from dataclasses import dataclass, field
import importlib.util
from pathlib import Path
import sys
import time
import types

import imageio.v2 as imageio
import numpy as np
import torch
import torch.nn as nn
import tyro
from einops import rearrange


def build_label_colormap(size):
    colormap = np.zeros((size, 3), dtype=np.uint8)
    indices = np.arange(size, dtype=np.uint32)
    for shift in range(8):
        for channel in range(3):
            colormap[:, channel] |= ((indices >> channel) & 1).astype(np.uint8) << (7 - shift)
        indices >>= 3
    return colormap


def install_import_stubs():
    sys.modules['h5py'] = types.ModuleType('h5py')

    transforms3d = types.ModuleType('transforms3d')
    axangles = types.ModuleType('transforms3d.axangles')
    euler = types.ModuleType('transforms3d.euler')

    def mat2axangle(matrix):
        del matrix
        return np.array([1.0, 0.0, 0.0], dtype=np.float32), 0.0

    def euler2mat(ai, aj, ak):
        del ai, aj, ak
        return np.eye(3, dtype=np.float32)

    axangles.mat2axangle = mat2axangle
    euler.euler2mat = euler2mat
    transforms3d.axangles = axangles
    transforms3d.euler = euler

    sys.modules['transforms3d'] = transforms3d
    sys.modules['transforms3d.axangles'] = axangles
    sys.modules['transforms3d.euler'] = euler

    mmcv = types.ModuleType('mmcv')
    mmcv_cnn = types.ModuleType('mmcv.cnn')

    class ConvModule(nn.Module):
        def __init__(
            self,
            in_channels,
            out_channels,
            kernel_size,
            stride=1,
            padding=0,
            conv_cfg=None,
            norm_cfg=None,
            act_cfg=None,
            inplace=False,
        ):
            del conv_cfg, norm_cfg, act_cfg, inplace
            super().__init__()
            self.conv = nn.Conv2d(
                in_channels,
                out_channels,
                kernel_size,
                stride=stride,
                padding=padding,
            )

        def forward(self, x):
            return self.conv(x)

    mmcv_cnn.ConvModule = ConvModule
    mmcv.cnn = mmcv_cnn
    sys.modules['mmcv'] = mmcv
    sys.modules['mmcv.cnn'] = mmcv_cnn

    mmengine = types.ModuleType('mmengine')
    mmengine_model = types.ModuleType('mmengine.model')

    class BaseModule(nn.Module):
        def __init__(self, init_cfg=None):
            del init_cfg
            super().__init__()

    mmengine_model.BaseModule = BaseModule
    mmengine.model = mmengine_model
    sys.modules['mmengine'] = mmengine
    sys.modules['mmengine.model'] = mmengine_model

    mmdet = types.ModuleType('mmdet')
    mmdet_registry = types.ModuleType('mmdet.registry')
    mmdet_utils = types.ModuleType('mmdet.utils')
    mmdet_registry.MODELS = object()
    mmdet_utils.ConfigType = dict
    mmdet_utils.MultiConfig = dict
    mmdet_utils.OptConfigType = dict
    mmdet.registry = mmdet_registry
    mmdet.utils = mmdet_utils
    sys.modules['mmdet'] = mmdet
    sys.modules['mmdet.registry'] = mmdet_registry
    sys.modules['mmdet.utils'] = mmdet_utils


@dataclass
class Args:
    official_repo: Path = Path('/mnt/public/cjw/projs/SemanticFrustum/ref/GP-NeRF')
    ported_repo: Path = Path('/mnt/public/cjw/projs/sfrustum')
    config_path: Path = Path('/mnt/public/cjw/projs/SemanticFrustum/ref/GP-NeRF/configs/gpnerf_replica.txt')
    scene_list: Path = Path('/mnt/public/cjw/projs/SemanticFrustum/ref/GP-NeRF/configs/replica_test_split.txt')
    checkpoint: Path = Path('/mnt/public/cjw/projs/SemanticFrustum/ckpts/gpnerf_replica.pth')
    rootdir: Path = Path('/tmp/gpnerf_ref_root')
    output_dir: Path = Path('/mnt/public/cjw/projs/SemanticFrustum/outputs/official_gpnerf_replica_stride1')
    render_stride: int = 1
    chunk_size: int = 8000
    num_images_per_scene: int = 10
    scenes: list[str] = field(default_factory=list)


