"""Chat assistant persistence helpers."""

from __future__ import annotations

import json
from datetime import datetime

from app.db.llm_insights import repair_mojibake_json, repair_mojibake_text
from app.db.postgres_connection import ensure_migrations_once
from app.db.schema import get_conn


def _now() -> str:
    return datetime.now().isoformat(timespec="seconds")


def _loads(value, fallback=None):
    try:
        if isinstance(value, str) and value.strip():
            return repair_mojibake_json(json.loads(value))
        if value is not None:
            return repair_mojibake_json(value)
    except Exception:
        pass
    return fallback if fallback is not None else {}


def _dumps(value) -> str:
    return json.dumps(repair_mojibake_json(value if value is not None else {}), ensure_ascii=False, sort_keys=True, default=str)


def init_chat_tables():
    ensure_migrations_once()


def _normalize_title(title: str) -> str:
    title = str(title or "").strip()
    return title[:32] or "新对话"


def _load_session(row):
    if not row:
        return None
    item = dict(row)
    item["memory"] = _loads(item.pop("memory_json", "{}"), {})
    return item


def _load_message(row):
    if not row:
        return None
    item = dict(row)
    item["content_text"] = repair_mojibake_text(item.get("content_text", ""))
    item["content"] = _loads(item.pop("content_json", "{}"), {})
    item["context"] = _loads(item.pop("context_json", "{}"), {})
    return item


def get_user_preferences(user_id: int) -> dict:
    init_chat_tables()
    conn = get_conn()
    try:
        row = conn.execute("SELECT * FROM chat_user_preferences WHERE user_id=%s", (int(user_id),)).fetchone()
    finally:
        conn.close()
    if not row:
        return {
            "preferred_symbols": [],
            "preferred_timeframes": ["15m", "1h", "4h", "1d"],
            "answer_style": "two_stage",
            "risk_profile": "balanced",
            "last_intent": "",
            "last_symbol": "",
            "recent_topics": [],
        }
    prefs = _loads(row.get("preferences_json"), {})
    prefs.setdefault("preferred_symbols", [])
    prefs.setdefault("preferred_timeframes", ["15m", "1h", "4h", "1d"])
    prefs.setdefault("answer_style", "two_stage")
    prefs.setdefault("risk_profile", "balanced")
    prefs.setdefault("last_intent", "")
    prefs.setdefault("last_symbol", "")
    prefs.setdefault("recent_topics", [])
    return prefs


def update_user_preferences(user_id: int, patch: dict) -> dict:
    init_chat_tables()
    current = get_user_preferences(user_id)
    patch = patch or {}
    for key, value in patch.items():
        if key in ("preferred_symbols", "preferred_timeframes", "recent_topics") and isinstance(value, list):
            merged = list(dict.fromkeys([str(x) for x in current.get(key, []) if str(x).strip()] + [str(x) for x in value if str(x).strip()]))
            current[key] = merged[-12:]
        elif value is not None:
            current[key] = value
    now = _now()
    conn = get_conn()
    try:
        conn.execute(
            """
            INSERT INTO chat_user_preferences (user_id, preferences_json, updated_at)
            VALUES (%s, %s, %s)
            ON CONFLICT(user_id) DO UPDATE SET
                preferences_json=excluded.preferences_json,
                updated_at=excluded.updated_at
            """,
            (int(user_id), _dumps(current), now),
        )
        conn.commit()
    finally:
        conn.close()
    return current


def create_chat_session(user_id: int, title: str = "", summary: str = "", last_symbol: str = "", last_intent: str = "") -> dict:
    init_chat_tables()
    now = _now()
    conn = get_conn()
    try:
        row = conn.execute(
            """
            INSERT INTO chat_sessions (user_id, title, summary, memory_json, last_symbol, last_intent, created_at, updated_at)
            VALUES (%s, %s, %s, %s, %s, %s, %s, %s)
            RETURNING *
            """,
            (int(user_id), _normalize_title(title), summary or "", _dumps({}), last_symbol or "", last_intent or "", now, now),
        ).fetchone()
        conn.commit()
    finally:
        conn.close()
    return _load_session(row)


def list_chat_sessions(user_id: int, limit: int = 20, offset: int = 0) -> dict:
    init_chat_tables()
    limit = max(1, min(int(limit or 20), 100))
    offset = max(0, int(offset or 0))
    conn = get_conn()
    try:
        total = conn.execute("SELECT COUNT(*) FROM chat_sessions WHERE user_id=%s AND COALESCE(archived_at, '')=''", (int(user_id),)).fetchone()[0]
        rows = conn.execute(
            """
            SELECT s.*,
                   (SELECT m.content_text FROM chat_messages m WHERE m.session_id=s.id ORDER BY m.id DESC LIMIT 1) AS last_message_text,
                   (SELECT m.role FROM chat_messages m WHERE m.session_id=s.id ORDER BY m.id DESC LIMIT 1) AS last_message_role,
                   (SELECT m.created_at FROM chat_messages m WHERE m.session_id=s.id ORDER BY m.id DESC LIMIT 1) AS last_message_at,
                   (SELECT COUNT(*) FROM chat_messages m WHERE m.session_id=s.id) AS message_count
            FROM chat_sessions s
            WHERE s.user_id=%s AND COALESCE(s.archived_at, '')=''
            ORDER BY s.updated_at DESC, s.id DESC
            LIMIT %s OFFSET %s
            """,
            (int(user_id), limit, offset),
        ).fetchall()
    finally:
        conn.close()
    items = []
    for row in rows:
        item = _load_session(row)
        item["last_message_text"] = item.pop("last_message_text", "")
        item["last_message_role"] = item.pop("last_message_role", "")
        item["last_message_at"] = item.pop("last_message_at", "")
        item["message_count"] = int(item.pop("message_count", 0) or 0)
        items.append(item)
    return {
        "items": items,
        "total": int(total or 0),
        "limit": limit,
        "offset": offset,
        "has_more": offset + len(items) < int(total or 0),
    }


