1 files changed, 97 insertions, 0 deletions
diff --git a/src/progress_bar.rs b/src/progress_bar.rs
new file mode 100644
index 0000000..d6962b8
--- /dev/null
+++ b/src/progress_bar.rs
@@ -0,0 +1,97 @@
+use anyhow::{bail, Result};
+use ratatui::text::{Line, Span};
+use std::fmt::Write;
+
+const PREFIX: &str = "Progress: [";
+const PREFIX_WIDTH: u16 = PREFIX.len() as u16;
+// Leaving the last char empty (_) for `total` > 99.
+const POSTFIX_WIDTH: u16 = "] xxx/xx exercises_".len() as u16;
+const WRAPPER_WIDTH: u16 = PREFIX_WIDTH + POSTFIX_WIDTH;
+const MIN_LINE_WIDTH: u16 = WRAPPER_WIDTH + 4;
+
+const PROGRESS_EXCEEDS_MAX_ERR: &str =
+    "The progress of the progress bar is higher than the maximum";
+
+pub fn progress_bar(progress: u16, total: u16, line_width: u16) -> Result<String> {
+    use crossterm::style::Stylize;
+
+    if progress > total {
+        bail!(PROGRESS_EXCEEDS_MAX_ERR);
+    }
+
+    if line_width < MIN_LINE_WIDTH {
+        return Ok(format!("Progress: {progress}/{total} exercises"));
+    }
+
+    let mut line = String::with_capacity(usize::from(line_width));
+    line.push_str(PREFIX);
+
+    let width = line_width - WRAPPER_WIDTH;
+    let filled = (width * progress) / total;
+
+    let mut green_part = String::with_capacity(usize::from(filled + 1));
+    for _ in 0..filled {
+        green_part.push('#');
+    }
+
+    if filled < width {
+        green_part.push('>');
+    }
+    write!(line, "{}", green_part.green()).unwrap();
+
+    let width_minus_filled = width - filled;
+    if width_minus_filled > 1 {
+        let red_part_width = width_minus_filled - 1;
+        let mut red_part = String::with_capacity(usize::from(red_part_width));
+        for _ in 0..red_part_width {
+            red_part.push('-');
+        }
+        write!(line, "{}", red_part.red()).unwrap();
+    }
+
+    writeln!(line, "] {progress:>3}/{total} exercises").unwrap();
+
+    Ok(line)
+}
+
+pub fn progress_bar_ratatui(progress: u16, total: u16, line_width: u16) -> Result<Line<'static>> {
+    use ratatui::style::Stylize;
+
+    if progress > total {
+        bail!(PROGRESS_EXCEEDS_MAX_ERR);
+    }
+
+    if line_width < MIN_LINE_WIDTH {
+        return Ok(Line::raw(format!("Progress: {progress}/{total} exercises")));
+    }
+
+    let mut spans = Vec::with_capacity(4);
+    spans.push(Span::raw(PREFIX));
+
+    let width = line_width - WRAPPER_WIDTH;
+    let filled = (width * progress) / total;
+
+    let mut green_part = String::with_capacity(usize::from(filled + 1));
+    for _ in 0..filled {
+        green_part.push('#');
+    }
+
+    if filled < width {
+        green_part.push('>');
+    }
+    spans.push(green_part.green());
+
+    let width_minus_filled = width - filled;
+    if width_minus_filled > 1 {
+        let red_part_width = width_minus_filled - 1;
+        let mut red_part = String::with_capacity(usize::from(red_part_width));
+        for _ in 0..red_part_width {
+            red_part.push('-');
+        }
+        spans.push(red_part.red());
+    }
+
+    spans.push(Span::raw(format!("] {progress:>3}/{total} exercises")));
+
+    Ok(Line::from(spans))
+}