"""Single-agent runners for home and floating chat contexts."""

from __future__ import annotations

import json
import logging
import re
from datetime import date
from collections.abc import AsyncGenerator
from typing import Any, Literal

from langchain_core.messages import AIMessage, HumanMessage, SystemMessage, ToolMessage
from langchain_core.tools import tool

from app.agents.note_agent import NOTE_TOOLS
from app.agents.project_agent import PROJECT_TOOLS
from app.agents.task_agent import TASK_TOOLS
from app.agents.timeline_agent import TIMELINE_TOOLS
from app.core.langfuse_client import extract_usage, get_langfuse, get_prompt_or_fallback, langfuse_context
from app.core.llm import get_agent_llm, model_for_agent
from app.core.memory_middleware import MemoryMiddleware
from app.core.ws_context import clear_tool_result_collector, execute_on_client, set_tool_result_collector
from app.db import async_session

logger = logging.getLogger(__name__)

FloatingDomainType = Literal["task", "timeline", "project", "node"]
FloatingDomainSection = Literal["task", "timeline", "note"]

# Mapping of core-memory language values to natural-language names for prompts.
_LANGUAGE_NAMES: dict[str, str] = {
    "en": "English", "it": "Italian", "es": "Spanish",
    "fr": "French", "de": "German",
    "english": "English", "italian": "Italian", "italiano": "Italian",
    "spanish": "Spanish", "español": "Spanish",
    "french": "French", "français": "French",
    "german": "German", "deutsch": "German",
}


def _language_instruction(context: dict[str, Any]) -> str:
    """Return a system-prompt suffix that tells the LLM to respond in the user's language.

    Returns an empty string when the language is English or unknown — saves tokens.
    """
    core = context.get("core_memory") or {}
    raw = (core.get("language") or "").strip().lower()
    if not raw:
        return ""
    lang = _LANGUAGE_NAMES.get(raw, raw.title())  # best-effort capitalisation
    if lang.lower() == "english":
        return ""
    return (
        f"\n\nIMPORTANT: Always respond in {lang}. "
        f"All your output text must be written in {lang}."
    )

def _proactive_hints_injection(context: dict[str, Any]) -> str:
    """Return a system-prompt paragraph listing proactive behavioral hints.

    Returns empty string when no hints or confidence below threshold.
    Capped at 600 chars.
    """
    hints: list[str] = context.get("proactive_hints") or []
    if not hints:
        return ""
    body = "\n".join(f"- {h}" for h in hints)
    section = f"\n\nI noticed (behavioral patterns):\n{body}"
    if len(section) > 600:
        section = section[:597] + "..."
    return section


def _relational_memory_injection(context: dict[str, Any]) -> str:
    """Return a system-prompt paragraph listing known people/projects from relational memory.

    Returns empty string when no relational rows or tier is Free.
    Capped at 800 chars to control token spend.
    """
    relations: list[str] = context.get("relational_memory") or []
    if not relations:
        return ""
    body = "\n".join(f"- {r}" for r in relations)
    section = f"\n\nKnown people & projects:\n{body}"
    if len(section) > 800:
        section = section[:797] + "..."
    return section


_HOME_SYSTEM_PROMPT = (
    "You are the home assistant with direct access to all tools: tasks, projects, notes, timelines, and memory tools. "
    "Always use tools for factual data retrieval before answering. "
    "When the user asks to remember, forget, or update what you know about them, use memory tools. "
    "If context.context.resolved_project_id exists, use it as project_id for scoped list calls. "
    "Return markdown and use tags when relevant: <project>[ids]</project>, <task>[ids]</task>, "
    "<note>[ids]</note>, <timeline>[ids]</timeline>, <chart>{json}</chart>. "
    "When listing tasks or timelines, each id tag must be on its own line with no prefix/suffix text. "
    "Never put titles, priorities, or dates on the same line as <task> or <timeline> tags. "
    "For questions about upcoming timelines (e.g. 'prossimi eventi'), include only future items in the current month unless the user asks a different range. "
    "For upcoming tasks, after tag lines add a short recommendation based on due date and priority."
)

_FLOATING_SYSTEM_PROMPT = (
    "You are the floating assistant with direct access to all tools: tasks, projects, notes, timelines, and memory tools. "
    "Stay focused on the floating scope in context.scope and answer concisely. "
    "Return plain text only. Do not output XML/HTML-like tags such as <task>, <project>, <note>, <timeline>, or any bracketed id tag wrappers. "
    "Always use tools for factual data retrieval before answering. "
    "When the user asks to remember, forget, or update what you know about them, use memory tools. "
    "If context.context.resolved_project_id exists, use it as project_id for scoped list calls. "
)

