"""Functions for discovering and executing various cookiecutter hooks."""

from __future__ import annotations

import errno
import logging
import os
import subprocess
import sys
import tempfile
from pathlib import Path
from typing import Any

from jinja2.exceptions import UndefinedError

from aiclimate import utils
from aiclimate.exceptions import FailedHookException
from aiclimate.utils import (
    create_env_with_context,
    create_tmp_repo_dir,
    rmtree,
    work_in,
)

logger = logging.getLogger(__name__)

_HOOKS = [
    'pre_prompt',
    'pre_gen_project',
    'post_gen_project',
]
EXIT_SUCCESS = 0


def valid_hook(hook_file: str, hook_name: str) -> bool:
    """Determine if a hook file is valid.

    :param hook_file: The hook file to consider for validity
    :param hook_name: The hook to find
    :return: The hook file validity
    """
    filename = os.path.basename(hook_file)
    basename = os.path.splitext(filename)[0]
    matching_hook = basename == hook_name
    supported_hook = basename in _HOOKS
    backup_file = filename.endswith('~')

    return matching_hook and supported_hook and not backup_file


def find_hook(hook_name: str, hooks_dir: str = 'hooks') -> list[str] | None:
    """Return a dict of all hook scripts provided.

    Must be called with the project template as the current working directory.
    Dict's key will be the hook/script's name, without extension, while values
    will be the absolute path to the script. Missing scripts will not be
    included in the returned dict.

    :param hook_name: The hook to find
    :param hooks_dir: The hook directory in the template
    :return: The absolute path to the hook script or None
    """
    logger.debug('hooks_dir is %s', os.path.abspath(hooks_dir))

    if not os.path.isdir(hooks_dir):
        logger.debug('No hooks/dir in template_dir')
        return None

    scripts = [
        os.path.abspath(os.path.join(hooks_dir, hook_file))
        for hook_file in os.listdir(hooks_dir)
        if valid_hook(hook_file, hook_name)
    ]

    if len(scripts) == 0:
        return None
    return scripts


def run_script(script_path: str, cwd: Path | str = '.') -> None:
    """Execute a script from a working directory.

    :param script_path: Absolute path to the script to run.
    :param cwd: The directory to run the script from.
    """
    run_thru_shell = sys.platform.startswith('win')
    if script_path.endswith('.py'):
        script_command = [sys.executable, script_path]
    else:
        script_command = [script_path]

    utils.make_executable(script_path)

    try:
        proc = subprocess.Popen(script_command, shell=run_thru_shell, cwd=cwd)  # nosec
        exit_status = proc.wait()
        if exit_status != EXIT_SUCCESS:
            msg = f'Hook script failed (exit status: {exit_status})'
            raise FailedHookException(msg)
    except OSError as err:
        if err.errno == errno.ENOEXEC:
            msg = 'Hook script failed, might be an empty file or missing a shebang'
            raise FailedHookException(msg) from err
        msg = f'Hook script failed (error: {err})'
        raise FailedHookException(msg) from err


def run_script_with_context(
    script_path: Path | str, cwd: Path | str, context: dict[str, Any]
) -> None:
    """Execute a script after rendering it with Jinja.

    :param script_path: Absolute path to the script to run.
    :param cwd: The directory to run the script from.
    :param context: Cookiecutter project template context.
    """
    _, extension = os.path.splitext(script_path)

    contents = Path(script_path).read_text(encoding='utf-8')

    with tempfile.NamedTemporaryFile(delete=False, mode='wb', suffix=extension) as temp:
        env = create_env_with_context(context)
        template = env.from_string(contents)
        output = template.render(**context)
        temp.write(output.encode('utf-8'))

    run_script(temp.name, cwd)


def run_hook(hook_name: str, project_dir: Path | str, context: dict[str, Any]) -> None:
    """
    Try to find and execute a hook from the specified project directory.

    :param hook_name: The hook to execute.
    :param project_dir: The directory to execute the script from.
    :param context: Cookiecutter project context.
    """
    scripts = find_hook(hook_name)
    if not scripts:
        logger.debug('No %s hook found', hook_name)
        return
    logger.debug('Running hook %s', hook_name)
    for script in scripts:
        run_script_with_context(script, project_dir, context)


def run_hook_from_repo_dir(
    repo_dir: Path | str,
    hook_name: str,
    project_dir: Path | str,
    context: dict[str, Any],
    delete_project_on_failure: bool,
) -> None:
    """Run hook from repo directory, clean project directory if hook fails.

    :param repo_dir: Project template input directory.
    :param hook_name: The hook to execute.
    :param project_dir: The directory to execute the script from.
    :param context: Cookiecutter project context.
    :param delete_project_on_failure: Delete the project directory on hook
        failure?
    """
    with work_in(repo_dir):
        try:
            run_hook(hook_name, project_dir, context)
        except (
            FailedHookException,
            UndefinedError,
        ):
            if delete_project_on_failure:
                rmtree(project_dir)
            logger.exception(
                "Stopping generation because %s hook "
                "script didn't exit successfully",
                hook_name,
            )
            raise


def run_pre_prompt_hook(repo_dir: Path | str) -> Path | str:
    """Run pre_prompt hook from repo directory.

    :param repo_dir: Project template input directory.
    """
    # Check if we have a valid pre_prompt script
    with work_in(repo_dir):
        scripts = find_hook('pre_prompt')
        if not scripts:
            return repo_dir

    # Create a temporary directory
    repo_dir = create_tmp_repo_dir(repo_dir)
    with work_in(repo_dir):
        scripts = find_hook('pre_prompt') or []
        for script in scripts:
            try:
                run_script(script, str(repo_dir))
            except FailedHookException as e:  # noqa: PERF203
                msg = 'Pre-Prompt Hook script failed'
                raise FailedHookException(msg) from e
    return repo_dir
