import os
import platform

if "PYOPENGL_PLATFORM" not in os.environ:
    os.environ["PYOPENGL_PLATFORM"] = "egl"
import torch
import numpy as np
import pyrender
import trimesh
import cv2
from yacs.config import CfgNode
from typing import List, Optional
from hmr2.utils.renderer import Renderer

# For Windows, remove PYOPENGL_PLATFORM to enable default rendering backend
sys_name = platform.system()
if sys_name == "Windows":
    os.environ.pop("PYOPENGL_PLATFORM")

def get_light_poses(n_lights=5, elevation=np.pi / 3, dist=12):
    # get lights in a circle around origin at elevation
    thetas = elevation * np.ones(n_lights)
    phis = 2 * np.pi * np.arange(n_lights) / n_lights
    poses = []
    trans = make_translation(torch.tensor([0, 0, dist]))
    for phi, theta in zip(phis, thetas):
        rot = make_rotation(rx=-theta, ry=phi, order="xyz")
        poses.append((rot @ trans).numpy())
    return poses

def make_translation(t):
    return make_4x4_pose(torch.eye(3), t)

def make_rotation(rx=0, ry=0, rz=0, order="xyz"):
    Rx = rotx(rx)
    Ry = roty(ry)
    Rz = rotz(rz)
    if order == "xyz":
        R = Rz @ Ry @ Rx
    elif order == "xzy":
        R = Ry @ Rz @ Rx
    elif order == "yxz":
        R = Rz @ Rx @ Ry
    elif order == "yzx":
        R = Rx @ Rz @ Ry
    elif order == "zyx":
        R = Rx @ Ry @ Rz
    elif order == "zxy":
        R = Ry @ Rx @ Rz
    return make_4x4_pose(R, torch.zeros(3))

def make_4x4_pose(R, t):
    """
    :param R (*, 3, 3)
    :param t (*, 3)
    return (*, 4, 4)
    """
    dims = R.shape[:-2]
    pose_3x4 = torch.cat([R, t.view(*dims, 3, 1)], dim=-1)
    bottom = (
        torch.tensor([0, 0, 0, 1], device=R.device)
        .reshape(*(1,) * len(dims), 1, 4)
        .expand(*dims, 1, 4)
    )
    return torch.cat([pose_3x4, bottom], dim=-2)

def rotx(theta):
    return torch.tensor(
        [
            [1, 0, 0],
            [0, np.cos(theta), -np.sin(theta)],
            [0, np.sin(theta), np.cos(theta)],
        ],
        dtype=torch.float32,
    )

def roty(theta):
    return torch.tensor(
        [
            [np.cos(theta), 0, np.sin(theta)],
            [0, 1, 0],
            [-np.sin(theta), 0, np.cos(theta)],
        ],
        dtype=torch.float32,
    )

def rotz(theta):
    return torch.tensor(
        [
            [np.cos(theta), -np.sin(theta), 0],
            [np.sin(theta), np.cos(theta), 0],
            [0, 0, 1],
        ],
        dtype=torch.float32,
    )


def create_raymond_lights() -> List[pyrender.Node]:
    """
    Return raymond light nodes for the scene.
    """
    thetas = np.pi * np.array([1.0 / 6.0, 1.0 / 6.0, 1.0 / 6.0])
    phis = np.pi * np.array([0.0, 2.0 / 3.0, 4.0 / 3.0])

    nodes = []

    for phi, theta in zip(phis, thetas):
        xp = np.sin(theta) * np.cos(phi)
        yp = np.sin(theta) * np.sin(phi)
        zp = np.cos(theta)

        z = np.array([xp, yp, zp])
        z = z / np.linalg.norm(z)
        x = np.array([-z[1], z[0], 0.0])
        if np.linalg.norm(x) == 0:
            x = np.array([1.0, 0.0, 0.0])
        x = x / np.linalg.norm(x)
        y = np.cross(z, x)

        matrix = np.eye(4)
        matrix[:3, :3] = np.c_[x, y, z]
        nodes.append(
            pyrender.Node(
                light=pyrender.DirectionalLight(color=np.ones(3), intensity=1.0),
                matrix=matrix,
            )
        )

    return nodes

class SemanticRenderer(Renderer):

    def __init__(
        self, cfg: CfgNode, faces: np.array, lbs: np.array, viewport_size=(768, 768)
    ):
        """
        Wrapper around the pyrender renderer to render SMPL meshes's semantic map for Champ.
        Args:
            cfg (CfgNode): Model config file.
            faces (np.array): Array of shape (F, 3) containing the mesh faces.
        """
        self.cfg = cfg
        self.focal_length = cfg.EXTRA.FOCAL_LENGTH
        self.img_res = cfg.MODEL.IMAGE_SIZE

        self.camera_center = [self.img_res // 2, self.img_res // 2]
        self.faces = faces
        self.lbs = lbs
        # self.joint_names = smplx.joint_names.JOINT_NAMES

