from __future__ import annotations

import os
import re
from functools import lru_cache
import moderngl

from manimlib.utils.directories import get_shader_dir
from manimlib.utils.file_ops import find_file

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from typing import Sequence, Optional


@lru_cache()
def get_shader_program(
        ctx: moderngl.context.Context,
        vertex_shader: str,
        fragment_shader: Optional[str] = None,
        geometry_shader: Optional[str] = None,
    ) -> moderngl.Program:
    return ctx.program(
        vertex_shader=vertex_shader,
        fragment_shader=fragment_shader,
        geometry_shader=geometry_shader,
    )


@lru_cache()
def get_shader_code_from_file(filename: str) -> str | None:
    if not filename:
        return None

    try:
        filepath = find_file(
            filename,
            directories=[get_shader_dir(), "/"],
            extensions=[],
        )
    except IOError:
        return None

    with open(filepath, "r") as f:
        result = f.read()

    # To share functionality between shaders, some functions are read in
    # from other files an inserted into the relevant strings before
    # passing to ctx.program for compiling
    # Replace "#INSERT " lines with relevant code
    insertions = re.findall(r"^#INSERT .*\.glsl$", result, flags=re.MULTILINE)
    for line in insertions:
        inserted_code = get_shader_code_from_file(
            os.path.join("inserts", line.replace("#INSERT ", ""))
        )
        result = result.replace(line, inserted_code)
    return result


def get_colormap_code(rgb_list: Sequence[float]) -> str:
    data = ",".join(
        "vec3({}, {}, {})".format(*rgb)
        for rgb in rgb_list
    )
    return f"vec3[{len(rgb_list)}]({data})"