from fastapi import (APIRouter, 
                     Request, 
                     status,
                     Depends
                     )
from fastapi.responses import HTMLResponse, RedirectResponse
from fastapi.templating import Jinja2Templates
from ...db.db_connect import  get_db
from sqlalchemy.orm import Session, joinedload
from ...models.tickets import Ticket
from ...models.resolutions import Resolution, ResolutionType

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


# route to historic tickets page 
@router.get("/ticket/history", response_class=HTMLResponse)
def my_tickets(request: Request, db: Session = Depends(get_db)):
    # store user session in variable
    session_user = request.session.get("user")
    # if user session doesn't exist return to login to start user session 
    if not session_user:
        return RedirectResponse(url="/login", status_code=status.HTTP_303_SEE_OTHER)
    
    # store tickets that the current user session has created, in tickets variable
    tickets = (
        db.query(Ticket)
        # filter tickets by current user created tickets 
        .filter(Ticket.requester_id == session_user.get("id"))
        # order in a descending order, most recent first 
        .order_by(Ticket.created_at.desc())
        .all()
    )
    # render template with ticket context and user session context 
    return templates.TemplateResponse(
        "tickets/ticket_history.html",
        {"request": request, "active": "tickets", "user": session_user, "tickets": tickets},
    )

# route to specific ticket display page using ticket id
@router.get("/tickets/{ticket_id}", response_class=HTMLResponse)
def ticket_detail(request: Request, ticket_id: int, db: Session = Depends(get_db)):
    # user session validation 
    session_user = request.session.get("user")
    if not session_user:
        # redirect to login if not validated
        return RedirectResponse(url="/login", status_code=status.HTTP_303_SEE_OTHER)
    # query ticket by id
    ticket = db.query(Ticket).filter(Ticket.id == ticket_id).first()
    # if ticket does not exist return not found error
    if not ticket:
        return templates.TemplateResponse(
            "tickets/show.html",
            {"request": request, "active": "tickets", "user": session_user, "not_found": True},
            status_code=status.HTTP_404_NOT_FOUND,
        )
    # retrieve user session role
    role = (session_user.get("role") or "").lower()
    # if the user is not an admin or an it agent 
    # and the ticket creator is not the user accessing the ticket 
    # return see other error 
    if role not in {"admin", "it_agent"} and ticket.requester_id != session_user.get("id"):
        user_role = (session_user.get("role") or "end_user").lower()
        return RedirectResponse(url=f"/dashboard/{user_role}", status_code=status.HTTP_303_SEE_OTHER)

    # once validated fetch resolutions filtered by ticket id
    # and the resolution type being suggestion 
    try:
       suggestions = (
            db.query(Resolution)
            .filter(
                Resolution.ticket_id == ticket_id,
                Resolution.type == ResolutionType.SUGGESTION,
            )
            # load the related author in context to the ticket
            .options(joinedload(Resolution.author))
            # order most recent first
            .order_by(Resolution.created_at.desc())
            .all()
        )
    except Exception:
        suggestions = []

    # fetch any errors or messages
    msg = request.query_params.get("message")
    err = request.query_params.get("error")
    # render ticket page in reference to the context variables
    return templates.TemplateResponse(
        "tickets/show.html",
        {
            "request": request,
            "active": "tickets",
            "user": session_user,
            "ticket": ticket,
            "suggestions": suggestions,
            "message": msg,
            "error": err,
        },
    )