# Reference: https://github.com/ByteDance-Seed/Depth-Anything-3
# Variant of `baselines/da3.py` that loads DA3's *monocular* preset(s).
# DA3 README: "DA3 Monocular Series (DA3Mono-Large). A dedicated model for high-quality
# relative monocular depth estimation. Unlike disparity-based models (e.g. Depth Anything 2),
# it directly predicts depth, resulting in superior geometric accuracy."
#
# Strictly follows the same Python API as da3.py:
#   model = DepthAnything3.from_pretrained(<hf_id>)
#   output = model(image)   # image shape [B, N, 3, H, W]
#   depth  = output['depth'][:, 0]   # [B, H, W]
#
# NOTE on output key: DA3-Mono outputs depth directly (per README), not disparity.
# We therefore return `depth_scale_invariant` instead of `disparity_affine_invariant`.

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

import click
import torch
import torch.nn.functional as F
import torchvision.transforms as T
import torchvision.transforms.functional as TF

from moge.test.baseline import MGEBaselineInterface


class Baseline(MGEBaselineInterface):
    def __init__(self, repo_path: str, hf_id: str, num_tokens: Optional[int], device: Union[torch.device, str]):
        repo_path = os.path.abspath(repo_path)
        if not Path(repo_path).exists():
            raise FileNotFoundError(
                f"Cannot find Depth-Anything-3 repo at {repo_path}. Clone "
                f"https://github.com/ByteDance-Seed/Depth-Anything-3."
            )
        src_path = os.path.join(repo_path, 'src')
        if src_path not in sys.path:
            sys.path.insert(0, src_path)

        # Silence DA3's verbose per-image INFO logs (DA3_LOG_LEVEL is read at logger init)
        os.environ.setdefault('DA3_LOG_LEVEL', 'WARN')

        from depth_anything_3.api import DepthAnything3

        device = torch.device(device)
        model = DepthAnything3.from_pretrained(hf_id)
        model.to(device).eval()

        self.model = model
        self.num_tokens = num_tokens
        self.device = device

    @click.command()
    @click.option('--repo', 'repo_path', type=click.Path(), default='../Depth-Anything-3',
                  help='Path to the ByteDance-Seed/Depth-Anything-3 repository.')
    @click.option('--hf_id', type=str, default='depth-anything/DA3MONO-LARGE',
                  help='HF repo id of the DA3-Mono variant (e.g. depth-anything/DA3MONO-LARGE).')
    @click.option('--num_tokens', type=int, default=None,
                  help='Number of tokens; None uses 518 / min(H, W) factor as in da3.py.')
    @click.option('--device', type=str, default='cuda')
    @staticmethod
    def load(repo_path: str, hf_id: str, num_tokens: Optional[int], device: str = 'cuda'):
        return Baseline(repo_path, hf_id, num_tokens, device)

    @torch.inference_mode()
    def infer(self, image: torch.Tensor, intrinsics: Optional[torch.Tensor] = None) -> Dict[str, torch.Tensor]:
        # Same input pipeline as baselines/da3.py to keep apples-to-apples.
        assert intrinsics is None, "DA3-Mono does not consume intrinsics."
        original_height, original_width = image.shape[-2:]

        if image.ndim == 3:
            image = image.unsqueeze(0)
            omit_batch_dim = True
        else:
            omit_batch_dim = False

        # Use DA3's high-level `model.inference()` API per README. Direct `model(x)`
        # goes through `forward(... export_feat_layers=None)` and the DA3-Mono backbone
        # (DINOv2 fork) crashes inside `_get_intermediate_layers_not_chunked` because it
        # tries `i in export_feat_layers` on None. `inference()` handles processing,
        # autocast, and post-processing correctly.
        import numpy as np
        np_img = (image[0].cpu().permute(1, 2, 0).clamp(0, 1).numpy() * 255).astype(np.uint8)
        prediction = self.model.inference([np_img])

        # prediction.depth: [N, H, W] float32
        depth_t = torch.as_tensor(prediction.depth[0], device=self.device, dtype=torch.float32)
        if depth_t.shape != (original_height, original_width):
            depth_t = F.interpolate(depth_t[None, None], size=(original_height, original_width),
                                    mode='bilinear', align_corners=False)[0, 0]

        if not omit_batch_dim:
            depth_t = depth_t.unsqueeze(0)
        return {'depth_scale_invariant': depth_t}