import asyncio
from typing import Any, Dict, List, Optional, Literal, Tuple
from fastapi import FastAPI, HTTPException
from fastapi.encoders import jsonable_encoder
from fastapi.responses import StreamingResponse
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
import json
import re
from datetime import datetime

from app.api import upload, llm, skills, users, datasources, projects, semantic
from app.connectors.postgres import postgres_connector
from app.connectors.clickhouse import clickhouse_connector
from app.core.nanobot import nanobot_service
from app.core.session_alias_store import session_alias_store
from app.agent.nl2sql import process_nl2sql, NL2SQLRequest, NL2SQLResponse
from app.database import engine, Base
# Import all models to ensure they are registered
from app.models.user import User
from app.models.project import Project
from app.models.datasource import DataSource

app = FastAPI()

app.add_middleware(
    CORSMiddleware,
    allow_origins=["http://localhost:5173", "http://localhost:5174", "*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Initialize database tables
Base.metadata.create_all(bind=engine)

app.include_router(upload.router, prefix="/api/v1")
app.include_router(llm.router, prefix="/api/v1")
app.include_router(skills.router, prefix="/api/v1")
app.include_router(users.router, prefix="/api/v1")
app.include_router(projects.router, prefix="/api/v1")
app.include_router(datasources.router, prefix="/api/v1")
app.include_router(semantic.router, prefix="/api/v1")

STREAM_DELTA_CHUNK_SIZE = 48

SQL_INTENT_DENY_PATTERNS = [
    re.compile(r"\b(sql|query)\b.*(解释|说明|改写|优化|翻译)", re.IGNORECASE),
    re.compile(r"(解释|说明|改写|优化|翻译).*\b(sql|query)\b", re.IGNORECASE),
    re.compile(r"(写|生成).*(python|脚本|代码)", re.IGNORECASE),
]

SQL_INTENT_POSITIVE_PATTERNS = [
    re.compile(r"\b(select|from|where|group by|order by|having|join|union|limit|count|sum|avg|max|min)\b", re.IGNORECASE),
    re.compile(r"(按|按.*维度|按.*分组|统计|汇总|分组|排序|筛选|过滤|环比|同比|top\s*\d+|前\d+|占比|均值|平均|最大|最小|总数|总量|明细)", re.IGNORECASE),
    re.compile(r"(数据库|数据源|数据表|表|字段|列|行|记录).*(查询|检索|列出|统计|分析|对比|查看)", re.IGNORECASE),
    re.compile(r"(查询|检索|列出|统计|分析|对比|查看).*(数据库|数据源|数据表|表|字段|列|行|记录)", re.IGNORECASE),
]

VISUAL_INTENT_PATTERN = re.compile(r"(图表|可视化|画图|作图|柱状图|折线图|饼图|趋势|分布|dashboard|chart|plot|visuali[sz]e)", re.IGNORECASE)

@app.on_event("startup")
async def startup_event():
    # Initialize nanobot in background
    try:
        await nanobot_service.start()
    except Exception as e:
        print(f"Nanobot startup failed: {e}")

@app.on_event("shutdown")
async def shutdown_event():
    await nanobot_service.stop()

@app.get("/")
def read_root():
    return {"Hello": "DataClaw Backend"}

@app.get("/connect/postgres")
def test_postgres():
    if postgres_connector.test_connection():
        return {"status": "success", "message": "Connected to PostgreSQL"}
    raise HTTPException(status_code=500, detail="Failed to connect to PostgreSQL")

@app.get("/connect/clickhouse")
def test_clickhouse():
    if clickhouse_connector.test_connection():
        return {"status": "success", "message": "Connected to ClickHouse"}
    raise HTTPException(status_code=500, detail="Failed to connect to ClickHouse")

