from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session
from typing import List

from src.infrastructure.database import get_db
from src.core.domain.schemas import UserCreate, UserResponse, UserUpdate, PasswordChange, AdminUserUpdate
from src.core.domain.db_models import User, UserRole
from src.core.security import (
    get_password_hash, verify_password,
    get_current_user, require_super_admin
)

router = APIRouter()


# ── Public ────────────────────────────────────────────────────────────────────

@router.post("/register", response_model=UserResponse, status_code=status.HTTP_201_CREATED)
def register(user: UserCreate, db: Session = Depends(get_db)):
    """Register a new user account (role defaults to 'user')."""
    existing = db.query(User).filter(
        (User.username == user.username) | (User.email == user.email)
    ).first()
    if existing:
        raise HTTPException(status_code=400, detail="Username or email already registered")

    new_user = User(
        username=user.username,
        email=user.email,
        full_name=user.full_name,
        hashed_password=get_password_hash(user.password),
        role=UserRole.user,
    )
    db.add(new_user)
    db.commit()
    db.refresh(new_user)
    return new_user


# ── Authenticated user ────────────────────────────────────────────────────────

@router.patch("/me", response_model=UserResponse)
def update_profile(
    body: UserUpdate,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """Update own profile (username, full_name, email)."""
    if body.username and body.username != current_user.username:
        if db.query(User).filter(User.username == body.username).first():
            raise HTTPException(status_code=400, detail="Username already taken")
        current_user.username = body.username
    if body.email and body.email != current_user.email:
        if db.query(User).filter(User.email == body.email).first():
            raise HTTPException(status_code=400, detail="Email already in use")
        current_user.email = body.email
    if body.full_name is not None:
        current_user.full_name = body.full_name

    db.commit()
    db.refresh(current_user)
    return current_user


@router.post("/me/change-password", status_code=status.HTTP_204_NO_CONTENT)
def change_password(
    body: PasswordChange,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """Change own password."""
    if not verify_password(body.current_password, current_user.hashed_password):
        raise HTTPException(status_code=400, detail="Current password is incorrect")
    current_user.hashed_password = get_password_hash(body.new_password)
    db.commit()


# ── Super admin only ──────────────────────────────────────────────────────────

@router.get("/users", response_model=List[UserResponse])
def list_users(
    skip: int = 0,
    limit: int = 50,
    _admin: User = Depends(require_super_admin),
    db: Session = Depends(get_db)
):
    """List all users (super_admin only)."""
    return db.query(User).offset(skip).limit(limit).all()


@router.get("/users/{user_id}", response_model=UserResponse)
def get_user(
    user_id: int,
    _admin: User = Depends(require_super_admin),
    db: Session = Depends(get_db)
):
    """Get a specific user by ID (super_admin only)."""
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    return user


@router.patch("/users/{user_id}", response_model=UserResponse)
def admin_update_user(
    user_id: int,
    body: AdminUserUpdate,
    _admin: User = Depends(require_super_admin),
    db: Session = Depends(get_db)
):
    """Update a user's role or active status (super_admin only)."""
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    if body.is_active is not None:
        user.is_active = body.is_active
    if body.role is not None:
        try:
            user.role = UserRole(body.role)
        except ValueError:
            raise HTTPException(status_code=400, detail="Invalid role. Must be 'super_admin' or 'user'")
    db.commit()
    db.refresh(user)
    return user


@router.delete("/users/{user_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_user(
    user_id: int,
    admin: User = Depends(require_super_admin),
    db: Session = Depends(get_db)
):
    """Delete a user (super_admin only). Cannot delete yourself."""
    if user_id == admin.id:
        raise HTTPException(status_code=400, detail="Cannot delete your own account")
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    db.delete(user)
    db.commit()