"use strict";

// Type letters to see matches narrow; backspace to undo; Ctrl+C to quit.
// Usage: node demo.js

const fs = require("fs");
const path = require("path");
const { Predictor } = require("./predictor");

const { words } = JSON.parse(
  fs.readFileSync(path.join(__dirname, "wordlist.json"), "utf8")
);
const predictor = new Predictor(words);

let prefix = "";

function render() {
  const { matches, isWord, completion } = predictor.predict(prefix);
  console.clear();
  console.log(`typed: ${prefix || "(nothing yet)"}`);
  if (completion) {
    console.log(`-> unique match: ${completion}`);
  } else if (matches.length === 0) {
    console.log("-> no matches");
  } else {
    const shown = matches.slice(0, 15);
    console.log(
      `-> ${matches.length} matches: ${shown.join(", ")}` +
        (matches.length > shown.length ? ", ..." : "")
    );
  }
  if (isWord && matches.length > 1) {
    console.log(`   (note: "${prefix}" is itself a word, but is also a prefix of others)`);
  }
}

process.stdin.setRawMode(true);
process.stdin.resume();
process.stdin.setEncoding("utf8");
render();

process.stdin.on("data", (key) => {
  if (key === "\u0003") process.exit(0); // Ctrl+C
  if (key === "\u007f" || key === "\b") {
    prefix = prefix.slice(0, -1);
  } else if (/^[a-z]$/i.test(key)) {
    prefix += key.toLowerCase();
  }
  render();
});