"""
ESP32 TTS Server — Hugging Face Space
WAV output: 22050Hz, Mono, 8-bit unsigned
ESP32 DAC ke liye perfect — direct mapping, no conversion
"""

from flask import Flask, request, Response
import os
import io
import hashlib
from gtts import gTTS
from pydub import AudioSegment
from pydub.effects import normalize

app = Flask(__name__)

BASE_DIR  = os.path.dirname(os.path.abspath(__file__))
CACHE_DIR = os.path.join(BASE_DIR, "tts_cache")
os.makedirs(CACHE_DIR, exist_ok=True)


def text_to_wav_bytes(text, lang):
    # Step 1: gTTS → MP3 in memory
    mp3_buf = io.BytesIO()
    tts = gTTS(text, lang=lang)
    tts.write_to_fp(mp3_buf)
    mp3_buf.seek(0)

    # Step 2: Load audio
    audio = AudioSegment.from_file(mp3_buf, format="mp3")

    # Step 3: Normalize — consistent volume
    audio = normalize(audio)

    # Step 4: Convert — 22050Hz, Mono, 8-bit unsigned
    # ESP32 DAC = 8-bit (0-255), 22050Hz enough for clear voice
    audio = audio.set_frame_rate(22050)
    audio = audio.set_channels(1)
    audio = audio.set_sample_width(1)   # 8-bit unsigned (0-255)

    # Step 5: WAV bytes
    wav_buf = io.BytesIO()
    audio.export(wav_buf, format="wav")
    wav_buf.seek(0)
    return wav_buf.read()


def get_wav(text, lang):
    key        = hashlib.md5((text + lang).encode()).hexdigest()
    cache_path = os.path.join(CACHE_DIR, key + ".wav")

    if os.path.exists(cache_path):
        print(f'[Cache HIT] "{text}"')
        with open(cache_path, "rb") as f:
            return f.read()

    print(f'[Generating] "{text}" | {lang}')
    wav_data = text_to_wav_bytes(text, lang)

    with open(cache_path, "wb") as f:
        f.write(wav_data)

    return wav_data


@app.route("/tts", methods=["GET"])
def tts_get():
    text = request.args.get("text", "Hello").replace("+", " ")
    lang = request.args.get("lang", "en")
    try:
        wav_data = get_wav(text, lang)
    except Exception as e:
        print(f"[ERROR] {e}")
        return f"Error: {e}", 500
    return Response(wav_data, mimetype="audio/wav",
                    headers={"Content-Length": str(len(wav_data))})


@app.route("/tts", methods=["POST"])
def tts_post():
    data = request.get_json(silent=True) or {}
    text = data.get("text", "Hello")
    lang = data.get("lang", "en")
    try:
        wav_data = get_wav(text, lang)
    except Exception as e:
        print(f"[ERROR] {e}")
        return f"Error: {e}", 500
    return Response(wav_data, mimetype="audio/wav",
                    headers={"Content-Length": str(len(wav_data))})


@app.route("/ping")
def ping():
    return {"status": "ok", "server": "ESP32 TTS Server"}


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=7860, debug=False)