from __future__ import annotations

import asyncio
import dataclasses
import gzip
import itertools
import logging
from pathlib import Path
from typing import Union, List, Tuple, Set, Sequence, Dict

from hippolyzer.lib.base import llsd
from hippolyzer.lib.base.datatypes import UUID
from hippolyzer.lib.base.inventory import InventoryModel, InventoryCategory, InventoryItem, InventoryNodeBase
from hippolyzer.lib.base.message.message import Message, Block
from hippolyzer.lib.base.templates import AssetType, FolderType, InventoryType, Permissions
from hippolyzer.lib.client.state import BaseClientSession
from hippolyzer.lib.base.templates import WearableType

LOG = logging.getLogger(__name__)


class CannotMoveError(Exception):
    def __init__(self):
        pass


def _get_node_id(node_or_id: InventoryNodeBase | UUID) -> UUID:
    if isinstance(node_or_id, UUID):
        return node_or_id
    return node_or_id.node_id


class InventoryManager:
    def __init__(self, session: BaseClientSession):
        self._session = session
        self.model: InventoryModel = InventoryModel()
        self._load_skeleton()
        self._session.message_handler.subscribe("BulkUpdateInventory", self._handle_bulk_update_inventory)
        self._session.message_handler.subscribe("UpdateCreateInventoryItem", self._handle_update_create_inventory_item)
        self._session.message_handler.subscribe("RemoveInventoryItem", self._handle_remove_inventory_item)
        self._session.message_handler.subscribe("RemoveInventoryFolder", self._handle_remove_inventory_folder)
        self._session.message_handler.subscribe("MoveInventoryItem", self._handle_move_inventory_item)
        self._session.message_handler.subscribe("MoveInventoryFolder", self._handle_move_inventory_folder)

    def _load_skeleton(self):
        assert not self.model.nodes
        skel_cats: List[dict] = self._session.login_data.get('inventory-skeleton', [])
        for skel_cat in skel_cats:
            self.model.add(InventoryCategory(
                name=skel_cat["name"],
                cat_id=UUID(skel_cat["folder_id"]),
                parent_id=UUID(skel_cat["parent_id"]),
                # Don't use the version from the skeleton, this flags the inventory as needing
                # completion from the inventory cache. This matches indra's behavior.
                version=InventoryCategory.VERSION_NONE,
                type=AssetType.CATEGORY,
                pref_type=FolderType(skel_cat.get("type_default", FolderType.NONE)),
                owner_id=self._session.agent_id,
            ))

    def load_cache(self, path: Union[str, Path]):
        # Per indra, rough flow for loading inv on login is:
        # 1. Look at inventory skeleton from login response
        # 2. Pre-populate model with categories from the skeleton, including their versions
        # 3. Read the inventory cache, tracking categories and items separately
        # 4. Walk the list of categories in our cache. If the cat exists in the skeleton and the versions
        #    match, then we may load the category and its descendants from cache.
        # 5. Any categories in the skeleton but not in the cache, or those with mismatched versions must be fetched.
        #    The viewer does this by setting the local version of the cats to -1 and forcing a descendent fetch
        #    over AIS.
        #
        # By the time you call this function call, you should have already loaded the inventory skeleton
        # into the model set its inventory category versions to VERSION_NONE.

        skel_cats: List[dict] = self._session.login_data['inventory-skeleton']
        # UUID -> version map for inventory skeleton
        skel_versions = {UUID(cat["folder_id"]): cat["version"] for cat in skel_cats}
        LOG.info(f"Parsing inv cache at {path}")
        cached_categories, cached_items = self._parse_cache(path)
        LOG.info(f"Done parsing inv cache at {path}")
        loaded_cat_ids: Set[UUID] = set()

        for cached_cat in cached_categories:
            existing_cat: InventoryCategory = self.model.get(cached_cat.cat_id)  # noqa
            # Don't clobber an existing cat unless it just has a placeholder version,
            # maybe from loading the skeleton?
            if existing_cat and existing_cat.version != InventoryCategory.VERSION_NONE:
                continue
            # Cached cat isn't the same as what the inv server says it should be, can't use it.
            if cached_cat.version != skel_versions.get(cached_cat.cat_id):
                continue
            # Update any existing category in-place, or add if not present
            self.model.upsert(cached_cat)
            # Any items in this category in our cache file are usable and should be added
            loaded_cat_ids.add(cached_cat.cat_id)

