"""Saved playlists: one TOML file each in ~/.config/SaraSuite/SaraTune/Playlists/,
holding the playlist's name and its files' paths in order. Also reads and
writes .m3u/.m3u8, so playlists can move to and from other players."""

import re
from dataclasses import dataclass, field
from pathlib import Path

import tomlkit

from Core import IsAudioFile, IsWindows, PlaylistsDir


@dataclass
class Playlist:
    Name: str
    Tracks: list[str] = field(default_factory=list)

    @property
    def FilePath(self) -> Path:
        return PlaylistsDir / f"{SafeFileName(self.Name)}.toml"

    def Save(self) -> None:
        PlaylistsDir.mkdir(parents=True, exist_ok=True)
        Document = tomlkit.document()
        Document["Name"] = self.Name
        Document["Tracks"] = tomlkit.array()
        Document["Tracks"].multiline(True)
        Document["Tracks"].extend(self.Tracks)
        self.FilePath.write_text(tomlkit.dumps(Document), encoding="utf-8")

    def Delete(self) -> None:
        self.FilePath.unlink(missing_ok=True)


def SafeFileName(Name: str) -> str:
    """A name that works as a file name on Linux and Windows."""
    return re.sub(r'[<>:"/\\|?*\x00-\x1f]', "_", Name).strip(" .") or "Playlist"


def LoadPlaylists() -> list[Playlist]:
    Result: list[Playlist] = []
    if not PlaylistsDir.is_dir():
        return Result
    for FilePath in PlaylistsDir.glob("*.toml"):
        try:
            Data = tomlkit.parse(FilePath.read_text(encoding="utf-8")).unwrap()
        except (OSError, tomlkit.exceptions.TOMLKitError):
            continue
        Tracks = [str(Item) for Item in Data.get("Tracks", []) if isinstance(Item, str)]
        Result.append(Playlist(str(Data.get("Name") or FilePath.stem), Tracks))
    return sorted(Result, key=lambda Item: Item.Name.lower())


def NameTaken(Name: str, Except: str = "") -> bool:
    """Two names that make the same file count as the same playlist."""
    Wanted = SafeFileName(Name).lower()
    return any(SafeFileName(Item.Name).lower() == Wanted and Item.Name != Except for Item in LoadPlaylists())


def ExportM3U(Item: Playlist, Destination: Path) -> None:
    Lines = ["#EXTM3U", f"#PLAYLIST:{Item.Name}"] + Item.Tracks
    Destination.write_text("\n".join(Lines) + "\n", encoding="utf-8")


def ReadM3U(Source: Path) -> Playlist:
    """Relative entries count from the .m3u file's folder; URLs and missing
    files are skipped."""
    Name = Source.stem
    Tracks: list[str] = []
    for Line in Source.read_text(encoding="utf-8", errors="replace").splitlines():
        Line = Line.strip().lstrip("")
        if Line.startswith("#PLAYLIST:"):
            Name = Line.split(":", 1)[1].strip() or Name
            continue
        if not Line or Line.startswith("#") or "://" in Line:
            continue
        # Playlists made on Windows use backslashes, which Linux paths don't split on.
        Entry = Path(Line if IsWindows else Line.replace("\\", "/"))
        if not Entry.is_absolute():
            Entry = Source.parent / Entry
        if Entry.is_file() and IsAudioFile(Entry):
            Tracks.append(str(Entry.resolve()))
    return Playlist(Name, Tracks)