import os
import json
import logging
from server.common.utils import dtype_to_schema
from server.common.errors import DatasetAccessError, ConfigurationError
from server.common.utils import path_join
from server.common.constants import Axis
from server.data_common.data_adaptor import DataAdaptor
from server.data_common.fbs.matrix import encode_matrix_fbs
from server.data_cxg.cxg_util import pack_selector_from_mask
import server.compute.diffexp_cxg as diffexp_cxg
from server.common.immutable_kvcache import ImmutableKVCache
import tiledb
import numpy as np
import pandas as pd
from server_timing import Timing as ServerTiming
import threading


class CxgAdaptor(DataAdaptor):

    # TODO:  The tiledb context parameters should be a configuration option
    tiledb_ctx = tiledb.Ctx(
        {"sm.tile_cache_size": 8 * 1024 * 1024 * 1024, "sm.num_reader_threads": 32, "vfs.s3.region": "us-east-1"}
    )

    def __init__(self, data_locator, config=None):
        super().__init__(config)
        self.lock = threading.Lock()

        self.data_locator = data_locator
        self.url = data_locator.uri_or_path
        if self.url[-1] != "/":
            self.url += "/"

        # caching immutable state
        self.lsuri_results = ImmutableKVCache(lambda key: self._lsuri(uri=key, tiledb_ctx=self.tiledb_ctx))
        self.arrays = ImmutableKVCache(lambda key: self._open_array(uri=key, tiledb_ctx=self.tiledb_ctx))
        self.schema = None

        self._validate_and_initialize()

    def cleanup(self):
        """close all the open tiledb arrays"""
        for array in self.arrays.values():
            array.close()
        self.arrays.clear()

    @staticmethod
    def set_tiledb_context(context_params):
        """Set the tiledb context.  This should be set before any instances of CxgAdaptor are created"""
        try:
            CxgAdaptor.tiledb_ctx = tiledb.Ctx(context_params)
        except tiledb.libtiledb.TileDBError as e:
            raise ConfigurationError(f"Invalid tiledb context: {str(e)}")

    @staticmethod
    def pre_load_validation(data_locator):
        location = data_locator.uri_or_path
        if not CxgAdaptor.isvalid(location):
            logging.error(f"cxg matrix is not valid: {location}")
            raise DatasetAccessError("cxg matrix is not valid")

    @staticmethod
    def file_size(data_locator):
        return 0

    @staticmethod
    def open(data_locator, args):
        return CxgAdaptor(data_locator, args)

    def get_about(self):
        return self.about if self.about else super().get_about()

    def get_title(self):
        return self.title if self.title else super().get_title()

    def get_location(self):
        return self.url

    def get_data_locator(self):
        return self.data_locator

    def get_name(self):
        return "cellxgene cxg adaptor version"

    def get_library_versions(self):
        return dict(tiledb=tiledb.__version__)

    def get_path(self, *urls):
        return path_join(self.url, *urls)

    @staticmethod
    def _lsuri(uri, tiledb_ctx):
        def _cleanpath(p):
            if p[-1] == "/":
                return p[:-1]
            else:
                return p

        result = []
        tiledb.ls(uri, lambda path, type: result.append((_cleanpath(path), type)), ctx=tiledb_ctx)
        return result

    def lsuri(self, uri):
        """
        given a URI, do a tiledb.ls but normalizing for all path weirdness:
        * S3 URIs require trailing slash.  file: doesn't care.
        * results on S3 *have* a trailing slash, Posix does not.

        returns list of (absolute paths, type) *without* trailing slash
        in the path.
        """
        if uri[-1] != "/":
            uri += "/"
        return self.lsuri_results[uri]

    @staticmethod
    def isvalid(url):
        """
        Return True if this looks like a valid CXG, False if not.  Just a quick/cheap
        test, not to be fully trusted.
        """
        if not tiledb.object_type(url, ctx=CxgAdaptor.tiledb_ctx) == "group":
            return False
        if not tiledb.object_type(path_join(url, "obs"), ctx=CxgAdaptor.tiledb_ctx) == "array":
            return False
        if not tiledb.object_type(path_join(url, "var"), ctx=CxgAdaptor.tiledb_ctx) == "array":
            return False
        if not tiledb.object_type(path_join(url, "X"), ctx=CxgAdaptor.tiledb_ctx) == "array":
            return False
        if not tiledb.object_type(path_join(url, "emb"), ctx=CxgAdaptor.tiledb_ctx) == "group":
            return False
        return True

    def _validate_and_initialize(self):
        """
        remember, preload_validation() has already been called, so
        no need to repeat anything it has done.