_FLOATING_DOMAIN_CLASSIFIER_PROMPT = (
    "You are a strict domain classifier for websocket floating requests. "
    "Return ONLY a JSON object with keys: type, id, section. "
    "Allowed type values: task, timeline, project, node. "
    "Allowed section values: task, timeline, note, or null. "
    "Rules: infer from user message intent first; do not blindly trust scope.type. "
    "If user asks tasks/timeline/notes for a project, set type=project and section accordingly. "
    "If project id is unknown but context.resolved_project_id exists, use it as id. "
    "If id is unknown, use null. "
    "No markdown, no prose, JSON only."
)


def _as_text(content: Any) -> str:
    if content is None:
        return ""
    if isinstance(content, str):
        return content
    if isinstance(content, list):
        parts: list[str] = []
        for item in content:
            if isinstance(item, str):
                parts.append(item)
            elif isinstance(item, dict):
                text = item.get("text")
                if isinstance(text, str):
                    parts.append(text)
        return "".join(parts)
    return str(content)


def _candidate_tokens(message: str) -> list[str]:
    tokens = re.findall(r"[a-zA-Z0-9_-]+", message.lower())
    return [token for token in tokens if len(token) >= 3]


async def _resolve_project_id_from_message(message: str) -> str | None:
    """Resolve likely project UUID from user message using client project list."""
    try:
        result = await execute_on_client(action="select", table="projects")
    except Exception as exc:
        logger.warning("deep_agent: project resolve select failed: %s", exc)
        return None

    rows = result.get("rows", [])
    if not isinstance(rows, list) or not rows:
        return None

    tokens = _candidate_tokens(message)
    scored: list[tuple[int, dict[str, Any]]] = []
    for row in rows:
        if not isinstance(row, dict):
            continue
        name = str(row.get("name", "")).lower()
        score = sum(1 for token in tokens if token in name)
        if score > 0:
            scored.append((score, row))

    if not scored:
        return None

    scored.sort(key=lambda item: item[0], reverse=True)
    top_score = scored[0][0]
    top_rows = [row for score, row in scored if score == top_score]
    if len(top_rows) != 1:
        return None

    project_id = top_rows[0].get("id")
    return project_id if isinstance(project_id, str) else None


def _needs_project_resolution(message: str) -> bool:
    lowered = message.lower()
    return any(keyword in lowered for keyword in ["project", "progetto", "progetti", "whitelist"])


async def _prepare_context(message: str, context: dict[str, Any]) -> dict[str, Any]:
    prepared = dict(context)
    if _needs_project_resolution(message):
        resolved_project_id = await _resolve_project_id_from_message(message)
        if resolved_project_id:
            prepared["resolved_project_id"] = resolved_project_id
            logger.info("deep_agent: resolved_project_id=%s", resolved_project_id)
    return prepared


def _all_tools() -> list[Any]:
    return [*TASK_TOOLS, *PROJECT_TOOLS, *NOTE_TOOLS, *TIMELINE_TOOLS]


def _trace_id_from_context(context: dict[str, Any]) -> str | None:
    debug = context.get("_debug")
    if isinstance(debug, dict):
        request_id = debug.get("request_id")
        if isinstance(request_id, str) and request_id:
            return request_id
    return None


def _session_id_from_context(context: dict[str, Any]) -> str | None:
    debug = context.get("_debug")
    if isinstance(debug, dict):
        session_id = debug.get("session_id")
        if isinstance(session_id, str) and session_id:
            return session_id
    return None


def _context_for_model(context: dict[str, Any]) -> dict[str, Any]:
    sanitized = dict(context)
    sanitized.pop("_debug", None)
    return sanitized


_TAG_LINE_RE = re.compile(r"<(task|timeline)>\[[^\]]+\]</\1>")
_TIMELINE_DMY_RE = re.compile(r"(?P<d>\d{2})/(?P<m>\d{2})/(?P<y>\d{4})")


def _is_upcoming_timeline_query(message: str) -> bool:
    lowered = message.lower()
    has_upcoming = "prossim" in lowered or "upcoming" in lowered or "next" in lowered
    has_timeline_topic = any(
        token in lowered
        for token in ("event", "evento", "eventi", "timeline", "milestone", "scaden")
    )
    return has_upcoming and has_timeline_topic


def _timeline_date_in_current_month_or_future(dmy: str) -> bool:
    match = _TIMELINE_DMY_RE.search(dmy)
    if not match:
        return True
    try:
        parsed = date(
            int(match.group("y")),
            int(match.group("m")),
            int(match.group("d")),
        )
    except ValueError:
        return True

    today = date.today()
    return parsed >= today and parsed.year == today.year and parsed.month == today.month


