split lib.rs functionality into separate modules

1 files changed, 68 insertions, 0 deletions

diff --git a/src/lookup.rs b/src/lookup.rs
new file mode 100644
index 0000000..e9882a4
--- /dev/null
+++ b/src/lookup.rs
@@ -0,0 +1,68 @@
+use std::{io::*, fs::File};
+// note that bufread::MultiBzDecoder is _distinct_ from read::MultiBzDecoder
+use bzip2::bufread::*;
+
+// i don't like that there are multiple result types
+// that seems Bad
+// also having to explicitly box dyn Error sucks, fine fuck you it's the rust way
+type Lookup = std::result::Result<Option<String>, Box<dyn std::error::Error>>;
+
+// WHY can you not implement traits on external types, like what??
+// fortunately we needed to copy-paste the parse_wiki_text library to fix some bugs anyhow
+pub fn lookup(word: &str) -> Lookup {
+    if let Ok(file) = File::open(crate::index_path) {
+        return lookup_local(word, file);
+    } else {
+        return lookup_online(word);
+    }
+}
+
+fn lookup_local(word: &str, file: File) -> Lookup {
+    let reader = BufReader::new(MultiBzDecoder::new(BufReader::new(file)));
+    for line in reader.lines() {
+        let line = line.expect("Failed to read line");
+
+        // format: file-offset:page-id:page-title
+        let line = line.splitn(3, ":").collect::<Vec<&str>>();
+        assert!(line.len() == 3, "Failed to parse line. Is your index file valid?");
+
+        let offset = line.get(0).unwrap().parse::<u64>()?;
+        let id = line.get(1).unwrap().parse::<u64>()?;
+        let title = *line.get(2).unwrap(); // this dereference now makes sense
+
+        if title == word {
+            let file = File::open(crate::dictionary_path)?;
+            let mut reader = BufReader::new(file);
+
+            // note: our chunk contains multiple pages
+            let offset = reader.seek(SeekFrom::Start(offset))
+                .expect("Bad offset. Is your index file valid?");
+            let reader = BufReader::new(BzDecoder::new(reader));
+
+            let mut buffer = String::new();
+            let mut page = false;
+            for line in reader.lines() {
+                let line = line.unwrap();
+                if line == format!("    <title>{}</title>", title) {
+                    buffer.push_str("  <page>");
+                    buffer.push_str("\n");
+                    page = true;
+                }
+                if page {
+                    buffer.push_str(&line);
+                    buffer.push_str("\n");
+                    if line == "  </page>" {
+                        break;
+                    }
+                }
+            }
+            return Ok(Some(buffer));
+        }
+    }
+    return Ok(None);
+}
+
+fn lookup_online(word: &str) -> Lookup {
+    todo!();
+}
+