utils.py

from typing import Dict, List, Optional

class SplitBillCalculator:
    """Smart Split Bill Calculator"""
    
    def __init__(self):
        self.items = []
        self.participants = []
    
    def add_item(self, name: str, price: float, quantity: int = 1):
        """Tambah item ke bill"""
        self.items.append({
            "name": name,
            "price": price,
            "quantity": quantity,
            "total": price * quantity
        })
        return self.items[-1]
    
    def add_participant(self, name: str):
        """Tambah peserta patungan"""
        self.participants.append({
            "name": name,
            "items": [],
            "split_percentage": None
        })
        return self.participants[-1]
    
    def assign_item_to_person(self, person_name: str, item_index: int):
        """Assign item ke orang tertentu"""
        for p in self.participants:
            if p["name"] == person_name:
                if item_index not in p["items"]:
                    p["items"].append(item_index)
                return True
        return False
    
    def calculate_equal_split(self, subtotal: float, tip_pct: float = 0, 
                              tax_pct: float = 0, discount: float = 0) -> Dict:
        """Hitung split rata"""
        tax_amount = subtotal * (tax_pct / 100)
        tip_amount = subtotal * (tip_pct / 100)
        total = subtotal - discount + tax_amount + tip_amount
        
        if len(self.participants) == 0:
            return {"error": "Belum ada peserta"}
        
        per_person = total / len(self.participants)
        
        return {
            "subtotal": subtotal,
            "discount": discount,
            "tax_amount": tax_amount,
            "tip_amount": tip_amount,
            "total": total,
            "num_people": len(self.participants),
            "per_person": per_person,
            "breakdown": [
                {
                    "person": p["name"],
                    "amount": per_person
                } for p in self.participants
            ]
        }
    
    def calculate_individual_split(self, subtotal: float, tip_pct: float = 0,
                                   tax_pct: float = 0, discount: float = 0) -> Dict:
        """Hitung split berdasarkan pesanan individual"""
        if not self.items:
            return {"error": "Belum ada item"}
        
        tax_amount = subtotal * (tax_pct / 100)
        tip_amount = subtotal * (tip_pct / 100)
        total = subtotal - discount + tax_amount + tip_amount
        
        breakdown = []
        total_check = 0
        
        for person in self.participants:
            # Hitung total item orang ini
            person_items_total = sum(
                self.items[i]["total"] for i in person["items"]
            )
            
            # Proporsi orang ini terhadap subtotal
            proportion = person_items_total / subtotal if subtotal > 0 else 0
            
            # Hitung bagian tax, tip, discount secara proporsional
            person_tax = tax_amount * proportion
            person_tip = tip_amount * proportion
            person_discount = discount * proportion
            
            person_total = person_items_total + person_tax + person_tip - person_discount
            
            breakdown.append({
                "person": person["name"],
                "items_total": person_items_total,
                "tax_share": person_tax,
                "tip_share": person_tip,
                "discount_share": person_discount,
                "total_to_pay": person_total,
                "items": [self.items[i]["name"] for i in person["items"]]
            })
            
            total_check += person_total
        
        return {
            "subtotal": subtotal,
            "discount": discount,
            "tax_amount": tax_amount,
            "tip_amount": tip_amount,
            "total": total,
            "breakdown": breakdown,
            "total_check": total_check,
            "is_balanced": abs(total_check - total) < 0.01
        }
    
    def format_currency(self, amount: float) -> str:
        """Format ke Rupiah"""
        return f"Rp {amount:,.0f}"


# Utility functions
def parse_bill_text(text: str) -> Dict:
    """Parse text bill dari user"""
    # Ini bakal dipake AI agent nanti
    return {"raw_text": text}


def validate_split(total_bill: float, individual_amounts: List[float]) -> bool:
    """Validasi apakah total individual = total bill"""
    return abs(sum(individual_amounts) - total_bill) < 0.01


def generate_summary(calculation_result: Dict) -> str:
    """Generate ringkasan text dari hasil kalkulasi"""
    calc = calculation_result
    
    summary = "📊 **RINGKASAN SPLIT BILL**\n\n"
    summary += f"💰 Subtotal: Rp {calc['subtotal']:,.0f}\n"
    summary += f"🏷️  Tax: Rp {calc['tax_amount']:,.0f}\n"
    summary += f"💝 Tip: Rp {calc['tip_amount']:,.0f}\n"
    summary += f"🎫 Discount: Rp {calc.get('discount', 0):,.0f}\n"
    summary += f"💵 **TOTAL: Rp {calc['total']:,.0f}**\n\n"
    
    if 'per_person' in calc:
        summary += f"👤 Per orang (rata): **Rp {calc['per_person']:,.0f}**\n\n"
    
    summary += "**Detail per Orang:**\n"
    for person in calc['breakdown']:
        summary += f"\n🧑 {person['person']}:\n"
        if 'items' in person:
            summary += f"   📋 Pesanan: {', '.join(person['items'])}\n"
        summary += f"   💰 Harus bayar: **Rp {person.get('total_to_pay', person.get('amount', 0)):,.0f}**\n"
    
    return summary