import torch
import torch.nn as nn
import numpy as np
import os
from util import *


class Face_3DMM(nn.Module):
    def __init__(self, modelpath, id_dim, exp_dim, tex_dim, point_num):
        super(Face_3DMM, self).__init__()
        # id_dim = 100
        # exp_dim = 79
        # tex_dim = 100
        self.point_num = point_num
        DMM_info = np.load(
            os.path.join(modelpath, "3DMM_info.npy"), allow_pickle=True
        ).item()
        base_id = DMM_info["b_shape"][:id_dim, :]
        mu_id = DMM_info["mu_shape"]
        base_exp = DMM_info["b_exp"][:exp_dim, :]
        mu_exp = DMM_info["mu_exp"]
        mu = mu_id + mu_exp
        mu = mu.reshape(-1, 3)
        for i in range(3):
            mu[:, i] -= np.mean(mu[:, i])
        mu = mu.reshape(-1)
        self.base_id = torch.as_tensor(base_id).cuda() / 100000.0
        self.base_exp = torch.as_tensor(base_exp).cuda() / 100000.0
        self.mu = torch.as_tensor(mu).cuda() / 100000.0
        base_tex = DMM_info["b_tex"][:tex_dim, :]
        mu_tex = DMM_info["mu_tex"]
        self.base_tex = torch.as_tensor(base_tex).cuda()
        self.mu_tex = torch.as_tensor(mu_tex).cuda()
        sig_id = DMM_info["sig_shape"][:id_dim]
        sig_tex = DMM_info["sig_tex"][:tex_dim]
        sig_exp = DMM_info["sig_exp"][:exp_dim]
        self.sig_id = torch.as_tensor(sig_id).cuda()
        self.sig_tex = torch.as_tensor(sig_tex).cuda()
        self.sig_exp = torch.as_tensor(sig_exp).cuda()

        keys_info = np.load(
            os.path.join(modelpath, "keys_info.npy"), allow_pickle=True
        ).item()
        self.keyinds = torch.as_tensor(keys_info["keyinds"]).cuda()
        self.left_contours = torch.as_tensor(keys_info["left_contour"]).cuda()
        self.right_contours = torch.as_tensor(keys_info["right_contour"]).cuda()
        self.rigid_ids = torch.as_tensor(keys_info["rigid_ids"]).cuda()

    def get_3dlandmarks(self, id_para, exp_para, euler_angle, trans, focal_length, cxy):
        id_para = id_para * self.sig_id
        exp_para = exp_para * self.sig_exp
        batch_size = id_para.shape[0]
        num_per_contour = self.left_contours.shape[1]
        left_contours_flat = self.left_contours.reshape(-1)
        right_contours_flat = self.right_contours.reshape(-1)
        sel_index = torch.cat(
            (
                3 * left_contours_flat.unsqueeze(1),
                3 * left_contours_flat.unsqueeze(1) + 1,
                3 * left_contours_flat.unsqueeze(1) + 2,
            ),
            dim=1,
        ).reshape(-1)
        left_geometry = (
            torch.mm(id_para, self.base_id[:, sel_index])
            + torch.mm(exp_para, self.base_exp[:, sel_index])
            + self.mu[sel_index]
        )
        left_geometry = left_geometry.view(batch_size, -1, 3)
        proj_x = forward_transform(
            left_geometry, euler_angle, trans, focal_length, cxy
        )[:, :, 0]
        proj_x = proj_x.reshape(batch_size, 8, num_per_contour)
        arg_min = proj_x.argmin(dim=2)
        left_geometry = left_geometry.view(batch_size * 8, num_per_contour, 3)
        left_3dlands = left_geometry[
            torch.arange(batch_size * 8), arg_min.view(-1), :
        ].view(batch_size, 8, 3)

        sel_index = torch.cat(
            (
                3 * right_contours_flat.unsqueeze(1),
                3 * right_contours_flat.unsqueeze(1) + 1,
                3 * right_contours_flat.unsqueeze(1) + 2,
            ),
            dim=1,
        ).reshape(-1)
        right_geometry = (
            torch.mm(id_para, self.base_id[:, sel_index])
            + torch.mm(exp_para, self.base_exp[:, sel_index])
            + self.mu[sel_index]
        )
        right_geometry = right_geometry.view(batch_size, -1, 3)
        proj_x = forward_transform(
            right_geometry, euler_angle, trans, focal_length, cxy
        )[:, :, 0]
        proj_x = proj_x.reshape(batch_size, 8, num_per_contour)
        arg_max = proj_x.argmax(dim=2)
        right_geometry = right_geometry.view(batch_size * 8, num_per_contour, 3)
        right_3dlands = right_geometry[
            torch.arange(batch_size * 8), arg_max.view(-1), :
        ].view(batch_size, 8, 3)

        sel_index = torch.cat(
            (
                3 * self.keyinds.unsqueeze(1),
                3 * self.keyinds.unsqueeze(1) + 1,
                3 * self.keyinds.unsqueeze(1) + 2,
            ),
            dim=1,
        ).reshape(-1)
        geometry = (
            torch.mm(id_para, self.base_id[:, sel_index])
            + torch.mm(exp_para, self.base_exp[:, sel_index])
            + self.mu[sel_index]
        )
        lands_3d = geometry.view(-1, self.keyinds.shape[0], 3)
        lands_3d[:, :8, :] = left_3dlands
        lands_3d[:, 9:17, :] = right_3dlands
        return lands_3d

    def forward_geo_sub(self, id_para, exp_para, sub_index):
        id_para = id_para * self.sig_id
        exp_para = exp_para * self.sig_exp
        sel_index = torch.cat(
            (
                3 * sub_index.unsqueeze(1),
                3 * sub_index.unsqueeze(1) + 1,
                3 * sub_index.unsqueeze(1) + 2,
            ),
            dim=1,
        ).reshape(-1)
        geometry = (
            torch.mm(id_para, self.base_id[:, sel_index])
            + torch.mm(exp_para, self.base_exp[:, sel_index])
            + self.mu[sel_index]
        )
        return geometry.reshape(-1, sub_index.shape[0], 3)

    def forward_geo(self, id_para, exp_para):
        id_para = id_para * self.sig_id
        exp_para = exp_para * self.sig_exp
        geometry = (
            torch.mm(id_para, self.base_id)
            + torch.mm(exp_para, self.base_exp)
            + self.mu
        )
        return geometry.reshape(-1, self.point_num, 3)

    def forward_tex(self, tex_para):
        tex_para = tex_para * self.sig_tex
        texture = torch.mm(tex_para, self.base_tex) + self.mu_tex
        return texture.reshape(-1, self.point_num, 3)