from __future__ import print_function, division, absolute_import

import zipfile
from fsspec import AbstractFileSystem, open_files
from fsspec.utils import tokenize, DEFAULT_BLOCK_SIZE


class ZipFileSystem(AbstractFileSystem):
    """Read contents of ZIP archive as a file-system

    Keeps file object open while instance lives.

    This class is pickleable, but not necessarily thread-safe
    """

    root_marker = ""

    def __init__(self, fo="", mode="r", **storage_options):
        """
        Parameters
        ----------
        fo: str or file-like
            Contains ZIP, and must exist. If a str, will fetch file using
            `open_files()`, which must return one file exactly.
        mode: str
            Currently, only 'r' accepted
        storage_options: key-value
            May be credentials, e.g., `{'auth': ('username', 'pword')}` or any
            other parameters for requests
        """
        if self._cached:
            return
        AbstractFileSystem.__init__(self)
        if mode != "r":
            raise ValueError("Only read from zip files accepted")
        self.in_fo = fo
        if isinstance(fo, str):
            files = open_files(fo)
            if len(files) != 1:
                raise ValueError(
                    'Path "{}" did not resolve to exactly'
                    'one file: "{}"'.format(fo, files)
                )
            fo = files[0]
        self.fo = fo.__enter__()  # the whole instance is a context
        self.zip = zipfile.ZipFile(self.fo)
        self.block_size = storage_options.get("block_size", DEFAULT_BLOCK_SIZE)
        self.dir_cache = None

    @classmethod
    def _strip_protocol(cls, path):
        # zip file paths are always relative to the archive root
        return super()._strip_protocol(path).lstrip("/")

    def _get_dirs(self):
        if self.dir_cache is None:
            files = self.zip.infolist()
            self.dir_cache = {}
            for z in files:
                f = {s: getattr(z, s) for s in zipfile.ZipInfo.__slots__}
                f.update(
                    {
                        "name": z.filename,
                        "size": z.file_size,
                        "type": ("directory" if z.is_dir() else "file"),
                    }
                )
                self.dir_cache[f["name"]] = f

    def ls(self, path, detail=False):
        self._get_dirs()
        paths = {}
        for p, f in self.dir_cache.items():
            p = p.rstrip("/")
            if "/" in p:
                root = p.rsplit("/", 1)[0]
            else:
                root = ""
            if root == path.rstrip("/"):
                paths[p] = f
            elif path and all(
                (a == b) for a, b in zip(path.split("/"), p.strip("/").split("/"))
            ):
                # implicit directory
                ppath = "/".join(p.split("/")[: len(path.split("/")) + 1])
                if ppath not in paths:
                    out = {"name": ppath + "/", "size": 0, "type": "directory"}
                    paths[ppath] = out

            elif all(
                (a == b)
                for a, b in zip(path.split("/"), [""] + p.strip("/").split("/"))
            ):
                # root directory entry
                ppath = p.rstrip("/").split("/", 1)[0]
                if ppath not in paths:
                    out = {"name": ppath + "/", "size": 0, "type": "directory"}
                    paths[ppath] = out
        out = list(paths.values())
        if detail:
            return out
        else:
            return list(sorted(f["name"] for f in out))

    def cat(self, path):
        return self.zip.read(path)

    def _open(self, path, mode="rb", **kwargs):
        path = self._strip_protocol(path)
        if mode != "rb":
            raise NotImplementedError
        info = self.info(path)
        out = self.zip.open(path, "r")
        out.size = info["size"]
        out.name = info["name"]
        return out

    def ukey(self, path):
        return tokenize(path, self.in_fo, self.protocol)