def get_chat_session(session_id: int, user_id: int) -> dict | None:
    init_chat_tables()
    conn = get_conn()
    try:
        row = conn.execute(
            "SELECT * FROM chat_sessions WHERE id=%s AND user_id=%s AND COALESCE(archived_at, '')=''",
            (int(session_id), int(user_id)),
        ).fetchone()
    finally:
        conn.close()
    return _load_session(row)


def update_chat_session(session_id: int, user_id: int, **fields) -> dict | None:
    init_chat_tables()
    session = get_chat_session(session_id, user_id)
    if not session:
        return None
    allowed = {"title", "summary", "memory_json", "last_symbol", "last_intent", "archived_at"}
    updates = {}
    for key, value in fields.items():
        if key not in allowed or value is None:
            continue
        updates[key] = value
    if not updates:
        return session
    updates["updated_at"] = _now()
    if "title" in updates:
        updates["title"] = _normalize_title(updates["title"])
    if "memory_json" in updates and not isinstance(updates["memory_json"], str):
        updates["memory_json"] = _dumps(updates["memory_json"])
    if updates.get("archived_at") == "now":
        updates["archived_at"] = _now()
    sets = ", ".join(f"{key}=%s" for key in updates)
    params = list(updates.values()) + [int(session_id), int(user_id)]
    conn = get_conn()
    try:
        row = conn.execute(
            f"UPDATE chat_sessions SET {sets} WHERE id=%s AND user_id=%s RETURNING *",
            tuple(params),
        ).fetchone()
        conn.commit()
    finally:
        conn.close()
    return _load_session(row)


def list_chat_messages(session_id: int, user_id: int, limit: int = 50, offset: int = 0) -> dict:
    init_chat_tables()
    limit = max(1, min(int(limit or 50), 200))
    offset = max(0, int(offset or 0))
    conn = get_conn()
    try:
        total = conn.execute(
            "SELECT COUNT(*) FROM chat_messages WHERE session_id=%s AND user_id=%s",
            (int(session_id), int(user_id)),
        ).fetchone()[0]
        rows = conn.execute(
            """
            SELECT * FROM chat_messages
            WHERE session_id=%s AND user_id=%s
            ORDER BY id ASC
            LIMIT %s OFFSET %s
            """,
            (int(session_id), int(user_id), limit, offset),
        ).fetchall()
    finally:
        conn.close()
    return {
        "items": [_load_message(row) for row in rows],
        "total": int(total or 0),
        "limit": limit,
        "offset": offset,
        "has_more": offset + len(rows) < int(total or 0),
    }


def append_chat_message(
    session_id: int,
    user_id: int,
    role: str,
    content_text: str = "",
    content_json=None,
    context_json=None,
    intent: str = "",
    symbol: str = "",
    timeframe: str = "",
    model: str = "",
) -> dict:
    init_chat_tables()
    now = _now()
    conn = get_conn()
    try:
        row = conn.execute(
            """
            INSERT INTO chat_messages (
                session_id, user_id, role, content_text, content_json, context_json,
                intent, symbol, timeframe, model, created_at
            ) VALUES (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s)
            RETURNING *
            """,
            (
                int(session_id),
                int(user_id),
                str(role or "user"),
                repair_mojibake_text(str(content_text or "")),
                _dumps(content_json or {}),
                _dumps(context_json or {}),
                str(intent or ""),
                str(symbol or ""),
                str(timeframe or ""),
                str(model or ""),
                now,
            ),
        ).fetchone()
        conn.commit()
    finally:
        conn.close()
    return _load_message(row)


def bootstrap_chat(user_id: int) -> dict:
    prefs = get_user_preferences(user_id)
    sessions = list_chat_sessions(user_id=user_id, limit=20, offset=0)
    prompts = [
        "分析 BTC/USDT 现在的技术面",
        "解释当前看板里这条推荐为什么是等回踩",
        "看一下市场总览，今天是偏强还是偏弱",
        "这个币的链上异动有哪些",
        "帮我复盘最近一次纸面交易",
    ]
    return {
        "preferences": prefs,
        "sessions": sessions,
        "suggested_prompts": prompts,
    }


__all__ = [
    "append_chat_message",
    "bootstrap_chat",
    "create_chat_session",
    "get_chat_session",
    "get_user_preferences",
    "init_chat_tables",
    "list_chat_messages",
    "list_chat_sessions",
    "update_chat_session",
    "update_user_preferences",
]