(maze: &'m Maze) -> Self {
+        Self { maze }
+    }
+
+    /// Constructor for [`Guess`].
+    /// Takes a path, that is a vector of positions from the starting point to the position to discover on the next call to `progress`.
+    pub fn guess(&self, pos: Vec<Pos>) -> Guess {
+        Guess(pos)
+    }
+
+    /// Returns the position of the `start` of the [`Maze`].
+    pub fn start(&self) -> Pos {
+        self.maze.start()
+    }
+
+    /// Returns the position of the `end` of the [`Maze`].
+    pub fn end(&self) -> Pos {
+        self.maze.end()
+    }
+
+    /// Returns the `width` of the [`Maze`].
+    pub fn width(&self) -> isize {
+        self.maze.width()
+    }
+
+    /// Returns the `height` of the [`Maze`].
+    pub fn height(&self) -> isize {
+        self.maze.width()
+    }
+
+    /// Returns a tuple containing both the `width` and `height` of the [`Maze`].
+    pub fn size(&self) -> (isize, isize) {
+        self.maze.size()
+    }
+}
+
+/// Trait encapsulating the behavior of an algorithm solving mazes.
+/// Implementing this trait is done by providing a `progress` method which gets called iteratively on each steps of a [`Maze`] resolution.
+pub trait Algorithm {
+    /// will be called on each step of the traversal of the [`Maze`].
+    /// `insight` is a view on the position discovered on the previous movement.
+    /// `ctx` is a view on the [`Maze`], useful for accessing properties of the maze.
+    fn progress(&mut self, insight: &Insight, ctx: &mut Context) -> Guess;
+}
+
+/// A structure holding a [`Maze`] and iteratively solving it with a provided [`Algorithm`].
+pub struct Executor<Algo>
+where
+    Algo: Algorithm,
+{
+    maze: Maze,
+    algorithm: Algo,
+}
+
+impl<A> Executor<A>
+where
+    A: Algorithm,
+{
+    /// Constructor.
+    pub fn new(maze: Maze, algorithm: A) -> Self {
+        Self { maze, algorithm }
+    }
+
+    /// Submit the maze to the [`Algorithm`] and iteratively progress through the maze driven by said algorithm.
+    pub fn run(&mut self) {
+        let Self { maze, algorithm } = self;
+        let mut insight = Insight::from_position(maze.start(), &maze);
+        let mut tick = 0;
+        let mut tried = HashSet::new();
+        loop {
+            let mut context = Context::new(maze);
+            let Guess(guess) = algorithm.progress(&insight, &mut context);
+            // TODO:
+            // - extract metrics from the context
+            // - check if path is actually a path
+            guess.iter().for_each(|&p| {
+                tried.insert(p);
+            });
+            let tail = *guess.last().expect("returned an empty path");
+
+            // draw
+            Self::draw(maze, &tried, tick, &guess);
+            thread::sleep(Duration::from_millis(100));
+            tick += 1;
+
+            // check for next iteration
+            if maze.is_end(tail) {
+                break;
+            } else {
+                insight = Insight::from_position(tail, maze)
+            }
+        }
+    }
+
+    fn draw(maze: &Maze, tried: &HashSet<Pos>, tick: usize, path: &Vec<Pos>) {
+        let mut overlay = HashMap::new();
+        for position in tried {
+            overlay.insert(*position, 'T');
+        }
+
+        for position in path {
+            overlay.insert(*position, '#');
+        }
+
+        overlay.insert(*path.last().unwrap(), 'G');
+
+        let text = maze.display(Some(overlay));
+
+        // DIRTY!
+        // print the frame on top of the previous one
+        if tick > 0 {
+            let count = text.lines().count() + 1;
+            let up = termion::cursor::Up(count as u16);
+            print!("{up}")
+        }
+
+        print!("tick {tick}:\n{text}\n");
+    }
+}