import os
import platform
import subprocess
import tempfile
import zipfile

import blobfile as bf
import numpy as np
from PIL import Image

from shap_e.rendering.mesh import TriMesh

from .constants import BASIC_AMBIENT_COLOR, BASIC_DIFFUSE_COLOR, UNIFORM_LIGHT_DIRECTION

SCRIPT_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)), "blender_script.py")


def render_model(
    model_path: str,
    output_path: str,
    num_images: int,
    backend: str = "BLENDER_EEVEE",
    light_mode: str = "random",
    camera_pose: str = "random",
    camera_dist_min: float = 2.0,
    camera_dist_max: float = 2.0,
    fast_mode: bool = False,
    extract_material: bool = False,
    delete_material: bool = False,
    verbose: bool = False,
    timeout: float = 15 * 60,
):
    with tempfile.TemporaryDirectory() as tmp_dir:
        tmp_in = model_path
        tmp_out = os.path.join(tmp_dir, "out")
        zip_out = tmp_out + ".zip"
        os.mkdir(tmp_out)
        args = []
        if platform.system() == "Linux":
            # Needed to enable Eevee backend on headless linux.
            args = ["xvfb-run", "-a"]
        args.extend(
            [
                _blender_binary_path(),
                "-b",
                "-P",
                SCRIPT_PATH,
                "--",
                "--input_path",
                tmp_in,
                "--output_path",
                tmp_out,
                "--num_images",
                str(num_images),
                "--backend",
                backend,
                "--light_mode",
                light_mode,
                "--camera_pose",
                camera_pose,
                "--camera_dist_min",
                str(camera_dist_min),
                "--camera_dist_max",
                str(camera_dist_max),
                "--uniform_light_direction",
                *[str(x) for x in UNIFORM_LIGHT_DIRECTION],
                "--basic_ambient",
                str(BASIC_AMBIENT_COLOR),
                "--basic_diffuse",
                str(BASIC_DIFFUSE_COLOR),
            ]
        )
        if fast_mode:
            args.append("--fast_mode")
        if extract_material:
            args.append("--extract_material")
        if delete_material:
            args.append("--delete_material")
        if verbose:
            subprocess.check_call(args)
        else:
            try:
                output = subprocess.check_output(args, stderr=subprocess.STDOUT, timeout=timeout)
            except subprocess.CalledProcessError as exc:
                raise RuntimeError(f"{exc}: {exc.output}") from exc
        if not os.path.exists(os.path.join(tmp_out, "info.json")):
            if verbose:
                # There is no output available, since it was
                # logged directly to stdout/stderr.
                raise RuntimeError(f"render failed: output file missing")
            else:
                raise RuntimeError(f"render failed: output file missing. Output: {output}")
        _combine_rgba(tmp_out)
        with zipfile.ZipFile(zip_out, mode="w") as zf:
            for name in os.listdir(tmp_out):
                zf.write(os.path.join(tmp_out, name), name)
        bf.copy(zip_out, output_path, overwrite=True)


def render_mesh(
    mesh: TriMesh,
    output_path: str,
    num_images: int,
    backend: str = "BLENDER_EEVEE",
    **kwargs,
):
    if mesh.has_vertex_colors() and backend not in ["BLENDER_EEVEE", "CYCLES"]:
        raise ValueError(f"backend does not support vertex colors: {backend}")

    with tempfile.TemporaryDirectory() as tmp_dir:
        ply_path = os.path.join(tmp_dir, "out.ply")
        with open(ply_path, "wb") as f:
            mesh.write_ply(f)
        render_model(
            ply_path, output_path=output_path, num_images=num_images, backend=backend, **kwargs
        )


def _combine_rgba(out_dir: str):
    i = 0
    while True:
        paths = [os.path.join(out_dir, f"{i:05}_{ch}.png") for ch in "rgba"]
        if not os.path.exists(paths[0]):
            break
        joined = np.stack(
            [(np.array(Image.open(path)) >> 8).astype(np.uint8) for path in paths], axis=-1
        )
        Image.fromarray(joined).save(os.path.join(out_dir, f"{i:05}.png"))
        for path in paths:
            os.remove(path)
        i += 1


def _blender_binary_path() -> str:
    path = os.getenv("BLENDER_PATH", None)
    if path is not None:
        return path

    if os.path.exists("/Applications/Blender.app/Contents/MacOS/Blender"):
        return "/Applications/Blender.app/Contents/MacOS/Blender"

    raise EnvironmentError(
        "To render 3D models, install Blender version 3.3.1 or higher and "
        "set the environment variable `BLENDER_PATH` to the path of the Blender executable."
    )