        for cached_item in cached_items:
            # The skeleton doesn't have any items, so if we run into any items they should be exactly the
            # same as what we're trying to add. No point clobbering.
            if cached_item.item_id in self.model:
                continue
            # The parent category didn't have a cache hit against the inventory skeleton, can't add!
            # We don't even know if this item would be in the current version of its parent cat!
            if cached_item.parent_id not in loaded_cat_ids:
                continue
            self.model.add(cached_item)

        self.model.flag_if_dirty()

    def _parse_cache(self, path: Union[str, Path]) -> Tuple[List[InventoryCategory], List[InventoryItem]]:
        """Warning, may be incredibly slow due to llsd.parse_notation() behavior"""
        categories: List[InventoryCategory] = []
        items: List[InventoryItem] = []
        # Parse our cached items and categories out of the compressed inventory cache
        first_line = True
        with gzip.open(path, "rb") as f:
            # Line-delimited LLSD notation!
            for line in f.readlines():
                # TODO: Parsing of invcache is dominated by `parse_notation()`. It's stupidly inefficient.
                node_llsd = llsd.parse_notation(line)
                if first_line:
                    # First line is the file header
                    first_line = False
                    if node_llsd['inv_cache_version'] not in (2, 3):
                        raise ValueError(f"Unknown cache version: {node_llsd!r}")
                    continue

                if InventoryCategory.ID_ATTR in node_llsd:
                    if (cat_node := InventoryCategory.from_llsd(node_llsd)) is not None:
                        categories.append(cat_node)
                elif InventoryItem.ID_ATTR in node_llsd:
                    if (item_node := InventoryItem.from_llsd(node_llsd)) is not None:
                        items.append(item_node)
                else:
                    LOG.warning(f"Unknown node type in inv cache: {node_llsd!r}")
        return categories, items

    def _handle_bulk_update_inventory(self, msg: Message):
        any_cats = False
        for folder_block in msg["FolderData"]:
            if folder_block["FolderID"] == UUID.ZERO:
                continue
            any_cats = True
            self.model.upsert(
                InventoryCategory.from_folder_data(folder_block),
                # Don't clobber version, we only want to fetch the folder if it's new
                # and hasn't just moved.
                update_fields={"parent_id", "name", "pref_type"},
            )
        for item_block in msg["ItemData"]:
            if item_block["ItemID"] == UUID.ZERO:
                continue
            self.model.upsert(InventoryItem.from_inventory_data(item_block))

        if any_cats:
            self.model.flag_if_dirty()

    def _validate_recipient(self, recipient: UUID):
        if self._session.agent_id != recipient:
            raise ValueError(f"AgentID Mismatch {self._session.agent_id} != {recipient}")

    def _handle_update_create_inventory_item(self, msg: Message):
        self._validate_recipient(msg["AgentData"]["AgentID"])
        for inventory_block in msg["InventoryData"]:
            self.model.upsert(InventoryItem.from_inventory_data(inventory_block))

    def _handle_remove_inventory_item(self, msg: Message):
        self._validate_recipient(msg["AgentData"]["AgentID"])
        for inventory_block in msg["InventoryData"]:
            node = self.model.get(inventory_block["ItemID"])
            if node:
                self.model.unlink(node)

    def _handle_remove_inventory_folder(self, msg: Message):
        self._validate_recipient(msg["AgentData"]["AgentID"])
        for folder_block in msg["FolderData"]:
            node = self.model.get(folder_block["FolderID"])
            if node:
                self.model.unlink(node)

    def _handle_move_inventory_item(self, msg: Message):
        for inventory_block in msg["InventoryData"]:
            node = self.model.get(inventory_block["ItemID"])
            if not node:
                LOG.warning(f"Missing inventory item {inventory_block['ItemID']}")
                continue
            if inventory_block["NewName"]:
                node.name = str(inventory_block["NewName"])
            node.parent_id = inventory_block['FolderID']