def patch_official_modules(semantic_branch, replica_dataset_module):
    original_sem_init = semantic_branch.NeRFSemSegFPNHead.__init__

    def patched_sem_init(
        self,
        args,
        feature_strides=[2, 4, 8, 16],
        feature_channels=[128, 128, 128, 128],
        num_classes=20,
    ):
        del num_classes
        return original_sem_init(
            self,
            args,
            feature_strides=feature_strides,
            feature_channels=feature_channels,
            num_classes=args.num_classes,
        )

    semantic_branch.NeRFSemSegFPNHead.__init__ = patched_sem_init

    original_getitem = replica_dataset_module.ReplicaValDataset.__getitem__

    def patched_getitem(self, idx):
        item = original_getitem(self, idx)
        depth = item['true_depth']
        depth_range = item['depth_range']
        depth_mask = torch.ones_like(depth, dtype=torch.float32)
        depth_mask[depth > (depth_range[1] - 0.1)] = 0.0
        depth_mask[depth < (depth_range[0] + 0.1)] = 0.0
        item['depth_mask'] = depth_mask
        return item

    replica_dataset_module.ReplicaValDataset.__getitem__ = patched_getitem


def build_official_args(config_module, args: Args):
    parser = config_module.config_parser()
    official_args = parser.parse_args(
        [
            '--config',
            str(args.config_path),
            '--ckpt_path',
            str(args.checkpoint),
            '--rootdir',
            str(args.rootdir) + '/',
            '--expname',
            'official_gpnerf_replica_stride1',
            '--local_rank',
            '0',
        ]
    )
    official_args.distributed = False
    official_args.no_reload = False
    official_args.no_load_opt = True
    official_args.no_load_scheduler = True
    official_args.num_workers = 0
    official_args.render_stride = args.render_stride
    official_args.chunk_size = args.chunk_size
    return official_args


def save_prediction_images(output_dir, sample_idx, rgb_pred, sem_pred, color_map):
    rgb_path = output_dir / f'rgb_pred_{sample_idx:03d}.png'
    sem_path = output_dir / f'sem_pred_{sample_idx:03d}.png'

    imageio.imwrite(rgb_path, (255.0 * np.clip(rgb_pred, 0.0, 1.0)).astype(np.uint8))
    sem_labels = sem_pred.argmax(axis=-1)
    imageio.imwrite(sem_path, color_map[sem_labels])
    return rgb_path, sem_path


def build_full_resolution_semantic_head(args: Args, official_args):
    module_path = args.ported_repo / 'modules' / 'gpnerf_semantic_head.py'
    spec = importlib.util.spec_from_file_location('ported_gpnerf_semantic_head', module_path)
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)

    checkpoint = torch.load(args.checkpoint, map_location='cpu')
    sem_head = module.NeRFSemSegFPNHead(official_args.num_classes, n_p=official_args.n_p).cuda()
    sem_head.load_state_dict(checkpoint['sem_seg_head'], strict=True)
    sem_head.eval()
    return sem_head


def render_scene(scene_name, dataset, model, full_res_sem_head, projector, official_args, color_map, output_dir):
    from gpnerf.render_image import render_single_image
    from gpnerf.sample_ray import RaySamplerSingleImage

    output_dir.mkdir(parents=True, exist_ok=True)
    scene_records = []
    total_samples = min(len(dataset), official_args.num_images_per_scene if hasattr(official_args, 'num_images_per_scene') else len(dataset))

    for sample_idx in range(total_samples):
        start_time = time.time()
        print(f'[{scene_name}] rendering sample {sample_idx + 1}/{total_samples}', flush=True)
        raw = dataset[sample_idx]
        batch = {}
        for key, value in raw.items():
            if torch.is_tensor(value):
                batch[key] = value.unsqueeze(0)
            else:
                batch[key] = [value]

        ray_sampler = RaySamplerSingleImage(batch, 'cuda:0', render_stride=official_args.render_stride)
        ray_batch = ray_sampler.get_all()

        with torch.no_grad():
            ref_coarse_feats, _, ref_deep_semantics = model.feature_net(
                rearrange(ray_batch['src_rgbs'].squeeze(0), 'v h w c -> v c h w')
            )
            ref_coarse_feats = ref_coarse_feats.contiguous()
            ref_deep_semantics = model.feature_fpn(ref_deep_semantics).contiguous()

