from __future__ import annotations

import asyncio
import contextlib
import json
import os
import shutil
import time
import uuid
from pathlib import Path
from urllib.parse import quote

os.environ.setdefault("GRADIO_SSR_MODE", "false")

import spaces  # noqa: E402, F401 - must patch torch before model modules are imported

from fastapi import HTTPException
from fastapi.responses import FileResponse
from gradio import Server
from gradio.data_classes import FileData
from gradio.utils import get_upload_folder
from PIL import Image, ImageOps

from src.demo.hf_runtime import (
    InfiniSplatRuntime,
    export_browser_viewer,
    export_filtered_gaussian_ply,
    export_standalone_viewer,
    prepare_viewer_template,
)

GPU_DURATION_SECONDS = 6
REQUEST_CACHE_SECONDS = 3600
CACHE_CLEANUP_INTERVAL_SECONDS = 3600
SUPPORTED_IMAGE_SUFFIXES = {".jpg", ".jpeg", ".png", ".webp"}
EXAMPLE_FILENAMES = [
    "painting_room.jpg",
    "summer_room.jpg",
    "animate_room.jpg",
    "meerkat.jpg",
    "bedroom.jpg",
    "my_bedroom.JPG",
    "beggar_home.jpg",
    "cave_ai.jpg",
    "eth3d_courtyard.png",
    "dragon_ball.jpg",
    "flower_room.jpg",
    "maksim-shutov-unsplash.jpg",
    "ghibli_realroom.jpg",
    "ghibli_room.jpg",
    "pexels-masi.jpg",
    "gym.png",
    "living_room.jpg",
    "scannetpp_fe94fc30cf.JPG",
    "loft_room.jpg",
    "old_livingroom.png",
    "sofa_ai.jpg",
]
EXAMPLE_SPANS = [4, 4, 4, 3, 4, 5, 4, 5, 3, 3, 3, 5, 4, 5, 3, 5, 4, 5, 3, 3, 5]

REPO_ROOT = Path(__file__).resolve().parent
FRONTEND_ROOT = REPO_ROOT / "src/demo/server_frontend"
UPLOAD_ROOT = Path(get_upload_folder()).resolve()
OUTPUT_ROOT = UPLOAD_ROOT / "infinisplat"
OUTPUT_ROOT.mkdir(parents=True, exist_ok=True)
EXAMPLE_ROOT = Path(
    os.environ.get("INFINISPLAT_EXAMPLE_DIR", REPO_ROOT / "examples/data/rgb_demo")
).resolve()
EXAMPLE_THUMBNAIL_ROOT = OUTPUT_ROOT / "_example_thumbnails"


def _log_timing(stage: str, request_dir: Path, started_at: float, **metrics: int) -> None:
    payload = {
        "stage": stage,
        "request": request_dir.name,
        "seconds": round(time.perf_counter() - started_at, 3),
        **metrics,
    }
    print(f"INFINISPLAT_TIMING {json.dumps(payload, sort_keys=True)}", flush=True)


def _cleanup_request_directories(max_age_seconds: int | None) -> None:
    if not OUTPUT_ROOT.is_dir():
        return
    cutoff = None if max_age_seconds is None else time.time() - max_age_seconds
    for request_dir in OUTPUT_ROOT.iterdir():
        if request_dir.is_symlink() or not request_dir.is_dir():
            continue
        try:
            if uuid.UUID(hex=request_dir.name).hex != request_dir.name:
                continue
        except ValueError:
            continue
        if cutoff is not None and request_dir.stat().st_mtime > cutoff:
            continue
        with contextlib.suppress(FileNotFoundError):
            shutil.rmtree(request_dir)


async def _cleanup_loop() -> None:
    while True:
        await asyncio.sleep(CACHE_CLEANUP_INTERVAL_SECONDS)
        await asyncio.to_thread(_cleanup_request_directories, REQUEST_CACHE_SECONDS)


@contextlib.asynccontextmanager
async def _lifespan(_app: Server):
    await asyncio.to_thread(_cleanup_request_directories, REQUEST_CACHE_SECONDS)
    cleanup_task = asyncio.create_task(_cleanup_loop())
    try:
        yield
    finally:
        cleanup_task.cancel()
        with contextlib.suppress(asyncio.CancelledError):
            await cleanup_task
        await asyncio.to_thread(_cleanup_request_directories, None)


def _prepare_examples() -> list[dict[str, str | int]]:
    missing = [name for name in EXAMPLE_FILENAMES if not (EXAMPLE_ROOT / name).is_file()]
    if missing:
        raise FileNotFoundError(f"Missing example images in {EXAMPLE_ROOT}: {missing}")