    def _handle_move_inventory_folder(self, msg: Message):
        for inventory_block in msg["InventoryData"]:
            node = self.model.get(inventory_block["FolderID"])
            if not node:
                LOG.warning(f"Missing inventory folder {inventory_block['FolderID']}")
                continue
            node.parent_id = inventory_block['ParentID']

    def process_aisv3_response(self, payload: dict):
        if "name" in payload:
            # Just a rough guess. Assume this response is updating something if there's
            # a "name" key.
            if InventoryCategory.ID_ATTR_AIS in payload:
                if (cat_node := InventoryCategory.from_llsd(payload, flavor="ais")) is not None:
                    self.model.upsert(cat_node)
            elif InventoryItem.ID_ATTR in payload:
                if (item_node := InventoryItem.from_llsd(payload, flavor="ais")) is not None:
                    self.model.upsert(item_node)
            else:
                LOG.warning(f"Unknown node type in AIS payload: {payload!r}")

        # Parse the embedded stuff
        embedded_dict = payload.get("_embedded", {})
        for category_llsd in embedded_dict.get("categories", {}).values():
            self.model.upsert(InventoryCategory.from_llsd(category_llsd, flavor="ais"))
        for item_llsd in embedded_dict.get("items", {}).values():
            self.model.upsert(InventoryItem.from_llsd(item_llsd, flavor="ais"))
        for link_llsd in embedded_dict.get("links", {}).values():
            self.model.upsert(InventoryItem.from_llsd(link_llsd, flavor="ais"))

        for cat_id, version in payload.get("_updated_category_versions", {}).items():
            # The key will be a string, so convert to UUID first
            cat_node = self.model.get_category(UUID(cat_id))
            cat_node.version = version

        # Get rid of anything we were asked to
        for node_id in itertools.chain(
                payload.get("_broken_links_removed", ()),
                payload.get("_removed_items", ()),
                payload.get("_category_items_removed", ()),
                payload.get("_categories_removed", ()),
        ):
            node = self.model.get(node_id)
            if node:
                # Presumably this list is exhaustive, so don't unlink children.
                self.model.unlink(node, single_only=True)

    async def make_ais_request(
            self,
            method: str,
            path: str,
            params: dict,
            payload: dict | Sequence | dataclasses.MISSING = dataclasses.MISSING,
    ) -> dict:
        caps_client = self._session.main_region.caps_client
        async with caps_client.request(method, "InventoryAPIv3", path=path, params=params, llsd=payload) as resp:
            if resp.ok or resp.status == 400:
                data = await resp.read_llsd()
                if err_desc := data.get("error_description", ""):
                    err_desc: str
                    if err_desc.startswith("Cannot change parent_id."):
                        raise CannotMoveError()
                resp.raise_for_status()
                self.process_aisv3_response(data)
            else:
                resp.raise_for_status()

            return data

    async def create_folder(
            self,
            parent: InventoryCategory | UUID,
            name: str,
            pref_type: int = AssetType.NONE,
            cat_id: UUID | None = None
    ) -> InventoryCategory:
        parent_id = _get_node_id(parent)

        payload = {
            "categories": [
                {
                    "category_id": cat_id,
                    "name": name,
                    "type_default": pref_type,
                    "parent_id": parent_id
                }
            ]
        }
        data = await self.make_ais_request("POST", f"/category/{parent_id}", {"tid": UUID.random()}, payload)
        return self.model.get_category(data["_created_categories"][0])

    async def create_item(
            self,
            parent: UUID | InventoryCategory,
            name: str,
            type: AssetType,
            inv_type: InventoryType,
            wearable_type: WearableType,
            transaction_id: UUID,
            next_mask: int | Permissions = 0x0008e000,
            description: str = '',
    ) -> InventoryItem:
        parent_id = _get_node_id(parent)