def _normalize_tagged_list_lines(text: str, message: str) -> str:
    if not text:
        return text

    upcoming_timeline_only = _is_upcoming_timeline_query(message)
    output_lines: list[str] = []

    for line in text.splitlines():
        matches = list(_TAG_LINE_RE.finditer(line))
        if not matches:
            output_lines.append(line)
            continue

        had_non_tag_text = _TAG_LINE_RE.sub("", line).strip(" -\t0123456789.*:)")
        if not had_non_tag_text and len(matches) == 1:
            tag_text = matches[0].group(0)
            if (
                upcoming_timeline_only
                and "<timeline>" in tag_text
                and not _timeline_date_in_current_month_or_future(line)
            ):
                continue
            output_lines.append(tag_text)
            continue

        for match in matches:
            tag_text = match.group(0)
            if (
                upcoming_timeline_only
                and "<timeline>" in tag_text
                and not _timeline_date_in_current_month_or_future(line)
            ):
                continue
            output_lines.append(tag_text)

    return "\n".join(output_lines)


_GENERIC_TAG_RE = re.compile(r"</?(task|project|note|timeline|chart)>", re.IGNORECASE)
_BRACKETED_ID_RE = re.compile(r"\[(?:[0-9a-fA-F-]{8,}|[A-Za-z0-9_-]{8,})\]")
_FLOATING_EMPTY_FALLBACK = "No results found."


def _strip_floating_markup_fragment(text: str) -> str:
    if not text:
        return text
    cleaned = _GENERIC_TAG_RE.sub("", text)
    return _BRACKETED_ID_RE.sub("", cleaned)


def _strip_floating_markup(text: str) -> str:
    """Ensure floating responses stay plain text with no XML-like tag wrappers."""
    if not text:
        return text

    cleaned = _strip_floating_markup_fragment(text)
    # Collapse excessive spaces introduced by tag/id removal while preserving lines.
    lines = [re.sub(r"[ \t]{2,}", " ", line).strip() for line in cleaned.splitlines()]
    return "\n".join(line for line in lines if line)


def _fallback_from_raw_floating_text(raw_text: str) -> str:
    fallback = _strip_floating_markup_fragment(raw_text or "")
    fallback = re.sub(r"[ \t]{2,}", " ", fallback).strip()
    return fallback or _FLOATING_EMPTY_FALLBACK


class _FloatingStreamSanitizer:
    """Streaming sanitizer that removes floating markup without buffering the full answer."""

    def __init__(self) -> None:
        self._pending = ""

    @staticmethod
    def _split_safe_boundary(text: str) -> tuple[str, str]:
        boundary = len(text)

        last_lt = text.rfind("<")
        if last_lt != -1 and ">" not in text[last_lt:]:
            boundary = min(boundary, last_lt)

        last_lb = text.rfind("[")
        if last_lb != -1 and "]" not in text[last_lb:]:
            boundary = min(boundary, last_lb)

        if boundary == len(text):
            return text, ""
        return text[:boundary], text[boundary:]

    def feed(self, chunk: str) -> str:
        combined = f"{self._pending}{chunk}"
        safe_text, self._pending = self._split_safe_boundary(combined)
        return _strip_floating_markup_fragment(safe_text)

    def finalize(self) -> str:
        # Drop dangling unfinished wrappers at the very end.
        tail = re.sub(r"<[^>\n]*$", "", self._pending)
        tail = re.sub(r"\[[^\]\n]*$", "", tail)
        self._pending = ""
        return _strip_floating_markup_fragment(tail)


def _normalize_memory_label(path_or_label: str) -> str:
    value = path_or_label.strip()
    if value.startswith("/memories/"):
        value = value[len("/memories/"):]
    value = value.strip("/")
    return value


def _memory_tools(user_id: str, trace_id: str | None) -> list[Any]:
    @tool
    async def memory_list_blocks() -> str:
        """List all core memory blocks currently stored for the user."""
        logger.info("deep_agent: memory_list_blocks trace=%s user=%s", trace_id or "-", user_id)
        async with async_session() as db:
            memory = MemoryMiddleware(db)
            blocks = await memory.list_core_blocks(user_id)
        if not blocks:
            return "No memory blocks found."
        lines = [f"- {b['label']}: {b['value']}" for b in blocks]
        return "Memory blocks:\n" + "\n".join(lines)

    @tool
    async def memory_get(path_or_label: str) -> str:
        """Get one memory block by label or /memories/<label> path."""
        label = _normalize_memory_label(path_or_label)
        logger.info("deep_agent: memory_get trace=%s user=%s label=%s", trace_id or "-", user_id, label)
        if not label:
            return "Invalid memory label."
        async with async_session() as db:
            memory = MemoryMiddleware(db)
            value = await memory.get_core_block(user_id, label)
        if value is None:
            return f"Memory block '{label}' not found."
        return f"Memory block '{label}':\n{value}"