    EXAMPLE_THUMBNAIL_ROOT.mkdir(parents=True, exist_ok=True)
    examples = []
    for index, (filename, span) in enumerate(zip(EXAMPLE_FILENAMES, EXAMPLE_SPANS)):
        source = EXAMPLE_ROOT / filename
        thumbnail = EXAMPLE_THUMBNAIL_ROOT / f"{index:02d}-{source.stem}.webp"
        if not thumbnail.is_file() or thumbnail.stat().st_mtime < source.stat().st_mtime:
            with Image.open(source) as image:
                image = ImageOps.exif_transpose(image).convert("RGB")
                image.thumbnail((480, 320), Image.Resampling.LANCZOS)
                image.save(thumbnail, format="WEBP", quality=82, method=6)
        examples.append(
            {
                "index": index,
                "name": source.stem.replace("_", " "),
                "filename": filename,
                "span": span,
                "thumbnail_url": f"/infinisplat/examples/{index}/thumbnail",
                "source_url": f"/infinisplat/examples/{index}/source",
            }
        )
    return examples


def _file_url(path: Path) -> str:
    return f"/gradio_api/file={quote(str(path.resolve()), safe='/')}"


def _request_dir(request_id: str) -> Path:
    try:
        normalized = uuid.UUID(hex=request_id).hex
    except (ValueError, AttributeError) as error:
        raise ValueError("Invalid reconstruction request ID.") from error
    if normalized != request_id:
        raise ValueError("Invalid reconstruction request ID.")
    request_dir = (OUTPUT_ROOT / normalized).resolve()
    if request_dir.parent != OUTPUT_ROOT:
        raise ValueError("Invalid reconstruction request directory.")
    if not request_dir.is_dir():
        raise FileNotFoundError("The reconstruction result has expired.")
    request_dir.touch()
    return request_dir


def _uploaded_image_path(image: FileData | dict | str) -> Path:
    if isinstance(image, str):
        path_value = image
    elif isinstance(image, dict):
        path_value = image.get("path")
    else:
        path_value = getattr(image, "path", None)
    if not path_value:
        raise ValueError("Please upload an image.")
    image_path = Path(path_value).resolve()
    if not image_path.is_file() or image_path.suffix.lower() not in SUPPORTED_IMAGE_SUFFIXES:
        raise ValueError("Please upload a JPG, PNG, or WebP image.")
    try:
        image_path.relative_to(UPLOAD_ROOT)
    except ValueError as error:
        raise ValueError("The uploaded image is outside the Gradio upload directory.") from error
    return image_path


runtime = InfiniSplatRuntime.load()
viewer_template = prepare_viewer_template(OUTPUT_ROOT)
examples = _prepare_examples()

app = Server(
    title="InfiniSplat",
    description="Implicit Gaussian decoding for large-baseline monocular view synthesis.",
    lifespan=_lifespan,
)


@spaces.GPU(duration=GPU_DURATION_SECONDS)
def _run_reconstruction(image_path: Path, artifact_path: Path) -> str:
    """Run one GPU reconstruction and persist only CPU-resident tensors."""
    return str(runtime.infer_to_artifact(image_path=image_path, artifact_path=artifact_path))


@app.api(
    name="reconstruct",
    description="Reconstruct a 3D Gaussian scene from one RGB image.",
    queue=True,
    concurrency_limit=1,
    concurrency_id="infinisplat-gpu",
    time_limit=30,
)
def reconstruct(image: FileData) -> dict[str, str | int]:
    """Reconstruct a 3D Gaussian scene from one RGB image."""
    _cleanup_request_directories(REQUEST_CACHE_SECONDS)
    request_dir = OUTPUT_ROOT / uuid.uuid4().hex
    request_dir.mkdir(parents=True, exist_ok=False)
    started_at = time.perf_counter()
    artifact = Path(
        _run_reconstruction(
            _uploaded_image_path(image),
            request_dir / "gaussians.pt",
        )
    )
    _log_timing(
        "gpu_reconstruct",
        request_dir,
        started_at,
        artifact_bytes=artifact.stat().st_size,
    )
    return {"request_id": request_dir.name, "artifact_size": artifact.stat().st_size}


