"""Locating ffmpeg / ffprobe and running them without flashing console windows."""

from __future__ import annotations

import os
import re
import shutil
import subprocess
import sys
from dataclasses import dataclass, field
from pathlib import Path

IS_WINDOWS = sys.platform.startswith("win")
EXE_SUFFIX = ".exe" if IS_WINDOWS else ""

# Keep ffprobe/ffmpeg helper calls from popping up a console on Windows.
_NO_WINDOW = {"creationflags": subprocess.CREATE_NO_WINDOW} if IS_WINDOWS else {}


def app_dir() -> Path:
    """Directory holding the executable (frozen) or the project root (source)."""
    if getattr(sys, "frozen", False):
        return Path(sys.executable).resolve().parent
    return Path(__file__).resolve().parent.parent


def run_quiet(args: list[str], timeout: float | None = 60) -> subprocess.CompletedProcess:
    return subprocess.run(
        args,
        stdin=subprocess.DEVNULL,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        timeout=timeout,
        **_NO_WINDOW,
    )


@dataclass
class FFmpegTools:
    ffmpeg: str
    ffprobe: str
    version: str = ""
    encoders: set[str] = field(default_factory=set)

    @property
    def ok(self) -> bool:
        return bool(self.ffmpeg and self.ffprobe)


def _candidate_dirs(configured_dir: str | None) -> list[Path]:
    dirs: list[Path] = []
    if configured_dir:
        dirs.append(Path(configured_dir))
    base = app_dir()
    dirs += [base, base / "ffmpeg", base / "ffmpeg" / "bin", base / "bin"]
    return dirs


def _find_in(dirs: list[Path], name: str) -> str | None:
    for d in dirs:
        p = d / f"{name}{EXE_SUFFIX}"
        if p.is_file() and (IS_WINDOWS or os.access(p, os.X_OK)):
            return str(p)
    return None


def locate_tools(configured_dir: str | None = None) -> FFmpegTools | None:
    """Find ffmpeg + ffprobe: configured dir, next to the app, then PATH."""
    dirs = _candidate_dirs(configured_dir)
    ffmpeg = _find_in(dirs, "ffmpeg")
    if ffmpeg:
        # Prefer the ffprobe that ships alongside the chosen ffmpeg.
        ffprobe = _find_in([Path(ffmpeg).parent], "ffprobe") or _find_in(dirs, "ffprobe")
    else:
        ffmpeg = shutil.which("ffmpeg")
        ffprobe = None
    if ffmpeg and not ffprobe:
        ffprobe = _find_in([Path(ffmpeg).parent], "ffprobe") or shutil.which("ffprobe")
    if not ffmpeg or not ffprobe:
        return None

    tools = FFmpegTools(ffmpeg=ffmpeg, ffprobe=ffprobe)
    try:
        out = run_quiet([ffmpeg, "-hide_banner", "-version"], timeout=15).stdout.decode(errors="replace")
        first = out.splitlines()[0] if out else ""
        m = re.match(r"ffmpeg version (\S+)", first)
        tools.version = m.group(1) if m else first
        enc = run_quiet([ffmpeg, "-hide_banner", "-encoders"], timeout=15).stdout.decode(errors="replace")
        tools.encoders = parse_encoders(enc)
    except (OSError, subprocess.SubprocessError):
        return None
    return tools


def parse_encoders(text: str) -> set[str]:
    names = set()
    for line in text.splitlines():
        # " V....D libx264   libx264 H.264 ..."
        m = re.match(r"^\s*([VAS])[\w.]{5}\s+(\S+)\s", line)
        if m and m.group(2) != "=":
            names.add(m.group(2))
    return names