from __future__ import annotations

import asyncio
from collections.abc import AsyncIterator
from pathlib import Path

from lambda_agent_api.server import MsgEventSendFile, MsgEventTextChunk

from sdk.agent_api_wrapper import AgentApiWrapper
from sdk.interface import (
    Attachment,
    MessageChunk,
    MessageResponse,
    PlatformClient,
    PlatformError,
    User,
    UserSettings,
)
from sdk.prototype_state import PrototypeStateStore


class RealPlatformClient(PlatformClient):
    def __init__(
        self,
        agent_api: AgentApiWrapper,
        prototype_state: PrototypeStateStore,
        platform: str = "matrix",
    ) -> None:
        self._agent_api = agent_api
        self._prototype_state = prototype_state
        self._platform = platform
        self._chat_apis: dict[str, AgentApiWrapper] = {}
        self._chat_api_lock = asyncio.Lock()
        self._chat_send_locks: dict[str, asyncio.Lock] = {}

    @property
    def agent_api(self) -> AgentApiWrapper:
        return self._agent_api

    async def _get_chat_api(self, chat_id: str):
        chat_key = str(chat_id)
        chat_api = self._chat_apis.get(chat_key)
        if chat_api is None:
            async with self._chat_api_lock:
                chat_api = self._chat_apis.get(chat_key)
                if chat_api is None:
                    chat_api = self._agent_api.for_chat(chat_key)
                    await chat_api.connect()
                    self._chat_apis[chat_key] = chat_api
        return chat_api

    def _get_chat_send_lock(self, chat_id: str) -> asyncio.Lock:
        chat_key = str(chat_id)
        lock = self._chat_send_locks.get(chat_key)
        if lock is None:
            lock = asyncio.Lock()
            self._chat_send_locks[chat_key] = lock
        return lock

    async def get_or_create_user(
        self,
        external_id: str,
        platform: str,
        display_name: str | None = None,
    ) -> User:
        return await self._prototype_state.get_or_create_user(
            external_id=external_id,
            platform=platform,
            display_name=display_name,
        )

    async def send_message(
        self,
        user_id: str,
        chat_id: str,
        text: str,
        attachments: list[Attachment] | None = None,
    ) -> MessageResponse:
        response_parts: list[str] = []
        sent_attachments: list[Attachment] = []
        message_id = user_id

        lock = self._get_chat_send_lock(chat_id)
        async with lock:
            chat_api = await self._get_chat_api(chat_id)

            try:
                async for event in self._stream_agent_events(
                    chat_api, text, attachments=attachments
                ):
                    message_id = user_id
                    if isinstance(event, MsgEventTextChunk) and event.text:
                        response_parts.append(event.text)
                    elif isinstance(event, MsgEventSendFile):
                        attachment = self._attachment_from_send_file_event(event)
                        if attachment is not None:
                            sent_attachments.append(attachment)
            except Exception as exc:
                await self._handle_chat_api_failure(chat_id, exc)

            await self._prototype_state.set_last_tokens_used(str(chat_id), 0)

        response_kwargs = {
            "message_id": message_id,
            "response": "".join(response_parts),
            "tokens_used": 0,
            "finished": True,
            "attachments": sent_attachments,
        }
        return MessageResponse(**response_kwargs)

    async def stream_message(
        self,
        user_id: str,
        chat_id: str,
        text: str,
        attachments: list[Attachment] | None = None,
    ) -> AsyncIterator[MessageChunk]:
        lock = self._get_chat_send_lock(chat_id)
        async with lock:
            chat_api = await self._get_chat_api(chat_id)
            try:
                async for event in self._stream_agent_events(
                    chat_api, text, attachments=attachments
                ):
                    if isinstance(event, MsgEventTextChunk):
                        yield MessageChunk(
                            message_id=user_id,
                            delta=event.text,
                            finished=False,
                        )
                    elif isinstance(event, MsgEventSendFile):
                        continue
            except Exception as exc:
                await self._handle_chat_api_failure(chat_id, exc)
            await self._prototype_state.set_last_tokens_used(str(chat_id), 0)
            yield MessageChunk(
                message_id=user_id,
                delta="",
                finished=True,
                tokens_used=0,
            )

    async def get_settings(self, user_id: str) -> UserSettings:
        return await self._prototype_state.get_settings(user_id)

    async def update_settings(self, user_id: str, action) -> None:
        await self._prototype_state.update_settings(user_id, action)

    async def disconnect_chat(self, chat_id: str) -> None:
        chat_key = str(chat_id)
        chat_api = self._chat_apis.pop(chat_key, None)
        self._chat_send_locks.pop(chat_key, None)
        if chat_api is not None:
            close = getattr(chat_api, "close", None)
            if callable(close):
                await close()

    async def close(self) -> None:
        for chat_api in list(self._chat_apis.values()):
            close = getattr(chat_api, "close", None)
            if callable(close):
                await close()
        self._chat_apis.clear()
        self._chat_send_locks.clear()

    async def _stream_agent_events(
        self,
        chat_api,
        text: str,
        attachments: list[Attachment] | None = None,
    ) -> AsyncIterator[object]:
        attachment_paths = self._attachment_paths(attachments)
        event_stream = chat_api.send_message(text, attachments=attachment_paths or None)
        async for event in event_stream:
            yield event

    async def _handle_chat_api_failure(self, chat_id: str, exc: Exception) -> None:
        await self.disconnect_chat(chat_id)
        code = getattr(exc, "code", None) or "PLATFORM_CONNECTION_ERROR"
        raise PlatformError(str(exc), code=code) from exc

    @staticmethod
    def _attachment_paths(attachments: list[Attachment] | None) -> list[str]:
        if not attachments:
            return []
        paths = []
        for attachment in attachments:
            if attachment.workspace_path:
                paths.append(attachment.workspace_path)
        return paths

    @staticmethod
    def _attachment_from_send_file_event(event: MsgEventSendFile) -> Attachment:
        location = str(event.path)
        filename = Path(location).name or None
        workspace_path = location
        if workspace_path.startswith("/workspace/"):
            workspace_path = workspace_path[len("/workspace/") :]
        elif workspace_path == "/workspace":
            workspace_path = ""
        return Attachment(
            url=location,
            mime_type="application/octet-stream",
            size=None,
            filename=filename,
            workspace_path=workspace_path or None,
        )