refactor code

src/line.rs

@@ -2,18 +2,55 @@ use std::fmt;
 use std::fmt::Formatter;
 use std::ops::Deref;
 
+pub trait Line: fmt::Display {
+    fn is_difference(&self) -> bool;
+}
+
+/// Line represents a non-differing line.
+pub(crate) struct MatchedLine {
+    line_number: i32,
+    line: String,
+}
+
+impl MatchedLine {
+    /// Constructs a new Line instance
+    pub fn new(line_number: i32, line: String) -> MatchedLine {
+        MatchedLine { line_number, line }
+    }
+
+    /// get_line returns the line.
+    pub fn get_line(&self) -> &String {
+        &self.line
+    }
+}
+
+impl fmt::Display for MatchedLine {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        write!(f, r#"{}. {}"#, self.line_number, self.get_line(),)
+            .expect("Failed to write MatchedLine");
+        writeln!(f)
+    }
+}
+
+impl Line for MatchedLine {
+    fn is_difference(&self) -> bool {
+       false
+    }
+}
+
 /// A line difference is represented by the Difference struct.
 #[derive(Debug)]
-pub(crate) struct Difference {
+pub(crate) struct DifferingLine {
     line_number: i32,
     missing_line_indicator: String,
     left_line: String,
     right_line: String,
 }
 
-impl Difference {
-    pub fn new(line_number: i32, left_line: String, right_line: String) -> Difference {
-        Difference {
+impl DifferingLine {
+    /// Constructs a new difference instance.
+    pub fn new(line_number: i32, left_line: String, right_line: String) -> DifferingLine {
+        DifferingLine {
             line_number,
             missing_line_indicator: String::from("<missing line>"),
             left_line: left_line.into(),
@@ -40,20 +77,24 @@ impl Difference {
     }
 }
 
-/// Implements the display trait.
-impl fmt::Display for Difference {
+impl fmt::Display for DifferingLine {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         write!(
             f,
-            r#"Line: {}.
-< {}
-----
-> {}
-
-"#,
-            self.line_number,
+            r#"  - {}
+{}. ----
+  + {}"#,
             self.left_line(),
+            self.line_number,
             self.right_line()
         )
+        .expect("Failed to write DifferingLines");
+        writeln!(f)
+    }
+}
+
+impl Line for DifferingLine {
+    fn is_difference(&self) -> bool {
+        true
     }
 }

src/main.rs

@@ -1,41 +1,46 @@
-use crate::difference::Difference;
+use crate::line::{DifferingLine, Line, MatchedLine};
 use itertools::Itertools;
 use std::fs::read_to_string;
+use std::ops::Deref;
 
-mod difference;
+mod line;
 
-/// Gets the differences of lines that differ in the given text.
+/// Gets the lines of two given texts
 ///
-/// It returns a [`Vec<Difference>`]
-fn get_differences(left_text: &String, right_text: &String) -> Vec<Difference> {
+/// It returns a [`Vec<Box<dyn Line>>`]
+fn get_lines(left_text: &String, right_text: &String) -> Vec<Box<dyn Line>> {
     left_text
         .lines()
         .map(String::from)
         .zip_longest(right_text.lines().map(String::from))
         .enumerate()
-        .filter_map(|(line, item)| -> Option<Difference> {
+        .map(|(line, item)| -> Box<dyn Line> {
             let left = item.clone().left().unwrap_or(String::from(""));
             let right = item.right().unwrap_or(String::from(""));
 
             if left != right {
-                Some(Difference::new(line as i32 + 1, left, right))
+                Box::new(DifferingLine::new(line as i32 + 1, left, right))
             } else {
-                return None;
+                Box::new(MatchedLine::new(line as i32 + 1, left))
             }
         })
         .collect()
 }
 
 fn main() {
-    let left_file =
-        read_to_string("a.txt").expect("Left file not found");
-    let right_file =
-        read_to_string("b.txt").expect("Right file not found");
+    let left_file = read_to_string("a.txt").expect("Left file not found");
+    let right_file = read_to_string("b.txt").expect("Right file not found");
 
-    let res: Vec<Difference> = get_differences(&left_file, &right_file);
+    let lines: Vec<Box<dyn Line>> = get_lines(&left_file, &right_file);
 
-    for diff in res.iter() {
-        print!("{diff}")
+    let mut differences_counter: i32 = 0;
+    for line in lines.iter() {
+        let line = line.deref();
+        print!("{}", line);
+        if line.is_difference() {
+            differences_counter += 1;
         }
-    println!("Found {} differences.", res.len())
+    }
+    println!();
+    println!("Found {} differences.", differences_counter);
 }