@app.api(
    name="export_ply",
    description="Export the reconstructed scene as a filtered Gaussian PLY.",
    queue=True,
    concurrency_limit=2,
    concurrency_id="infinisplat-export",
    time_limit=180,
)
def export_ply(request_id: str) -> dict[str, str | int]:
    """Export the reconstructed scene as a filtered Gaussian PLY."""
    request_dir = _request_dir(request_id)
    artifact = request_dir / "gaussians.pt"
    if not artifact.is_file():
        raise FileNotFoundError("The reconstruction artifact is unavailable.")
    started_at = time.perf_counter()
    scene_ply = export_filtered_gaussian_ply(artifact_path=artifact, output_dir=request_dir)
    artifact.unlink()
    _log_timing("ply_export", request_dir, started_at, ply_bytes=scene_ply.stat().st_size)
    return {"url": _file_url(scene_ply), "size": scene_ply.stat().st_size}


@app.api(
    name="export_viewer",
    description="Create an optimized browser viewer for a reconstructed scene.",
    queue=True,
    concurrency_limit=2,
    concurrency_id="infinisplat-export",
    time_limit=180,
)
def export_viewer(request_id: str) -> dict[str, str | int]:
    """Create an optimized browser viewer for a reconstructed scene."""
    request_dir = _request_dir(request_id)
    scene_ply = request_dir / "scene.ply"
    if not scene_ply.is_file():
        raise FileNotFoundError("The PLY export is unavailable.")
    started_at = time.perf_counter()
    exported = export_browser_viewer(scene_ply=scene_ply, viewer_template=viewer_template)
    _log_timing(
        "browser_viewer",
        request_dir,
        started_at,
        sog_bytes=exported.scene_sog.stat().st_size,
        viewer_html_bytes=exported.viewer_html.stat().st_size,
    )
    return {"url": _file_url(exported.viewer_html), "size": exported.viewer_html.stat().st_size}


@app.api(
    name="export_html",
    description="Bundle the browser viewer into one standalone HTML file.",
    queue=True,
    concurrency_limit=2,
    concurrency_id="infinisplat-export",
    time_limit=180,
)
def export_html(request_id: str) -> dict[str, str | int]:
    """Bundle the browser viewer into one standalone HTML file."""
    request_dir = _request_dir(request_id)
    viewer_html = request_dir / "viewer.html"
    if not viewer_html.is_file():
        raise FileNotFoundError("The browser viewer is unavailable.")
    started_at = time.perf_counter()
    standalone = export_standalone_viewer(
        viewer_html=viewer_html,
        viewer_template=viewer_template,
    )
    _log_timing("standalone_html", request_dir, started_at, html_bytes=standalone.stat().st_size)
    return {"url": _file_url(standalone), "size": standalone.stat().st_size}


@app.api(name="viewer_template", queue=False, api_visibility="undocumented")
def get_viewer_template() -> dict[str, str]:
    """Return the shared viewer shell used to warm browser assets."""
    return {"url": _file_url(viewer_template.viewer_html)}


@app.get("/")
async def homepage() -> FileResponse:
    return FileResponse(FRONTEND_ROOT / "index.html", media_type="text/html")


@app.get("/infinisplat/assets/{filename}")
async def frontend_asset(filename: str) -> FileResponse:
    assets = {
        "styles.css": (FRONTEND_ROOT / "styles.css", "text/css"),
        "app.js": (FRONTEND_ROOT / "app.js", "text/javascript"),
    }
    if filename not in assets:
        raise HTTPException(status_code=404, detail="Asset not found")
    path, media_type = assets[filename]
    return FileResponse(path, media_type=media_type)


@app.get("/infinisplat/examples")
async def list_examples() -> list[dict[str, str | int]]:
    return examples


def _example(index: int) -> dict[str, str | int]:
    if index < 0 or index >= len(examples):
        raise HTTPException(status_code=404, detail="Example not found")
    return examples[index]


@app.get("/infinisplat/examples/{index}/thumbnail")
async def example_thumbnail(index: int) -> FileResponse:
    example = _example(index)
    filename = f"{index:02d}-{Path(str(example['filename'])).stem}.webp"
    return FileResponse(EXAMPLE_THUMBNAIL_ROOT / filename, media_type="image/webp")


@app.get("/infinisplat/examples/{index}/source")
async def example_source(index: int) -> FileResponse:
    example = _example(index)
    return FileResponse(EXAMPLE_ROOT / str(example["filename"]))


demo = app


if __name__ == "__main__":
    app.launch(
        server_name="0.0.0.0",
        server_port=int(os.environ.get("PORT", "7860")),
        allowed_paths=[str(OUTPUT_ROOT)],
        max_file_size="20mb",
        show_error=True,
        ssr_mode=False,
        footer_links=[],
    )