from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel
from sqlalchemy.orm import Session
import httpx

from app.config import settings
from app.database import get_db
from app.models.user import User
from app.models.ai_model_config import AIModelConfig
from app.schemas.auth import UserResponse, UserUpdateRole, UserCreate
from app.schemas.admin import AIModelConfigCreate, AIModelConfigResponse, AIModelConfigUpdate
from app.utils.auth import require_admin, get_current_user, get_password_hash

router = APIRouter()


# --- User Management ---

@router.get("/users", response_model=list[UserResponse])
def list_users(
    db: Session = Depends(get_db),
    admin: User = Depends(require_admin),
):
    return db.query(User).order_by(User.created_at.desc()).all()


@router.put("/users/{user_id}/role", response_model=UserResponse)
def update_user_role(
    user_id: int,
    role_data: UserUpdateRole,
    db: Session = Depends(get_db),
    admin: User = Depends(require_admin),
):
    if role_data.role not in ("admin", "moderator", "user"):
        raise HTTPException(status_code=400, detail="Role must be admin, moderator, or user")

    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    if user.id == admin.id:
        raise HTTPException(status_code=400, detail="Cannot change your own role")

    user.role = role_data.role
    db.commit()
    db.refresh(user)
    return user


@router.post("/users", response_model=UserResponse)
def create_user(
    user_data: UserCreate,
    db: Session = Depends(get_db),
    admin: User = Depends(require_admin),
):
    """Admin creates a user directly — email is auto-verified."""
    from app.models.email_verification import EmailVerification
    from datetime import datetime

    if db.query(User).filter(User.email == user_data.email).first():
        raise HTTPException(status_code=400, detail="Email already registered")

    user = User(
        email=user_data.email,
        hashed_password=get_password_hash(user_data.password),
        name=user_data.name,
        role="user",
    )
    db.add(user)
    db.flush()
    db.add(EmailVerification(
        user_id=user.id,
        token=f"admin_created_{user.id}",
        expires_at=datetime.utcnow(),
        verified_at=datetime.utcnow(),
    ))
    db.commit()
    db.refresh(user)
    return user


# --- AI Model Configuration ---

@router.get("/models/available")
def list_available_models(
    task: str = Query("extraction"),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Returns active models for a given task — for users to choose when taking/creating a quiz."""
    models = db.query(AIModelConfig).filter(
        AIModelConfig.task == task,
        AIModelConfig.is_active == True,
    ).order_by(AIModelConfig.is_default.desc(), AIModelConfig.name).all()
    result = [{"id": m.id, "name": m.name, "model_id": m.model_id, "is_default": m.is_default} for m in models]
    # Always include env default as fallback if nothing configured
    if not result:
        result.append({"id": None, "name": "Default (from config)", "model_id": settings.LITELLM_MODEL, "is_default": True})
    return result


class LiteLLMModelQuery(BaseModel):
    api_key: str | None = None
    api_base: str | None = None


@router.post("/litellm/models")
def search_litellm_models(
    body: LiteLLMModelQuery = LiteLLMModelQuery(),
    admin: User = Depends(require_admin),
):
    """Query available models from LiteLLM proxy or OpenAI-compatible API."""
    base = (body.api_base or settings.LITELLM_API_BASE or "").rstrip("/")
    key = body.api_key or settings.LITELLM_API_KEY

    if base:
        try:
            headers = {"Authorization": f"Bearer {key}"} if key else {}
            resp = httpx.get(f"{base}/v1/models", headers=headers, timeout=10)
            resp.raise_for_status()
            data = resp.json()
            models = sorted([m["id"] for m in data.get("data", [])])
            return {"models": models, "source": base}
        except Exception as e:
            raise HTTPException(status_code=400, detail=f"Failed to query models API: {e}")

    # Fall back to LiteLLM's built-in model list
    try:
        import litellm
        models = sorted(litellm.utils.get_valid_models())
        return {"models": models, "source": "litellm-builtin"}
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Failed to get LiteLLM models: {e}")


@router.get("/models", response_model=list[AIModelConfigResponse])
def list_models(
    db: Session = Depends(get_db),
    admin: User = Depends(require_admin),
):
    return db.query(AIModelConfig).order_by(AIModelConfig.task, AIModelConfig.name).all()


@router.post("/models", response_model=AIModelConfigResponse)
def create_model(
    data: AIModelConfigCreate,
    db: Session = Depends(get_db),
    admin: User = Depends(require_admin),
):
    if data.task not in ("extraction", "tts", "general"):
        raise HTTPException(status_code=400, detail="Task must be extraction, tts, or general")

    if data.is_default:
        db.query(AIModelConfig).filter(
            AIModelConfig.task == data.task,
            AIModelConfig.is_default == True,
        ).update({"is_default": False})

    model = AIModelConfig(**data.model_dump())
    db.add(model)
    db.commit()
    db.refresh(model)
    return model


@router.put("/models/{model_id}", response_model=AIModelConfigResponse)
def update_model(
    model_id: int,
    data: AIModelConfigUpdate,
    db: Session = Depends(get_db),
    admin: User = Depends(require_admin),
):
    model = db.query(AIModelConfig).filter(AIModelConfig.id == model_id).first()
    if not model:
        raise HTTPException(status_code=404, detail="Model config not found")

    update_data = data.model_dump(exclude_unset=True)

    task = update_data.get("task", model.task)
    if update_data.get("is_default"):
        db.query(AIModelConfig).filter(
            AIModelConfig.task == task,
            AIModelConfig.is_default == True,
            AIModelConfig.id != model_id,
        ).update({"is_default": False})

    for key, value in update_data.items():
        setattr(model, key, value)

    db.commit()
    db.refresh(model)
    return model


@router.delete("/models/{model_id}", status_code=204)
def delete_model(
    model_id: int,
    db: Session = Depends(get_db),
    admin: User = Depends(require_admin),
):
    model = db.query(AIModelConfig).filter(AIModelConfig.id == model_id).first()
    if not model:
        raise HTTPException(status_code=404, detail="Model config not found")
    db.delete(model)
    db.commit()