/** tts_bridge.js — Persistent Node.js bridge for aquestalk.js TTS synthesis.

Protocol (via stdin/stdout):
  - On startup, prints "READY" to stdout.
  - Reads lines from stdin in format:  INPUT_PATH|OUTPUT_PATH
  - Reads kana text from INPUT_PATH, synthesizes WAV, writes to OUTPUT_PATH.
  - Prints "OK:OUTPUT_PATH" on success, "ERR:message" on failure.
  - Exits when stdin is closed.

Usage:
  node tts_bridge.js --voice f1 --speed 100
*/

import { readFileSync, writeFileSync } from "fs";
import { createInterface } from "readline";
import { fileURLToPath, pathToFileURL } from "url";
import { dirname, join } from "path";

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

// Parse CLI arguments
const args = process.argv.slice(2);
let voice = "f1";
let speed = 100;

for (let i = 0; i < args.length; i++) {
  if (args[i] === "--voice" && i + 1 < args.length) {
    voice = args[++i];
  } else if (args[i] === "--speed" && i + 1 < args.length) {
    speed = parseInt(args[++i], 10);
  }
}

// Import aquestalk.js from sibling directory
const aquestalkMod = pathToFileURL(join(__dirname, "..", "aquestalk.js", "dist", "index.js")).href;
const { load } = await import(aquestalkMod);

console.error(`[bridge] Loading aquestalk.js with voice="${voice}", speed=${speed}...`);

let aq;
try {
  aq = await load(voice);
  console.error("[bridge] aquestalk.js loaded successfully.");
} catch (err) {
  console.error("[bridge] Failed to load aquestalk.js:", err.message);
  process.stdout.write("ERR:FAILED_TO_LOAD\n");
  process.exit(1);
}

process.stdout.write("READY\n");

const rl = createInterface({
  input: process.stdin,
  output: process.stdout,
  terminal: false,
});

rl.on("line", (line) => {
  line = line.trim();
  if (!line) return;

  const sepIdx = line.indexOf("|");
  if (sepIdx === -1) {
    process.stdout.write(`ERR:INVALID_FORMAT:${line}\n`);
    return;
  }

  const inputPath = line.substring(0, sepIdx);
  const outputPath = line.substring(sepIdx + 1);

  try {
    const kanaText = readFileSync(inputPath, "utf-8").trim();

    if (!kanaText) {
      process.stdout.write(`ERR:EMPTY_TEXT\n`);
      return;
    }

    const wav = aq.run(kanaText, speed);

    writeFileSync(outputPath, Buffer.from(wav));

    process.stdout.write(`OK:${outputPath}\n`);
  } catch (err) {
    process.stdout.write(`ERR:${err.message}\n`);
  }
});

rl.on("close", () => {
  console.error("[bridge] stdin closed, shutting down.");
  aq.destroy().then(() => {
    process.exit(0);
  });
});