from typing import Optional

from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel
from sqlalchemy.ext.asyncio import AsyncSession

from deps.db import get_db
from services import classifier, storage

router = APIRouter(prefix="/api/topics", tags=["topics"])


class TopicCreate(BaseModel):
    name: str
    description: str = ""
    color: str = "#6366f1"


class TopicUpdate(BaseModel):
    name: Optional[str] = None
    description: Optional[str] = None
    color: Optional[str] = None


class SuggestRequest(BaseModel):
    document_id: str


@router.get("")
async def list_topics(session: AsyncSession = Depends(get_db)):
    topics = await storage.load_topics(session)
    counts = await storage.topic_doc_counts(session)
    for t in topics:
        t["doc_count"] = counts.get(t["name"], 0)
    return {"topics": topics}


@router.post("")
async def create_topic(body: TopicCreate, session: AsyncSession = Depends(get_db)):
    topic = await storage.create_topic(session, body.name, body.description, body.color)
    topic["doc_count"] = 0
    return topic


@router.patch("/{topic_id}")
async def update_topic(
    topic_id: str,
    body: TopicUpdate,
    session: AsyncSession = Depends(get_db),
):
    topic = await storage.update_topic(
        session,
        topic_id,
        name=body.name,
        description=body.description,
        color=body.color,
    )
    if topic is None:
        raise HTTPException(404, "Topic not found")
    counts = await storage.topic_doc_counts(session)
    topic["doc_count"] = counts.get(topic["name"], 0)
    return topic


@router.delete("/{topic_id}")
async def delete_topic(topic_id: str, session: AsyncSession = Depends(get_db)):
    name = await storage.delete_topic(session, topic_id)
    if name is None:
        raise HTTPException(404, "Topic not found")
    return {"success": True, "removed_from_documents": True}


@router.post("/suggest")
async def suggest_topics(body: SuggestRequest, session: AsyncSession = Depends(get_db)):
    meta = await storage.get_metadata(session, body.document_id)
    if meta is None:
        raise HTTPException(404, "Document not found")
    try:
        suggestions = await classifier.suggest_topics_for_document(session, body.document_id)
    except Exception as e:
        raise HTTPException(500, f"Suggestion failed: {e}")
    return {"suggested": suggestions}