@app.get("/nanobot/status")
def nanobot_status():
    if nanobot_service.agent:
        return {"status": "running", "model": nanobot_service.agent.model}
    return {"status": "stopped"}

class ChatRequest(BaseModel):
    message: str
    session_id: str = "api:default"
    skill_ids: Optional[List[str]] = None
    model_id: Optional[str] = None
    source: str = "postgres"
    prefer_sql_chart: bool = False
    file_url: Optional[str] = None
    route_mode: Literal["auto", "chat", "sql"] = "auto"


def _session_context_for_routing(session_id: str) -> Dict[str, Any]:
    if not nanobot_service.agent:
        return {}
    session = nanobot_service.agent.sessions.get_or_create(session_id)
    return session.metadata or {}


def _looks_like_sql_intent(message: str) -> bool:
    text = (message or "").strip().lower()
    if not text:
        return False
    for pattern in SQL_INTENT_DENY_PATTERNS:
        if pattern.search(text):
            return False
    for pattern in SQL_INTENT_POSITIVE_PATTERNS:
        if pattern.search(text):
            return True
    return False


def _looks_like_visual_intent(message: str) -> bool:
    return bool(VISUAL_INTENT_PATTERN.search((message or "").strip().lower()))


def _should_use_nl2sql(request: ChatRequest) -> Tuple[bool, str, str]:
    # Determine the effective data source from session context or request
    session_ctx = _session_context_for_routing(request.session_id)
    session_source = (session_ctx.get("selected_data_source") or "").strip().lower()
    request_source = (request.source or "").strip().lower()
    
    # Priority: Session bound source > Request source > "postgres"
    effective_source = request_source
    if session_source.startswith("ds:") or session_source == "upload":
        effective_source = session_source

    if request.route_mode == "sql":
        return True, "route_mode=sql", effective_source
    if request.route_mode == "chat":
        return False, "route_mode=chat", effective_source
    if request.prefer_sql_chart:
        return True, "prefer_sql_chart=true", effective_source
        
    has_sql_intent = _looks_like_sql_intent(request.message)
    if not has_sql_intent:
        return False, "message_non_sql_intent", effective_source
        
    # If we have intent, check if we have a valid source context
    if effective_source.startswith("ds:") or effective_source == "upload":
        return True, "message_sql_intent_with_datasource", effective_source
    
    # Even if just "postgres" (default), if intent is strong, we might allow it?
    # But usually we want a bound source. 
    # Let's keep existing logic: if intent is strong, return True.
    # But effectively, if source is "postgres", it might fail later if no tables are there.
    return True, "message_sql_intent", effective_source


class SessionAliasUpdateRequest(BaseModel):
    title: Optional[str] = None
    pinned: Optional[bool] = None
    archived: Optional[bool] = None


class BatchDeleteRequest(BaseModel):
    session_ids: List[str]


class SessionFileContextUpdateRequest(BaseModel):
    active_data_file: Optional[Dict[str, Any]] = None
    selected_data_source: Optional[str] = None


def _build_sql_chart_text(nl2sql_result: NL2SQLResponse) -> str:
    chart = nl2sql_result.chart
    can_visualize = bool(chart and chart.can_visualize and chart.chart_spec)
    text = (
        f"已为你生成 SQL 并查询到 {len(nl2sql_result.result)} 行数据。"
        f"{'可视化面板已同步更新图表。' if can_visualize else '本次结果不适合图表展示。'}"
    )
    if chart and chart.reasoning:
        return f"{text}\n\n可视化说明：{chart.reasoning}"
    return text


def _build_sql_chart_viz(nl2sql_result: NL2SQLResponse) -> dict:
    chart = nl2sql_result.chart
    payload = {
        "sql": nl2sql_result.sql,
        "result": nl2sql_result.result,
        "chart": chart.model_dump() if chart else None,
        "error": nl2sql_result.error,
    }
    return jsonable_encoder(payload)


def _persist_session_turn(
    session_id: str,
    user_message: str,
    assistant_message: str,
    assistant_extra: Optional[dict] = None,
) -> None:
    if not nanobot_service.agent:
        return
    session = nanobot_service.agent.sessions.get_or_create(session_id)
    session.add_message("user", user_message)
    session.add_message("assistant", assistant_message, **(assistant_extra or {}))
    nanobot_service.agent.sessions.save(session)