    @tool
    async def memory_create(path_or_label: str, value: str) -> str:
        """Create or overwrite a memory block value by label or /memories/<label> path."""
        label = _normalize_memory_label(path_or_label)
        logger.info("deep_agent: memory_create trace=%s user=%s label=%s", trace_id or "-", user_id, label)
        if not label:
            return "Invalid memory label."
        async with async_session() as db:
            memory = MemoryMiddleware(db)
            await memory.update_core(user_id, label, value, trace_id=trace_id)
        return f"Memory block '{label}' saved."

    @tool
    async def memory_append(path_or_label: str, content: str) -> str:
        """Append content to a memory block, creating it if missing."""
        label = _normalize_memory_label(path_or_label)
        logger.info("deep_agent: memory_append trace=%s user=%s label=%s", trace_id or "-", user_id, label)
        if not label:
            return "Invalid memory label."
        async with async_session() as db:
            memory = MemoryMiddleware(db)
            await memory.append_core(user_id, label, content)
        return f"Memory block '{label}' appended."

    @tool
    async def memory_replace(path_or_label: str, old_string: str, new_string: str) -> str:
        """Replace one exact string in a memory block."""
        label = _normalize_memory_label(path_or_label)
        logger.info("deep_agent: memory_replace trace=%s user=%s label=%s", trace_id or "-", user_id, label)
        if not label:
            return "Invalid memory label."
        async with async_session() as db:
            memory = MemoryMiddleware(db)
            changed = await memory.replace_core(user_id, label, old_string, new_string)
        if not changed:
            return f"No replacement made in '{label}' (old string not found)."
        return f"Memory block '{label}' updated."

    @tool
    async def memory_delete(path_or_label: str) -> str:
        """Delete a memory block by label or /memories/<label> path."""
        label = _normalize_memory_label(path_or_label)
        logger.info("deep_agent: memory_delete trace=%s user=%s label=%s", trace_id or "-", user_id, label)
        if not label:
            return "Invalid memory label."
        async with async_session() as db:
            memory = MemoryMiddleware(db)
            deleted = await memory.delete_core(user_id, label)
        if not deleted:
            return f"Memory block '{label}' not found."
        return f"Memory block '{label}' deleted."

    @tool
    async def archival_memory_insert(content: str) -> str:
        """Insert a long-term archival memory entry."""
        logger.info("deep_agent: archival_memory_insert trace=%s user=%s", trace_id or "-", user_id)
        async with async_session() as db:
            memory = MemoryMiddleware(db)
            await memory.insert_archival(user_id, content, source="assistant")
        return "Archival memory saved."

    @tool
    async def archival_memory_search(query: str, top_k: int = 5) -> str:
        """Search long-term archival memory by semantic fallback (keyword currently)."""
        logger.info("deep_agent: archival_memory_search trace=%s user=%s query=%s", trace_id or "-", user_id, query[:80])
        async with async_session() as db:
            memory = MemoryMiddleware(db)
            results = await memory.search_archival(user_id, query, top_k=top_k)
        if not results:
            return "No archival memory results found."
        lines = [f"- {item}" for item in results]
        return "Archival memory results:\n" + "\n".join(lines)

    @tool
    async def conversation_search(query: str, top_k: int = 5) -> str:
        """Search recall memory from prior episodic conversation summaries."""
        logger.info("deep_agent: conversation_search trace=%s user=%s query=%s", trace_id or "-", user_id, query[:80])
        async with async_session() as db:
            memory = MemoryMiddleware(db)
            results = await memory.search_recall(user_id, query, top_k=top_k)
        if not results:
            return "No recall memory results found."
        lines = [f"- {item}" for item in results]
        return "Recall memory results:\n" + "\n".join(lines)

    return [
        memory_list_blocks,
        memory_get,
        memory_create,
        memory_append,
        memory_replace,
        memory_delete,
        archival_memory_insert,
        archival_memory_search,
        conversation_search,
    ]


def _read_only_memory_tools(user_id: str, trace_id: str | None) -> list[Any]:
    """Return memory tools that only read — safe for the read-only brief-agent subset."""
    all_mem = _memory_tools(user_id, trace_id)
    _read_names = {"memory_list_blocks", "memory_get", "archival_memory_search", "conversation_search"}
    return [t for t in all_mem if t.name in _read_names]


def _all_tools_for_user(user_id: str, trace_id: str | None) -> list[Any]:
    return [*_all_tools(), *_memory_tools(user_id, trace_id)]


