"""Introspect an execution environment image."""
from __future__ import annotations

import json
import os
import re
import subprocess
import sys
import threading

from queue import Queue
from types import SimpleNamespace
from typing import Any
from typing import Callable
from typing import Union


JSONTypes = Union[bool, int, str, dict, list]


class Command(SimpleNamespace):
    """Abstraction for a details about a shell command."""

    id_: str
    command: str
    parse: Callable
    stdout: str = ""
    stderr: str = ""
    details: list | dict | str = ""
    errors: list = []


def run_command(command: Command) -> None:
    """Run a command using subprocess.

    :param command: Details of the command to run
    """
    try:
        proc_out = subprocess.run(
            command.command,
            capture_output=True,
            check=True,
            text=True,
            shell=True,
        )
        command.stdout = proc_out.stdout
    except subprocess.CalledProcessError as exc:
        command.stderr = str(exc.stderr)
        command.errors = [str(exc.stderr)]


def worker(pending_queue: Queue, completed_queue: Queue) -> None:
    """Run a command from pending, parse, and place in completed.

    :param pending_queue: A queue with plugins to process
    :param completed_queue: The queue in which extracted documentation will be placed
    """
    while True:
        command = pending_queue.get()
        if command is None:
            break
        run_command(command)
        try:
            command.parse(command)
        except Exception as exc:  # noqa: BLE001
            command.errors = command.errors + [str(exc)]
        completed_queue.put(command)


class CommandRunner:
    """A command runner.

    Run commands using single or multiple processes.
    """

    def __init__(self):
        """Initialize the command runner."""
        self._completed_queue: Queue | None = None
        self._pending_queue: Queue | None = None

    def run_multi_thread(self, command_classes):
        """Run commands with multiple threads.

        Workers are started to read from pending queue.
        Exit when the number of results is equal to the number
        of commands needing to be run.

        :param command_classes: All command classes to be run
        :returns: The results from running all commands
        """
        if self._completed_queue is None:
            self._completed_queue = Queue()
        if self._pending_queue is None:
            self._pending_queue = Queue()
        results = {}
        all_commands = tuple(
            command for command_class in command_classes for command in command_class.commands
        )
        self.start_workers(all_commands)
        results = []
        while len(results) != len(all_commands):
            results.append(self._completed_queue.get())
        return results

    def start_workers(self, jobs):
        """Start workers and submit jobs to pending queue.

        :param jobs: The jobs to be run
        """
        worker_count = len(jobs)
        processes = []
        for _proc in range(worker_count):
            proc = threading.Thread(
                target=worker,
                args=(self._pending_queue, self._completed_queue),
            )
            processes.append(proc)
            proc.start()
        for job in jobs:
            self._pending_queue.put(job)
        for _proc in range(worker_count):
            self._pending_queue.put(None)
        for proc in processes:
            proc.join()


class CmdParser:
    """A base class for command parsers with common parsing functions."""

    @staticmethod
    def _strip(value: str) -> str:
        """Remove quotes, leading and trailing whitespace.

        :param value: The string to act on
        :returns: The string after removing quotes, leading and trailing whitespace
        """
        return value.strip('"').strip("'").strip()

    @staticmethod
    def re_partition(content, separator):
        """Partition a string using a regular expression.

        :param content: The content to partition
        :param separator: The separator to use for the partitioning
        :returns: The first partition, separator, and final partition
        """
        separator_match = re.search(separator, content)
        if not separator_match or content.startswith(" "):
            return "", "", content
        delim = separator_match.group(0)
        key, content = re.split(delim, content, maxsplit=1)
        return key, delim, content

    def splitter(self, lines, line_split, section_delim=None):
        """Split lines given a delimiter.

        :param lines: The lines to split
        :param line_split: The delimiter use for splitting each line
        :param section_delim: The separator between different packages
        :returns: All lines split on the delimiter
        """
        results = []
        result = {}
        current_key = ""
        while lines:
            line = lines.pop(0)
            key, delim, content = self.re_partition(line, line_split)
            content = self._strip(content)
            if section_delim and line == section_delim:
                results.append(result)
                result = {}
                continue
            if not delim and current_key:
                result[current_key] += f" {content}"
                continue
            current_key = key.lower().replace("_", "-").strip()
            # system_packages description field needs special handling
            if current_key == "description":
                description = []
                while lines:
                    line = lines.pop(0)
                    if line == section_delim:
                        break
                    description.append(line)
                if description:
                    result[current_key] = " ".join(description)
                else:
                    result[current_key] = "No description available"
                results.append(result)
                return result
            result[current_key] = content

        if result:
            results.append(result)
        return results


class AnsibleCollections(CmdParser):
    """Available ansible collections collector."""

    @property
    def commands(self):
        """Define the ansible-galaxy command to list ansible collections.

        :returns: The defined command
        """
        command = "ansible-galaxy collection list"
        return [
            Command(
                id_="ansible_collections",
                command=command,
                parse=self.parse,
            ),
        ]

    @staticmethod
    def parse(command: Command):
        """Parse the output of the ansible-galaxy command.

