app.py

import gradio as gr
import requests
import random
import tempfile
import os
import base64
import time
import threading
from datetime import datetime, timedelta, timezone

# --- Configuration ---
API_URL = "https://gen.pollinations.ai/v1/chat/completions"
# Default system key (Used for Free Tier)
SYSTEM_API_KEY = os.getenv("POLLINATIONS_TOKEN")

# VOICES
VOICES = [
    "alloy", "echo", "fable", "onyx", "nova", "shimmer"
]

# --- Rate Limiting Globals ---
MAX_CHAR_LIMIT = 200        # Limit input characters for Free Tier
COOLDOWN_SECONDS = 50       # 50s wait to ensure stability
LAST_REQUEST_TIME = 0       # Tracks the last successful FREE generation time

# THE TRAFFIC CONTROLLER
free_tier_lock = threading.Lock() 

def generate_audio_api(prompt: str, voice: str, emotion: str, seed: int, api_key: str) -> bytes:
    """
    Core function that hits the Pollinations/OpenAI API.
    """
    print(f"DEBUG: Generating audio | Voice: {voice} | Emotion: {emotion}")

    headers = {
        "Content-Type": "application/json",
    }
    # Inject Key if provided
    if api_key:
        headers["Authorization"] = f"Bearer {api_key}"

    # Your "Secret Sauce" Prompt Engineering
    system_instruction = (
        f"Only repeat what I say. "
        f"Now say with proper emphasis in a \"{emotion}\" emotion this statement."
    )

    payload = {
        "model": "openai-audio",
        "modalities": ["text", "audio"],
        "audio": {"voice": voice, "format": "mp3"},
        "messages": [
            {"role": "system", "content": system_instruction},
            {"role": "user", "content": prompt}
        ],
        "seed": seed
    }

    try:
        response = requests.post(API_URL, headers=headers, json=payload, timeout=60)
        
        if response.status_code != 200:
            # Error Handling
            if response.status_code == 402 or response.status_code == 429:
                raise gr.Error(f"⚠️ Server Limit: The Free Tier is busy. Please wait or use a Premium Key.")
            elif response.status_code == 401:
                raise gr.Error("401 Unauthorized: The provided API Key is invalid.")
            else:
                raise gr.Error(f"API Error {response.status_code}: {response.text}")

        data = response.json()
        try:
            audio_b64 = data['choices'][0]['message']['audio']['data']
            return base64.b64decode(audio_b64)
        except KeyError:
            raise gr.Error("API returned empty audio data.")

    except requests.exceptions.RequestException as e:
        raise gr.Error(f"Network error: {str(e)}")


def text_to_speech_app(prompt: str, voice: str, emotion: str, use_random_seed: bool, specific_seed: int, api_key_input: str):
    global LAST_REQUEST_TIME
    
    # 1. User Status Check
    user_provided_key = api_key_input.strip()
    # Use Client Key if present, otherwise fall back to System Key
    active_key = user_provided_key if user_provided_key else SYSTEM_API_KEY
    is_paid_user = len(user_provided_key) > 5

    # 2. Validation
    if not prompt.strip():
        raise gr.Error("Prompt cannot be empty.")
    
    # RULE: Character Limit applies ONLY to Free Tier
    if not is_paid_user and len(prompt) > MAX_CHAR_LIMIT:
        raise gr.Error(f"Free Tier Limit: {MAX_CHAR_LIMIT} chars. Enter an API Key for unlimited length.")

    # 3. Execution Logic (The Traffic Split)
    try:
        seed = random.randint(0, 2**32 - 1) if use_random_seed else int(specific_seed)
        
        if is_paid_user:
            # === FAST LANE (Paid) ===
            # Bypasses the lock entirely. No waiting.
            print("LOG: Premium Request Processing...")
            audio_bytes = generate_audio_api(prompt, voice, emotion, seed, active_key)
            status_msg = "Generated! (Premium Speed ⚡)"
            
        else:
            # === SLOW LANE (Free) ===
            # Must wait for the lock (Bathroom Key)
            print("LOG: Free Request - Attempting to acquire lock...")
            with free_tier_lock:
                # Once we have the key, we check the timer
                elapsed_time = time.time() - LAST_REQUEST_TIME
                
                if elapsed_time < COOLDOWN_SECONDS:
                    wait_time = COOLDOWN_SECONDS - elapsed_time
                    print(f"Queueing User: Sleeping for {wait_time:.1f}s...")
                    time.sleep(wait_time)
                
