Add redirects command

brood/src/commands.rs

@@ -1,4 +1,5 @@
 pub mod export;
 pub mod ingest;
 pub mod path;
+pub mod redirects;
 pub mod show;

brood/src/commands/redirects.rs

@@ -0,0 +1,107 @@
+use std::{cmp::Reverse, collections::HashSet, io};
+
+use thousands::Separable;
+
+use crate::{data::Data, graph::NodeIdx, util};
+
+fn find_redirects(data: &Data) -> Vec<(NodeIdx, NodeIdx, usize)> {
+    let mut redirects = Vec::<(NodeIdx, NodeIdx, usize)>::new();
+
+    for node in data.graph.nodes() {
+        if !data.pages[node.usize()].redirect {
+            continue;
+        }
+
+        let mut seen = HashSet::new();
+
+        let mut curr = node;
+        seen.insert(node);
+
+        while let Some(next) = data.redirect_target(curr) {
+            if seen.contains(&next) {
+                println!("  Redirect loop: {}", data.pages[node.usize()].title);
+                break;
+            }
+
+            curr = next;
+            seen.insert(next);
+        }
+
+        redirects.push((node, curr, seen.len() - 1));
+    }
+
+    redirects
+}
+
+fn follow_redirect(data: &Data, start: NodeIdx) -> Vec<NodeIdx> {
+    let mut seen = HashSet::new();
+    let mut nodes = Vec::new();
+
+    let mut curr = start;
+    seen.insert(curr);
+    nodes.push(curr);
+
+    while let Some(next) = data.redirect_target(curr) {
+        if seen.contains(&next) {
+            break;
+        }
+
+        curr = next;
+        seen.insert(curr);
+        nodes.push(curr);
+    }
+
+    nodes
+}
+
+/// Show interesting redirect stats.
+#[derive(Debug, clap::Parser)]
+pub struct Cmd {
+    #[arg(long, short)]
+    long: bool,
+}
+
+impl Cmd {
+    pub fn run(self, data: Data) -> io::Result<()> {
+        println!(">> Resolving redirects");
+        let redirects = find_redirects(&data);
+
+        println!();
+        println!(
+            "There is a total of {} redirects.",
+            redirects.len().separate_with_underscores()
+        );
+
+        let mut long = redirects
+            .iter()
+            .filter(|(_, _, l)| *l > 1)
+            .collect::<Vec<_>>();
+        long.sort_by_key(|(_, _, l)| Reverse(l));
+
+        println!(
+            "{} redirects take more than one step to reach an article.",
+            long.len().separate_with_underscores()
+        );
+
+        println!(
+            "The longest redirect chain takes {} steps.",
+            long.iter().map(|(_, _, l)| l).max().copied().unwrap_or(0),
+        );
+
+        println!("Though these redirect chains are usually swiftly fixed by bots.");
+
+        if self.long {
+            println!();
+            println!("Redirect chains with length > 1:");
+
+            for (start, _, _) in long {
+                println!();
+                for step in follow_redirect(&data, *start) {
+                    println!("{}", util::fmt_page(&data.pages[step.usize()]));
+                }
+            }
+        }
+
+        Ok(())
+    }
+}

brood/src/main.rs

@@ -15,6 +15,7 @@ enum Command {
     Export(commands::export::Cmd),
     Show(commands::show::Cmd),
     Path(commands::path::Cmd),
+    Redirects(commands::redirects::Cmd),
 }
 
 #[derive(Debug, Parser)]
@@ -73,5 +74,6 @@ fn main() -> io::Result<()> {
         Command::Export(cmd) => cmd.run(data),
         Command::Show(cmd) => cmd.run(data),
         Command::Path(cmd) => cmd.run(data),
+        Command::Redirects(cmd) => cmd.run(data),
     }
 }