import gpu
from pathlib import Path


class LazyDict(dict):
    def __getitem__(self, k):
        v = super().__getitem__(k)
        if callable(v):
            v = v()
            super().__setitem__(k, v)
        return v

    def get(self, k, default=None):
        if k in self:
            return self.__getitem__(k)
        return default


PICKERS = {}


MODULE_DIR = Path(__file__).parent
SHADER_DIR = MODULE_DIR / "shaders"

SHADERS = LazyDict()

vertex_shader = Path(SHADER_DIR, "dash_shader.vert").read_text(encoding="utf-8")
fragment_shader = Path(SHADER_DIR, "dash_shader.frag").read_text(encoding="utf-8")


def create_dashed_line_shader() -> gpu.types.GPUShader:
    shader_info = gpu.types.GPUShaderCreateInfo()

    shader_info.vertex_in(0, "VEC2", "pos")

    shader_info.vertex_source(vertex_shader)
    shader_info.fragment_source(fragment_shader)

    shader = gpu.shader.create_from_info(shader_info)
    del shader_info
    return shader


SHADERS["dashed_line"] = (
    create_dashed_line_shader  # lambda: gpu.types.GPUShader(vertex_shader, fragment_shader)
)