import ulid
from datetime import datetime, timedelta
from sqlalchemy.orm import Session
from sqlalchemy import select
from typing import Optional, List
from fastapi import HTTPException, status

from app.models.ServiceModel import ServiceJob, ServiceJobEvent
from app.models.ServiceQuoteModel import ServiceJobQuote
from app.schemas.ServiceQuoteSchema import ServiceJobQuoteCreate

class QuoteService:
    def create_or_revise_quote(
        self, db: Session, job_id: str, staff_id: str, data: ServiceJobQuoteCreate
    ) -> ServiceJobQuote:
        job = db.get(ServiceJob, job_id)
        if not job:
            raise HTTPException(status_code=404, detail="Service job not found")

        # Find existing quotes to determine version
        stmt = select(ServiceJobQuote).where(ServiceJobQuote.service_job_id == job_id).order_by(ServiceJobQuote.version.desc())
        existing_quotes = db.execute(stmt).scalars().all()

        version = 1
        if existing_quotes:
            version = existing_quotes[0].version + 1
            # Supersede all older quotes
            for old_q in existing_quotes:
                if old_q.status in ["PENDING_CUSTOMER", "DRAFT"]:
                    old_q.status = "SUPERSEDED"

        # Create new quote version
        expiry_time = datetime.utcnow() + timedelta(days=4)
        quote = ServiceJobQuote(
            quote_id=str(ulid.ULID()),
            service_job_id=job_id,
            version=version,
            subtotal=data.subtotal,
            tax=data.tax,
            additional_damage_amount=data.additional_damage_amount,
            total=data.total,
            status="PENDING_CUSTOMER",
            reason=data.reason,
            expires_at=data.expires_at or expiry_time,
            created_by=staff_id,
        )
        db.add(quote)

        # Log Event & Update Job status
        job.status = "QUOTE_SENT"
        event = ServiceJobEvent(
            event_id=str(ulid.ULID()),
            job_id=job_id,
            event_type="QUOTE_SENT",
            performed_by=staff_id,
            notes=f"Repair estimate quote V{version} for {data.total} INR sent to customer."
        )
        db.add(event)
        db.commit()
        db.refresh(quote)
        return quote

    def respond_to_quote(self, db: Session, quote_id: str, customer_id: str, action: str) -> ServiceJobQuote:
        quote = db.get(ServiceJobQuote, quote_id)
        if not quote:
            raise HTTPException(status_code=404, detail="Quote estimate not found")

        job = db.get(ServiceJob, quote.service_job_id)
        if not job or job.customer_id != customer_id:
            raise HTTPException(status_code=403, detail="Not authorized to respond to this quote")

        if quote.status != "PENDING_CUSTOMER":
            raise HTTPException(status_code=400, detail=f"Cannot respond to quote in status {quote.status}")

        if action.upper() == "ACCEPT":
            quote.status = "ACCEPTED"
            quote.accepted_at = datetime.utcnow()
            job.status = "QUOTE_ACCEPTED"
            note = "Customer accepted the quote estimate."
        elif action.upper() == "REJECT":
            quote.status = "REJECTED"
            quote.rejected_at = datetime.utcnow()
            job.status = "CUSTOMER_REJECTED"
            note = "Customer rejected the quote estimate."
        else:
            raise HTTPException(status_code=400, detail="Invalid quote response action")

        event = ServiceJobEvent(
            event_id=str(ulid.ULID()),
            job_id=job.job_id,
            event_type=f"QUOTE_{quote.status}",
            performed_by=customer_id,
            notes=note
        )
        db.add(event)
        db.commit()
        db.refresh(quote)
        return quote