        with self._session.main_region.message_handler.subscribe_async(
                ("UpdateCreateInventoryItem",),
                predicate=lambda x: x["AgentData"]["TransactionID"] == transaction_id,
                take=False,
        ) as get_msg:
            await self._session.main_region.circuit.send_reliable(
                Message(
                    'CreateInventoryItem',
                    Block('AgentData', AgentID=self._session.agent_id, SessionID=self._session.id),
                    Block(
                        'InventoryBlock',
                        CallbackID=0,
                        FolderID=parent_id,
                        TransactionID=transaction_id,
                        NextOwnerMask=next_mask,
                        Type=type,
                        InvType=inv_type,
                        WearableType=wearable_type,
                        Name=name,
                        Description=description,
                    )
                )
            )
            msg = await asyncio.wait_for(get_msg(), 5.0)
            # We assume that _handle_update_create_inventory_item() has already been called internally
            # by the time that the `await` returns given asyncio scheduling
            return self.model.get_item(msg["InventoryData"]["ItemID"])

    async def move(self, node: InventoryNodeBase, new_parent: UUID | InventoryCategory) -> None:
        # AIS error messages suggest using the MOVE HTTP method instead of setting a new parent
        # via PATCH. MOVE is not implemented in AIS. Instead, we do what the viewer does and use
        # legacy UDP messages for reparenting things
        new_parent = _get_node_id(new_parent)

        msg = Message(
            "MoveInventoryFolder",
            Block("AgentData", AgentID=self._session.agent_id, SessionID=self._session.id, Stamp=0),
        )

        if isinstance(node, InventoryItem):
            msg.add_block(Block("InventoryData", ItemID=node.node_id, FolderID=new_parent, NewName=b''))
        else:
            msg.add_block(Block("InventoryData", FolderID=node.node_id, ParentID=new_parent))

        # No message to say if this even succeeded. Great.
        # TODO: probably need to update category versions for both source and target
        await self._session.main_region.circuit.send_reliable(msg)
        node.parent_id = new_parent

    async def copy(self, node: InventoryNodeBase, destination: UUID | InventoryCategory, contents: bool = True)\
            -> InventoryItem | InventoryCategory:
        destination = _get_node_id(destination)
        if isinstance(node, InventoryItem):
            with self._session.main_region.message_handler.subscribe_async(
                    ("BulkUpdateInventory",),
                    # Not ideal, but there doesn't seem to be an easy way to determine the transaction ID,
                    # and using the callback ID seems a bit crap.
                    predicate=lambda x: x["ItemData"]["Name"] == node.name,
                    take=False,
            ) as get_msg:
                await self._session.main_region.circuit.send_reliable(Message(
                    'CopyInventoryItem',
                    Block('AgentData', AgentID=self._session.agent_id, SessionID=self._session.id),
                    Block(
                        'InventoryData',
                        CallbackID=0,
                        OldAgentID=self._session.agent_id,
                        OldItemID=node.item_id,
                        NewFolderID=destination,
                        NewName=b''
                    )
                ))
                msg = await asyncio.wait_for(get_msg(), 5.0)
                return self.model.get(msg["ItemData"]["ItemID"])  # type: ignore
        elif isinstance(node, InventoryCategory):
            # Keep a list of the original descendents in case we're copy a folder within itself
            to_copy = list(node.descendents)
            # There's not really any way to "copy" a category, we just create a new one with the same properties.
            new_cat = await self.create_folder(destination, node.name, node.pref_type)
            if contents:
                cat_lookup: Dict[UUID, UUID] = {node.node_id: new_cat.node_id}
                # Recreate the category hierarchy first, keeping note of the new category IDs.
                for node in to_copy:
                    if isinstance(node, InventoryCategory):
                        new_parent = cat_lookup[node.parent_id]
                        cat_lookup[node.node_id] = (await self.copy(node, new_parent, contents=False)).node_id
                # Items have to be explicitly copied individually
                for node in to_copy:
                    if isinstance(node, InventoryItem):
                        new_parent = cat_lookup[node.parent_id]
                        await self.copy(node, new_parent, contents=False)
            return new_cat
        else:
            assert False

    async def update(self, node: InventoryNodeBase, data: dict) -> None:
        path = f"/category/{node.node_id}"
        if isinstance(node, InventoryItem):
            path = f"/item/{node.node_id}"
        await self.make_ais_request("PATCH", path, {}, data)
