from fastapi import (APIRouter, 
                     Request, 
                     status, 
                     Depends, 
                     Form
                     )
from fastapi.responses import (HTMLResponse, 
                               RedirectResponse
                               )
from fastapi.templating import Jinja2Templates
from sqlalchemy.orm import Session
from ..db.db_connect import get_db
from ..models.users import User


router = APIRouter()
# Get html templates 
templates = Jinja2Templates(directory="app/frontend/templates")

# retrieve the current user session info
def _get_session_user(request: Request):
    return request.session.get("user")

# check if the current user is an admin
def _is_admin(session_user) -> bool:
    try:
        return (session_user.get("role") or "").lower() == "admin"
    except Exception:
        return False


def _authorize_or_redirect(request: Request, target_user_id: int) -> RedirectResponse | None:
    # Retrieve current session user info
    session_user = _get_session_user(request)
    # if no session redirect to login
    if not session_user:
        return RedirectResponse(url="/login", status_code=status.HTTP_303_SEE_OTHER)
    # if the user is not an admin and trying to access another profile redirect to own profile
    if session_user.get("id") != target_user_id and not _is_admin(session_user):
        return RedirectResponse(url=f"/users/{session_user.get('id')}/profile", status_code=status.HTTP_303_SEE_OTHER)
    
    return None

# Routing to the user profile page 
@router.get("/users/{user_id}/profile", response_class=HTMLResponse)

def profile_page(request: Request, user_id: int, db: Session = Depends(get_db)):

    # redirection logic application for authorization test 
    redirect = _authorize_or_redirect(request, user_id)
    if redirect:
        return redirect
    # define user variable to query the database for user info
    user = db.query(User).filter(User.id == user_id).first()
    # Error handling for non existent users 
    if not user:
        # return profile not found if user does not exist
        return templates.TemplateResponse(
            "account/profile.html",
            {"request": request, "not_found": True, "active": "profile", "user": _get_session_user(request)},
            status_code=status.HTTP_404_NOT_FOUND,
        )
    # passing all validation direct to profile page with user info
    return templates.TemplateResponse(
        "account/profile.html",
        {"request": request, "active": "profile", "user": _get_session_user(request), "profile_user": user},
    )

# Updating profile info to the database using post method 
@router.post("/users/{user_id}/profile", response_class=HTMLResponse)
# Defining profile update variables i.e full name and email and db session 
def profile_update(
    request: Request,
    user_id: int,
    first_name: str = Form(...),
    surname: str = Form(None),
    email: str = Form(...),
    db: Session = Depends(get_db),
):
    redirect = _authorize_or_redirect(request, user_id)
    if redirect:
        return redirect

    user = db.query(User).filter(User.id == user_id).first()
    # Error handling for non existent users
    if not user:
        return templates.TemplateResponse(
            "account/profile.html",
            {"request": request, "not_found": True, "active": "profile", "user": _get_session_user(request)},
            status_code=status.HTTP_404_NOT_FOUND,
        )

    first_name = (first_name or "").strip()
    surname = (surname or "").strip() or None
    email = (email or "").strip()

    if not first_name or len(first_name) > 255:
        return templates.TemplateResponse(
            "account/profile.html",
            {
                "request": request,
                "active": "profile",
                "user": _get_session_user(request),
                "profile_user": user,
                "error": "Please provide a first name up to 255 characters.",
            },
            status_code=status.HTTP_400_BAD_REQUEST,
        )
    if not email or len(email) > 255:
        return templates.TemplateResponse(
            "account/profile.html",
            {
                "request": request,
                "active": "profile",
                "user": _get_session_user(request),
                "profile_user": user,
                "error": "Please provide an email up to 255 characters.",
            },
            status_code=status.HTTP_400_BAD_REQUEST,
        )

    # Update user info in the database
    user.first_name = first_name
    user.surname = surname
    user.email = email
    db.add(user)
    db.commit()

    # update session info when profile is updated
    try:
        session_user = request.session.get("user") or {}
        if session_user.get("id") == user.id:
            session_user["name"] = (user.full_name or user.email)
            request.session["user"] = session_user
    except Exception:
        pass

    # reload profile with success message 
    return templates.TemplateResponse(
        "account/profile.html",
        {
            "request": request,
            "active": "profile",
            "user": _get_session_user(request),
            "profile_user": user,
            "message": "Profile updated.",
        },
    )

# routing to the user settings page(iteration 2) currently a placeholder
@router.get("/users/{user_id}/settings", response_class=HTMLResponse)
def settings_page(request: Request, user_id: int, db: Session = Depends(get_db)):
    redirect = _authorize_or_redirect(request, user_id)
    if redirect:
        return redirect

    user = db.query(User).filter(User.id == user_id).first()
    # Error handling for non existent users
    if not user:
        return templates.TemplateResponse(
            "account/settings.html",
            {"request": request, "not_found": True, "active": "settings", "user": _get_session_user(request)},
            status_code=status.HTTP_404_NOT_FOUND,
        )
    # if validate load settings page for the user
    return templates.TemplateResponse(
        "account/settings.html",
        {"request": request, "active": "settings", "user": _get_session_user(request), "profile_user": user},
    )