from __future__ import annotations

import asyncio
import logging

from yuxi.channel.extensions.feishu.card_kit import (
    CardKitState,
    open_card_stream,
    push_card_update,
    close_card_stream,
    send_card_fallback,
    should_send_update,
    merge_content,
    STREAMING_THROTTLE_MS,
    SIGNIFICANT_DELTA_CHARS,
)

from yuxi.channel.extensions.feishu.client import get_client

logger = logging.getLogger(__name__)


class FeishuStreamingAdapter:
    def __init__(
        self,
        throttle_ms: int = STREAMING_THROTTLE_MS,
        significant_delta_chars: int = SIGNIFICANT_DELTA_CHARS,
    ):
        self._throttle_ms = throttle_ms
        self._significant_delta_chars = significant_delta_chars

    async def start_stream(
        self,
        app_id: str,
        app_secret: str,
        domain: str,
        target_id: str,
        reply_to_id: str | None = None,
        thread_id: str | None = None,
        http_timeout_ms: int = 30000,
    ) -> CardKitState | None:
        try:
            client = get_client(app_id, app_secret, domain, http_timeout_ms)
        except Exception:
            logger.exception("Failed to create client for streaming")
            return None

        return await open_card_stream(
            client,
            target_id,
            reply_to_id=reply_to_id,
            thread_id=thread_id,
            app_id=app_id,
        )

    async def stream_update(
        self,
        state: CardKitState,
        app_id: str,
        app_secret: str,
        domain: str,
        content: str,
        previous_content: str = "",
        http_timeout_ms: int = 30000,
    ) -> str:
        merged = merge_content(previous_content, content)
        if merged == previous_content:
            return previous_content

        if not should_send_update(merged, previous_content):
            return previous_content

        try:
            client = get_client(app_id, app_secret, domain, http_timeout_ms)
            await push_card_update(client, state, merged, throttle_ms=self._throttle_ms)
            return merged
        except Exception:
            logger.exception("Card Kit push_card_update failed")
            return previous_content

    async def stop_stream(
        self,
        state: CardKitState,
        app_id: str,
        app_secret: str,
        domain: str,
        http_timeout_ms: int = 30000,
    ) -> None:
        try:
            client = get_client(app_id, app_secret, domain, http_timeout_ms)
            await close_card_stream(client, state)
        except Exception:
            logger.exception("Card Kit close_card_stream failed")

    async def send_fallback(
        self,
        state: CardKitState,
        content: str,
        app_id: str,
        app_secret: str,
        domain: str,
        http_timeout_ms: int = 30000,
    ) -> dict:
        try:
            client = get_client(app_id, app_secret, domain, http_timeout_ms)
            return await send_card_fallback(client, state, content)
        except Exception:
            logger.exception("Card Kit fallback failed")
            return {"success": False, "error": "Internal error"}


class FeishuStreamingRunner:
    def __init__(
        self,
        state: CardKitState,
        app_id: str,
        app_secret: str,
        domain: str,
        http_timeout_ms: int = 30000,
    ):
        self._state = state
        self._app_id = app_id
        self._app_secret = app_secret
        self._domain = domain
        self._http_timeout_ms = http_timeout_ms
        self._adapter = FeishuStreamingAdapter()
        self._content = ""
        self._last_pushed = ""
        self._running = False
        self._pending: str | None = None
        self._update_event = asyncio.Event()

    @property
    def state(self) -> CardKitState:
        return self._state

    async def feed_delta(self, text: str) -> None:
        self._pending = text
        self._update_event.set()

    async def feed_end(self) -> None:
        self._running = False
        self._update_event.set()

    async def freeze_and_reset(self) -> None:
        if self._state.card_id:
            await self._adapter.stop_stream(
                self._state, self._app_id, self._app_secret, self._domain, self._http_timeout_ms
            )
        self._state.card_id = ""
        self._state.message_id = ""
        self._state.version = 0
        self._content = ""
        self._last_pushed = ""

    async def run(self) -> str:
        self._running = True

        try:
            while self._running:
                await self._update_event.wait()
                self._update_event.clear()

                if not self._state.card_id and (self._pending is not None or self._content):
                    new_state = await self._adapter.start_stream(
                        self._app_id, self._app_secret, self._domain,
                        self._state.target_id,
                        reply_to_id=self._state.reply_to_id,
                        thread_id=self._state.thread_id,
                        http_timeout_ms=self._http_timeout_ms,
                    )
                    if new_state is None:
                        continue
                    self._state.card_id = new_state.card_id
                    self._state.message_id = new_state.message_id
                    self._state.version = 0

                if self._pending is not None:
                    self._content += self._pending
                    self._pending = None
                    for _ in range(3):
                        await asyncio.sleep(0)
                        if self._pending is not None:
                            self._content += self._pending
                            self._pending = None
                        else:
                            break

                if self._content != self._last_pushed:
                    self._last_pushed = await self._adapter.stream_update(
                        self._state,
                        self._app_id,
                        self._app_secret,
                        self._domain,
                        self._content,
                        self._last_pushed,
                        self._http_timeout_ms,
                    )

        finally:
            if self._state.card_id:
                await self._adapter.stop_stream(
                    self._state,
                    self._app_id,
                    self._app_secret,
                    self._domain,
                    self._http_timeout_ms,
                )

        return self._content


async def stream_reply(
    app_id: str,
    app_secret: str,
    domain: str,
    target_id: str,
    reply_to_id: str | None,
    content_iterator,
    http_timeout_ms: int = 30000,
) -> dict:
    adapter = FeishuStreamingAdapter()

    state = await adapter.start_stream(
        app_id, app_secret, domain, target_id,
        reply_to_id=reply_to_id,
        http_timeout_ms=http_timeout_ms,
    )

    if state is None:
        try:
            client = get_client(app_id, app_secret, domain, http_timeout_ms)
            return await send_card_fallback(
                client,
                CardKitState(target_id=target_id, reply_to_id=reply_to_id),
                content_accumulator(content_iterator),
            )
        except Exception:
            return {"success": False, "error": "Streaming and fallback both failed"}

    runner = FeishuStreamingRunner(state, app_id, app_secret, domain, http_timeout_ms)
    task = asyncio.create_task(runner.run())

    try:
        async for chunk in content_iterator:
            await runner.feed_delta(chunk)

        await runner.feed_end()
        final_content = await task
    except Exception:
        await runner.feed_end()
        await task
        raise

    return {"success": True, "msg_id": state.message_id, "content": final_content}


async def content_accumulator(content_iterator) -> str:
    parts = []
    async for chunk in content_iterator:
        parts.append(chunk)
    return "".join(parts)