import torch
import math
import struct

def load_torch_file(ckpt, safe_load=False):
    if ckpt.lower().endswith(".safetensors"):
        import safetensors.torch
        sd = safetensors.torch.load_file(ckpt, device="cpu")
    else:
        if safe_load:
            if not 'weights_only' in torch.load.__code__.co_varnames:
                print("Warning torch.load doesn't support weights_only on this pytorch version, loading unsafely.")
                safe_load = False
        if safe_load:
            pl_sd = torch.load(ckpt, map_location="cpu", weights_only=True)
        else:
            pl_sd = torch.load(ckpt, map_location="cpu")
        if "global_step" in pl_sd:
            print(f"Global Step: {pl_sd['global_step']}")
        if "state_dict" in pl_sd:
            sd = pl_sd["state_dict"]
        else:
            sd = pl_sd
    return sd

def transformers_convert(sd, prefix_from, prefix_to, number):
    resblock_to_replace = {
        "ln_1": "layer_norm1",
        "ln_2": "layer_norm2",
        "mlp.c_fc": "mlp.fc1",
        "mlp.c_proj": "mlp.fc2",
        "attn.out_proj": "self_attn.out_proj",
    }

    for resblock in range(number):
        for x in resblock_to_replace:
            for y in ["weight", "bias"]:
                k = "{}.transformer.resblocks.{}.{}.{}".format(prefix_from, resblock, x, y)
                k_to = "{}.encoder.layers.{}.{}.{}".format(prefix_to, resblock, resblock_to_replace[x], y)
                if k in sd:
                    sd[k_to] = sd.pop(k)

        for y in ["weight", "bias"]:
            k_from = "{}.transformer.resblocks.{}.attn.in_proj_{}".format(prefix_from, resblock, y)
            if k_from in sd:
                weights = sd.pop(k_from)
                shape_from = weights.shape[0] // 3
                for x in range(3):
                    p = ["self_attn.q_proj", "self_attn.k_proj", "self_attn.v_proj"]
                    k_to = "{}.encoder.layers.{}.{}.{}".format(prefix_to, resblock, p[x], y)
                    sd[k_to] = weights[shape_from*x:shape_from*(x + 1)]
    return sd

def safetensors_header(safetensors_path, max_size=100*1024*1024):
    with open(safetensors_path, "rb") as f:
        header = f.read(8)
        length_of_header = struct.unpack('<Q', header)[0]
        if length_of_header > max_size:
            return None
        return f.read(length_of_header)

def bislerp(samples, width, height):
    def slerp(b1, b2, r):
        '''slerps batches b1, b2 according to ratio r, batches should be flat e.g. NxC'''
        
        c = b1.shape[-1]

        #norms
        b1_norms = torch.norm(b1, dim=-1, keepdim=True)
        b2_norms = torch.norm(b2, dim=-1, keepdim=True)

        #normalize
        b1_normalized = b1 / b1_norms
        b2_normalized = b2 / b2_norms

        #zero when norms are zero
        b1_normalized[b1_norms.expand(-1,c) == 0.0] = 0.0
        b2_normalized[b2_norms.expand(-1,c) == 0.0] = 0.0

        #slerp
        dot = (b1_normalized*b2_normalized).sum(1)
        omega = torch.acos(dot)
        so = torch.sin(omega)

        #technically not mathematically correct, but more pleasing?
        res = (torch.sin((1.0-r.squeeze(1))*omega)/so).unsqueeze(1)*b1_normalized + (torch.sin(r.squeeze(1)*omega)/so).unsqueeze(1) * b2_normalized
        res *= (b1_norms * (1.0-r) + b2_norms * r).expand(-1,c)

        #edge cases for same or polar opposites
        res[dot > 1 - 1e-5] = b1[dot > 1 - 1e-5] 
        res[dot < 1e-5 - 1] = (b1 * (1.0-r) + b2 * r)[dot < 1e-5 - 1]
        return res
    
    def generate_bilinear_data(length_old, length_new):
        coords_1 = torch.arange(length_old).reshape((1,1,1,-1)).to(torch.float32)
        coords_1 = torch.nn.functional.interpolate(coords_1, size=(1, length_new), mode="bilinear")
        ratios = coords_1 - coords_1.floor()
        coords_1 = coords_1.to(torch.int64)
        
        coords_2 = torch.arange(length_old).reshape((1,1,1,-1)).to(torch.float32) + 1
        coords_2[:,:,:,-1] -= 1
        coords_2 = torch.nn.functional.interpolate(coords_2, size=(1, length_new), mode="bilinear")
        coords_2 = coords_2.to(torch.int64)
        return ratios, coords_1, coords_2
    
    n,c,h,w = samples.shape
    h_new, w_new = (height, width)
    
