From e1e1063d15a97bf93ec6dd1a082f78b0c3191d1d Mon Sep 17 00:00:00 2001
From: mat <git@matdoes.dev>
Date: Tue, 9 May 2023 22:05:46 -0500
Subject: astar

---
 azalea/src/pathfinder/astar.rs | 106 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 azalea/src/pathfinder/astar.rs

(limited to 'azalea/src/pathfinder/astar.rs')

diff --git a/azalea/src/pathfinder/astar.rs b/azalea/src/pathfinder/astar.rs
new file mode 100644
index 00000000..858e7720
--- /dev/null
+++ b/azalea/src/pathfinder/astar.rs
@@ -0,0 +1,106 @@
+use std::{cmp::Reverse, collections::HashMap, fmt::Debug, hash::Hash, ops::Add};
+
+use priority_queue::PriorityQueue;
+
+pub fn a_star<N, W, HeuristicFn, SuccessorsFn, SuccessFn>(
+    start: N,
+    heuristic: HeuristicFn,
+    successors: SuccessorsFn,
+    success: SuccessFn,
+) -> Option<Vec<N>>
+where
+    N: Eq + Hash + Copy + Debug,
+    W: PartialOrd + Default + Copy + num_traits::Bounded + Debug + Add<Output = W>,
+    HeuristicFn: Fn(&N) -> W,
+    SuccessorsFn: Fn(&N) -> Vec<Edge<N, W>>,
+    SuccessFn: Fn(&N) -> bool,
+{
+    let mut open_set = PriorityQueue::new();
+    open_set.push(start, Reverse(Weight(W::default())));
+    let mut nodes: HashMap<N, Node<N, W>> = HashMap::new();
+    nodes.insert(
+        start,
+        Node {
+            data: start,
+            came_from: None,
+            g_score: W::default(),
+            f_score: W::max_value(),
+        },
+    );
+
+    while let Some((current_node, _)) = open_set.pop() {
+        if success(&current_node) {
+            return Some(reconstruct_path(&nodes, current_node));
+        }
+
+        let current_g_score = nodes
+            .get(&current_node)
+            .map(|n| n.g_score)
+            .unwrap_or(W::max_value());
+
+        for neighbor in successors(&current_node) {
+            let tentative_g_score = current_g_score + neighbor.cost;
+            let neighbor_g_score = nodes
+                .get(&neighbor.target)
+                .map(|n| n.g_score)
+                .unwrap_or(W::max_value());
+            if tentative_g_score < neighbor_g_score {
+                let f_score = tentative_g_score + heuristic(&neighbor.target);
+                nodes.insert(
+                    neighbor.target,
+                    Node {
+                        data: neighbor.target,
+                        came_from: Some(current_node),
+                        g_score: tentative_g_score,
+                        f_score,
+                    },
+                );
+                open_set.push(neighbor.target, Reverse(Weight(f_score)));
+            }
+        }
+    }
+
+    None
+}
+
+fn reconstruct_path<N, W>(nodes: &HashMap<N, Node<N, W>>, current: N) -> Vec<N>
+where
+    N: Eq + Hash + Copy + Debug,
+    W: PartialOrd + Default + Copy + num_traits::Bounded + Debug,
+{
+    let mut path = vec![current];
+    let mut current = current;
+    while let Some(node) = nodes.get(&current) {
+        if let Some(came_from) = node.came_from {
+            path.push(came_from);
+            current = came_from;
+        } else {
+            break;
+        }
+    }
+    path.reverse();
+    path
+}
+
+pub struct Node<N, W> {
+    pub data: N,
+    pub came_from: Option<N>,
+    pub g_score: W,
+    pub f_score: W,
+}
+
+pub struct Edge<N: Eq + Hash + Copy, W: PartialOrd + Copy> {
+    pub target: N,
+    pub cost: W,
+}
+
+#[derive(PartialOrd, PartialEq)]
+pub struct Weight<W: PartialOrd + Debug>(W);
+impl<W: PartialOrd + Debug> Ord for Weight<W> {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        self.0
+            .partial_cmp(&other.0)
+            .unwrap_or(std::cmp::Ordering::Equal)
+    }
+}
+impl<W: PartialOrd + Debug> Eq for Weight<W> {}
-- 
cgit v1.2.3


From 80172e43640d2ec3c761611d2269d12a9abdd424 Mon Sep 17 00:00:00 2001
From: mat <github@matdoes.dev>
Date: Fri, 12 May 2023 18:53:08 +0000
Subject: fix warnings

---
 azalea-brigadier/src/arguments/bool_argument_type.rs   | 2 +-
 azalea-brigadier/src/arguments/string_argument_type.rs | 2 +-
 azalea/src/pathfinder/astar.rs                         | 7 ++++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

(limited to 'azalea/src/pathfinder/astar.rs')

diff --git a/azalea-brigadier/src/arguments/bool_argument_type.rs b/azalea-brigadier/src/arguments/bool_argument_type.rs
index 01828c87..57fa8a03 100644
--- a/azalea-brigadier/src/arguments/bool_argument_type.rs
+++ b/azalea-brigadier/src/arguments/bool_argument_type.rs
@@ -12,7 +12,7 @@ impl ArgumentType for bool {
     }
 }
 
-pub fn get_bool<'a, S>(context: &'a CommandContext<S>, name: &str) -> Option<bool> {
+pub fn get_bool<S>(context: &CommandContext<S>, name: &str) -> Option<bool> {
     context
         .argument(name)
         .unwrap()
diff --git a/azalea-brigadier/src/arguments/string_argument_type.rs b/azalea-brigadier/src/arguments/string_argument_type.rs
index f23af3ba..27363bd4 100644
--- a/azalea-brigadier/src/arguments/string_argument_type.rs
+++ b/azalea-brigadier/src/arguments/string_argument_type.rs
@@ -44,7 +44,7 @@ pub fn string() -> impl ArgumentType {
 pub fn greedy_string() -> impl ArgumentType {
     StringArgument::GreedyPhrase
 }
-pub fn get_string<'a, S>(context: &'a CommandContext<S>, name: &str) -> Option<String> {
+pub fn get_string<S>(context: &CommandContext<S>, name: &str) -> Option<String> {
     context
         .argument(name)
         .unwrap()
diff --git a/azalea/src/pathfinder/astar.rs b/azalea/src/pathfinder/astar.rs
index 858e7720..65caf337 100644
--- a/azalea/src/pathfinder/astar.rs
+++ b/azalea/src/pathfinder/astar.rs
@@ -94,7 +94,7 @@ pub struct Edge<N: Eq + Hash + Copy, W: PartialOrd + Copy> {
     pub cost: W,
 }
 
-#[derive(PartialOrd, PartialEq)]
+#[derive(PartialEq)]
 pub struct Weight<W: PartialOrd + Debug>(W);
 impl<W: PartialOrd + Debug> Ord for Weight<W> {
     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
@@ -104,3 +104,8 @@ impl<W: PartialOrd + Debug> Ord for Weight<W> {
     }
 }
 impl<W: PartialOrd + Debug> Eq for Weight<W> {}
+impl<W: PartialOrd + Debug> PartialOrd for Weight<W> {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        self.0.partial_cmp(&other.0)
+    }
+}
-- 
cgit v1.2.3