import os
from pathlib import Path
import traceback
import json
import time
import sys

import numpy as np
import cv2
import open3d as o3d
import torch
import trimesh
from transformers import AutoImageProcessor, AutoModelForDepthEstimation

# Pipeline settings
DEPTH_CHECKPOINT = os.environ.get("DEPTH_CHECKPOINT", "LiheYoung/depth-anything-large-hf") # Default to HF Hub model if local not found
USE_GPU = int(os.environ.get("USE_GPU", "0")) # Default to CPU for HF Spaces
POISSON_DEPTH = int(os.environ.get("POISSON_DEPTH", "9"))
OUTLIER_NEIGHBORS = int(os.environ.get("OUTLIER_NEIGHBORS", "15"))
OUTLIER_STD_RATIO = float(os.environ.get("OUTLIER_STD_RATIO", "1.0"))
ORTHO_SCALE_FACTOR = float(os.environ.get("ORTHO_SCALE_FACTOR", "255"))
INFERENCE_RESIZE = int(os.environ.get("INFERENCE_RESIZE", "0"))
RESULT_PREFIX = os.environ.get("RESULT_PREFIX", "")

try:
    torch.set_num_threads(max(1, (os.cpu_count() or 2) // 2))
except Exception:
    pass

_model = None
_processor = None
_device = "cpu"

def log(msg):
    print(msg, flush=True)
    sys.stdout.flush()

def load_model():
    global _model, _processor, _device
    if _model is None:
        log(f"Loading model: {DEPTH_CHECKPOINT}")
        _processor = AutoImageProcessor.from_pretrained(DEPTH_CHECKPOINT)
        _model = AutoModelForDepthEstimation.from_pretrained(DEPTH_CHECKPOINT)
        if USE_GPU and torch.cuda.is_available():
            _device = "cuda"
            _model = _model.to("cuda")
        else:
            _device = "cpu"
        _model.eval()
    return _model, _processor, _device

def normalize_depth_uint8(depth_np: np.ndarray) -> np.ndarray:
    m = np.max(depth_np)
    if m <= 0:
        return np.zeros_like(depth_np, dtype=np.uint8)
    return (depth_np * 255.0 / m).astype("uint8")

def build_orthographic_point_cloud(depth_u8: np.ndarray, color_rgb: np.ndarray) -> o3d.geometry.PointCloud:
    depth_map = depth_u8.astype(np.float32)
    h, w = depth_map.shape
    y, x = np.meshgrid(np.arange(h), np.arange(w), indexing='ij')
    z = (depth_map / ORTHO_SCALE_FACTOR) * (h / 2.0)
    points = np.stack((x, y, z), axis=-1).reshape(-1, 3)
    mask = points[:, 2] != 0
    points = points[mask]
    pcd = o3d.geometry.PointCloud()
    pcd.points = o3d.utility.Vector3dVector(points)
    colors = color_rgb.reshape(-1, 3)[mask] / 255.0
    pcd.colors = o3d.utility.Vector3dVector(colors)
    return pcd

def process_image_task(image_path: str, result_dir: str, job_id: str, status_callback):
    start = time.time()
    try:
        status_callback(job_id, "RUNNING", "Loading model")
        model, processor, device = load_model()
        log(f"[{job_id}] Model loaded on {device}")

        img_bgr = cv2.imread(image_path)
        if img_bgr is None:
            raise RuntimeError("Failed to read image")
        img_rgb = cv2.cvtColor(img_bgr, cv2.COLOR_BGR2RGB)
        orig_h, orig_w = img_rgb.shape[:2]

        # Optional resize (not used in your notebook; keep 0 for fidelity)
        if INFERENCE_RESIZE and INFERENCE_RESIZE > 0:
            scale = INFERENCE_RESIZE / max(orig_h, orig_w)
            new_w = int(orig_w * scale)
            new_h = int(orig_h * scale)
            img_proc = cv2.resize(img_rgb, (new_w, new_h), interpolation=cv2.INTER_AREA)
        else:
            img_proc = img_rgb

        status_callback(job_id, "RUNNING", "Running depth inference")
        depth_inputs = processor(images=img_proc, return_tensors="pt").to(device)
        with torch.no_grad():
            outputs = model(**depth_inputs)
        depth = outputs.predicted_depth.squeeze().detach().cpu().numpy()

        # Match notebook: use depth resolution, resize color to depth size
        dh, dw = depth.shape
        color_resized = cv2.resize(img_proc, (dw, dh), interpolation=cv2.INTER_LINEAR)

        depth_u8 = normalize_depth_uint8(depth)

        status_callback(job_id, "RUNNING", "Building orthographic point cloud")
        pcd = build_orthographic_point_cloud(depth_u8, color_resized)

        # Outlier removal (nb=15, std_ratio=1.0)
        try:
            cl, ind = pcd.remove_statistical_outlier(nb_neighbors=OUTLIER_NEIGHBORS,
                                                     std_ratio=OUTLIER_STD_RATIO)
            pcd = pcd.select_by_index(ind)
        except Exception as e:
            log(f"[{job_id}] Outlier removal warning: {e}")

        # Normals (your notebook: estimate_normals + orient_normals_to_align_with_direction)
        if len(pcd.points) >= 10:
            try:
                pcd.estimate_normals()
                pcd.orient_normals_to_align_with_direction()
            except Exception as e:
                log(f"[{job_id}] Normal estimation warning: {e}")

        num_pts = np.asarray(pcd.points).shape[0]
        log(f"[{job_id}] Point cloud size after cleanup: {num_pts}")
        if num_pts == 0:
            raise RuntimeError("Empty point cloud after cleanup")

        status_callback(job_id, "RUNNING", f"Poisson reconstruction depth={POISSON_DEPTH}")
        mesh, densities = o3d.geometry.TriangleMesh.create_from_point_cloud_poisson(
            pcd, depth=POISSON_DEPTH
        )

        # Compute normals
        try:
            mesh.compute_vertex_normals()
        except Exception:
            pass
        mesh.compute_triangle_normals()

        num_vertices = np.asarray(mesh.vertices).shape[0]
        num_tris = np.asarray(mesh.triangles).shape[0]
        log(f"[{job_id}] Mesh stats vertices={num_vertices} triangles={num_tris}")
        if num_tris == 0:
            raise RuntimeError("Poisson produced empty mesh")

        Path(result_dir).mkdir(parents=True, exist_ok=True)
        stl_path = Path(result_dir) / f"{RESULT_PREFIX}{job_id}.stl"

        status_callback(job_id, "RUNNING", "Exporting STL")
        tm = trimesh.Trimesh(vertices=np.asarray(mesh.vertices),
                             faces=np.asarray(mesh.triangles),
                             process=True)
        tm.export(str(stl_path), file_type="stl")

        total = time.time() - start
        status_callback(job_id, "SUCCESS", f"Done in {total:.2f}s", str(stl_path))
        log(f"[{job_id}] SUCCESS total={total:.2f}s STL={stl_path}")
        return {
            "status": "success",
            "stl": str(stl_path),
            "mesh_stats": {"vertices": int(num_vertices), "triangles": int(num_tris)}
        }
    except Exception as e:
        traceback.print_exc()
        status_callback(job_id, "FAILURE", str(e))
        log(f"[{job_id}] FAILURE: {e}")
        raise