# Reference: https://github.com/gangweiX/Pixel-Perfect-Depth
# Strictly follows official `run.py`:
#   from ppd.models.ppd import PixelPerfectDepth
#   model = PixelPerfectDepth(semantics_model='DA2', semantics_pth='checkpoints/depth_anything_v2_vitl.pth',
#                             sampling_steps=4)
#   model.load_state_dict(torch.load(model_pth, map_location='cpu'), strict=False)
#   model = model.to(DEVICE).eval()
#   image = cv2.imread(filename)        # BGR uint8 numpy
#   H, W = image.shape[:2]
#   depth, _ = model.infer_image(image) # torch.Tensor, may be (1, 1, h, w)
#   depth = F.interpolate(depth, size=(H, W), mode='bilinear', align_corners=False)[0, 0]

import os
import sys
from typing import *
from pathlib import Path

import click
import torch
import torch.nn.functional as F
import numpy as np

from moge.test.baseline import MGEBaselineInterface


class Baseline(MGEBaselineInterface):
    def __init__(self, repo_path: str, semantics_model: str, semantics_pth: str,
                 model_pth: str, sampling_steps: int, device: Union[torch.device, str]):
        repo_path = os.path.abspath(repo_path)
        if not Path(repo_path).exists():
            raise FileNotFoundError(
                f"Cannot find PPD repo at {repo_path}. Clone https://github.com/gangweiX/Pixel-Perfect-Depth."
            )
        if repo_path not in sys.path:
            sys.path.insert(0, repo_path)

        from ppd.models.ppd import PixelPerfectDepth
        from ppd.utils.set_seed import set_seed
        set_seed(666)  # mirror run.py

        # Allow relative paths against repo root (mirror run.py expectations).
        if not os.path.isabs(semantics_pth):
            semantics_pth = os.path.join(repo_path, semantics_pth)
        if not os.path.isabs(model_pth):
            model_pth = os.path.join(repo_path, model_pth)
        if not os.path.exists(semantics_pth):
            raise FileNotFoundError(f"Cannot find PPD semantics checkpoint at {semantics_pth}.")
        if not os.path.exists(model_pth):
            raise FileNotFoundError(f"Cannot find PPD model checkpoint at {model_pth}.")

        device = torch.device(device)
        model = PixelPerfectDepth(
            semantics_model=semantics_model,
            semantics_pth=semantics_pth,
            sampling_steps=sampling_steps,
        )
        model.load_state_dict(torch.load(model_pth, map_location='cpu'), strict=False)
        model = model.to(device).eval()

        self.model = model
        self.device = device

    @click.command()
    @click.option('--repo', 'repo_path', type=click.Path(), default='../Pixel-Perfect-Depth',
                  help='Path to the gangweiX/Pixel-Perfect-Depth repository.')
    @click.option('--semantics_model', type=click.Choice(['DA2', 'MoGe2']), default='DA2',
                  help='Semantics encoder used by PPD (run.py default DA2).')
    @click.option('--semantics_pth', type=click.Path(),
                  default='checkpoints/depth_anything_v2_vitl.pth',
                  help='Semantics encoder ckpt path (relative to --repo if not absolute).')
    @click.option('--model_pth', type=click.Path(), default='checkpoints/ppd.pth',
                  help='PPD model ckpt path (relative to --repo if not absolute).')
    @click.option('--sampling_steps', type=int, default=4,
                  help='Number of DiT sampling steps (run.py default 4).')
    @click.option('--device', type=str, default='cuda')
    @staticmethod
    def load(repo_path: str, semantics_model: str, semantics_pth: str,
             model_pth: str, sampling_steps: int, device: str = 'cuda'):
        return Baseline(repo_path, semantics_model, semantics_pth, model_pth, sampling_steps, device)

    @torch.inference_mode()
    def infer(self, image: torch.Tensor, intrinsics: Optional[torch.Tensor] = None) -> Dict[str, torch.Tensor]:
        omit_batch = image.ndim == 3
        if omit_batch:
            image = image.unsqueeze(0)
        assert image.shape[0] == 1, "PPD baseline only supports batch size 1"
        _, _, H, W = image.shape

        # run.py calls cv2.imread which returns BGR uint8 numpy (H, W, 3).
        rgb_uint8 = (image[0].cpu().permute(1, 2, 0).clamp(0, 1).numpy() * 255).astype(np.uint8)
        bgr_uint8 = rgb_uint8[..., ::-1].copy()  # BGR for cv2 parity

        depth, _ = self.model.infer_image(bgr_uint8)
        # run.py: depth = F.interpolate(depth, size=(H, W), ...)[0, 0]; so depth here is 4D.
        if depth.ndim == 4:
            depth = F.interpolate(depth, size=(H, W), mode='bilinear', align_corners=False)[0, 0]
        elif depth.ndim == 2 and depth.shape != (H, W):
            depth = F.interpolate(depth[None, None], size=(H, W), mode='bilinear', align_corners=False)[0, 0]
        depth = depth.to(self.device).float()

        # PPD predicts affine-invariant depth (Xu et al., 2025). Emit only this physical key.
        result = {'depth_affine_invariant': depth}
        if not omit_batch:
            result['depth_affine_invariant'] = result['depth_affine_invariant'].unsqueeze(0)
        return result