"""会话通信工具集 — Agent 间会话通信能力"""

import os

from langgraph.prebuilt.tool_node import ToolRuntime
from pydantic import BaseModel, Field

from yuxi.agents.toolkits.registry import tool
from yuxi.utils import logger

_LITE_MODE = os.environ.get("LITE_MODE", "").lower() in ("true", "1")

# ── 常量 ──────────────────────────────────────────────────

_HISTORY_CONTENT_MAX_CHARS = 4000
_HISTORY_BYTES_MAX = 80 * 1024


# ── 辅助函数 ──────────────────────────────────────────────


def _get_runtime_uid(runtime: ToolRuntime) -> str:
    """从 ToolRuntime.context 获取当前用户 uid。"""
    uid = getattr(runtime.context, "uid", None)
    if not uid:
        raise ValueError("当前运行时缺少 uid")
    return str(uid)


def _get_runtime_thread_id(runtime: ToolRuntime) -> str:
    """从 ToolRuntime.context 获取当前线程 ID。

    注意：子智能体的 file_thread_id 继承自父会话，不能用于标识当前会话。
    会话通信场景应使用 thread_id（当前智能体自身的线程）。
    """
    thread_id = getattr(runtime.context, "thread_id", None)
    if not thread_id:
        raise ValueError("当前运行时缺少 thread_id")
    return str(thread_id)


# ── 权限校验 ──────────────────────────────────────────────


async def _check_session_access(uid: str, thread_id: str) -> None:
    """
    检查用户是否有权访问指定会话（tree 级可见性）。
    1. 会话的 uid 与当前用户一致 → 允许
    2. 沿 parent_thread_id 链上溯，任一祖先属于当前用户 → 允许
    3. 否则 → 拒绝
    """
    from yuxi.repositories.conversation_repository import ConversationRepository
    from yuxi.storage.postgres.manager import pg_manager

    async with pg_manager.get_async_session_context() as db:
        repo = ConversationRepository(db)
        visited: set[str] = set()
        current_tid = thread_id

        while current_tid and current_tid not in visited:
            visited.add(current_tid)
            conv = await repo.get_conversation_by_thread_id(current_tid)
            if not conv:
                raise ValueError(f"会话不存在: {thread_id}")
            if conv.uid == uid:
                return
            parent_tid = conv.parent_thread_id
            if not parent_tid:
                break
            current_tid = parent_tid

    raise PermissionError(f"无权访问会话: {thread_id}")


# ── LITE 模式下不注册会话通信工具 ─────────────────────────

if _LITE_MODE:
    logger.info("LITE_MODE enabled, session communication tools not registered")
else:

    # ── list_sessions ─────────────────────────────────────────

    class ListSessionsInput(BaseModel):
        status: str | None = Field(default=None, description="按状态过滤: active / archived")
        agent_id: str | None = Field(default=None, description="按智能体 ID 过滤")
        limit: int = Field(default=20, ge=1, le=50, description="返回数量上限")

    @tool(
        category="buildin",
        tags=["会话"],
        display_name="列出会话",
        args_schema=ListSessionsInput,
    )
    async def list_sessions(
        status: str | None = None,
        agent_id: str | None = None,
        limit: int = 20,
        runtime: ToolRuntime = None,
    ) -> str:
        """
        列出当前用户可见的对话会话，包括自己创建的和子智能体的会话。
        返回每个会话的 thread_id、agent_id、状态、标题、最近更新时间。
        """
        from yuxi.repositories.conversation_repository import ConversationRepository
        from yuxi.storage.postgres.manager import pg_manager

        uid = _get_runtime_uid(runtime)

        async with pg_manager.get_async_session_context() as db:
            repo = ConversationRepository(db)
            conversations = await repo.list_conversations(
                uid=uid,
                agent_id=agent_id,
                status=status or "active",
                limit=limit,
            )

        if not conversations:
            return "当前无可见的会话"

        lines = []
        for conv in conversations:
            parent_marker = " [子智能体]" if conv.parent_thread_id else ""
            lines.append(
                f"- thread_id: {conv.thread_id} | agent: {conv.agent_id} | "
                f"状态: {conv.status} | 标题: {conv.title or '无'}{parent_marker} | "
                f"更新: {conv.updated_at}"
            )
        return "\n".join(lines)

    # ── get_session_history ───────────────────────────────────

    class GetSessionHistoryInput(BaseModel):
        thread_id: str = Field(description="目标会话线程 ID")
        limit: int = Field(default=10, ge=1, le=50, description="返回消息数量")
        include_tools: bool = Field(default=False, description="是否包含工具调用消息")

