import mimetypes
import os
import re
import uuid
from collections.abc import Iterator
from pathlib import Path

import magic
from fastapi import HTTPException, UploadFile
from folkugat_web.config import db
from folkugat_web.dal.sql.temes import links as links_dal
from folkugat_web.log import logger


async def get_mimetype(upload_file: UploadFile) -> str:
    info = magic.detect_from_content(await upload_file.read(2048))
    await upload_file.seek(0)
    return info.mime_type


ACCEPTED_MIMETYPES = [
    re.compile(r"image/.+"),
    re.compile(r".+/pdf"),
]


def check_mimetype(mimetype: str) -> None:
    if not any(regex.match(mimetype) for regex in ACCEPTED_MIMETYPES):
        raise HTTPException(status_code=400, detail=f"Unsupported file type: {mimetype}")


def get_db_file_path(filepath: Path) -> str:
    return f"{db.DB_FILES_URL}/{filepath.relative_to(db.DB_FILES_DIR)}"


async def store_file(tema_id: int, upload_file: UploadFile) -> str:
    if not upload_file.size:
        raise HTTPException(status_code=400, detail="Couldn't find out the size of the file")
    if upload_file.size > db.FILE_MAX_SIZE:
        raise HTTPException(
            status_code=400,
            detail=f"The uploaded file is too big (max size = {db.FILE_MAX_SIZE} bytes)",
        )

    mimetype = await get_mimetype(upload_file)
    check_mimetype(mimetype)

    extension = mimetypes.guess_extension(mimetype) or ""
    filename = str(uuid.uuid4().hex) + extension
    filedir = db.DB_FILES_DIR / str(tema_id)
    filedir.mkdir(exist_ok=True)
    filepath = filedir / filename

    with open(filepath, "wb") as f:
        _ = f.write(await upload_file.read())

    return get_db_file_path(filepath)


def list_files(tema_id: str) -> list[str]:
    filedir = db.DB_FILES_DIR / str(tema_id)
    return [get_db_file_path(f) for f in filedir.iterdir()]


def get_orphan_files() -> Iterator[Path]:
    alive_files = {link.url for link in links_dal.get_links()}
    return filter(
        lambda p: p.is_file() and get_db_file_path(p) not in alive_files,
        db.DB_FILES_DIR.rglob("*"),
    )


def clean_orphan_files():
    for path in get_orphan_files():
        logger.info(f"Deleting the orphan file: {path}")
        os.remove(path)