def _detect_domain_section(message: str) -> FloatingDomainSection | None:
    lowered = message.lower()
    if any(keyword in lowered for keyword in ["timeline", "milestone", "release", "schedule"]):
        return "timeline"
    if any(keyword in lowered for keyword in ["task", "tasks", "todo", "attivit", "azione"]):
        return "task"
    if any(keyword in lowered for keyword in ["note", "notes", "memo", "document"]):
        return "note"
    return None


def _normalize_domain_payload(payload: dict[str, Any], fallback_id: str | None) -> dict[str, str | None]:
    type_raw = str(payload.get("type") or "").strip().lower()
    domain_type: FloatingDomainType = "task"
    if type_raw in {"task", "timeline", "project", "node"}:
        domain_type = type_raw

    id_value = payload.get("id")
    domain_id = id_value if isinstance(id_value, str) and id_value.strip() else None
    if domain_type == "project" and not domain_id:
        domain_id = fallback_id

    section_raw = payload.get("section")
    section: FloatingDomainSection | None = None
    if isinstance(section_raw, str):
        section_candidate = section_raw.strip().lower()
        if section_candidate in {"task", "timeline", "note"}:
            section = section_candidate

    if domain_type != "project":
        section = None

    return {
        "type": domain_type,
        "id": domain_id,
        "section": section,
    }


def _parse_json_object(text: str) -> dict[str, Any] | None:
    raw = text.strip()
    if not raw:
        return None
    try:
        parsed = json.loads(raw)
        return parsed if isinstance(parsed, dict) else None
    except json.JSONDecodeError:
        pass

    match = re.search(r"\{.*\}", raw, re.DOTALL)
    if not match:
        return None
    try:
        parsed = json.loads(match.group(0))
    except json.JSONDecodeError:
        return None
    return parsed if isinstance(parsed, dict) else None


def _infer_floating_domain_rule_based(message: str, context: dict[str, Any]) -> dict[str, str | None]:
    section = _detect_domain_section(message)
    scope = context.get("scope") if isinstance(context, dict) else None
    resolved_project_id = context.get("resolved_project_id") if isinstance(context, dict) else None
    project_id = resolved_project_id if isinstance(resolved_project_id, str) and resolved_project_id else None

    if isinstance(scope, dict):
        scope_type = str(scope.get("type") or "").strip().lower()
        scope_id = scope.get("id")
        scope_id_value = scope_id if isinstance(scope_id, str) and scope_id else None

        if scope_type in {"task", "tasks"}:
            return {"type": "task", "id": scope_id_value, "section": None}
        if scope_type in {"project", "projects"}:
            project_scope_id = scope_id_value or project_id
            return {
                "type": "project",
                "id": project_scope_id,
                "section": section,
            }
        if scope_type in {"note", "notes"}:
            return {
                "type": "node",
                "id": scope_id_value,
                "section": None,
            }
        if scope_type in {"timeline", "timelines"}:
            return {"type": "timeline", "id": scope_id_value, "section": None}

    lowered = message.lower()
    if any(keyword in lowered for keyword in ["project", "progetto", "client"]) or project_id:
        return {
            "type": "project",
            "id": project_id,
            "section": section,
        }
    if section == "timeline":
        return {"type": "timeline", "id": None, "section": None}
    if section == "note":
        return {"type": "node", "id": None, "section": None}
    return {"type": "task", "id": None, "section": None}


async def _infer_floating_domain(message: str, context: dict[str, Any]) -> dict[str, str | None]:
    resolved_project_id = context.get("resolved_project_id") if isinstance(context, dict) else None
    project_id = resolved_project_id if isinstance(resolved_project_id, str) and resolved_project_id else None

    classifier_context = {
        "scope": context.get("scope") if isinstance(context.get("scope"), dict) else None,
        "resolved_project_id": project_id,
    }

    try:
        llm = get_agent_llm("classifier")
        classifier_messages = [
            SystemMessage(content=_FLOATING_DOMAIN_CLASSIFIER_PROMPT),
            HumanMessage(
                content=(
                    f"Message:\n{message}\n\n"
                    f"Context:\n{json.dumps(classifier_context, ensure_ascii=True)}"
                )
            ),
        ]
        lf = get_langfuse()
        _, classifier_prompt_obj = get_prompt_or_fallback(
            "floating_domain_classifier", _FLOATING_DOMAIN_CLASSIFIER_PROMPT
        )

