from __future__ import annotations

import os
import shutil
import warnings
from glob import glob
from typing import TYPE_CHECKING

import numpy as np
from monty.io import zopen
from monty.os.path import zpath

from pymatgen.core import SETTINGS
from pymatgen.io.vasp import Potcar, PotcarSingle
from pymatgen.io.vasp.sets import _load_yaml_config
from pymatgen.util.testing import VASP_IN_DIR

if TYPE_CHECKING:
    from typing import Self


class PotcarScrambler:
    """
    Takes a POTCAR and replaces its values with completely random values.
    Does type matching and attempts precision matching on floats to ensure
    file is read correctly by Potcar and PotcarSingle classes.

    Used to generate copyright-compliant POTCARs for PMG tests.

    In case of questions, contact Aaron Kaplan <aaron.kaplan.physics@gmail.com>.

    Recommended use:
        PotcarScrambler.from_file(
            input_filename = <input POTCAR name as str>,
            output_filename = <name of desired randomized POTCAR as str>
        )
    to generate a POTCAR with name `output_filename` with completely random values
    from existing POTCAR `input_filename`
    """

    def __init__(self, potcars: Potcar | PotcarSingle) -> None:
        self.PSP_list = [potcars] if isinstance(potcars, PotcarSingle) else potcars
        self.scrambled_potcars_str: str = ""
        for psp in self.PSP_list:
            scrambled_potcar_str = self.scramble_single_potcar(psp)
            self.scrambled_potcars_str += scrambled_potcar_str

    def _rand_float_from_str_with_prec(self, input_str: str, bloat: float = 1.5) -> float:
        """Generate a random float from str to replace true values."""
        n_prec: int = len(input_str.split(".")[1])
        bd: float = max(1.0, bloat * abs(float(input_str)))  # ensure we don't get 0
        return round(bd * np.random.default_rng().random(), n_prec)

    def _read_fortran_str_and_scramble(self, input_str: str, bloat: float = 1.5):
        input_str = input_str.strip()
        rng = np.random.default_rng()

        if input_str.lower() in {"t", "f", "true", "false"}:
            return rng.choice((True, False))

        if input_str.upper() == input_str.lower() and input_str[0].isnumeric():
            if "." in input_str:
                return self._rand_float_from_str_with_prec(input_str, bloat=bloat)
            integer = int(input_str)
            fac = int(np.sign(integer))  # return int of same sign
            return fac * rng.integers(abs(max(1, int(np.ceil(bloat * integer)))))
        try:
            float(input_str)
            return self._rand_float_from_str_with_prec(input_str, bloat=bloat)
        except ValueError:
            return input_str

    def scramble_single_potcar(self, potcar: PotcarSingle) -> str:
        """Scramble the body of a POTCAR, retain the PSCTR header information.

        To the best of my (ADK) knowledge, in the OUTCAR file,
        almost all information from the POTCAR in the "PSCTR" block
            ```
            parameters from PSCTR are:
            ....
            END of PSCTR-controll parameters
            ```
        is printed to OUTCAR. Specifically, all information above the line
            `Error from kinetic energy argument (eV)`
        is included. This information is not scrambled below.
        """
        scrambled_potcar_str = ""
        needs_sha256 = scramble_values = False
        og_sha_str = "SHA256 = None\n"
        for line in potcar.data.split("\n")[:-1]:
            single_line_rows = line.split(";")

            if "SHA256" in line:
                scrambled_potcar_str += og_sha_str
                needs_sha256 = True
                continue

            if ("Error from kinetic energy argument (eV)" in line) or ("END of PSCTR-controll parameters" in line):
                # start to scramble values, logic described above
                scramble_values = True

            cline = ""
            for idx, row in enumerate(single_line_rows):
                if scramble_values:
                    split_row = row.split()
                    for itmp, tmp in enumerate(split_row):
                        cline += f"{self._read_fortran_str_and_scramble(tmp)}"
                        if itmp < len(split_row) - 1:
                            cline += " "
                else:
                    cline += row
                if len(single_line_rows) > 1 and idx == 0:
                    cline += "; "

            aux_str = ""
            if "TITEL" in line:
                aux_str = " ; FAKE"
            scrambled_potcar_str += f"{cline}{aux_str}\n"

        if needs_sha256:
            tps = PotcarSingle(scrambled_potcar_str)
            scrambled_potcar_str = scrambled_potcar_str.replace(
                og_sha_str, f"SHA256 = {tps.sha256_computed_file_hash}\n"
            )
        return scrambled_potcar_str

    def to_file(self, filename: str) -> None:
        """Write scrambled POTCAR to file."""
        with zopen(filename, mode="wt", encoding="utf-8") as file:
            file.write(self.scrambled_potcars_str)

