/**
 * TTS HTTP server — wraps chatterbox-server.py and exposes a simple HTTP API.
 * Requests are serialized so generation and playback stay in order.
 *
 * Usage:
 *   node tts-server.mjs
 *   TTS_PORT=11500 node tts-server.mjs
 *
 * API:
 *   POST /speak   { "text": "...", "audio_prompt": "/path/to/voice.wav", ... }
 *                 → 200 { "ok": true }  (after generation, playback continues in background)
 *   GET  /voices  → 200 { "voices": ["rommie", ...], "current": "rommie" | null }
 *   POST /voice   { "name": "rommie" }
 *                 → 200 { "ok": true, "name": "rommie", "path": "..." }
 *   GET  /health  → 200 { "ok": true }
 */

import * as http from 'node:http'
import * as fs   from 'node:fs'
import * as path from 'node:path'
import yaml from 'js-yaml'
import { Chatterbox_Tts } from './lib/chatterbox-tts.mjs'

const PORT        = parseInt(process.env.TTS_PORT ?? '11500')
const VOICES_FILE = path.join(import.meta.dirname, 'voices.yaml')

function reload_voices() {
	try {
		const doc = yaml.load(fs.readFileSync(VOICES_FILE, 'utf8'))
		return doc?.voices ?? {}
	} catch {
		return {}
	}
}

let voices = reload_voices()
let current_voice = null  // name of active voice, or null

// --- TTS setup ---
const tts = new Chatterbox_Tts()
process.stderr.write('[tts-server] starting chatterbox...\n')
await tts.init()
process.stderr.write('[tts-server] chatterbox ready\n')

// Serialize all speak requests through a promise chain
let queue = Promise.resolve()

function enqueue(fn) {
	const result = queue.then(fn)
	// Don't let a failed request poison the queue
	queue = result.catch(() => {})
	return result
}

function read_body(req) {
	return new Promise((resolve, reject) => {
		let buf = ''
		req.on('data', chunk => { buf += chunk })
		req.on('end', () => {
			try { resolve(JSON.parse(buf)) } catch (e) { reject(e) }
		})
		req.on('error', reject)
	})
}

function send(res, status, body) {
	const payload = JSON.stringify(body)
	res.writeHead(status, { 'Content-Type': 'application/json' })
	res.end(payload)
}

const server = http.createServer(async (req, res) => {
	if (req.method === 'GET' && req.url === '/health') {
		return send(res, 200, { ok: true })
	}

	if (req.method === 'GET' && req.url === '/voices') {
		voices = reload_voices()
		const list = Object.entries(voices).map(([name, v]) => ({
			name,
			description: v.description ?? '',
			active: name === current_voice,
		}))
		return send(res, 200, { voices: list, current: current_voice })
	}

	if (req.method === 'POST' && req.url === '/voice') {
		let body
		try { body = await read_body(req) } catch {
			return send(res, 400, { error: 'invalid JSON' })
		}
		const { name } = body
		if (!name) return send(res, 400, { error: 'name required' })
		voices = reload_voices()
		if (!voices[name]) return send(res, 404, { error: `unknown voice: ${name}` })
		current_voice = name
		process.stderr.write(`[tts-server] voice switched to: ${name}\n`)
		return send(res, 200, { ok: true, name, path: voices[name].path })
	}

	if (req.method === 'POST' && req.url === '/speak') {
		let body
		try {
			body = await read_body(req)
		} catch {
			return send(res, 400, { error: 'invalid JSON' })
		}

		const { text, ...opts } = body
		if (!text) {
			return send(res, 400, { error: 'text required' })
		}

		// Inject current voice as default audio_prompt if none provided
		if (!opts.audio_prompt && current_voice && voices[current_voice]) {
			opts.audio_prompt = voices[current_voice].path
		}

		try {
			await enqueue(() => tts.speak_streaming(text, { preprocess: false, ...opts }))
			send(res, 200, { ok: true })
		} catch (err) {
			send(res, 500, { error: err.message })
		}
		return
	}

	send(res, 404, { error: 'not found' })
})

server.listen(PORT, () => {
	process.stderr.write(`[tts-server] listening on port ${PORT}\n`)
})