"""中控 AI：单会话聊天（直到用户点击新开）。"""
from __future__ import annotations

from typing import Any, Optional

from hub_ai.attachments import parse_chat_attachments
from hub_ai.client import generate_text, model_label
from hub_ai.config import (
    CHAT_CONTEXT_MAX_CHARS,
    CHAT_MAX_HISTORY_TURNS,
    CHAT_MAX_OUTPUT_TOKENS,
    CHAT_SUMMARY_EXCERPT_MAX_CHARS,
    CHAT_TEMPERATURE,
)
from hub_ai.context import build_daily_context, format_chat_context_for_chat
from hub_ai.prompts import CHAT_SYSTEM, build_chat_user_prompt
from hub_ai.store import (
    append_chat_message,
    create_new_session,
    ensure_active_session,
    get_active_session,
    load_chat_store,
    summary_excerpt_for_chat,
)


def _history_lines(messages: list[dict], max_turns: int = CHAT_MAX_HISTORY_TURNS) -> str:
    rows = [m for m in (messages or []) if m.get("role") in ("user", "assistant")]
    rows = rows[-max_turns * 2 :]
    lines = []
    for m in rows:
        role = "用户" if m.get("role") == "user" else "搭档"
        content = m.get("content") or ""
        att = m.get("attachments") or []
        if att:
            names = "、".join(str(a.get("name") or "附件") for a in att[:3])
            content = f"{content} [附件: {names}]".strip()
        lines.append(f"{role}：{content}")
    return "\n".join(lines)


def get_chat_state() -> dict[str, Any]:
    store = load_chat_store()
    session = get_active_session()
    return {
        "active_session_id": store.get("active_session_id"),
        "session": session,
        "model": model_label(),
    }


def start_new_chat(*, trading_day: str) -> dict:
    session = create_new_session(trading_day=trading_day)
    return {"ok": True, "session": session, "model": model_label()}


def send_chat_message(
    exchanges: list[dict],
    message: str,
    *,
    trading_day: str | None = None,
    raw_attachments: Optional[list[dict]] = None,
) -> dict[str, Any]:
    text = (message or "").strip()
    parsed = parse_chat_attachments(raw_attachments or [])
    if parsed.get("errors") and not text and not parsed.get("images_b64"):
        return {"ok": False, "msg": "；".join(parsed["errors"])}
    if not text and not parsed.get("images_b64") and not parsed.get("text_append"):
        return {"ok": False, "msg": "消息不能为空"}

    user_visible = text
    if parsed.get("text_append"):
        user_visible = (user_visible + "\n\n" + parsed["text_append"]).strip()
    if not user_visible and parsed.get("attachment_note"):
        user_visible = f"（上传了 {parsed['attachment_note']}）"

    ctx = build_daily_context(exchanges, trading_day=trading_day)
    day = ctx["trading_day"]
    session = ensure_active_session(trading_day=day)
    sid = session["id"]
    history = _history_lines(session.get("messages") or [])

    append_chat_message(
        sid,
        "user",
        user_visible,
        attachments=parsed.get("attachment_meta") or [],
    )

    brief_ctx = format_chat_context_for_chat(ctx, max_chars=CHAT_CONTEXT_MAX_CHARS)
    excerpt = summary_excerpt_for_chat(day, max_chars=CHAT_SUMMARY_EXCERPT_MAX_CHARS)

    user_prompt = build_chat_user_prompt(
        context_text=brief_ctx,
        trading_day=day,
        summary_excerpt=excerpt,
        history_lines=history,
        user_message=text or user_visible,
        attachment_note=str(parsed.get("attachment_note") or ""),
    )
    if parsed.get("text_append"):
        user_prompt += "\n\n【附件正文】\n" + parsed["text_append"]

    reply = generate_text(
        system=CHAT_SYSTEM,
        user=user_prompt,
        temperature=CHAT_TEMPERATURE,
        images_b64=parsed.get("images_b64") or None,
        max_tokens=CHAT_MAX_OUTPUT_TOKENS,
    )
    if reply.startswith("AI 调用失败"):
        return {"ok": False, "msg": reply, "session_id": sid}

    session = append_chat_message(sid, "assistant", reply)
    return {
        "ok": True,
        "trading_day": day,
        "session": session,
        "reply": reply,
        "model": model_label(),
        "attachment_warnings": parsed.get("errors") or [],
    }