B.Tech-Project-III/negot8/backend/features/expenses.py

from features.base_feature import BaseFeature
from tools.calculator import CalculatorTool

_calc = CalculatorTool()


class ExpensesFeature(BaseFeature):

    async def get_context(self, preferences_a: dict, preferences_b: dict, user_a_id: int = None, user_b_id: int = None) -> str:
        """
        Pre-calculate expense totals using the safe Calculator tool.
        Inject exact figures so the LLM never does arithmetic.
        """
        raw_a = preferences_a.get("raw_details", {})
        raw_b = preferences_b.get("raw_details", {})

        # Collect line items from both parties
        items = {}
        for raw in (raw_a, raw_b):
            expenses = raw.get("expenses") or raw.get("items") or raw.get("line_items") or []
            if isinstance(expenses, list):
                for item in expenses:
                    if isinstance(item, dict):
                        name = item.get("name") or item.get("item") or "item"
                        amount = item.get("amount") or item.get("cost") or item.get("price") or 0
                        try:
                            amount = float(amount)
                        except (TypeError, ValueError):
                            amount = 0
                        if amount > 0:
                            items[name] = items.get(name, 0) + amount

        lines = ["EXPENSE SPLITTING DOMAIN RULES:"]
        lines.append("• Use ONLY the pre-calculated amounts below. NEVER estimate or round differently.")
        lines.append("• Equal splits (50-50) are the default. Unequal splits need explicit justification.")
        lines.append("• After reaching agreement, include a 'settlement' key with who pays whom and how much.")
        lines.append("• Use the calculator results below — do NOT re-calculate with different numbers.")

        if items:
            total = sum(items.values())
            lines.append(f"\nLine items (pre-verified by Calculator tool):")
            for name, amount in items.items():
                half = amount / 2
                lines.append(f"  • {name}: ₹{amount:,.0f}  →  50-50 split = ₹{half:,.2f} each")
            lines.append(f"\nTotal: ₹{total:,.0f}  →  50-50 = ₹{total/2:,.2f} each")
        else:
            lines.append("\nNo line items found — extract amounts from the preferences and calculate fair splits.")

        # UPI info
        upi_a = raw_a.get("upi_id") or raw_a.get("upi")
        upi_b = raw_b.get("upi_id") or raw_b.get("upi")
        if upi_a:
            lines.append(f"\nParty A UPI ID: {upi_a}")
        if upi_b:
            lines.append(f"\nParty B UPI ID: {upi_b}")
        if upi_a or upi_b:
            lines.append("Include the relevant UPI ID in the settlement details of your proposal.")

        return "\n".join(lines)

    def format_resolution(
        self, resolution: dict, preferences_a: dict, preferences_b: dict
    ) -> str:
        status = resolution.get("status", "resolved")
        final = resolution.get("final_proposal", {})
        details = final.get("details", {})
        rounds = resolution.get("rounds_taken", "?")
        summary = resolution.get("summary", "Agreement reached")

        if status == "escalated":
            return (
                f"⚠️ *Expenses — Human Review Needed*\n\n"
                f"_{summary}_\n\n"
                f"Agents couldn't fully agree in {rounds} round(s). "
                f"Please review the proposed split above."
            )

        # Build breakdown table
        line_items = details.get("line_items") or details.get("items") or []
        raw_settlement = details.get("settlement") or {}
        # Guard: settlement may be a string summary instead of a dict
        settlement = raw_settlement if isinstance(raw_settlement, dict) else {}
        payer = settlement.get("payer") or settlement.get("from") or ""
        payee = settlement.get("payee") or settlement.get("to") or ""
        amount = (settlement.get("amount") or details.get("amount")
                  or details.get("total_owed") or (str(raw_settlement) if isinstance(raw_settlement, str) else ""))

        lines = ["💰 *Expenses Settled!*\n"]

        if line_items and isinstance(line_items, list):
            lines.append("📊 *Breakdown:*")
            for item in line_items:
                if isinstance(item, dict):
                    name = item.get("name") or item.get("item", "Item")
                    cost = item.get("amount") or item.get("cost") or ""
                    split = item.get("split") or item.get("ratio") or "50-50"
                    a_pays = item.get("party_a") or item.get("a_pays") or ""
                    b_pays = item.get("party_b") or item.get("b_pays") or ""
                    if a_pays and b_pays:
                        lines.append(f"  • {name} (₹{cost}) — {split} → A: ₹{a_pays} / B: ₹{b_pays}")
                    else:
                        lines.append(f"  • {name}: {split} split")
            lines.append("")

        if payer and amount:
            lines.append(f"💸 *{payer} owes {payee}: ₹{amount}*")
        elif amount:
            lines.append(f"💸 *Settlement amount: ₹{amount}*")

        lines.append(f"\n⏱ Agreed in {rounds} round(s)")
        if summary and summary != "Agreement reached":
            lines.append(f"_{summary}_")

        return "\n".join(lines)