# Copyright 2024-2025 The Alibaba Wan Team Authors. All rights reserved.
import argparse
import binascii
import os
import os.path as osp
import torchvision.transforms.functional as TF
import torch.nn.functional as F

import imageio
import torch
import decord
import torchvision
from PIL import Image
import numpy as np
from rembg import remove, new_session


__all__ = ['cache_video', 'cache_image', 'str2bool']



from PIL import Image


def resample(video_fps, video_frames_count, max_frames, target_fps):
    import math

    video_frame_duration = 1 /video_fps
    target_frame_duration = 1 / target_fps 
    
    cur_time = 0
    target_time = 0
    frame_no = 0
    frame_ids =[]
    while True:
        if max_frames != 0 and len(frame_ids) >= max_frames:
            break
        add_frames_count = math.ceil( (target_time -cur_time) / video_frame_duration )
        frame_no += add_frames_count
        if frame_no >= video_frames_count:             
            break
        frame_ids.append(frame_no)
        cur_time += add_frames_count * video_frame_duration
        target_time += target_frame_duration
    return frame_ids

def get_video_frame(file_name, frame_no):
    decord.bridge.set_bridge('torch')
    reader = decord.VideoReader(file_name)

    frame = reader.get_batch([frame_no]).squeeze(0)
    img = Image.fromarray(frame.numpy().astype(np.uint8))
    return img

def resize_lanczos(img, h, w):
    img = Image.fromarray(np.clip(255. * img.movedim(0, -1).cpu().numpy(), 0, 255).astype(np.uint8))
    img = img.resize((w,h), resample=Image.Resampling.LANCZOS) 
    return torch.from_numpy(np.array(img).astype(np.float32) / 255.0).movedim(-1, 0)


def remove_background(img, session=None):
    if session ==None:
        session = new_session() 
    img = Image.fromarray(np.clip(255. * img.movedim(0, -1).cpu().numpy(), 0, 255).astype(np.uint8))
    img = remove(img, session=session, alpha_matting = True, bgcolor=[255, 255, 255, 0]).convert('RGB')
    return torch.from_numpy(np.array(img).astype(np.float32) / 255.0).movedim(-1, 0)




def resize_and_remove_background(img_list, canvas_width, canvas_height, rm_background ):
    if rm_background:
        session = new_session() 

    output_list =[]
    for img in img_list:
        width, height =  img.size 
        white_canvas = np.full( (canvas_height, canvas_width, 3), 255, dtype= np.uint8 ) 
        scale = min(canvas_height / height, canvas_width / width)
        new_height = int(height * scale)
        new_width = int(width * scale)
        resized_image= img.resize((new_width,new_height), resample=Image.Resampling.LANCZOS) 
        if rm_background:
            resized_image = remove(resized_image, session=session, alpha_matting = True, bgcolor=[255, 255, 255, 0]).convert('RGB')
        top = (canvas_height - new_height) // 2
        left = (canvas_width - new_width) // 2
        white_canvas[top:top + new_height, left:left + new_width, :] =  np.array(resized_image)
        img = Image.fromarray(white_canvas)
        output_list.append(img)
    return output_list


def rand_name(length=8, suffix=''):
    name = binascii.b2a_hex(os.urandom(length)).decode('utf-8')
    if suffix:
        if not suffix.startswith('.'):
            suffix = '.' + suffix
        name += suffix
    return name


def cache_video(tensor,
                save_file=None,
                fps=30,
                suffix='.mp4',
                nrow=8,
                normalize=True,
                value_range=(-1, 1),
                retry=5):
    # cache file
    cache_file = osp.join('/tmp', rand_name(
        suffix=suffix)) if save_file is None else save_file

    # save to cache
    error = None
    for _ in range(retry):
        try:
            # preprocess
            tensor = tensor.clamp(min(value_range), max(value_range))
            tensor = torch.stack([
                torchvision.utils.make_grid(
                    u, nrow=nrow, normalize=normalize, value_range=value_range)
                for u in tensor.unbind(2)
            ],
                                 dim=1).permute(1, 2, 3, 0)
            tensor = (tensor * 255).type(torch.uint8).cpu()

            # write video
            writer = imageio.get_writer(
                cache_file, fps=fps, codec='libx264', quality=8)
            for frame in tensor.numpy():
                writer.append_data(frame)
            writer.close()
            return cache_file
        except Exception as e:
            error = e
            continue
    else:
        print(f'cache_video failed, error: {error}', flush=True)
        return None


def cache_image(tensor,
                save_file,
                nrow=8,
                normalize=True,
                value_range=(-1, 1),
                retry=5):
    # cache file
    suffix = osp.splitext(save_file)[1]
    if suffix.lower() not in [
            '.jpg', '.jpeg', '.png', '.tiff', '.gif', '.webp'
    ]:
        suffix = '.png'

    # save to cache
    error = None
    for _ in range(retry):
        try:
            tensor = tensor.clamp(min(value_range), max(value_range))
            torchvision.utils.save_image(
                tensor,
                save_file,
                nrow=nrow,
                normalize=normalize,
                value_range=value_range)
            return save_file
        except Exception as e:
            error = e
            continue


def str2bool(v):
    """
    Convert a string to a boolean.

    Supported true values: 'yes', 'true', 't', 'y', '1'
    Supported false values: 'no', 'false', 'f', 'n', '0'

    Args:
        v (str): String to convert.

    Returns:
        bool: Converted boolean value.

    Raises:
        argparse.ArgumentTypeError: If the value cannot be converted to boolean.
    """
    if isinstance(v, bool):
        return v
    v_lower = v.lower()
    if v_lower in ('yes', 'true', 't', 'y', '1'):
        return True
    elif v_lower in ('no', 'false', 'f', 'n', '0'):
        return False
    else:
        raise argparse.ArgumentTypeError('Boolean value expected (True/False)')