            ret = render_single_image(
                ray_sampler=ray_sampler,
                ray_batch=ray_batch,
                model=model,
                projector=projector,
                chunk_size=official_args.chunk_size,
                N_samples=official_args.N_samples,
                inv_uniform=official_args.inv_uniform,
                det=True,
                N_importance=official_args.N_importance,
                white_bkgd=official_args.white_bkgd,
                render_stride=official_args.render_stride,
                featmaps=ref_coarse_feats,
                deep_semantics=ref_deep_semantics,
                ret_alpha=official_args.N_importance > 0,
                single_net=official_args.single_net,
            )

            semantic_key = 'outputs_fine' if ret['outputs_fine'] is not None else 'outputs_coarse'
            semantic_feats = ret[semantic_key]['feats_out']
            semantic_feats = rearrange(semantic_feats, 'h w c -> 1 c h w')
            target_feat_size = (
                official_args.original_height // full_res_sem_head.common_stride,
                official_args.original_width // full_res_sem_head.common_stride,
            )
            if semantic_feats.shape[-2:] != target_feat_size:
                semantic_feats = torch.nn.functional.interpolate(
                    semantic_feats,
                    size=target_feat_size,
                    mode='bilinear',
                    align_corners=True,
                )
            sem_pred, _, _ = full_res_sem_head(semantic_feats.to(ref_deep_semantics.device), None, None)
            sem_pred = rearrange(sem_pred[0], 'c h w -> h w c').detach().cpu().numpy()

            rgb_pred = (
                ret['outputs_fine']['rgb']
                if ret['outputs_fine'] is not None
                else ret['outputs_coarse']['rgb']
            ).detach().cpu().numpy()

        rgb_path, sem_path = save_prediction_images(output_dir, sample_idx, rgb_pred, sem_pred, color_map)
        scene_records.append(
            {
                'sample_idx': sample_idx,
                'rgb_input_path': batch['rgb_path'][0],
                'rgb_pred_path': str(rgb_path),
                'sem_pred_path': str(sem_path),
                'render_time_sec': time.time() - start_time,
            }
        )
        print(
            f'[{scene_name}] finished sample {sample_idx + 1}/{total_samples} in {scene_records[-1]["render_time_sec"]:.2f}s',
            flush=True,
        )

    return {
        'scene': scene_name,
        'num_images': len(scene_records),
        'records': scene_records,
    }


def main():
    args = tyro.cli(Args)
    torch.backends.cudnn.enabled = False
    install_import_stubs()
    sys.path.insert(0, str(args.official_repo))

    import config as official_config
    import gpnerf.semantic_branch as semantic_branch
    import gpnerf.data_loaders.replica_dataset as replica_dataset_module
    from gpnerf.model import GPNeRFModel
    from gpnerf.projection import Projector

    patch_official_modules(semantic_branch, replica_dataset_module)
    official_args = build_official_args(official_config, args)
    official_args.num_images_per_scene = args.num_images_per_scene

    scene_names = args.scenes
    if not scene_names:
        scene_names = np.loadtxt(args.scene_list, dtype=str).tolist()
        if isinstance(scene_names, str):
            scene_names = [scene_names]

    color_map = build_label_colormap(official_args.num_classes + 1)

    torch.cuda.set_device(0)
    model = GPNeRFModel(official_args, load_opt=False, load_scheduler=False)
    model.switch_to_eval()
    full_res_sem_head = build_full_resolution_semantic_head(args, official_args)
    projector = Projector(device='cuda:0')

    summary = {
        'render_stride': official_args.render_stride,
        'chunk_size': official_args.chunk_size,
        'checkpoint': str(args.checkpoint),
        'scenes': [],
    }

    for scene_name in scene_names:
        dataset = replica_dataset_module.ReplicaValDataset(official_args, is_train=False, scenes=scene_name)
        scene_output_dir = args.output_dir / scene_name
        summary['scenes'].append(
            render_scene(
                scene_name,
                dataset,
                model,
                full_res_sem_head,
                projector,
                official_args,
                color_map,
                scene_output_dir,
            )
        )

    args.output_dir.mkdir(parents=True, exist_ok=True)
    (args.output_dir / 'summary.json').write_text(
        __import__('json').dumps(summary, indent=2, ensure_ascii=False)
    )


if __name__ == '__main__':
    main()