    @tool(
        category="buildin",
        tags=["会话"],
        display_name="查看会话历史",
        args_schema=GetSessionHistoryInput,
    )
    async def get_session_history(
        thread_id: str,
        limit: int = 10,
        include_tools: bool = False,
        runtime: ToolRuntime = None,
    ) -> str:
        """
        获取指定会话的最近消息。
        仅可查看自己或子智能体的会话历史。
        超长内容会被截断，工具调用消息默认不包含。
        """
        from yuxi.repositories.conversation_repository import ConversationRepository
        from yuxi.storage.postgres.manager import pg_manager

        uid = _get_runtime_uid(runtime)
        await _check_session_access(uid, thread_id)

        async with pg_manager.get_async_session_context() as db:
            repo = ConversationRepository(db)
            # get_messages_by_thread_id 按 created_at.asc() 排序 + limit 返回最旧消息，
            # 但我们需要最近消息，所以先降序查再反转。
            conversation = await repo.get_conversation_by_thread_id(thread_id)
            if not conversation:
                return f"会话 {thread_id} 暂无消息"
            from sqlalchemy import select

            from yuxi.storage.postgres.models_business import Message

            result = await db.execute(
                select(Message)
                .where(Message.conversation_id == conversation.id)
                .order_by(Message.created_at.desc())
                .limit(limit)
            )
            messages = list(reversed(result.scalars().unique().all()))

        if not messages:
            return f"会话 {thread_id} 暂无消息"

        total_bytes = 0
        lines = []
        truncated = False

        for msg in messages:
            # 过滤工具消息
            if not include_tools and msg.message_type in ("tool_call", "tool_result"):
                continue

            content = msg.content or ""
            # 截断超长内容
            if len(content) > _HISTORY_CONTENT_MAX_CHARS:
                content = content[:_HISTORY_CONTENT_MAX_CHARS] + "...[已截断]"
                truncated = True

            line = f"[{msg.role}] {content}"
            line_bytes = len(line.encode("utf-8"))
            if total_bytes + line_bytes > _HISTORY_BYTES_MAX:
                truncated = True
                break
            total_bytes += line_bytes
            lines.append(line)

        suffix = "\n(部分内容已截断)" if truncated else ""
        return "\n".join(lines) + suffix

    # ── send_to_session ───────────────────────────────────────

    class SendToSessionInput(BaseModel):
        thread_id: str = Field(description="目标会话线程 ID")
        message: str = Field(description="要发送的消息内容")

    @tool(
        category="buildin",
        tags=["会话"],
        display_name="发送会话消息",
        args_schema=SendToSessionInput,
    )
    async def send_to_session(
        thread_id: str,
        message: str,
        runtime: ToolRuntime = None,
    ) -> str:
        """
        向指定会话发送消息。
        消息会以 user 角色注入目标会话的历史记录。
        如果目标会话正在运行，消息将作为下一轮输入；否则仅写入历史。
        不能向自己所在的会话发送消息（避免循环）。
        """
        from yuxi.repositories.conversation_repository import ConversationRepository
        from yuxi.storage.postgres.manager import pg_manager

        uid = _get_runtime_uid(runtime)
        current_thread_id = _get_runtime_thread_id(runtime)

        # 防止向自身会话发送消息
        if thread_id == current_thread_id:
            return "不能向当前所在的会话发送消息"

        await _check_session_access(uid, thread_id)

        # 标注消息来源
        annotated_message = f"[来自会话 {current_thread_id}] {message}"

        async with pg_manager.get_async_session_context() as db:
            repo = ConversationRepository(db)
            await repo.add_message_by_thread_id(
                thread_id=thread_id,
                role="user",
                content=annotated_message,
                message_type="text",
                extra_metadata={
                    "source_thread_id": current_thread_id,
                    "source_type": "inter_session",
                },
            )

        return f"消息已发送到会话 {thread_id}"

    # ── get_agent_progress ────────────────────────────────────

    class GetAgentProgressInput(BaseModel):
        thread_id: str = Field(description="会话线程 ID")

    @tool(
        category="buildin",
        tags=["会话"],
        display_name="查看智能体进度",
        args_schema=GetAgentProgressInput,
    )
    async def get_agent_progress(
        thread_id: str,
        runtime: ToolRuntime = None,
    ) -> str:
        """
        查看指定智能体的运行进度。
        返回运行状态、开始时间、运行类型等信息。
        """
        from sqlalchemy import select

        from yuxi.storage.postgres.manager import pg_manager
        from yuxi.storage.postgres.models_business import AgentRun

        uid = _get_runtime_uid(runtime)
        await _check_session_access(uid, thread_id)

        async with pg_manager.get_async_session_context() as db:
            result = await db.execute(
                select(AgentRun)
                .where(
                    AgentRun.thread_id == thread_id,
                    AgentRun.uid == uid,
                )
                .order_by(AgentRun.created_at.desc())
                .limit(1)
            )
            run = result.scalar_one_or_none()

        if not run:
            return f"会话 {thread_id} 暂无运行记录"

        lines = [
            f"运行 ID: {run.id}",
            f"状态: {run.status}",
            f"类型: {run.run_type}",
            f"智能体: {run.agent_id}",
            f"创建时间: {run.created_at}",
        ]
        if run.started_at:
            lines.append(f"开始时间: {run.started_at}")
        if run.finished_at:
            lines.append(f"完成时间: {run.finished_at}")
        if run.error_message:
            lines.append(f"错误: {run.error_message}")

        return "\n".join(lines)