from __future__ import annotations

import hashlib
import hmac
import os
from typing import Any

from yuxi.channels.models import ChannelIdentity, ChannelMessage, ChannelType, EventType, MessageType
from yuxi.utils.logging_config import logger


def verify_slash_hmac(body: bytes, signature: str, secret: str) -> bool:
    if not secret or not signature:
        return False
    expected = hmac.new(secret.encode(), body, hashlib.sha256).hexdigest()
    return hmac.compare_digest(expected, signature)


async def handle_slash_command(
    body: bytes,
    headers: dict,
    adapter: Any,
) -> dict:
    signing_secret = os.getenv("MATTERMOST_SIGNING_SECRET", "")
    signature = headers.get("X-Mattermost-Signature", "") or headers.get("x-mattermost-signature", "")

    if not verify_slash_hmac(body, signature, signing_secret):
        return {"response_type": "ephemeral", "text": "签名验证失败"}

    import json

    try:
        data = json.loads(body)
    except json.JSONDecodeError:
        return {"response_type": "ephemeral", "text": "无效的请求数据"}

    command = data.get("command", "").strip()
    text = data.get("text", "").strip()
    user_id = data.get("user_id", "")
    channel_id = data.get("channel_id", "")
    team_id = data.get("team_id", "")

    logger.info(f"[Mattermost] Slash command received: {command} '{text}' from {user_id} in channel {channel_id}")

    if command in ("/forcepilot", "/fp"):
        msg = ChannelMessage(
            identity=ChannelIdentity(
                channel_id="mattermost",
                channel_type=ChannelType.MATTERMOST,
                channel_user_id=user_id,
                channel_chat_id=f"channel_{channel_id}",
            ),
            event_type=EventType.MESSAGE_RECEIVED,
            message_type=MessageType.COMMAND,
            content=text or "你好",
            metadata={"slash_command": command, "team_id": team_id},
        )
        await adapter._handle_message(msg)
        return {
            "response_type": "in_channel",
            "text": f"已收到命令 `{command}`，正在处理…",
        }

    if command == "/help":
        return {
            "response_type": "ephemeral",
            "text": (
                "**ForcePilot Mattermost 命令**\n\n"
                "| 命令 | 说明 |\n"
                "|------|------|\n"
                "| `/forcepilot <msg>` | 与 AI 助手对话 |\n"
                "| `/fp <msg>` | 快捷对话 |\n"
                "| `/model` | 切换 AI 模型 |\n"
                "| `/clear` | 清除对话上下文 |\n"
                "| `/help` | 显示帮助信息 |"
            ),
        }

    if command == "/clear":
        return {
            "response_type": "ephemeral",
            "text": "对话上下文已清除 ✅",
        }

    if command == "/model":
        from .model_picker import build_model_picker_attachment

        attachments = [build_model_picker_attachment()]
        return {
            "response_type": "in_channel",
            "text": "选择一个 AI 模型：",
            "attachments": attachments,
        }

    return {"response_type": "ephemeral", "text": f"未知命令: {command}"}