import ast
import contextlib
import importlib.util
import os
import re
import socket
import sys
import time
import unicodedata
from collections import defaultdict
from datetime import datetime
from pathlib import Path
from types import ModuleType
from typing import Optional, Sequence, Union
from urllib.parse import ParseResult, urlparse

import chardet
import requests
from construct import ValidationError
from langcodes import Language, closest_match
from pymp4.parser import Box
from unidecode import unidecode

from unshackle.core.config import config
from unshackle.core.constants import LANGUAGE_MAX_DISTANCE


def rotate_log_file(log_path: Path, keep: int = 20) -> Path:
    """
    Update Log Filename and delete old log files.
    It keeps only the 20 newest logs by default.
    """
    if not log_path:
        raise ValueError("A log path must be provided")

    try:
        log_path.relative_to(Path(""))  # file name only
    except ValueError:
        pass
    else:
        log_path = config.directories.logs / log_path

    log_path = log_path.parent / log_path.name.format_map(
        defaultdict(str, name="root", time=datetime.now().strftime("%Y%m%d-%H%M%S"))
    )

    if log_path.parent.exists():
        log_files = [x for x in log_path.parent.iterdir() if x.suffix == log_path.suffix]
        for log_file in log_files[::-1][keep - 1 :]:
            # keep n newest files and delete the rest
            log_file.unlink()

    log_path.parent.mkdir(parents=True, exist_ok=True)
    return log_path


def import_module_by_path(path: Path) -> ModuleType:
    """Import a Python file by Path as a Module."""
    if not path:
        raise ValueError("Path must be provided")
    if not isinstance(path, Path):
        raise TypeError(f"Expected path to be a {Path}, not {path!r}")
    if not path.exists():
        raise ValueError("Path does not exist")

    # compute package hierarchy for relative import support
    if path.is_relative_to(config.directories.core_dir):
        name = []
        _path = path.parent
        while _path.stem != config.directories.core_dir.stem:
            name.append(_path.stem)
            _path = _path.parent
        name = ".".join([config.directories.core_dir.stem] + name[::-1])
    else:
        # is outside the src package
        if str(path.parent.parent) not in sys.path:
            sys.path.insert(1, str(path.parent.parent))
        name = path.parent.stem

    spec = importlib.util.spec_from_file_location(name, path)
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)

    return module


def sanitize_filename(filename: str, spacer: str = ".") -> str:
    """
    Sanitize a string to be filename safe.

    The spacer is safer to be a '.' for older DDL and p2p sharing spaces.
    This includes web-served content via direct links and such.
    """
    # replace all non-ASCII characters with ASCII equivalents
    filename = unidecode(filename)

    # remove or replace further characters as needed
    filename = "".join(c for c in filename if unicodedata.category(c) != "Mn")  # hidden characters
    filename = filename.replace("/", " & ").replace(";", " & ")  # e.g. multi-episode filenames
    filename = re.sub(r"[:; ]", spacer, filename)  # structural chars to (spacer)
    filename = re.sub(r"[\\*!?¿,'\"" "()<>|$#~]", "", filename)  # not filename safe chars
    filename = re.sub(rf"[{spacer}]{{2,}}", spacer, filename)  # remove extra neighbouring (spacer)s

    return filename


def is_close_match(language: Union[str, Language], languages: Sequence[Union[str, Language, None]]) -> bool:
    """Check if a language is a close match to any of the provided languages."""
    languages = [x for x in languages if x]
    if not languages:
        return False
    return closest_match(language, list(map(str, languages)))[1] <= LANGUAGE_MAX_DISTANCE


def get_boxes(data: bytes, box_type: bytes, as_bytes: bool = False) -> Box:
    """
    Scan a byte array for a wanted MP4/ISOBMFF box, then parse and yield each find.

    This function searches through binary MP4 data to find and parse specific box types.
    The MP4/ISOBMFF box format consists of:
    - 4 bytes: size of the box (including size and type fields)
    - 4 bytes: box type identifier (e.g., 'moov', 'trak', 'pssh')
    - Remaining bytes: box data

    The function uses slicing to directly locate the requested box type in the data
    rather than recursively traversing the box hierarchy. This is efficient when
    looking for specific box types regardless of their position in the hierarchy.

    Parameters:
        data: Binary data containing MP4/ISOBMFF boxes
        box_type: 4-byte identifier of the box type to find (e.g., b'pssh')
        as_bytes: If True, returns the box as bytes, otherwise returns parsed box object

    Yields:
        Box objects of the requested type found in the data

    Notes:
        - For each box found, the function updates the search offset to skip past
          the current box to avoid finding the same box multiple times
        - The function handles validation errors for certain box types (e.g., tenc)
        - The size field is located 4 bytes before the box type identifier
    """
    # using slicing to get to the wanted box is done because parsing the entire box and recursively
    # scanning through each box and its children often wouldn't scan far enough to reach the wanted box.
    # since it doesn't care what child box the wanted box is from, this works fine.
    if not isinstance(data, (bytes, bytearray)):
        raise ValueError("data must be bytes")

    offset = 0
    while offset < len(data):
        try:
            index = data[offset:].index(box_type)
        except ValueError:
            break

        pos = offset + index

        if pos < 4:
            offset = pos + len(box_type)
            continue

        box_start = pos - 4

        try:
            box = Box.parse(data[box_start:])
            if as_bytes:
                box = Box.build(box)

            yield box

            box_size = len(Box.build(box))
            offset = box_start + box_size

        except IOError:
            break
        except ValidationError as e:
            if box_type == b"tenc":
                offset = pos + len(box_type)
                continue
            raise e


def ap_case(text: str, keep_spaces: bool = False, stop_words: tuple[str] = None) -> str:
    """
    Convert a string to title case using AP/APA style.
    Based on https://github.com/words/ap-style-title-case