        :param command: The result of running the command
        """
        if "invalid choice: 'list'" in command.stderr:
            command.details = "This command is not supported with ansible 2.9."
            return
        collections = {}
        for line in command.stdout.splitlines():
            parts = line.split()
            if len(parts) == 2 and parts[1][0].isdigit():
                collections[parts[0].strip()] = parts[1].strip()
        command.details = collections


class AnsibleVersion(CmdParser):
    """Ansible version collector."""

    @property
    def commands(self) -> list[Command]:
        """Define the ansible command to get the version.

        :returns: The defined command
        """
        return [Command(id_="ansible_version", command="ansible --version", parse=self.parse)]

    @staticmethod
    def parse(command: Command) -> None:
        """Parse the output of the ansible command.

        :param command: The result of running the command
        """
        version = command.stdout.splitlines()[0]
        command.details = version


class OsRelease(CmdParser):
    """OS release information collector."""

    @property
    def commands(self) -> list[Command]:
        """Define the command to collect os release information.

        :returns: The defined command
        """
        return [Command(id_="os_release", command="cat /etc/os-release", parse=self.parse)]

    def parse(self, command) -> None:
        """Parse the output of the cat command.

        :param command: The result of running the command
        """
        parsed = self.splitter(command.stdout.splitlines(), "=")
        command.details = parsed


class PythonPackages(CmdParser):
    """Python package collector."""

    @property
    def commands(self) -> list[Command]:
        """Define the pip command to list installed pip packages.

        :returns: The defined command
        """
        pre = Command(
            id_="pip_freeze", command="/usr/bin/python3 -m pip freeze", parse=self.parse_freeze
        )
        run_command(pre)
        pre.parse(pre)
        pkgs = " ".join(pkg for pkg in pre.details[0]) if pre.details else ""
        return [
            Command(
                id_="python_packages",
                command=f"/usr/bin/python3 -m pip show {pkgs}",
                parse=self.parse,
            ),
        ]

    def parse(self, command):
        """Parse the output of the pip command.

        :param command: The result of running the command
        """
        parsed = self.splitter(command.stdout.splitlines(), line_split=":", section_delim="---")
        for pkg in parsed:
            for entry in ["required-by", "requires"]:
                if pkg[entry]:
                    pkg[entry] = [p.strip() for p in pkg[entry].split(",")]
                else:
                    pkg[entry] = []
        command.details = parsed

    def parse_freeze(self, command):
        """Parse the output of the pip freeze command, skipping editables.

        :param command: The result of running the command
        """
        lines = [line for line in command.stdout.splitlines() if not line.startswith("-e")]
        parsed = self.splitter(lines, "(==|@)")
        command.details = parsed


class RedhatRelease(CmdParser):
    """Red Hat release collector."""

    @property
    def commands(self) -> list[Command]:
        """Define the command to get the redhat release information.

        :returns: The defined command
        """
        return [Command(id_="redhat_release", command="cat /etc/redhat-release", parse=self.parse)]

    @staticmethod
    def parse(command):
        """Parse the output of the cat redhat release command.

        :param command: The result of running the command
        """
        parsed = command.stdout
        command.details = parsed


class SystemPackages(CmdParser):
    """System packages collector."""

    @property
    def commands(self) -> list[Command]:
        """Define the command to list system packages.

        :returns: The defined command
        """
        return [Command(id_="system_packages", command="rpm -qai", parse=self.parse)]

    def parse(self, command):
        """Parse the output of the rpm command.

        :param command: The result of running the command
        """
        packages = []
        package = []
        for line in command.stdout.splitlines():
            if re.match(r"^Name\s{2,}:", line) and package:
                packages.append(package)
                package = [line]
            else:
                package.append(line)
        if package:
            packages.append(package)

        parsed = []
        for package in packages:
            result = self.splitter(package, line_split=":")
            parsed.append(result)

        command.details = parsed


def main(serialize: bool = True) -> dict[str, JSONTypes] | None:
    """Enter the image introspection process.

    :param serialize: Whether to serialize the results
    :returns: The collected data or none if serialize is False
    """
    response: dict = {"errors": []}
    response["python_version"] = {"details": {"version": " ".join(sys.version.splitlines())}}
    response["environment_variables"] = {"details": dict(os.environ)}
    try:
        command_runner = CommandRunner()
        commands = [
            AnsibleCollections(),
            AnsibleVersion(),
            OsRelease(),
            RedhatRelease(),
            PythonPackages(),
            SystemPackages(),
        ]
        results = command_runner.run_multi_thread(commands)
        for result in results:
            result_as_dict = vars(result)
            result_as_dict.pop("parse")
            for key in list(result_as_dict.keys()):
                if key not in ["details", "errors"]:
                    result_as_dict[f"__{key}"] = result_as_dict[key]
                    result_as_dict.pop(key)
            response[result_as_dict["__id_"]] = result_as_dict
    except Exception as exc:  # noqa: BLE001
        response["errors"].append(str(exc))
    if serialize:
        print(json.dumps(response))
        return None
    return response


if __name__ == "__main__":
    main()