        # Extract user/session from context for Langfuse attribution
        _debug = context.get("_debug") if isinstance(context, dict) else None
        _lf_user = (_debug or {}).get("user_id") if isinstance(_debug, dict) else None
        _lf_session = (_debug or {}).get("session_id") if isinstance(_debug, dict) else None

        with langfuse_context(user_id=_lf_user, session_id=_lf_session):
            if lf:
                with lf.start_as_current_observation(
                    as_type="generation",
                    name="floating-classifier",
                    model=model_for_agent("classifier"),
                    prompt=classifier_prompt_obj,
                    input=classifier_messages,
                ) as gen:
                    response = await llm.ainvoke(classifier_messages)
                    gen.update(output=_as_text(response.content), usage_details=extract_usage(response))
            else:
                response = await llm.ainvoke(classifier_messages)
        parsed = _parse_json_object(_as_text(response.content))
        if parsed is not None:
            domain = _normalize_domain_payload(parsed, project_id)
            logger.info(
                "deep_agent: floating_domain_classified type=%s id=%s section=%s",
                domain.get("type"),
                domain.get("id"),
                domain.get("section"),
            )
            return domain
        logger.warning("deep_agent: floating_domain classifier returned non-json output")
    except Exception as exc:
        logger.warning("deep_agent: floating_domain classifier failed: %s", exc)

    return _infer_floating_domain_rule_based(message, context)


async def _run_single_agent(
    *,
    user_id: str,
    system_prompt: str,
    message: str,
    context: dict[str, Any],
    max_steps: int = 6,
    langfuse_prompt: Any = None,
    agent_name: str = "agent",
) -> str:
    trace_id = _trace_id_from_context(context)
    session_id = _session_id_from_context(context)
    lf = get_langfuse()
    llm = get_agent_llm(agent_name)
    tools = _all_tools_for_user(user_id, trace_id)
    model_context = _context_for_model(context)
    logger.info("deep_agent: run_single_agent_start trace=%s user=%s", trace_id or "-", user_id)
    llm_with_tools = llm.bind_tools(tools)
    messages: list[Any] = [
        SystemMessage(content=system_prompt),
        HumanMessage(
            content=(
                f"User message:\n{message}\n\n"
                f"Context:\n{json.dumps({'context': model_context}, ensure_ascii=True)[:3500]}"
            )
        ),
    ]

    tool_calls_count = 0
    collected: list[dict[str, Any]] = []
    set_tool_result_collector(collected)

    _lf_ctx = langfuse_context(user_id=user_id, session_id=session_id)
    _lf_ctx.__enter__()

    _span_ctx = (
        lf.start_as_current_observation(
            as_type="span",
            name=agent_name,
            metadata={"user_id": user_id, "session_id": trace_id},
            input=message,
        )
        if lf else None
    )
    _span = _span_ctx.__enter__() if _span_ctx else None

    try:
        for _ in range(max_steps):
            _gen_ctx = (
                lf.start_as_current_observation(
                    as_type="generation",
                    name=f"{agent_name}-llm",
                    model=model_for_agent(agent_name),
                    prompt=langfuse_prompt,
                    input=messages,
                )
                if lf else None
            )
            _gen = _gen_ctx.__enter__() if _gen_ctx else None
            response: AIMessage = await llm_with_tools.ainvoke(messages)
            if _gen_ctx:
                _gen.update(output=_as_text(response.content), usage_details=extract_usage(response))
                _gen_ctx.__exit__(None, None, None)

            messages.append(response)

            if not response.tool_calls:
                final_text = _as_text(response.content)
                logger.info(
                    "deep_agent: run_single_agent_end trace=%s user=%s tool_calls=%d response_chars=%d",
                    trace_id or "-",
                    user_id,
                    tool_calls_count,
                    len(final_text),
                )
                if _span:
                    _span.update(output=final_text)
                return final_text

            tool_map = {tool_def.name: tool_def for tool_def in tools}
            for call in response.tool_calls:
                tool_calls_count += 1
                call_id = str(call.get("id", ""))
                call_name = str(call.get("name", ""))
                call_args = call.get("args", {})
                logger.info(
                    "deep_agent: AI->Tool tool_call_id=%s tool=%s args=%s",
                    call_id,
                    call_name,
                    json.dumps(call_args, ensure_ascii=True)[:800],
                )

                tool_fn = tool_map.get(call_name)
                if tool_fn is None:
                    tool_output = f"Unknown tool: {call_name}"
                else:
                    tool_output = await tool_fn.ainvoke(call_args)

                logger.info(
                    "deep_agent: Tool->AI tool_call_id=%s tool=%s output=%s",
                    call_id,
                    call_name,
                    str(tool_output)[:1200],
                )

                messages.append(ToolMessage(content=str(tool_output), tool_call_id=call["id"]))