    Parameters:
        text: The text string to title case with AP/APA style.
        keep_spaces: To keep the original whitespace, or to just use a normal space.
            This would only be needed if you have special whitespace between words.
        stop_words: Override the default stop words with your own ones.
    """
    if not text:
        return ""

    if not stop_words:
        stop_words = (
            "a",
            "an",
            "and",
            "at",
            "but",
            "by",
            "for",
            "in",
            "nor",
            "of",
            "on",
            "or",
            "so",
            "the",
            "to",
            "up",
            "yet",
        )

    splitter = re.compile(r"(\s+|[-‑–—])")
    words = splitter.split(text)

    return "".join(
        [
            [" ", word][keep_spaces]
            if re.match(r"\s+", word)
            else word
            if splitter.match(word)
            else word.lower()
            if i != 0 and i != len(words) - 1 and word.lower() in stop_words
            else word.capitalize()
            for i, word in enumerate(words)
        ]
    )


def get_ip_info(session: Optional[requests.Session] = None) -> dict:
    """
    Use ipinfo.io to get IP location information.

    If you provide a Requests Session with a Proxy, that proxies IP information
    is what will be returned.
    """
    return (session or requests.Session()).get("https://ipinfo.io/json").json()


def time_elapsed_since(start: float) -> str:
    """
    Get time elapsed since a timestamp as a string.
    E.g., `1h56m2s`, `15m12s`, `0m55s`, e.t.c.
    """
    elapsed = int(time.time() - start)

    minutes, seconds = divmod(elapsed, 60)
    hours, minutes = divmod(minutes, 60)

    time_string = f"{minutes:d}m{seconds:d}s"
    if hours:
        time_string = f"{hours:d}h{time_string}"

    return time_string


def try_ensure_utf8(data: bytes) -> bytes:
    """
    Try to ensure that the given data is encoded in UTF-8.

    Parameters:
        data: Input data that may or may not yet be UTF-8 or another encoding.

    Returns the input data encoded in UTF-8 if successful. If unable to detect the
    encoding of the input data, then the original data is returned as-received.
    """
    try:
        data.decode("utf8")
        return data
    except UnicodeDecodeError:
        try:
            # CP-1252 is a superset of latin1 but has gaps. Replace unknown
            # characters instead of failing on them.
            return data.decode("cp1252", errors="replace").encode("utf8")
        except UnicodeDecodeError:
            try:
                # last ditch effort to detect encoding
                detection_result = chardet.detect(data)
                if not detection_result["encoding"]:
                    return data
                return data.decode(detection_result["encoding"]).encode("utf8")
            except UnicodeDecodeError:
                return data


def get_free_port() -> int:
    """
    Get an available port to use between a-b (inclusive).

    The port is freed as soon as this has returned, therefore, it
    is possible for the port to be taken before you try to use it.
    """
    with contextlib.closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
        s.bind(("", 0))
        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        return s.getsockname()[1]


def get_extension(value: Union[str, Path, ParseResult]) -> Optional[str]:
    """
    Get a URL or Path file extension/suffix.

    Note: The returned value will begin with `.`.
    """
    if isinstance(value, ParseResult):
        value_parsed = value
    elif isinstance(value, (str, Path)):
        value_parsed = urlparse(str(value))
    else:
        raise TypeError(f"Expected {str}, {Path}, or {ParseResult}, got {type(value)}")

    if value_parsed.path:
        ext = os.path.splitext(value_parsed.path)[1]
        if ext and ext != ".":
            return ext


def get_system_fonts() -> dict[str, Path]:
    if sys.platform == "win32":
        import winreg

        with winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE) as reg:
            key = winreg.OpenKey(reg, r"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts", 0, winreg.KEY_READ)
            total_fonts = winreg.QueryInfoKey(key)[1]
            return {
                name.replace(" (TrueType)", ""): Path(r"C:\Windows\Fonts", filename)
                for n in range(0, total_fonts)
                for name, filename, _ in [winreg.EnumValue(key, n)]
            }
    else:
        # TODO: Get System Fonts for Linux and mac OS
        return {}


class FPS(ast.NodeVisitor):
    def visit_BinOp(self, node: ast.BinOp) -> float:
        if isinstance(node.op, ast.Div):
            return self.visit(node.left) / self.visit(node.right)
        raise ValueError(f"Invalid operation: {node.op}")

    def visit_Num(self, node: ast.Num) -> complex:
        return node.n

    def visit_Expr(self, node: ast.Expr) -> float:
        return self.visit(node.value)

    @classmethod
    def parse(cls, expr: str) -> float:
        return cls().visit(ast.parse(expr).body[0])