Split commands.rs into separate files (#2792)

crates/ruff_cli/src/commands/rule.rs

@@ -0,0 +1,98 @@
+use std::io::{self, BufWriter, Write};
+
+use anyhow::Result;
+use colored::control::SHOULD_COLORIZE;
+use mdcat::terminal::{TerminalProgram, TerminalSize};
+use mdcat::{Environment, ResourceAccess, Settings};
+use pulldown_cmark::{Options, Parser};
+use serde::Serialize;
+use syntect::parsing::SyntaxSet;
+
+use ruff::registry::{Linter, Rule, RuleNamespace};
+use ruff::AutofixAvailability;
+
+use crate::args::HelpFormat;
+
+#[derive(Serialize)]
+struct Explanation<'a> {
+    code: &'a str,
+    linter: &'a str,
+    summary: &'a str,
+}
+
+/// Explain a `Rule` to the user.
+pub fn rule(rule: &Rule, format: HelpFormat) -> Result<()> {
+    let (linter, _) = Linter::parse_code(rule.code()).unwrap();
+    let mut stdout = BufWriter::new(io::stdout().lock());
+    let mut output = String::new();
+
+    match format {
+        HelpFormat::Text | HelpFormat::Markdown => {
+            output.push_str(&format!("# {} ({})", rule.as_ref(), rule.code()));
+            output.push('\n');
+            output.push('\n');
+
+            let (linter, _) = Linter::parse_code(rule.code()).unwrap();
+            output.push_str(&format!("Derived from the **{}** linter.", linter.name()));
+            output.push('\n');
+            output.push('\n');
+
+            if let Some(autofix) = rule.autofixable() {
+                output.push_str(match autofix.available {
+                    AutofixAvailability::Sometimes => "Autofix is sometimes available.",
+                    AutofixAvailability::Always => "Autofix is always available.",
+                });
+                output.push('\n');
+                output.push('\n');
+            }
+
+            if let Some(explanation) = rule.explanation() {
+                output.push_str(explanation.trim());
+            } else {
+                output.push_str("Message formats:");
+                for format in rule.message_formats() {
+                    output.push('\n');
+                    output.push_str(&format!("* {format}"));
+                }
+            }
+        }
+        HelpFormat::Json => {
+            output.push_str(&serde_json::to_string_pretty(&Explanation {
+                code: rule.code(),
+                linter: linter.name(),
+                summary: rule.message_formats()[0],
+            })?);
+        }
+    };
+
+    match format {
+        HelpFormat::Json | HelpFormat::Text => {
+            writeln!(stdout, "{output}")?;
+        }
+        HelpFormat::Markdown => {
+            let parser = Parser::new_ext(
+                &output,
+                Options::ENABLE_TASKLISTS | Options::ENABLE_STRIKETHROUGH,
+            );
+
+            let cwd = std::env::current_dir()?;
+            let env = &Environment::for_local_directory(&cwd)?;
+
+            let terminal = if SHOULD_COLORIZE.should_colorize() {
+                TerminalProgram::detect()
+            } else {
+                TerminalProgram::Dumb
+            };
+
+            let settings = &Settings {
+                resource_access: ResourceAccess::LocalOnly,
+                syntax_set: SyntaxSet::load_defaults_newlines(),
+                terminal_capabilities: terminal.capabilities(),
+                terminal_size: TerminalSize::detect().unwrap_or_default(),
+            };
+
+            mdcat::push_tty(settings, env, &mut stdout, parser)?;
+        }
+    };
+    Ok(())
+}