    #linear w
    ratios, coords_1, coords_2 = generate_bilinear_data(w, w_new)
    coords_1 = coords_1.expand((n, c, h, -1))
    coords_2 = coords_2.expand((n, c, h, -1))
    ratios = ratios.expand((n, 1, h, -1))

    pass_1 = samples.gather(-1,coords_1).movedim(1, -1).reshape((-1,c))
    pass_2 = samples.gather(-1,coords_2).movedim(1, -1).reshape((-1,c))
    ratios = ratios.movedim(1, -1).reshape((-1,1))

    result = slerp(pass_1, pass_2, ratios)
    result = result.reshape(n, h, w_new, c).movedim(-1, 1)

    #linear h
    ratios, coords_1, coords_2 = generate_bilinear_data(h, h_new)
    coords_1 = coords_1.reshape((1,1,-1,1)).expand((n, c, -1, w_new))
    coords_2 = coords_2.reshape((1,1,-1,1)).expand((n, c, -1, w_new))
    ratios = ratios.reshape((1,1,-1,1)).expand((n, 1, -1, w_new))

    pass_1 = result.gather(-2,coords_1).movedim(1, -1).reshape((-1,c))
    pass_2 = result.gather(-2,coords_2).movedim(1, -1).reshape((-1,c))
    ratios = ratios.movedim(1, -1).reshape((-1,1))

    result = slerp(pass_1, pass_2, ratios)
    result = result.reshape(n, h_new, w_new, c).movedim(-1, 1)
    return result

def common_upscale(samples, width, height, upscale_method, crop):
        if crop == "center":
            old_width = samples.shape[3]
            old_height = samples.shape[2]
            old_aspect = old_width / old_height
            new_aspect = width / height
            x = 0
            y = 0
            if old_aspect > new_aspect:
                x = round((old_width - old_width * (new_aspect / old_aspect)) / 2)
            elif old_aspect < new_aspect:
                y = round((old_height - old_height * (old_aspect / new_aspect)) / 2)
            s = samples[:,:,y:old_height-y,x:old_width-x]
        else:
            s = samples

        if upscale_method == "bislerp":
            return bislerp(s, width, height)
        else:
            return torch.nn.functional.interpolate(s, size=(height, width), mode=upscale_method)

def get_tiled_scale_steps(width, height, tile_x, tile_y, overlap):
    return math.ceil((height / (tile_y - overlap))) * math.ceil((width / (tile_x - overlap)))

@torch.inference_mode()
def tiled_scale(samples, function, tile_x=64, tile_y=64, overlap = 8, upscale_amount = 4, out_channels = 3, pbar = None):
    output = torch.empty((samples.shape[0], out_channels, round(samples.shape[2] * upscale_amount), round(samples.shape[3] * upscale_amount)), device="cpu")
    for b in range(samples.shape[0]):
        s = samples[b:b+1]
        out = torch.zeros((s.shape[0], out_channels, round(s.shape[2] * upscale_amount), round(s.shape[3] * upscale_amount)), device="cpu")
        out_div = torch.zeros((s.shape[0], out_channels, round(s.shape[2] * upscale_amount), round(s.shape[3] * upscale_amount)), device="cpu")
        for y in range(0, s.shape[2], tile_y - overlap):
            for x in range(0, s.shape[3], tile_x - overlap):
                s_in = s[:,:,y:y+tile_y,x:x+tile_x]

                ps = function(s_in).cpu()
                mask = torch.ones_like(ps)
                feather = round(overlap * upscale_amount)
                for t in range(feather):
                        mask[:,:,t:1+t,:] *= ((1.0/feather) * (t + 1))
                        mask[:,:,mask.shape[2] -1 -t: mask.shape[2]-t,:] *= ((1.0/feather) * (t + 1))
                        mask[:,:,:,t:1+t] *= ((1.0/feather) * (t + 1))
                        mask[:,:,:,mask.shape[3]- 1 - t: mask.shape[3]- t] *= ((1.0/feather) * (t + 1))
                out[:,:,round(y*upscale_amount):round((y+tile_y)*upscale_amount),round(x*upscale_amount):round((x+tile_x)*upscale_amount)] += ps * mask
                out_div[:,:,round(y*upscale_amount):round((y+tile_y)*upscale_amount),round(x*upscale_amount):round((x+tile_x)*upscale_amount)] += mask
                if pbar is not None:
                    pbar.update(1)

        output[b:b+1] = out/out_div
    return output


PROGRESS_BAR_HOOK = None
def set_progress_bar_global_hook(function):
    global PROGRESS_BAR_HOOK
    PROGRESS_BAR_HOOK = function

class ProgressBar:
    def __init__(self, total):
        global PROGRESS_BAR_HOOK
        self.total = total
        self.current = 0
        self.hook = PROGRESS_BAR_HOOK

    def update_absolute(self, value, total=None):
        if total is not None:
            self.total = total
        if value > self.total:
            value = self.total
        self.current = value
        if self.hook is not None:
            self.hook(self.current, self.total)

    def update(self, value):
        self.update_absolute(self.current + value)
