"""BESS physical capacity model (degradation + augmentation).

This module only models *how much energy* the battery can store each year.
Actual dispatch (charge/discharge scheduling) happens in dispatch/hybrid_rtc.py.
"""

import numpy as np
import pandas as pd

from remodel_engine.catalog.defaults import PROJECT_LIFE_YEARS
from remodel_engine.schemas.generation import BessConfig


def simulate_bess_capacity(
    config: BessConfig,
    cum_cycles_per_year: list[float],
) -> pd.Series:
    """Return usable energy capacity (MWh) for each of 25 years.

    Degradation model:
      SOH = max(eol_soh, 1 - cum_cycles / design_cycles * (1 - eol_soh))
      Usable MWh = (nameplate + augmentation_so_far) * SOH

    Augmentation steps are additive to nameplate at the specified year.

    Args:
        config:               BessConfig with nameplate, design_cycles, eol_soh, schedule.
        cum_cycles_per_year:  Cumulative full-equivalent cycles at end of each year (25 values).
                              Caller supplies this from dispatch simulation; use a conservative
                              default (e.g. 365 cycles/yr * n) if dispatch hasn't run.

    Returns:
        pd.Series indexed 1-25, values = usable MWh.
    """
    if len(cum_cycles_per_year) != PROJECT_LIFE_YEARS:
        raise ValueError(
            f"cum_cycles_per_year must have {PROJECT_LIFE_YEARS} entries, "
            f"got {len(cum_cycles_per_year)}"
        )

    aug_by_year = {yr: mwh for yr, mwh in config.augmentation_schedule}

    usable = np.empty(PROJECT_LIFE_YEARS, dtype=np.float64)
    nameplate_running = config.capacity_mwh

    for i in range(PROJECT_LIFE_YEARS):
        year = i + 1  # 1-indexed

        # Augmentation: add capacity at start of this year
        if year in aug_by_year:
            nameplate_running += aug_by_year[year]

        cum_cyc = cum_cycles_per_year[i]
        soh = max(
            config.eol_soh,
            1.0 - (cum_cyc / config.design_cycles) * (1.0 - config.eol_soh),
        )
        usable[i] = nameplate_running * soh

    return pd.Series(usable, index=pd.RangeIndex(1, PROJECT_LIFE_YEARS + 1, name="year"))