"""Media conversion into web-friendly formats."""

import shutil
import subprocess
import uuid
from pathlib import Path

from PIL import Image, ImageSequence

IMAGE_EXTS = {".png", ".jpg", ".jpeg", ".webp", ".bmp", ".gif", ".tga", ".avif"}
AUDIO_EXTS = {".ogg", ".mp3", ".wav", ".opus", ".flac", ".m4a", ".oga"}
VIDEO_EXTS = {".webm", ".ogv", ".mp4", ".mkv", ".avi", ".mpg", ".mpeg", ".m4v"}
FONT_EXTS = {".ttf", ".otf", ".woff", ".woff2", ".ttc"}

WEBP_MAX = 16383


def kind_of(path: Path) -> str | None:
    ext = path.suffix.lower()
    if ext in IMAGE_EXTS:
        return "image"
    if ext in AUDIO_EXTS:
        return "audio"
    if ext in VIDEO_EXTS:
        return "video"
    if ext in FONT_EXTS:
        return "font"
    return None


def target_ext(path: Path) -> str:
    kind = kind_of(path)
    return {"image": ".webp", "audio": ".ogg", "video": ".webm"}.get(kind, path.suffix.lower())


def convert(src: Path, out_dir: Path) -> tuple[Path, str]:
    """Convert one file into out_dir. Returns (output file, extension used for the blob)."""
    kind = kind_of(src)
    tmp = str(out_dir / uuid.uuid4().hex)
    if kind == "image":
        return _image(src, Path(tmp))
    if kind == "audio":
        return _ffmpeg(src, Path(tmp + ".ogg"),
                       ["-vn", "-c:a", "libopus", "-b:a", "112k", "-vbr", "on"]), ".ogg"
    if kind == "video":
        if src.suffix.lower() == ".webm":
            out = Path(tmp + ".webm")
            shutil.copyfile(src, out)
            return out, ".webm"
        return _ffmpeg(src, Path(tmp + ".webm"),
                       ["-c:v", "libvpx-vp9", "-crf", "34", "-b:v", "0", "-deadline", "realtime",
                        "-cpu-used", "8", "-row-mt", "1", "-c:a", "libopus", "-b:a", "112k"]
                       ), ".webm"
    out = Path(tmp + src.suffix.lower())
    shutil.copyfile(src, out)
    return out, src.suffix.lower()


def _image(src: Path, tmp: Path) -> tuple[Path, str]:
    with Image.open(src) as img:
        animated = getattr(img, "is_animated", False)
        if max(img.size) > WEBP_MAX:
            out = tmp.with_suffix(".png")
            img.save(out, "PNG", optimize=False)
            return out, ".png"
        out = tmp.with_suffix(".webp")
        if animated:
            frames = [f.convert("RGBA") for f in ImageSequence.Iterator(img)]
            frames[0].save(out, "WEBP", save_all=True, append_images=frames[1:], quality=85,
                           duration=img.info.get("duration", 100), loop=0)
            return out, ".webp"
        has_alpha = img.mode in ("RGBA", "LA", "PA") or (img.mode == "P" and "transparency" in img.info)
        img = img.convert("RGBA" if has_alpha else "RGB")
        img.save(out, "WEBP", quality=88, method=4, alpha_quality=95)
        return out, ".webp"


def _ffmpeg(src: Path, out: Path, args: list[str]) -> Path:
    proc = subprocess.run(
        ["ffmpeg", "-nostdin", "-hide_banner", "-loglevel", "error", "-y", "-i", str(src),
         *args, str(out)],
        capture_output=True, text=True, timeout=3600,
    )
    if proc.returncode != 0:
        raise RuntimeError(f"ffmpeg: {proc.stderr.strip()[-300:]}")
    return out