#!/usr/bin/env python3
import hashlib
import importlib.util
import json
import os
import pathlib
from types import ModuleType

import pytest
import requests

PROJECT_EULER_DIR_PATH = pathlib.Path.cwd().joinpath("project_euler")
PROJECT_EULER_ANSWERS_PATH = pathlib.Path.cwd().joinpath(
 "scripts", "project_euler_answers.json"
)

with open(PROJECT_EULER_ANSWERS_PATH) as file_handle:
 PROBLEM_ANSWERS: dict[str, str] = json.load(file_handle)


def convert_path_to_module(file_path: pathlib.Path) -> ModuleType:
 """Converts a file path to a Python module"""
 spec = importlib.util.spec_from_file_location(file_path.name, str(file_path))
 module = importlib.util.module_from_spec(spec) # type: ignore[arg-type]
 spec.loader.exec_module(module) # type: ignore[union-attr]
 return module


def all_solution_file_paths() -> list[pathlib.Path]:
 """Collects all the solution file path in the Project Euler directory"""
 solution_file_paths = []
 for problem_dir_path in PROJECT_EULER_DIR_PATH.iterdir():
 if problem_dir_path.is_file() or problem_dir_path.name.startswith("_"):
 continue
 for file_path in problem_dir_path.iterdir():
 if file_path.suffix != ".py" or file_path.name.startswith(("_", "test")):
 continue
 solution_file_paths.append(file_path)
 return solution_file_paths


def get_files_url() -> str:
 """Return the pull request number which triggered this action."""
 with open(os.environ["GITHUB_EVENT_PATH"]) as file:
 event = json.load(file)
 return event["pull_request"]["url"] + "/files"


def added_solution_file_path() -> list[pathlib.Path]:
 """Collects only the solution file path which got added in the current
 pull request.

 This will only be triggered if the script is ran from GitHub Actions.
 """
 solution_file_paths = []
 headers = {
 "Accept": "application/vnd.github.v3+json",
 "Authorization": "token " + os.environ["GITHUB_TOKEN"],
 }
 files = requests.get(get_files_url(), headers=headers, timeout=10).json()
 for file in files:
 filepath = pathlib.Path.cwd().joinpath(file["filename"])
 if (
 filepath.suffix != ".py"
 or filepath.name.startswith(("_", "test"))
 or not filepath.name.startswith("sol")
 ):
 continue
 solution_file_paths.append(filepath)
 return solution_file_paths


def collect_solution_file_paths() -> list[pathlib.Path]:
 # Return only if there are any, otherwise default to all solutions
 if (
 os.environ.get("CI")
 and os.environ.get("GITHUB_EVENT_NAME") == "pull_request"
 and (filepaths := added_solution_file_path())
 ):
 return filepaths
 return all_solution_file_paths()


@pytest.mark.parametrize(
 "solution_path",
 collect_solution_file_paths(),
 ids=lambda path: f"{path.parent.name}/{path.name}",
)
def test_project_euler(solution_path: pathlib.Path) -> None:
 """Testing for all Project Euler solutions"""
 # problem_[extract this part] and pad it with zeroes for width 3
 problem_number: str = solution_path.parent.name[8:].zfill(3)
 expected: str = PROBLEM_ANSWERS[problem_number]
 solution_module = convert_path_to_module(solution_path)
 answer = str(solution_module.solution())
 answer = hashlib.sha256(answer.encode()).hexdigest()
 assert answer == expected, (
 f"Expected solution to {problem_number} to have hash {expected}, got {answer}"
 )