import os, stat, errno, fuse
from pathlib import Path
from collections.abc import Iterator

from .favro_client import FavroClient

fuse.fuse_python_api = (0, 2)

hello_path = '/hello'
hello_str = b'Hello World!\n'

class MyStat(fuse.Stat):
    def __init__(self):
        self.st_mode = 0
        self.st_ino = 0
        self.st_dev = 0
        self.st_nlink = 0
        self.st_uid = 0
        self.st_gid = 0
        self.st_size = 0
        self.st_atime = 0
        self.st_mtime = 0
        self.st_ctime = 0

class FavroFuse(fuse.Fuse):

    def __init__(self, favro_client: FavroClient, **kwargs):
        self.favro_client = favro_client
        super().__init__(**kwargs)

    def getattr(self, path: str) -> MyStat | int:
        st = MyStat()
        if path == '/':
            st.st_mode = stat.S_IFDIR | 0o755
            st.st_nlink = 2
        elif path == hello_path:
            st.st_mode = stat.S_IFREG | 0o444
            st.st_nlink = 1
            st.st_size = len(hello_str)
        else:
            return -errno.ENOENT
        return st

    def readdir(self, path: str, offset: int) -> Iterator[fuse.Direntry]:
        yield fuse.Direntry('.')
        yield fuse.Direntry('..')

        for card in self.favro_client.get_todo_list_cards():
            yield fuse.Direntry(card.seq_id_with_prefix)

    def open(self, path: str, flags) -> int:
        if path != hello_path:
            return -errno.ENOENT
        accmode = os.O_RDONLY | os.O_WRONLY | os.O_RDWR
        if (flags & accmode) != os.O_RDONLY:
            return -errno.EACCES

    def read(self, path: str, size: int, offset: int) -> bytes | int:
        if path != hello_path:
            return -errno.ENOENT
        slen = len(hello_str)
        if offset < slen:
            if offset + size > slen:
                size = slen - offset
            buf = hello_str[offset:offset+size]
        else:
            buf = b''
        return buf

HELP="""
Userspace hello example

""" + fuse.Fuse.fusage

def start_favro_fuse(favro_client: FavroClient):
    # TODO:
    server = FavroFuse(
            favro_client = favro_client,
            version='%prog ' + fuse.__version__,
                     usage=HELP,
                     dash_s_do='setsingle')
    server.parse(errex=1)
    server.main()