day(10): refactor and fix tests

Signed-off-by: Matej Focko <mfocko@redhat.com>

src/bin/day10.rs

@@ -1,13 +1,12 @@
-use std::str::FromStr;
+use std::{fmt::Display, str::FromStr};
 
 use aoc_2022::*;
 
 use color_eyre::{eyre::eyre, Report};
 use itertools::Itertools;
-use tracing::{debug, info};
 
 type Input = Vec<Instruction>;
-type Output = i32;
+type Output = Out;
 
 #[derive(Debug)]
 enum Instruction {
@@ -32,6 +31,35 @@ impl FromStr for Instruction {
     }
 }
 
+#[derive(Debug, PartialEq, Eq)]
+enum Out {
+    Strengths(i32),
+    Screen(Vec<Vec<char>>),
+}
+
+impl Out {
+    fn new_strengths() -> Out {
+        Out::Strengths(0)
+    }
+
+    fn new_screen() -> Out {
+        Out::Screen(vec![vec![]])
+    }
+}
+
+impl Display for Out {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Out::Screen(screen) => write!(
+                f,
+                "\n{}",
+                screen.iter().map(|line| line.iter().join("")).join("\n")
+            ),
+            Out::Strengths(strengths) => write!(f, "{strengths}"),
+        }
+    }
+}
+
 struct State {
     cycle: i32,
     register: i32,
@@ -45,21 +73,9 @@ impl State {
         }
     }
 
-    fn execute(&self, i: &Instruction) -> (State, i32) {
-        let next = match i {
-            Instruction::Addx(value) => State {
-                cycle: self.cycle + 2,
-                register: self.register + value,
-            },
-            Instruction::Noop => State {
-                cycle: self.cycle + 1,
-                register: self.register,
-            },
-        };
-        // debug!("New state of CPU: cycle={}, register={}", next.cycle, next.register);
-
-        let strength = if let Some(cycle) =
-            (self.cycle..next.cycle).find(|&c| c >= 20 && (c + 20) % 40 == 0)
+    fn check_signal_strength(&self, next_cycle: i32, total: &mut i32) {
+        *total += if let Some(cycle) =
+            (self.cycle..next_cycle).find(|&c| c >= 20 && (c + 20) % 40 == 0)
         {
             // debug!(
             //     "Adding {} x {} = {} to sum",
@@ -72,11 +88,27 @@ impl State {
         } else {
             0
         };
-
-        (next, strength)
     }
 
-    fn execute_and_draw(&self, i: &Instruction, screen: &mut Vec<Vec<char>>) -> State {
+    fn draw_crt(&self, next_cycle: i32, screen: &mut Vec<Vec<char>>) {
+        // debug!("Checking: {:?} {:?}", i, (self.cycle..next.cycle));
+        (self.cycle..next_cycle).for_each(|c| {
+            if screen.is_empty() || screen.last().unwrap().len() == 40 {
+                screen.push(vec![]);
+            }
+
+            let idx = screen.len() - 1;
+            screen[idx].push(
+                if self.register - 1 <= (c - 1) % 40 && (c - 1) % 40 <= self.register + 1 {
+                    '█'
+                } else {
+                    ' '
+                },
+            );
+        });
+    }
+
+    fn execute(&self, i: &Instruction, output: &mut Out) -> State {
         let next = match i {
             Instruction::Addx(value) => State {
                 cycle: self.cycle + 2,
@@ -89,27 +121,25 @@ impl State {
         };
         // debug!("New state of CPU: cycle={}, register={}", next.cycle, next.register);
 
-        // debug!("Checking: {:?} {:?}", i, (self.cycle..next.cycle));
-        (self.cycle..next.cycle).for_each(|c| {
-            let idx = screen.len() - 1;
-            screen[idx].push(
-                if self.register - 1 <= (c - 1) % 40 && (c - 1) % 40 <= self.register + 1 {
-                    '█'
-                } else {
-                    ' '
-                },
-            );
-            // debug!("{} ; {} <= {} <= {}", screen[idx].last().unwrap(), self.register - 1, c % 40, self.register + 1);
-
-            if c % 40 == 0 {
-                screen.push(Vec::new());
-            }
-        });
+        match output {
+            Out::Screen(screen) => self.draw_crt(next.cycle, screen),
+            Out::Strengths(strengths) => self.check_signal_strength(next.cycle, strengths),
+        }
 
         next
     }
 }
 
+fn evaluate_instructions(instructions: &[Instruction], mut out: Output) -> Output {
+    instructions
+        .iter()
+        .fold(State::new(), |state, instruction| {
+            state.execute(instruction, &mut out)
+        });
+
+    out
+}
+
 struct Day10;
 impl Solution<Input, Output> for Day10 {
     fn parse_input<P: AsRef<Path>>(pathname: P) -> Input {
@@ -117,29 +147,11 @@ impl Solution<Input, Output> for Day10 {
     }
 
     fn part_1(input: &Input) -> Output {
-        input
-            .iter()
-            .fold((State::new(), 0), |(state, strength_sum), instruction| {
-                let (new_state, strength) = state.execute(instruction);
-
-                (new_state, strength_sum + strength)
-            })
-            .1
+        evaluate_instructions(input, Out::new_strengths())
     }
 
     fn part_2(input: &Input) -> Output {
-        let mut screen: Vec<Vec<char>> = vec![vec![]];
-
-        input.iter().fold(State::new(), |state, instruction| {
-            state.execute_and_draw(instruction, &mut screen)
-        });
-
-        info!(
-            "Screen:\n{}",
-            screen.iter().map(|line| line.iter().join("")).join("\n")
-        );
-
-        0
+        evaluate_instructions(input, Out::new_screen())
     }
 }
 
@@ -147,4 +159,19 @@ fn main() -> Result<()> {
     Day10::main()
 }
 
-test_sample!(day_10, Day10, 13140, 1);
+test_sample!(
+    day_10,
+    Day10,
+    Out::Strengths(13140),
+    Out::Screen(
+        ("██  ██  ██  ██  ██  ██  ██  ██  ██  ██  \n\
+            ███   ███   ███   ███   ███   ███   ███ \n\
+            ████    ████    ████    ████    ████    \n\
+            █████     █████     █████     █████     \n\
+            ██████      ██████      ██████      ████\n\
+            ███████       ███████       ███████     ")
+            .lines()
+            .map(|l| l.chars().collect_vec())
+            .collect_vec()
+    )
+);