        final = await llm.ainvoke(messages)
        final_text = _as_text(final.content)
        logger.info(
            "deep_agent: run_single_agent_end trace=%s user=%s tool_calls=%d response_chars=%d fallback=1",
            trace_id or "-",
            user_id,
            tool_calls_count,
            len(final_text),
        )
        if _span:
            _span.update(output=final_text)
        return final_text
    finally:
        clear_tool_result_collector()
        if _span_ctx:
            _span_ctx.__exit__(None, None, None)
        _lf_ctx.__exit__(None, None, None)
        if lf:
            lf.flush()


async def _run_single_agent_stream(
    *,
    user_id: str,
    system_prompt: str,
    message: str,
    context: dict[str, Any],
    max_steps: int = 6,
    langfuse_prompt: Any = None,
    agent_name: str = "agent",
    tools: list[Any] | None = None,
) -> AsyncGenerator[tuple[str, Any], None]:
    trace_id = _trace_id_from_context(context)
    session_id = _session_id_from_context(context)
    lf = get_langfuse()
    llm = get_agent_llm(agent_name)
    if tools is None:
        tools = _all_tools_for_user(user_id, trace_id)
    model_context = _context_for_model(context)
    logger.info("deep_agent: run_single_agent_stream_start trace=%s user=%s", trace_id or "-", user_id)
    llm_with_tools = llm.bind_tools(tools)
    messages: list[Any] = [
        SystemMessage(content=system_prompt),
        HumanMessage(
            content=(
                f"User message:\n{message}\n\n"
                f"Context:\n{json.dumps({'context': model_context}, ensure_ascii=True)[:3500]}"
            )
        ),
    ]

    tool_calls_count = 0
    streamed_chars = 0
    collected: list[dict[str, Any]] = []
    set_tool_result_collector(collected)

    _lf_ctx = langfuse_context(user_id=user_id, session_id=session_id)
    _lf_ctx.__enter__()

    _span_ctx = (
        lf.start_as_current_observation(
            as_type="span",
            name=f"{agent_name}-stream",
            metadata={"user_id": user_id, "session_id": trace_id},
            input=message,
        )
        if lf else None
    )
    _span = _span_ctx.__enter__() if _span_ctx else None
    streamed_text: list[str] = []

    try:
        for _ in range(max_steps):
            _gen_ctx = (
                lf.start_as_current_observation(
                    as_type="generation",
                    name=f"{agent_name}-llm",
                    model=model_for_agent(agent_name),
                    prompt=langfuse_prompt,
                    input=messages,
                )
                if lf else None
            )
            _gen = _gen_ctx.__enter__() if _gen_ctx else None
            response: AIMessage = await llm_with_tools.ainvoke(messages)
            if _gen_ctx:
                _gen.update(output=_as_text(response.content), usage_details=extract_usage(response))
                _gen_ctx.__exit__(None, None, None)

            if not response.tool_calls:
                # Yield the content from the ainvoke response directly — no second LLM call.
                # Previously, messages.append(response) was called first, so the re-stream
                # received [System, Human, AI] and regenerated a response without tools bound.
                final_text = _as_text(response.content)
                if final_text:
                    streamed_chars += len(final_text)
                    streamed_text.append(final_text)
                    yield "token", final_text
                logger.info(
                    "deep_agent: run_single_agent_stream_end trace=%s user=%s tool_calls=%d response_chars=%d",
                    trace_id or "-",
                    user_id,
                    tool_calls_count,
                    streamed_chars,
                )
                if _span:
                    _span.update(output="".join(streamed_text))
                return

            messages.append(response)
            tool_map = {tool_def.name: tool_def for tool_def in tools}
            for call in response.tool_calls:
                tool_calls_count += 1
                call_id = str(call.get("id", ""))
                call_name = str(call.get("name", ""))
                call_args = call.get("args", {})
                logger.info(
                    "deep_agent: AI->Tool tool_call_id=%s tool=%s args=%s",
                    call_id,
                    call_name,
                    json.dumps(call_args, ensure_ascii=True)[:800],
                )

                tool_fn = tool_map.get(call_name)
                if tool_fn is None:
                    tool_output = f"Unknown tool: {call_name}"
                else:
                    tool_output = await tool_fn.ainvoke(call_args)

                logger.info(
                    "deep_agent: Tool->AI tool_call_id=%s tool=%s output=%s",
                    call_id,
                    call_name,
                    str(tool_output)[:1200],
                )

                messages.append(ToolMessage(content=str(tool_output), tool_call_id=call["id"]))

        async for chunk in llm.astream(messages):
            token = _as_text(getattr(chunk, "content", ""))
            if token:
                streamed_chars += len(token)
                streamed_text.append(token)
                yield "token", token
        logger.info(
            "deep_agent: run_single_agent_stream_end trace=%s user=%s tool_calls=%d response_chars=%d fallback=1",
            trace_id or "-",
            user_id,
            tool_calls_count,
            streamed_chars,
        )
        if _span:
            _span.update(output="".join(streamed_text))
    finally:
        clear_tool_result_collector()
        if _span_ctx:
            _span_ctx.__exit__(None, None, None)
        _lf_ctx.__exit__(None, None, None)
        if lf:
            lf.flush()


