import warnings

from diceplayer.dice.dice_input import (
    NPTEqConfig,
    NPTTerConfig,
    NVTEqConfig,
    NVTTerConfig,
)
from diceplayer.dice.dice_wrapper import (
    DiceEnvironment,
    DiceWrapper,
)
from diceplayer.environment import Atom, Molecule
from diceplayer.logger import logger
from diceplayer.state.state_model import StateModel

import shutil
from itertools import batched, chain, islice
from pathlib import Path
from threading import Thread


class DiceHandler:
    def __init__(self, step_directory: Path):
        self.dice_directory = step_directory / "dice"

    def run(self, state: StateModel, cycle: int) -> list[Atom]:
        if self.dice_directory.exists():
            logger.info(
                f"Found dice directory: {self.dice_directory}, this directory will be purged for a clean state"
            )
            shutil.rmtree(self.dice_directory)
        self.dice_directory.mkdir(parents=True)

        return self.run_simulations(state, cycle)

    def run_simulations(self, state: StateModel, cycle: int) -> list[Atom]:
        results: list[list[Atom]] = []

        threads = []
        for p in range(state.config.dice.nprocs):
            t = Thread(target=self._simulation_process, args=(state, cycle, p, results))
            threads.append(t)
            t.start()

        for t in threads:
            t.join()

        if len(results) != state.config.dice.nprocs:
            raise RuntimeError(
                f"Expected {state.config.dice.nprocs} simulation results, but got {len(results)}"
            )

        return self._aggregate_results(state, results)

    def _simulation_process(
        self,
        state: StateModel,
        cycle: int,
        proc: int,
        results: list[list[Atom]],
    ) -> None:
        proc_directory = self.dice_directory / f"{proc:02d}"
        if proc_directory.exists():
            shutil.rmtree(proc_directory)
        proc_directory.mkdir(parents=True)

        dice = DiceWrapper(state.config.dice, proc_directory)

        self._generate_phb_file(state, proc_directory)

        if state.config.dice.randominit == "first" and cycle >= 0:
            self._generate_last_xyz(state, proc_directory)
        else:
            nvt_ter_config = NVTTerConfig.from_config(state.config)
            dice.run(nvt_ter_config)

        if len(state.config.dice.nstep) == 2:
            nvt_eq_config = NVTEqConfig.from_config(state.config)
            dice.run(nvt_eq_config)

        elif len(state.config.dice.nstep) == 3:
            npt_ter_config = NPTTerConfig.from_config(state.config)
            dice.run(npt_ter_config)

            npt_eq_config = NPTEqConfig.from_config(state.config)
            dice.run(npt_eq_config)

        results.extend(
            [
                self._filter_environment_sites(state, environment)
                for environment in dice.parse_results()
            ]
        )

    @staticmethod
    def _generate_phb_file(state: StateModel, proc_directory: Path) -> None:
        fstr = "{:<3d} {:>3d}  {:>10.5f} {:>10.5f} {:>10.5f}  {:>10.6f} {:>9.5f} {:>7.4f}\n"

        phb_file = proc_directory / state.config.dice.ljname

        with open(phb_file, "w") as f:
            f.write(f"{state.config.dice.combrule}\n")
            f.write(f"{len(state.config.dice.nmol)}\n")

            for molecule in state.system.molecule:
                f.write(f"{len(molecule.atom)} {molecule.molname}\n")
                for atom in molecule.atom:
                    f.write(
                        fstr.format(
                            atom.lbl,
                            atom.na,
                            atom.rx,
                            atom.ry,
                            atom.rz,
                            atom.chg,
                            atom.eps,
                            atom.sig,
                        )
                    )

    def _generate_last_xyz(self, state: StateModel, proc_directory: Path) -> None: ...

    @staticmethod
    def _filter_environment_sites(
        state: StateModel, environment: DiceEnvironment
    ) -> list[Atom]:
        picked_environment = []

        ref_molecule = state.system.molecule[0]
        ref_molecule_sizes = ref_molecule.sizes_of_molecule()
        ref_n_sites = len(ref_molecule.atom) * state.config.dice.nmol[0]

        min_distance = min(
            (environment.thickness[i] - ref_molecule_sizes[i]) / 2 for i in range(3)
        )

        site_iter = iter(environment.items)
        _ = list(islice(site_iter, ref_n_sites))

        for molecule_index, molecule in enumerate(state.system.molecule[1:], start=1):
            molecule_n_atoms = len(molecule.atom)
            molecule_n_sites = molecule_n_atoms * state.config.dice.nmol[molecule_index]

            sites = list(islice(site_iter, molecule_n_sites))

            for molecule_sites in batched(sites, molecule_n_atoms):
                new_molecule = Molecule("ASEC TMP MOLECULE")

                for site_index, atom_site in enumerate(molecule_sites):
                    new_molecule.add_atom(
                        Atom(
                            molecule.atom[site_index].lbl,
                            molecule.atom[site_index].na,
                            atom_site.x,
                            atom_site.y,
                            atom_site.z,
                            molecule.atom[site_index].chg,
                            molecule.atom[site_index].eps,
                            molecule.atom[site_index].sig,
                        )
                    )

                if molecule.signature() != new_molecule.signature():
                    _message = f"Skipping sites because the molecule signature does not match the reference molecule. Expected {molecule.signature()} but got {new_molecule.signature()}"
                    warnings.warn(_message)
                    logger.warning(_message)
                    continue

                if ref_molecule.minimum_distance(new_molecule) >= min_distance:
                    continue

                picked_environment.extend(new_molecule.atom)

        return picked_environment

    @staticmethod
    def _aggregate_results(state: StateModel, results: list[list[Atom]]) -> list[Atom]:
        norm_factor = round(state.config.dice.nstep[-1] / state.config.dice.isave)

        agg_results = []
        for atom in chain(*[r for r in results]):
            atom.chg = atom.chg * norm_factor
            agg_results.append(atom)

        return agg_results