#![allow(unused)]
use std::io::{self, prelude::*};
use std::fs;
use std::time::*;
use std::env;
use std::path::Path;
use elasticlunr::{Index, Language};
use serde::Deserialize;
use bytelines::ByteLinesReader;

#[derive(Deserialize, Debug)]
struct Record {
    pub title: String,
    pub body: String,
    pub url: String,
}

const WIKIPEDIA_PATH: &str = "src/search/wiki-articles.json";
const OUTPUT_PATH: &str = "src/search/js/elasticlunr-wiki-index.json";

fn main() -> Result<(), io::Error> {
    let start = Instant::now();

    let mut index = Index::new(&["title", "body"]);

    let home: String = env::var("HOME").unwrap();
    let home_dir = Path::new(&home);
    let input_file = home_dir.join(WIKIPEDIA_PATH);
    assert!(input_file.exists(), "path does not exist: {}", input_file.display());

    let mut rdr = io::BufReader::new(fs::File::open(input_file)?);
    let mut lines = rdr.byte_lines();

    let mut n_indexed = 0;

    while let Some(line_result) = lines.next() {
        let line = line_result?;
        let rec: Record =
            serde_json::from_slice(line)
                .map_err(|e| {
                    io::Error::new(
                        io::ErrorKind::InvalidData, 
                        format!("deserializing failed: {}", e)
                    )
                })?;
        index.add_doc(&rec.url, &[&rec.title, &rec.body]);
        n_indexed += 1;
    }

    let output_file = home_dir.join(OUTPUT_PATH);
    let mut wtr = io::BufWriter::new(fs::File::create(&output_file)?);

    // hope you have plenty of ram!
    let index_json: String = index.to_json();

    wtr.write_all(index_json.as_bytes())?;

    let took = Instant::now() - start;
    println!("indexed {} records in {:?}", n_indexed, took);
    Ok(())
}