async def run_home(user_id: str, message: str, context: dict[str, Any]) -> str:
    prepared_context = await _prepare_context(message, context)
    system_prompt, langfuse_prompt = get_prompt_or_fallback(
        "home_system", _HOME_SYSTEM_PROMPT
    )
    system_prompt += _relational_memory_injection(context)
    system_prompt += _proactive_hints_injection(context)
    system_prompt += _language_instruction(context)
    response = await _run_single_agent(
        user_id=user_id,
        system_prompt=system_prompt,
        message=message,
        context=prepared_context,
        langfuse_prompt=langfuse_prompt,
        agent_name="home-agent",
    )
    return _normalize_tagged_list_lines(response, message)


async def run_floating(user_id: str, message: str, context: dict[str, Any]) -> tuple[str, dict[str, str | None]]:
    prepared_context = await _prepare_context(message, context)
    domain = await _infer_floating_domain(message, prepared_context)
    system_prompt, langfuse_prompt = get_prompt_or_fallback(
        "floating_system", _FLOATING_SYSTEM_PROMPT
    )
    system_prompt += _relational_memory_injection(context)
    system_prompt += _proactive_hints_injection(context)
    system_prompt += _language_instruction(context)
    response = await _run_single_agent(
        user_id=user_id,
        system_prompt=system_prompt,
        message=message,
        context=prepared_context,
        langfuse_prompt=langfuse_prompt,
        agent_name="floating-agent",
    )
    sanitized = _strip_floating_markup(response)
    if not sanitized and response:
        sanitized = _fallback_from_raw_floating_text(response)
    return sanitized, domain


async def run_home_stream(
    user_id: str,
    message: str,
    context: dict[str, Any],
) -> AsyncGenerator[tuple[str, Any], None]:
    prepared_context = await _prepare_context(message, context)
    system_prompt, langfuse_prompt = get_prompt_or_fallback(
        "home_system", _HOME_SYSTEM_PROMPT
    )
    system_prompt += _relational_memory_injection(context)
    system_prompt += _proactive_hints_injection(context)
    system_prompt += _language_instruction(context)
    text_chunks: list[str] = []
    async for event in _run_single_agent_stream(
        user_id=user_id,
        system_prompt=system_prompt,
        message=message,
        context=prepared_context,
        langfuse_prompt=langfuse_prompt,
        agent_name="home-agent",
    ):
        event_type, data = event
        if event_type != "token":
            yield event
            continue
        text_chunks.append(str(data or ""))

    normalized = _normalize_tagged_list_lines("".join(text_chunks), message)
    if normalized:
        yield "token", normalized


async def run_floating_stream(
    user_id: str,
    message: str,
    context: dict[str, Any],
) -> AsyncGenerator[tuple[str, Any], None]:
    prepared_context = await _prepare_context(message, context)
    domain = await _infer_floating_domain(message, prepared_context)
    yield "floating_domain", domain

    system_prompt, langfuse_prompt = get_prompt_or_fallback(
        "floating_system", _FLOATING_SYSTEM_PROMPT
    )
    system_prompt += _relational_memory_injection(context)
    system_prompt += _proactive_hints_injection(context)
    system_prompt += _language_instruction(context)
    sanitizer = _FloatingStreamSanitizer()
    emitted_sanitized = False
    raw_chunks: list[str] = []
    async for event in _run_single_agent_stream(
        user_id=user_id,
        system_prompt=system_prompt,
        message=message,
        context=prepared_context,
        langfuse_prompt=langfuse_prompt,
        agent_name="floating-agent",
    ):
        event_type, data = event
        if event_type != "token":
            yield event
            continue

        raw_chunk = str(data or "")
        raw_chunks.append(raw_chunk)
        sanitized_chunk = sanitizer.feed(raw_chunk)
        if sanitized_chunk:
            emitted_sanitized = True
            yield "token", sanitized_chunk

    tail = sanitizer.finalize()
    if tail:
        emitted_sanitized = True
        yield "token", tail

    if not emitted_sanitized and raw_chunks:
        yield "token", _fallback_from_raw_floating_text("".join(raw_chunks))


async def update_core_memory(user_id: str, key: str, value: str) -> None:
    """Compatibility helper kept for callers that expect explicit memory update API."""
    async with async_session() as db:
        memory = MemoryMiddleware(db)
        await memory.update_core(user_id, key, value)