@app.post("/nanobot/chat")
async def nanobot_chat(request: ChatRequest):
    try:
        use_nl2sql, route_reason, resolved_source = _should_use_nl2sql(request)
        if use_nl2sql:
            nl2sql_result = await process_nl2sql(
                NL2SQLRequest(
                    query=request.message,
                    source=resolved_source,
                    file_url=request.file_url,
                    generate_chart=request.prefer_sql_chart or _looks_like_visual_intent(request.message),
                )
            )
            text = _build_sql_chart_text(nl2sql_result)
            viz_payload = _build_sql_chart_viz(nl2sql_result)
            _persist_session_turn(request.session_id, request.message, text, {"viz": viz_payload})
            return {
                "response": text,
                "viz": viz_payload,
                "routing": {"selected": "sql", "reason": route_reason},
            }
        response = await nanobot_service.process_message(
            request.message,
            session_id=request.session_id,
            skill_ids=request.skill_ids,
            model_id=request.model_id,
        )
        return {"response": response, "routing": {"selected": "chat", "reason": route_reason}}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

@app.post("/nanobot/chat/stream")
async def nanobot_chat_stream(request: ChatRequest):
    async def event_generator():
        try:
            use_nl2sql, route_reason, resolved_source = _should_use_nl2sql(request)
            yield f"data: {json.dumps({'type': 'routing', 'selected': 'sql' if use_nl2sql else 'chat', 'reason': route_reason}, ensure_ascii=False)}\n\n"
            if use_nl2sql:
                nl2sql_result = await process_nl2sql(
                    NL2SQLRequest(
                        query=request.message,
                        source=resolved_source,
                        file_url=request.file_url,
                        generate_chart=request.prefer_sql_chart or _looks_like_visual_intent(request.message),
                    )
                )
                persisted_viz_payload = _build_sql_chart_viz(nl2sql_result)
                viz_payload = {
                    "type": "viz",
                    **persisted_viz_payload,
                }
                yield f"data: {json.dumps(viz_payload, ensure_ascii=False)}\n\n"
                text = _build_sql_chart_text(nl2sql_result)
                _persist_session_turn(request.session_id, request.message, text, {"viz": persisted_viz_payload})
                yield f"data: {json.dumps({'type': 'final', 'content': text}, ensure_ascii=False)}\n\n"
                yield f"data: {json.dumps({'type': 'done'}, ensure_ascii=False)}\n\n"
                return
            progress_queue: asyncio.Queue[str] = asyncio.Queue()

            async def _on_progress(content: str, **_: Any) -> None:
                if content:
                    await progress_queue.put(content)

            task = asyncio.create_task(
                nanobot_service.process_message(
                    request.message,
                    session_id=request.session_id,
                    skill_ids=request.skill_ids,
                    model_id=request.model_id,
                    on_progress=_on_progress,
                )
            )
            text = ""
            while True:
                if task.done() and progress_queue.empty():
                    break
                try:
                    progress = await asyncio.wait_for(progress_queue.get(), timeout=0.2)
                    yield f"data: {json.dumps({'type': 'delta', 'content': progress}, ensure_ascii=False)}\n\n"
                except asyncio.TimeoutError:
                    continue
            response = await task
            text = response or ""
            for idx in range(0, len(text), STREAM_DELTA_CHUNK_SIZE):
                chunk = text[idx: idx + STREAM_DELTA_CHUNK_SIZE]
                yield f"data: {json.dumps({'type': 'delta', 'content': chunk}, ensure_ascii=False)}\n\n"
            yield f"data: {json.dumps({'type': 'final', 'content': text}, ensure_ascii=False)}\n\n"
            yield f"data: {json.dumps({'type': 'done'}, ensure_ascii=False)}\n\n"
        except Exception as e:
            yield f"data: {json.dumps({'type': 'error', 'content': str(e)}, ensure_ascii=False)}\n\n"
            yield f"data: {json.dumps({'type': 'done'}, ensure_ascii=False)}\n\n"

    return StreamingResponse(
        event_generator(),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
            "X-Accel-Buffering": "no",
        },
    )