        self.vertex_labels = np.argmax(self.lbs.cpu().numpy(), axis=1)
        vertex_colors = cv2.applyColorMap(
            (10 * self.vertex_labels).astype(np.uint8), cv2.COLORMAP_VIRIDIS
        )
        semantic_background_rgb = cv2.applyColorMap(np.uint8([0]), cv2.COLORMAP_VIRIDIS)
        self.vertex_colors = np.squeeze(vertex_colors, axis=1)
        self.semantic_background_rgb = (
            np.squeeze(semantic_background_rgb.astype(np.float32), axis=1) / 255
        )
        self.renderer = pyrender.OffscreenRenderer(
            viewport_width=viewport_size[0],
            viewport_height=viewport_size[1],
            point_size=1.0,
        )

    def vertices_to_trimesh(
        self,
        vertices,
        camera_translation,
        mesh_base_color=(1.0, 1.0, 0.9),
        rot_axis=[1, 0, 0],
        rot_angle=0,
    ):
        vertex_colors = np.array([(*mesh_base_color, 1.0)] * vertices.shape[0])
        mesh = trimesh.Trimesh(
            vertices.copy() + camera_translation,
            self.faces.copy(),
            vertex_colors=vertex_colors,
        )
        # mesh = trimesh.Trimesh(vertices.copy(), self.faces.copy())

        rot = trimesh.transformations.rotation_matrix(np.radians(rot_angle), rot_axis)
        mesh.apply_transform(rot)

        rot = trimesh.transformations.rotation_matrix(np.radians(180), [1, 0, 0])
        mesh.apply_transform(rot)
        return mesh

    def render_all_multiple(
        self,
        vertices: List[np.array],
        cam_t: List[np.array],
        rot_axis=[1, 0, 0],
        rot_angle=0,
        mesh_base_color=(1.0, 1.0, 0.9),
        scene_bg_color=(0, 0, 0),
        render_res=[256, 256],
        focal_length=None,
    ):

        renderer = self.renderer
        trimesh_list = [
            self.vertices_to_trimesh(
                vvv, ttt.copy(), mesh_base_color, rot_axis, rot_angle
            )
            for vvv, ttt in zip(vertices, cam_t)
        ]
        for trimesh in trimesh_list:
            trimesh.visual.vertex_colors = self.vertex_colors
        mesh_list = [pyrender.Mesh.from_trimesh(trimesh) for trimesh in trimesh_list]

        scene = pyrender.Scene(
            bg_color=[*scene_bg_color, 0.0], ambient_light=(0.3, 0.3, 0.3)
        )
        for i, mesh in enumerate(mesh_list):
            scene.add(mesh, f"mesh_{i}")

        camera_pose = np.eye(4)
        camera_center = [render_res[0] / 2.0, render_res[1] / 2.0]
        focal_length = focal_length if focal_length is not None else self.focal_length
        camera = pyrender.IntrinsicsCamera(
            fx=focal_length,
            fy=focal_length,
            cx=camera_center[0],
            cy=camera_center[1],
            zfar=1e12,
        )

        # Create camera node and add it to pyRender scene
        camera_node = pyrender.Node(camera=camera, matrix=camera_pose)
        scene.add_node(camera_node)
        self.add_point_lighting(scene, camera_node)
        self.add_lighting(scene, camera_node)

        light_nodes = create_raymond_lights()
        for node in light_nodes:
            scene.add_node(node)

        color, rend_depth = renderer.render(
            scene, flags=pyrender.RenderFlags.FLAT | pyrender.RenderFlags.RGBA
        )
        color = color.astype(np.float32) / 255.0
        # renderer.delete()

        valid_mask = (color[:, :, -1])[:, :, np.newaxis]
        semantic_map = (
            color[:, :, :3] * valid_mask
            + (1 - valid_mask) * self.semantic_background_rgb
        )
        semantic_map = semantic_map.astype(np.float32)

        return {
            "Image": color,
            "Mask": valid_mask.astype(bool),
            "SemanticMap": semantic_map,
            "Depth": rend_depth,
        }

    def add_lighting(self, scene, cam_node, color=np.ones(3), intensity=1.0):
        # from phalp.visualize.py_renderer import get_light_poses
        light_poses = get_light_poses()
        light_poses.append(np.eye(4))
        cam_pose = scene.get_pose(cam_node)
        for i, pose in enumerate(light_poses):
            matrix = cam_pose @ pose
            node = pyrender.Node(
                name=f"light-{i:02d}",
                light=pyrender.DirectionalLight(color=color, intensity=intensity),
                matrix=matrix,
            )
            if scene.has_node(node):
                continue
            scene.add_node(node)

    def add_point_lighting(self, scene, cam_node, color=np.ones(3), intensity=1.0):
        # from phalp.visualize.py_renderer import get_light_poses
        light_poses = get_light_poses(dist=0.5)
        light_poses.append(np.eye(4))
        cam_pose = scene.get_pose(cam_node)
        for i, pose in enumerate(light_poses):
            matrix = cam_pose @ pose
            # node = pyrender.Node(
            #     name=f"light-{i:02d}",
            #     light=pyrender.DirectionalLight(color=color, intensity=intensity),
            #     matrix=matrix,
            # )
            node = pyrender.Node(
                name=f"plight-{i:02d}",
                light=pyrender.PointLight(color=color, intensity=intensity),
                matrix=matrix,
            )
            if scene.has_node(node):
                continue
            scene.add_node(node)