"""
pipeline.py — Main pipeline: PDF → Gemini → Manim → Upload/Email → Cleanup
"""

from __future__ import annotations

import os
import shutil
import subprocess
import textwrap
import time
from pathlib import Path
from typing import Callable

from queue_manager import State
from utils import (
    extract_pdf_text,
    generate_manim_code,
    send_video_email,
    upload_to_catbox,
    sanitize_manim_code,
)

MEDIA_ROOT = Path("media/videos")
JOBS_ROOT  = Path("jobs")


def run_pipeline(
    job_id: str,
    pdf_path: str,
    email: str,
    gemini_api_key: str,
    status_cb: Callable[[State, str, str | None], None],
) -> None:
    job_dir    = JOBS_ROOT / job_id
    script_path = job_dir / f"{job_id}.py"
    video_path  = MEDIA_ROOT / job_id / "720p30" / "OutputVideo.mp4"

    job_dir.mkdir(parents=True, exist_ok=True)

    try:
        # 1. Extract PDF
        status_cb(State.RUNNING, "📖 Extracting text from PDF…", None)
        pdf_text = extract_pdf_text(pdf_path)
        if not pdf_text.strip():
            raise ValueError("PDF appears empty or has no selectable text.")

        # 2. Generate Manim code via Gemini
        status_cb(State.RUNNING, "🤖 Generating Manim code with Gemini…", None)
        prompt     = _build_prompt(pdf_text)
        raw_code   = generate_manim_code(prompt, gemini_api_key)
        manim_code = sanitize_manim_code(raw_code, job_id)

        # Surface generated code to UI
        status_cb(State.RUNNING, "✏️ Manim code generated — starting render…", manim_code)

        script_path.write_text(manim_code, encoding="utf-8")

        # 3. Render
        status_cb(State.RUNNING, "🎬 Rendering animation (this may take a few minutes)…", None)
        _render_manim(script_path, job_id)

        if not video_path.exists():
            raise FileNotFoundError(f"Rendered video not found at {video_path}")

        # 4. Deliver
        status_cb(State.SENDING, "📧 Sending video to your inbox…", None)
        _deliver_video(str(video_path), email, status_cb)

    finally:
        _cleanup(job_dir, video_path)


# ── Helpers ───────────────────────────────────────────────────────────────────

def _build_prompt(pdf_text: str) -> str:
    truncated = pdf_text[:12_000]
    return textwrap.dedent(f"""
        You are an expert Manim animator. Given the following document content,
        create a concise, visually engaging Manim animation that summarises the
        key ideas. Use ONLY the class name `OutputVideo` extending `Scene`.

        Requirements:
        - Class name MUST be exactly `OutputVideo(Scene)`.
        - Use only standard Manim Community v0.18+ API.
        - Output ONLY valid Python code. No explanations, no markdown fences.
        - Keep runtime under 90 seconds.
        - Avoid custom LaTeX; prefer Text() over MathTex() where possible.
        - Animations should be clear, readable, and professional.

        Document content:
        ---
        {truncated}
        ---
    """).strip()


def _render_manim(script_path: Path, job_id: str, max_retries: int = 2) -> None:
    cmd = [
        "manim",
        str(script_path),
        "OutputVideo",
        "-qm",
        "--media_dir", "media",
        "--disable_caching",
    ]
    for attempt in range(max_retries + 1):
        result = subprocess.run(cmd, capture_output=True, text=True, timeout=600)
        if result.returncode == 0:
            return
        if attempt < max_retries:
            time.sleep(5 * (attempt + 1))

    raise RuntimeError(
        f"Manim render failed after {max_retries + 1} attempts.\n"
        f"STDERR: {result.stderr[-3000:]}"
    )


def _deliver_video(
    video_path: str,
    email: str,
    status_cb: Callable,
) -> None:
    file_size_mb = Path(video_path).stat().st_size / (1024 * 1024)

    if file_size_mb <= 24:
        try:
            send_video_email(email, video_path)
            return
        except Exception as exc:
            status_cb(State.UPLOADING, f"⚠️ Attachment failed ({exc}) — uploading to Catbox…", None)
    else:
        status_cb(State.UPLOADING, f"📦 {file_size_mb:.1f} MB video — uploading to Catbox…", None)

    url = upload_to_catbox(video_path)
    send_video_email(email, video_path=None, catbox_url=url)


def _cleanup(*paths) -> None:
    for p in paths:
        if p is None:
            continue
        path = Path(p)
        try:
            if path.is_dir():
                shutil.rmtree(path, ignore_errors=True)
            elif path.is_file():
                path.unlink(missing_ok=True)
        except Exception:
            pass