        Load the CXG "group" metadata and cache instance values.
        Be very aware of multiple versions of the CXG object.

        CXG versions in the wild:
        * version 0, aka "no version" -- can be detected by the lack
          of a cxg_group_metadata array.
        * version 0.1 -- metadata attache to cxg_group_metadata array.
          Same as 0, except it adds group metadata.
        """
        a_type = tiledb.object_type(path_join(self.url, "cxg_group_metadata"), ctx=self.tiledb_ctx)
        if a_type is None:
            # version 0
            cxg_version = "0.0"
            title = None
            about = None
        elif a_type == "array":
            # version >0
            gmd = self.open_array("cxg_group_metadata")
            cxg_version = gmd.meta["cxg_version"]
            if cxg_version == "0.1":
                cxg_properties = json.loads(gmd.meta["cxg_properties"])
                title = cxg_properties.get("title", None)
                about = cxg_properties.get("about", None)

        if cxg_version not in ["0.0", "0.1"]:
            raise DatasetAccessError(f"cxg matrix is not valid: {self.url}")

        self.title = title
        self.about = about
        self.cxg_version = cxg_version

    @staticmethod
    def _open_array(uri, tiledb_ctx):
        return tiledb.DenseArray(uri, mode="r", ctx=tiledb_ctx)

    def open_array(self, name):
        try:
            p = self.get_path(name)
            return self.arrays[p]
        except tiledb.libtiledb.TileDBError:
            raise DatasetAccessError(name)

    def get_embedding_array(self, ename, dims=2):
        array = self.open_array(f"emb/{ename}")
        return array[:, 0:dims]

    def compute_embedding(self, method, filter):
        raise NotImplementedError("CXG does not yet support re-embedding")

    def compute_diffexp_ttest(self, maskA, maskB, top_n=None, lfc_cutoff=None):
        if top_n is None:
            top_n = self.config.diffexp__top_n
        if lfc_cutoff is None:
            lfc_cutoff = self.config.diffexp__lfc_cutoff
        return diffexp_cxg.diffexp_ttest(self, maskA, maskB, top_n, lfc_cutoff)

    def get_X_array(self, obs_mask=None, var_mask=None):
        obs_items = pack_selector_from_mask(obs_mask)
        var_items = pack_selector_from_mask(var_mask)
        X = self.open_array("X")
        if obs_items == slice(None) and var_items == slice(None):
            data = X[:, :]
        else:
            data = X.multi_index[obs_items, var_items][""]
        return data

    def get_shape(self):
        X = self.open_array("X")
        return X.shape

    def get_X_array_dtype(self):
        X = self.open_array("X")
        return X.dtype

    def query_var_array(self, term_name):
        var = self.open_array("var")
        data = var.query(attrs=[term_name])[:][term_name]
        return data

    def query_obs_array(self, term_name):
        var = self.open_array("obs")
        try:
            data = var.query(attrs=[term_name])[:][term_name]
        except tiledb.libtiledb.TileDBError:
            raise DatasetAccessError("query_obs")
        return data

    def get_obs_names(self):
        # get the index from the meta data
        obs = self.open_array("obs")
        meta = json.loads(obs.meta["cxg_schema"])
        index_name = meta["index"]
        return index_name

    def get_obs_index(self):
        obs = self.open_array("obs")
        meta = json.loads(obs.meta["cxg_schema"])
        index_name = meta["index"]
        data = obs.query(attrs=[index_name])[:][index_name]
        return data

    def get_obs_columns(self):
        obs = self.open_array("obs")
        schema = obs.schema
        col_names = [attr.name for attr in schema]
        return pd.Index(col_names)

    def get_obs_keys(self):
        obs = self.open_array("obs")
        schema = obs.schema
        return [attr.name for attr in schema]

    def get_var_keys(self):
        var = self.open_array("var")
        schema = var.schema
        return [attr.name for attr in schema]

    # function to get the embedding
    # this function to iterate through embeddings.
    def get_embedding_names(self):
        with ServerTiming.time(f"layout.lsuri"):
            pemb = self.get_path("emb")
            embeddings = [os.path.basename(p) for (p, t) in self.lsuri(pemb) if t == "array"]
        if len(embeddings) == 0:
            raise DatasetAccessError("cxg matrix missing embeddings")
        return embeddings

