import json
import os
import subprocess as sp
import tempfile
from os.path import realpath, dirname
from time import time

import toml

from mach_nix import generate


def main():
    pwd = dirname(realpath(__file__))

    os.environ['py_ver_str'] = '3.7.5'
    os.environ['system'] = 'x86_64-linux'
    os.environ['out_file'] = f'{pwd}/overrides.nix'
    os.environ['disable_checks'] = 'true'

    with open(pwd + "/../mach_nix/provider_defaults.toml") as f:
        provider_settings = toml.load(f)
    if os.path.isfile("./providers.toml"):
        with open(pwd + "./providers.toml") as f:
            provider_settings.update(toml.load(f))
    provider_settings.update(dict(
        # _default = "conda"
    ))
    os.environ['providers'] = json.dumps(provider_settings)

    nixpkgs_json = tempfile.mktemp()
    cmd = f'nix-build {pwd}/../mach_nix/nix/nixpkgs-json.nix -o {nixpkgs_json} --show-trace'
    sp.check_call(cmd, shell=True)
    os.environ['nixpkgs_json'] = nixpkgs_json

    pypi_deps_db = tempfile.mktemp()
    cmd = f'nix-build {pwd}/../mach_nix/nix/deps-db-and-fetcher.nix -A pypi_deps_db_src -o {pypi_deps_db} --show-trace'
    sp.check_call(cmd, shell=True)
    os.environ['pypi_deps_db_src'] = pypi_deps_db

    providers = tempfile.mktemp()
    cmd = f'nix-build {pwd}/../mach_nix/nix/lib.nix -A parseProvidersToJson -o {providers} --show-trace'
    sp.check_call(cmd, shell=True)
    os.environ['providers'] = providers

    conda_channels_json = tempfile.mktemp()
    cmd = f'nix-build {pwd}/../mach_nix/nix/conda-channels.nix -A condaChannelsJson -o {conda_channels_json} --show-trace'
    sp.check_call(cmd, shell=True)
    os.environ['conda_channels_json'] = conda_channels_json

    for key in ('PYPI_FETCHER_COMMIT', 'PYPI_FETCHER_SHA256'):
        with open(f"{pypi_deps_db}/{key}") as f:
            os.environ[key.lower()] = f.read()

    with open(pwd + "/reqs.txt") as f:
        os.environ['requirements'] = f.read()

    # generates and writes nix expression into ./debug/expr.nix
    start = time()
    generate.main()
    dur = round(time() - start, 1)
    print(f"resolving took: {dur}s")


main()