@app.get("/nanobot/sessions")
def get_sessions():
    if not nanobot_service.agent:
        return session_alias_store.list_cached_sessions()
    sessions = nanobot_service.agent.sessions.list_sessions()
    return session_alias_store.sync_and_list(sessions)

@app.get("/nanobot/sessions/{session_id}")
def get_session(session_id: str):
    if not nanobot_service.agent:
        raise HTTPException(status_code=400, detail="Nanobot not running")
    session = nanobot_service.agent.sessions.get_or_create(session_id)
    alias = session_alias_store.get_alias(session_id)
    return {
        "key": session.key,
        "created_at": session.created_at,
        "updated_at": session.updated_at,
        "metadata": session.metadata,
        "alias": alias,
        "messages": session.messages
    }

@app.post("/nanobot/sessions/{session_id}/ensure")
def ensure_session(session_id: str):
    if not nanobot_service.agent:
        raise HTTPException(status_code=400, detail="Nanobot not running")
    session = nanobot_service.agent.sessions.get_or_create(session_id)
    nanobot_service.agent.sessions.save(session)
    alias = session_alias_store.get_alias(session_id)
    return {
        "key": session.key,
        "created_at": session.created_at,
        "updated_at": session.updated_at,
        "metadata": session.metadata,
        "alias": alias,
    }

@app.delete("/nanobot/sessions/{session_id}")
def delete_session(session_id: str):
    if not nanobot_service.agent:
        raise HTTPException(status_code=400, detail="Nanobot not running")
    
    # Try to remove from cache and delete file
    session = nanobot_service.agent.sessions.get_or_create(session_id)
    if session:
        nanobot_service.agent.sessions.invalidate(session_id)
        path = nanobot_service.agent.sessions._get_session_path(session_id)
        if path.exists():
            path.unlink()
        session_alias_store.delete_session(session_id)
        return {"status": "success"}
    raise HTTPException(status_code=404, detail="Session not found")


@app.post("/nanobot/sessions/batch-delete")
def batch_delete_sessions(request: BatchDeleteRequest):
    if not nanobot_service.agent:
        raise HTTPException(status_code=400, detail="Nanobot not running")
    
    deleted_ids = []
    for session_id in request.session_ids:
        try:
            # Try to remove from cache and delete file
            session = nanobot_service.agent.sessions.get_or_create(session_id)
            if session:
                nanobot_service.agent.sessions.invalidate(session_id)
                path = nanobot_service.agent.sessions._get_session_path(session_id)
                if path.exists():
                    path.unlink()
                session_alias_store.delete_session(session_id)
                deleted_ids.append(session_id)
        except Exception as e:
            print(f"Failed to delete session {session_id}: {e}")
    
    return {"status": "success", "deleted_count": len(deleted_ids), "deleted_ids": deleted_ids}


@app.put("/nanobot/sessions/{session_id}")
def update_session(session_id: str, payload: SessionAliasUpdateRequest):
    updated = session_alias_store.update_alias_meta(
        session_key=session_id,
        alias=payload.title,
        pinned=payload.pinned,
        archived=payload.archived,
    )
    return {"status": "success", **updated}


@app.put("/nanobot/sessions/{session_id}/context-file")
def update_session_context_file(session_id: str, payload: SessionFileContextUpdateRequest):
    if not nanobot_service.agent:
        raise HTTPException(status_code=400, detail="Nanobot not running")
    session = nanobot_service.agent.sessions.get_or_create(session_id)
    updated_fields = payload.model_fields_set
    if "active_data_file" in updated_fields:
        if payload.active_data_file is None:
            session.metadata.pop("active_data_file", None)
        else:
            session.metadata["active_data_file"] = payload.active_data_file
    if "selected_data_source" in updated_fields:
        if payload.selected_data_source:
            session.metadata["selected_data_source"] = payload.selected_data_source
        else:
            session.metadata.pop("selected_data_source", None)
    session.updated_at = datetime.now()
    nanobot_service.agent.sessions.save(session)
    return {"status": "success", "metadata": session.metadata}