    @classmethod
    def from_file(cls, input_filename: str, output_filename: str | None = None) -> Self:
        """Read a POTCAR from file and generate a scrambled version."""
        psp = Potcar.from_file(input_filename)
        psp_scrambled = cls(psp)
        if output_filename is not None:
            psp_scrambled.to_file(output_filename)
        return psp_scrambled


def generate_fake_potcar_libraries() -> None:
    """
    To test the `_gen_potcar_summary_stats` function in `pymatgen.io.vasp.inputs`,
    need a library of fake POTCARs which do not violate copyright
    """
    mp_relax_set = _load_yaml_config("MPRelaxSet")
    psp_variants = [mp_relax_set["POTCAR"][element] for element in mp_relax_set["POTCAR"]]

    output_dir = "./fake_potcar_library/"
    shutil.rmtree(output_dir, ignore_errors=True)

    vasp_psp_dir = SETTINGS.get("PMG_VASP_PSP_DIR")
    src_dirs = [f"{vasp_psp_dir}/{func_dir}" for func_dir in PotcarSingle.functional_dir.values()]

    if not any(map(os.path.isdir, src_dirs)):
        raise RuntimeError(f"No input POTCAR library found, tried {src_dirs}")

    for func_dir in src_dirs:
        if not os.path.isdir(func_dir):
            continue

        for psp_name in psp_variants:
            rebase_dir = f"{output_dir}/{func_dir}/{psp_name}/"
            paths_to_try = [
                zpath(f"{func_dir}/POTCAR.{psp_name}"),
                zpath(f"{func_dir}/{psp_name}/POTCAR"),
            ]
            if not any(map(os.path.isfile, paths_to_try)):
                warnings.warn(f"Could not find {psp_name} in {paths_to_try}", stacklevel=2)
            for potcar_path in paths_to_try:
                if os.path.isfile(potcar_path):
                    os.makedirs(rebase_dir, exist_ok=True)
                    PotcarScrambler.from_file(
                        input_filename=potcar_path,
                        output_filename=f"{rebase_dir}/POTCAR.gz",
                    )
                    break


def potcar_cleanser() -> None:
    """Replace copyrighted POTCARs used in io.vasp.sets testing
    with dummy POTCARs that have scrambled PSP and kinetic energy values
    (but retain the original header information which is also found in OUTCARs
    and freely shared by VASP)
    """

    search_dir = f"{VASP_IN_DIR}/fake_potcars/real_potcars/"
    rebase_dir = search_dir.replace("real", "fake")
    potcars_to_cleanse = glob(f"{search_dir}/**/POTCAR*", recursive=True)

    for potcar in potcars_to_cleanse:
        path_to_potcar, potcar_name = potcar.split("POTCAR")
        rebased = path_to_potcar.replace(search_dir, rebase_dir)
        new_path = f"{rebased}POTCAR{potcar_name}"
        if new_path[-3:] != ".gz":
            new_path += ".gz"
        os.makedirs(rebased, exist_ok=True)
        PotcarScrambler.from_file(input_filename=potcar, output_filename=new_path)


if __name__ == "__main__":
    potcar_cleanser()
    # generate_fake_potcar_libraries()

    """
    Note that vaspout.h5 files also contain full POTCARs. While the
    Vaspout class in `pymatgen.io.vasp.outputs` contains a method to
    replace the POTCAR with its spec (`remove_potcar_and_write_file`),
    for test purposes, its often useful to have a fake POTCAR in place
    of the real one.

    To use the scrambler on a vaspout.h5:
    ```
    vout = Vaspout("< path to vaspout.h5>")
    scrambled = PotcarScrambler(vout.potcar)
    vout.remove_potcar_and_write_file(
        filename = "< path to output vaspout.h5>",
        fake_potcar_str = scrambled.scrambled_potcars_str
    )
    ```
    """