    @staticmethod
    def _get_col_type(attr, schema_hints={}):
        type_hint = schema_hints.get(attr.name, {})
        dtype = attr.dtype
        schema = {}
        # type hints take precedence
        if "type" in type_hint:
            schema["type"] = type_hint["type"]
        elif dtype == np.float32:
            schema["type"] = "float32"
        elif dtype == np.int32:
            schema["type"] = "int32"
        elif dtype == np.bool_:
            schema["type"] = "boolean"
        elif dtype == np.str:
            schema["type"] = "string"
        elif dtype == "category":
            schema["type"] = "categorical"
            schema["categories"] = dtype.categories.tolist()
        else:
            raise TypeError(f"Annotations of type {dtype} are unsupported.")

        if schema["type"] == "categorical" and "categories" in schema_hints:
            schema["categories"] = schema_hints["categories"]
        return schema

    def _get_schema(self):
        if self.schema:
            return self.schema

        shape = self.get_shape()
        dtype = self.get_X_array_dtype()

        dataframe = {"nObs": shape[0], "nVar": shape[1], "type": dtype.name}

        annotations = {}
        for ax in ("obs", "var"):
            A = self.open_array(ax)
            schema_hints = json.loads(A.meta["cxg_schema"]) if "cxg_schema" in A.meta else {}
            if type(schema_hints) is not dict:
                raise TypeError(f"Array schema was malformed.")

            cols = []
            for attr in A.schema:
                schema = dict(name=attr.name, writable=False)
                type_hint = schema_hints.get(attr.name, {})
                # type hints take precedence
                if "type" in type_hint:
                    schema["type"] = type_hint["type"]
                    if schema["type"] == "categorical" and "categories" in type_hint:
                        schema["categories"] = type_hint["categories"]
                else:
                    schema.update(dtype_to_schema(attr.dtype))
                cols.append(schema)

            annotations[ax] = dict(columns=cols)

            if "index" in schema_hints:
                annotations[ax].update({"index": schema_hints["index"]})

        obs_layout = []
        embeddings = self.get_embedding_names()
        for ename in embeddings:
            A = self.open_array(f"emb/{ename}")
            obs_layout.append({"name": ename, "type": A.dtype.name, "dims": [f"{ename}_{d}" for d in range(0, A.ndim)]})

        schema = {"dataframe": dataframe, "annotations": annotations, "layout": {"obs": obs_layout}}
        return schema

    def get_schema(self):
        if self.schema is None:
            with self.lock:
                self.schema = self._get_schema()
        return self.schema

    def _annotations_field_split(self, axis, fields, A, labels):
        """
        fields: requested fields, may be None (all)
        labels: writable user annotations dataframe, if any

        Remove redundant fields, raise KeyError on non-existant fields,
        and split into three lists:
            fields_to_fetch_from_cxg
            fields_to_fetch_from_labels
            fields_to_return

        if we have to return from labels, the fetch fields will contain the index
        to join on, which may not be in fields_to_return
        """
        need_labels = axis == Axis.OBS and labels is not None and not labels.empty
        index_key = self.get_obs_names() if need_labels else None

        if not fields:
            return (None, None, None, index_key)

        cxg_keys = frozenset([a.name for a in A.schema])
        user_anno_keys = frozenset(labels.columns.tolist()) if need_labels else frozenset()
        return_keys = frozenset(fields)

        label_join_index = (
            frozenset([index_key]) if need_labels and (return_keys & user_anno_keys) else frozenset()
        )

        unknown_fields = return_keys - (cxg_keys | user_anno_keys)
        if unknown_fields:
            raise KeyError("_".join(unknown_fields))

        return (
            list((return_keys & cxg_keys) | label_join_index),
            list(return_keys & user_anno_keys),
            list(return_keys),
            index_key
        )

    def annotation_to_fbs_matrix(self, axis, fields=None, labels=None):
        with ServerTiming.time(f"annotations.{axis}.query"):
            A = self.open_array(str(axis))

            # may raise if fields contains unknown key
            cxg_fields, anno_fields, return_fields, index_field = self._annotations_field_split(axis, fields, A, labels)

            if cxg_fields is None:
                data = A[:]
            elif cxg_fields:
                data = A.query(attrs=cxg_fields)[:]
            else:
                data = {}

            df = pd.DataFrame.from_dict(data)

            if axis == Axis.OBS and labels is not None and not labels.empty:
                if anno_fields is None:
                    assert index_field
                    df = df.join(labels, index_field)
                elif anno_fields:
                    assert index_field
                    df = df.join(labels[anno_fields], index_field)

            if return_fields:
                df = df[return_fields]

        with ServerTiming.time(f"annotations.{axis}.encode"):
            fbs = encode_matrix_fbs(df, col_idx=df.columns)

        return fbs