#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""Deterministic DCF report helpers for the valuation_review skill."""

from __future__ import annotations

import json
from typing import Iterable


def build_dcf_report(rows: Iterable[dict], current_date: str) -> str:
    """Render a DCF valuation report from normalized row inputs."""
    lines = [f"=== DCF Valuation Analysis ({current_date}) ===\n"]

    for row in rows:
        error = row.get("error")
        ticker = row["ticker"]
        if error:
            lines.append(f"{ticker}: {error}\n")
            continue

        current_fcf = float(row["current_fcf"])
        growth_rate = float(row["growth_rate"])
        market_cap = float(row["market_cap"])
        discount_rate = float(row.get("discount_rate", 0.10))
        terminal_growth = float(row.get("terminal_growth", 0.03))
        num_years = int(row.get("num_years", 5))

        pv_fcf = sum(
            current_fcf
            * (1 + growth_rate) ** year
            / (1 + discount_rate) ** year
            for year in range(1, num_years + 1)
        )
        terminal_fcf = (
            current_fcf
            * (1 + growth_rate) ** num_years
            * (1 + terminal_growth)
        )
        terminal_value = terminal_fcf / (discount_rate - terminal_growth)
        pv_terminal = terminal_value / (1 + discount_rate) ** num_years
        enterprise_value = pv_fcf + pv_terminal
        value_gap = (enterprise_value - market_cap) / market_cap * 100

        if value_gap > 20:
            assessment = "SIGNIFICANTLY UNDERVALUED"
        elif value_gap > 0:
            assessment = "POTENTIALLY UNDERVALUED"
        elif value_gap > -20:
            assessment = "POTENTIALLY OVERVALUED"
        else:
            assessment = "SIGNIFICANTLY OVERVALUED"

        lines.append(f"{ticker}:")
        lines.append(f"  Current FCF: ${current_fcf:,.0f}")
        lines.append(f"  DCF Enterprise Value: ${enterprise_value:,.0f}")
        lines.append(f"  Market Cap: ${market_cap:,.0f}")
        lines.append(f"  Value Gap: {value_gap:+.1f}% -> {assessment}")
        lines.append("")

    return "\n".join(lines)


def main() -> None:
    """Read normalized rows from stdin and emit a text report."""
    payload = json.load(__import__("sys").stdin)
    print(build_dcf_report(payload["rows"], payload["current_date"]))


if __name__ == "__main__":
    main()