                # Generate inside the lock so nobody else steals the slot
                audio_bytes = generate_audio_api(prompt, voice, emotion, seed, active_key)
                
                # Reset the global timer
                LAST_REQUEST_TIME = time.time()
                status_msg = "Generated! (Free Tier 🐢)"

        # 4. Save and Return
        with tempfile.NamedTemporaryFile(delete=False, suffix=".mp3") as temp_audio_file:
            temp_audio_file.write(audio_bytes)
            return temp_audio_file.name, status_msg

    except Exception as e:
        return None, str(e)


def toggle_seed_input(use_random_seed):
    return gr.update(visible=not use_random_seed, value=12345)


# --- RESTORED ORIGINAL UI ---
with gr.Blocks() as app:
    gr.Markdown("# Advanced OpenAI Text-To-Speech Unlimited")
    gr.Markdown(
        """
        Enter text, choose a voice and emotion, and generate audio.
        
        **🚀 Skip the Queue & Run Locally:**
        To avoid the **50s cooldown** and generate instantly:
        1. **Duplicate this Space** to run it privately.
        2. Get your own API key from [Pollinations.ai](https://enter.pollinations.ai/).
        3. Paste it into the `POLLINATIONS_TOKEN` secret in your duplicated space.
        
        **Commercial Use:**
        For a **Lifetime Commercial Use License**, please refer to our terms here:
        [LICENSE TERMS](https://huggingface.co/spaces/NihalGazi/Text-To-Speech-Unlimited/raw/main/COMMERCIAL_LICENSE_TERMS.txt)
        
        **Like & follow** for more AI projects:
        • Instagram: [@nihal_gazi_io](https://www.instagram.com/nihal_gazi_io/) 
        • X.com: [@NihalGazi_](https://x.com/NihalGazi_?t=f9UtAv005GppiIIXFEWMSQ&s=09)
        • Discord: nihal_gazi_io
        """
    )

    with gr.Row():
        with gr.Column(scale=2):
            api_key_input = gr.Textbox(
                label="Pollinations API Key (Optional)", 
                placeholder="sk_...", 
                type="password",
                info="Enter your key to REMOVE the 50s cooldown and generate instantly."
            )
            prompt_input = gr.Textbox(
                label=f"Prompt (Max {MAX_CHAR_LIMIT} chars)", 
                placeholder="Enter the text you want to convert to speech...",
                max_lines=3
            )
            emotion_input = gr.Textbox(label="Emotion Style", placeholder="e.g., happy, sad, excited, calm...")
            voice_dropdown = gr.Dropdown(label="Voice", choices=VOICES, value="alloy")
        with gr.Column(scale=1):
            random_seed_checkbox = gr.Checkbox(label="Use Random Seed", value=True)
            seed_input = gr.Number(label="Specific Seed", value=12345, visible=False, precision=0)

    submit_button = gr.Button("Generate Audio", variant="primary")

    with gr.Row():
        audio_output = gr.Audio(label="Generated Audio", type="filepath")
        status_output = gr.Textbox(label="Status")

    random_seed_checkbox.change(fn=toggle_seed_input, inputs=[random_seed_checkbox], outputs=[seed_input])

    submit_button.click(
        fn=text_to_speech_app,
        inputs=[prompt_input, voice_dropdown, emotion_input, random_seed_checkbox, seed_input, api_key_input],
        outputs=[audio_output, status_output],
        # Concurrency must be HIGH to allow Premium users to bypass sleeping Free users
        concurrency_limit=20
    )

    gr.Examples(
        examples=[
            ["Hello there! This is a test of the text-to-speech system.", "alloy", "neutral", False, 12345, ""],
            ["Surely *you* wouldn't want *that*. [laughs]", "shimmer", "sarcastic and mocking", True, 12345, ""],
            ["[sobbing] I am feeling... [sighs] a bit down today [cry]", "onyx", "sad and depressed, with stammering", True, 662437, ""],
            ["This technology is absolutely amazing!", "nova", "excited and joyful", True, 12345, ""],
        ],
        inputs=[prompt_input, voice_dropdown, emotion_input, random_seed_checkbox, seed_input, api_key_input],
        outputs=[audio_output, status_output],
        fn=text_to_speech_app,
        cache_examples=False, 
    )

if __name__ == "__main__":
    app.launch()