"""Render a Plan as a plain-text sense-check table.

The DB-less inspection harness prints this so the modelled package — its SAP
band transition, cost, and each Plan Measure's attributed SAP / bill impact —
can be eyeballed and debugged by hand. Pure presentation: it reads a `Plan`
domain object and returns a string, computing nothing.
"""

from __future__ import annotations

from typing import Optional

from datatypes.epc.domain.epc import Epc
from domain.modelling.plan import Plan

_KG_PER_TONNE = 1000.0


def _band(sap_continuous: float) -> str:
    return Epc.from_sap_score(round(sap_continuous)).value


def _signed_gbp(value: Optional[float]) -> str:
    return "n/a" if value is None else f"{value:+,.0f}"


def _money(value: Optional[float]) -> str:
    if value is None:
        return "n/a"
    sign = "-" if value < 0 else ""
    return f"{sign}£{abs(value):,.0f}"


def _signed_kwh(value: Optional[float]) -> str:
    return "n/a" if value is None else f"{value:+,.0f}"


def format_plan_table(plan: Plan) -> str:
    """A multi-line table: one package summary line, then one line per Plan
    Measure (signed so positive is an improvement / a saving)."""
    co2_tonnes_saved: float = plan.co2_savings_kg_per_yr / _KG_PER_TONNE
    header = (
        f"Plan  SAP {plan.baseline.sap_continuous:.1f} ({_band(plan.baseline.sap_continuous)})"
        f" -> {plan.post_sap_continuous:.1f} ({plan.post_epc_rating.value})"
        f"   CO2 saved {co2_tonnes_saved:.2f} t/yr"
        f"   cost £{plan.cost_of_works:,.0f} (+£{plan.contingency_cost:,.0f} cont.)"
        f"   bill saved {_money(plan.energy_bill_savings)}/yr"
    )
    valuation = plan.valuation
    valuation_line = f"  valuation uplift {valuation.average_pct:+.1%}"
    if valuation.average_value is not None and valuation.post_retrofit_value is not None:
        valuation_line += (
            f"  ({_money(valuation.average_value)}"
            f" -> {_money(valuation.post_retrofit_value)})"
        )
    columns = (
        f"  {'measure':<30}{'SAP':>7}{'cost':>10}"
        f"{'kWh/yr':>10}{'£/yr':>9}"
    )
    rows = [
        f"  {measure.measure_type:<30}"
        f"{measure.impact.sap_points:>+7.1f}"
        f"{('£' + format(measure.cost.total, ',.0f')):>10}"
        f"{_signed_kwh(measure.kwh_savings):>10}"
        f"{_signed_gbp(measure.energy_cost_savings):>9}"
        for measure in plan.measures
    ]
    return "\n".join([header, valuation_line, columns, *rows])