"""Fluffy-compatible modinfo.ini and screenshot discovery."""
from __future__ import annotations

from dataclasses import dataclass
from pathlib import Path

IMAGE_EXTS = (".png", ".jpg", ".jpeg", ".webp")


@dataclass
class ModInfo:
    name: str = ""
    version: str = ""
    author: str = ""
    description: str = ""
    category: str = ""
    screenshot: str = ""   # as written in the ini (relative)
    nexus_mod_id: str = ""


def parse_modinfo(text: str) -> ModInfo:
    """Tolerant key=value parser; Fluffy files have no section header, but accept one."""
    vals: dict[str, str] = {}
    for line in text.splitlines():
        line = line.strip()
        if not line or line[0] in ";#[" or "=" not in line:
            continue
        k, _, v = line.partition("=")
        vals[k.strip().lower()] = v.strip()
    return ModInfo(
        name=vals.get("name", ""),
        version=vals.get("version", ""),
        author=vals.get("author", ""),
        description=vals.get("description", "").replace("\\n", "\n"),
        category=vals.get("category", ""),
        screenshot=vals.get("screenshot", ""),
        nexus_mod_id=vals.get("nexusid", vals.get("nexus_mod_id", "")),
    )


def _read_text(path: Path) -> str:
    raw = path.read_bytes()
    for enc in ("utf-8-sig", "utf-16", "latin-1"):
        try:
            return raw.decode(enc)
        except UnicodeError:
            continue
    return raw.decode("utf-8", "replace")


def find_modinfo(root: Path) -> Path | None:
    """modinfo.ini at the root or one directory down."""
    for base in [root, *sorted(p for p in root.iterdir() if p.is_dir())]:
        for p in base.iterdir():
            if p.is_file() and p.name.lower() == "modinfo.ini":
                return p
    return None


def read_modinfo(root: Path) -> tuple[ModInfo, Path | None]:
    p = find_modinfo(root)
    if p is None:
        return ModInfo(), None
    try:
        return parse_modinfo(_read_text(p)), p.parent
    except OSError:
        return ModInfo(), None


def find_screenshot(base: Path, hint: str = "") -> Path | None:
    """Explicit `screenshot=` wins, else screenshot.png|jpg in the mod root (Fluffy convention)."""
    if not base.is_dir():
        return None
    files = {p.name.lower(): p for p in base.iterdir() if p.is_file()}
    if hint:
        p = files.get(Path(hint).name.lower())
        if p:
            return p
    for ext in IMAGE_EXTS:
        p = files.get("screenshot" + ext)
        if p:
            return p
    return None