"""
PDF → Manim Animation Pipeline
Hugging Face Spaces — Gradio 6.x
"""

import asyncio
import atexit
import queue
import threading
import uuid
from pathlib import Path

import gradio as gr

from queue_manager import JobQueue, State
from pipeline import run_pipeline

# ── Asyncio cleanup fix (suppresses Invalid file descriptor errors) ───────────
def _cleanup_event_loop():
    try:
        loop = asyncio.get_event_loop()
        if not loop.is_closed():
            loop.close()
    except Exception:
        pass

atexit.register(_cleanup_event_loop)

# ── Global queue ──────────────────────────────────────────────────────────────
job_queue = JobQueue(max_workers=8, max_jobs=100)


# ── Pipeline streaming generator ──────────────────────────────────────────────
def submit_and_stream(pdf_file, email: str, api_key: str):
    """
    Generator — yields (status_md, code_text, code_visible) tuples live.
    Drives the entire UI update without any polling button.
    """

    # ── Validate ──────────────────────────────────────────────────────────────
    if pdf_file is None:
        yield "❌ Please upload a PDF file.", "", gr.update(visible=False)
        return
    if not email or "@" not in email:
        yield "❌ Please enter a valid email address.", "", gr.update(visible=False)
        return
    if not api_key or len(api_key) < 10:
        yield "❌ Please enter a valid Gemini API key.", "", gr.update(visible=False)
        return
    if job_queue.is_full():
        yield "⚠️ Queue is full (max 100 jobs). Please try again shortly.", "", gr.update(visible=False)
        return

    job_id = uuid.uuid4().hex
    pdf_path = pdf_file.name

    # Thread-safe channel for status + code updates
    update_q: queue.Queue = queue.Queue()

    def status_cb(state: State, message: str = "", code: str | None = None):
        update_q.put((state, message, code))

    def _run():
        try:
            run_pipeline(
                job_id=job_id,
                pdf_path=pdf_path,
                email=email,
                gemini_api_key=api_key,
                status_cb=status_cb,
            )
            update_q.put((State.DONE, "Video sent to your inbox! 🎉", None))
        except Exception as exc:
            update_q.put((State.FAILED, str(exc), None))
        finally:
            update_q.put(None)  # sentinel

    thread = threading.Thread(target=_run, daemon=True)
    thread.start()

    code_so_far = ""
    yield f"⏳ **Queued** — Starting…\n\n*Job ID: `{job_id}`*", "", gr.update(visible=False)

    while True:
        item = update_q.get()
        if item is None:
            break

        state, message, code = item

        icons = {
            State.QUEUED: "⏳",
            State.RUNNING: "⚙️",
            State.UPLOADING: "☁️",
            State.SENDING: "📧",
            State.DONE: "✅",
            State.FAILED: "❌",
        }
        icon = icons.get(state, "❓")
        status_text = f"{icon} **{state.value.title()}** — {message}\n\n*Job ID: `{job_id}`*"

        if code is not None:
            code_so_far = code

        yield (
            status_text,
            code_so_far,
            gr.update(visible=bool(code_so_far)),
        )


# ── UI ────────────────────────────────────────────────────────────────────────
with gr.Blocks(title="PDF → Manim Video") as demo:

    gr.Markdown(
        """
        # 🎬 PDF → Manim Animation Pipeline
        Upload a PDF, enter your details, and receive an animated video in your inbox.
        """
    )

    # Persistent browser-side storage (survives page refresh)
    saved_email = gr.BrowserState("")
    saved_api_key = gr.BrowserState("")

    with gr.Row():
        with gr.Column(scale=1):
            pdf_input = gr.File(label="📄 Upload PDF", file_types=[".pdf"])
            email_input = gr.Textbox(
                label="📧 Your Email",
                placeholder="you@example.com",
            )
            api_key_input = gr.Textbox(
                label="🔑 Gemini API Key",
                placeholder="AIza…",
                type="password",
            )
            submit_btn = gr.Button("🚀 Generate Video", variant="primary")

        with gr.Column(scale=1):
            status_md = gr.Markdown("*Submit a job to see live status here.*")
            code_box = gr.Code(
                label="📝 Generated Manim Code",
                language="python",
                visible=False,
                interactive=False,
            )

    gr.Markdown(
        """
        ---
        **Notes:**
        - Processing typically takes 2–5 minutes.
        - The video will be emailed once rendered; large files use a Catbox.moe link.
        - Your Gemini API key is used only for this request and never stored server-side.
        - Requires `SMTP_EMAIL` and `SMTP_PASSWORD` environment secrets on the Space.
        """
    )

    # ── Restore persisted values on page load ─────────────────────────────────
    demo.load(
        fn=lambda e, k: (e, k),
        inputs=[saved_email, saved_api_key],
        outputs=[email_input, api_key_input],
    )

    # ── Save values to browser storage whenever they change ───────────────────
    email_input.change(fn=lambda v: v, inputs=[email_input], outputs=[saved_email])
    api_key_input.change(fn=lambda v: v, inputs=[api_key_input], outputs=[saved_api_key])

    # ── Streaming job submission ───────────────────────────────────────────────
    submit_btn.click(
        fn=submit_and_stream,
        inputs=[pdf_input, email_input, api_key_input],
        outputs=[status_md, code_box, code_box],
    )


if __name__ == "__main__":
    demo.launch(
        theme=gr.themes.Soft(),
        ssr_mode=False,
        server_name="0.0.0.0",
        server_port=7860,
    )