From 77f1bc76895566a645f35e6ef9ef8ac3f783679b Mon Sep 17 00:00:00 2001
From: =?utf8?q?Gr=C3=A9gory=20Burri?= <gregory.burri@matisa.ch>
Date: Fri, 20 Dec 2019 09:52:38 +0100
Subject: [PATCH] Add movements (part2, WIP)

---
 src/day17.rs | 113 ++++++++++++++++++++++++++++++++-------------------
 1 file changed, 72 insertions(+), 41 deletions(-)

diff --git a/src/day17.rs b/src/day17.rs
index 6998995..c64ed0e 100644
--- a/src/day17.rs
+++ b/src/day17.rs
@@ -1,7 +1,7 @@
 use super::intcode;
 use std::collections::HashSet;
 
-#[derive(PartialEq, Eq, Copy, Clone)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
 enum Direction { Up, Left, Down, Right }
 
 impl Direction {
@@ -16,14 +16,19 @@ impl Direction {
     }
 }
 
-#[derive(PartialEq, Eq, Copy, Clone)]
-struct MovementCommand { dir: Direction, steps: u32 }
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+enum Movement { Left, Right }
+
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+struct MovementCommand { mov: Movement, steps: u32 }
 
 pub struct RobotTrackingSystem {
     output: Vec<i64>,
     board: Vec<Vec<char>>,
     start_position: (i32, i32),
     start_dir: Direction,
+    crossings: Vec<(i32, i32)>,
+    dir_commands: Vec<MovementCommand>,
 }
 
 impl RobotTrackingSystem {
@@ -33,6 +38,8 @@ impl RobotTrackingSystem {
             board: Vec::<Vec<char>>::new(),
             start_position: (0, 0),
             start_dir: Direction::Up,
+            crossings: Vec::<(i32, i32)>::new(),
+            dir_commands: Vec::<MovementCommand>::new(),
         }
     }
 
@@ -68,6 +75,63 @@ impl RobotTrackingSystem {
                 current_x += 1;
             }
         }
+
+        self.output.clear();
+        self.run_through();
+    }
+
+    // Run the path and find the crossings and define the movements.
+    fn run_through(&mut self) {
+        let (mut x, mut y) = self.start_position;
+        let mut dir = self.start_dir;
+        let mut visited_locations = HashSet::<(i32, i32)>::new();
+        visited_locations.insert((x, y));
+
+        let mut last_mov = Movement::Left;
+        let mut steps = 0;
+
+        'main: loop {
+            let positions = [(Direction::Up, (x, y - 1)), (Direction::Left, (x - 1, y)), (Direction::Right, (x + 1, y)), (Direction::Down, (x, y + 1))];
+
+            let next_position = positions.iter().find(|(d, _)| *d == dir).unwrap().1;
+
+            // If the robot can continue straightforward.
+            if self.get(next_position.0, next_position.1) == Some('#') {
+                if !visited_locations.insert(next_position) {
+                    self.crossings.push(next_position);
+                }
+                steps += 1;
+                x = next_position.0;
+                y = next_position.1;
+                continue;
+            }
+
+            if steps != 0 {
+                self.dir_commands.push(MovementCommand { mov: last_mov, steps });
+                steps = 0;
+            }
+
+            for (d, p) in &positions {
+                if self.get(p.0, p.1) == Some('#') && !visited_locations.contains(p) {
+
+                    last_mov =
+                        match (dir, *d) {
+                            (Direction::Up, Direction::Right) | (Direction::Right, Direction::Down) | (Direction::Down, Direction::Left) | (Direction::Left, Direction::Up) => Movement::Right,
+                            (Direction::Up, Direction::Left) | (Direction::Left, Direction::Down) | (Direction::Down, Direction::Right) | (Direction::Right, Direction::Up) => Movement::Left,
+                            _ => panic!("Unable to find a movement from {:?} to {:?}", dir, *d)
+                        };
+
+                    visited_locations.insert(*p);
+                    steps += 1;
+                    dir = *d;
+                    x = p.0;
+                    y = p.1;
+                    continue 'main;
+                }
+            }
+
+            break;
+        }
     }
 }
 
@@ -75,7 +139,7 @@ impl intcode::IO for RobotTrackingSystem {
     // May block.
     fn read(&mut self) -> i64 {
         self.build_board_from_output();
-        42
+        42 // TODO: part2.
     }
 
     // Send to the output channel.
@@ -91,44 +155,11 @@ impl intcode::IO for RobotTrackingSystem {
 pub fn scaffold_intersections(code: &[i64]) -> i32 {
     let mut rts = RobotTrackingSystem::new();
     intcode::execute_op_code_with_custom_io(code, &mut rts);
-
-    let (mut x, mut y) = rts.start_position;
-    let mut dir = rts.start_dir;
-    let mut visited_locations = HashSet::<(i32, i32)>::new();
-    let mut crosses = Vec::<(i32, i32)>::new();
-    visited_locations.insert((x, y));
-
-    'main: loop {
-        let positions = [(Direction::Up, (x, y - 1)), (Direction::Left, (x - 1, y)), (Direction::Right, (x + 1, y)), (Direction::Down, (x, y + 1))];
-
-        let next_position = positions.iter().find(|(d, _)| *d == dir).unwrap().1;
-
-        // If the robot can continue straightforward.
-        if rts.get(next_position.0, next_position.1) == Some('#') {
-            if !visited_locations.insert(next_position) {
-                crosses.push(next_position);
-            }
-            x = next_position.0;
-            y = next_position.1;
-            continue;
-        }
-
-        for (d, p) in &positions {
-            if rts.get(p.0, p.1) == Some('#') && !visited_locations.contains(p) {
-                visited_locations.insert(*p);
-                dir = *d;
-                x = p.0;
-                y = p.1;
-                continue 'main;
-            }
-        }
-
-        break;
-    }
-
-    crosses.iter().fold(0, |sum, cross| sum + cross.0 * cross.1)
+    rts.crossings.iter().fold(0, |sum, crossing| sum + crossing.0 * crossing.1)
 }
 
 pub fn part2(code: &[i64]) {
+    let mut rts = RobotTrackingSystem::new();
+    intcode::execute_op_code_with_custom_io(code, &mut rts);
 
-}
\ No newline at end of file
+}
-- 
2.45.2