Remodel/packages/web/lib/api.ts

const API_BASE = process.env.NEXT_PUBLIC_API_URL ?? "http://localhost:8000";

// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------

export interface Scenario {
  id: string;
  name: string;
  status: string;
  kpis_json: string | null;
  created_at: string;
  runtime_s?: number | null;
}

export interface ScenarioDetail extends Scenario {
  inputs_json: string | null;
  statements_json: string | null;
  debt_schedule_json: string | null;
  error_message: string | null;
}

export interface KpiSummary {
  solved_tariff_inr_per_kwh?: number | null;
  equity_irr?: number | null;
  project_irr?: number | null;
  min_dscr?: number | null;
  avg_dscr?: number | null;
  total_capex_cr?: number | null;
  idc_cr?: number | null;
  debt_cr?: number | null;
  solar_y1_cuf?: number | null;
  wind_y1_plf?: number | null;
  lcoe_inr_per_kwh?: number | null;
  payback_years?: number | null;
  rtc_cuf_achieved?: number | null;
  total_shortfall_mwh?: number | null;
  total_curtailed_mwh?: number | null;
  total_mcp_revenue_cr?: number | null;
}

export interface PnLRow {
  year: number;
  revenue_cr: number;
  ppa_revenue_cr: number;
  mcp_revenue_cr: number;
  ppa_tariff_inr_per_kwh: number;
  ppa_units_mwh: number;
  mcp_units_mwh: number;
  opex_total_cr: number;
  om_cr: number;
  insurance_cr: number;
  land_lease_cr: number;
  am_fee_cr: number;
  misc_opex_cr: number;
  ebitda_cr: number;
  depreciation_book_cr: number;
  ebit_cr: number;
  interest_cr: number;
  pbt_cr: number;
  tax_cr: number;
  pat_cr: number;
}

export interface CfsRow {
  year: number;
  pat_cr: number;
  depreciation_cr: number;
  delta_working_capital_cr: number;
  cfo_cr: number;
  capex_cr: number;
  cfi_cr: number;
  debt_drawdown_cr: number;
  debt_repayment_cr: number;
  equity_injection_cr: number;
  cff_cr: number;
  net_cash_flow_cr: number;
  opening_cash_cr: number;
  closing_cash_cr: number;
}

export interface BsRow {
  year: number;
  gross_block_cr: number;
  accumulated_depr_cr: number;
  net_block_cr: number;
  cash_cr: number;
  receivables_cr: number;
  total_assets_cr: number;
  equity_cr: number;
  reserves_cr: number;
  long_term_debt_cr: number;
  payables_cr: number;
  total_liabilities_cr: number;
}

export interface DebtYearRow {
  year: number;
  opening_balance_cr: number;
  interest_cr: number;
  principal_cr: number;
  total_debt_service_cr: number;
  closing_balance_cr: number;
  dscr: number;
}

export interface GenerationRow {
  year: number;
  solar_mwh: number;
  wind_mwh: number;
  gross_mwh: number;
  aux_loss_mwh: number;
  tx_loss_mwh: number;
  dsm_loss_mwh: number;
  net_billable_mwh: number;
  solar_cuf_pct: number | null;
  wind_plf_pct: number | null;
  revenue_cr: number;
}

export interface IdcMonthRow {
  month: number;
  equity_draw_cr: number;
  debt_draw_cr: number;
  idc_accrual_cr: number;
  cum_equity_cr: number;
  cum_debt_cr: number;
  cum_idc_cr: number;
  cum_tpc_cr: number;
}

export interface IdcPhasing {
  construction_months: number;
  base_capex_cr: number;
  idc_cr: number;
  total_capex_cr: number;
  debt_cr: number;
  equity_cr: number;
  monthly: IdcMonthRow[];
}

export interface Statements {
  pnl: PnLRow[];
  cfs: CfsRow[];
  bs: BsRow[];
  generation?: GenerationRow[];
  idc_phasing?: IdcPhasing;
}

export type CostBasis =
  | "PER_WP_DC"
  | "PER_MWP_DC"
  | "PER_MW_AC"
  | "PER_MW_WIND"
  | "PER_MWH_BESS"
  | "PER_ACRE"
  | "PCT_OF_HARDCOST"
  | "ABS_INR_CR";

export type DeprClass =
  | "Plant"
  | "BESS"
  | "Building"
  | "Land_NoDepr"
  | "LandLease_Amortized"
  | "Intangible"
  | "Capitalized_NoDepr"
  | "Expensed";

export type CostAttribution = "SolarOnly" | "WindOnly" | "BESSOnly" | "Common";

export interface CostItem {
  id: string;
  name: string;
  category: "HardCost" | "SoftCost" | "EPCOverhead" | "EPCMargin" | "FinancingCost" | "Contingency";
  basis: CostBasis;
  value: number;
  depr_class: DeprClass;
  tax_pct?: number;  // GST/tax rate, default 5% for modules
  attribution: CostAttribution;
  phasing_id?: string;
  escalation_pct?: number;
}

export interface ScenarioInputPayload {
  project?: {
    name?: string;
    state?: string | null;
    capacity_solar_mwp?: number;
    capacity_wind_mw?: number;
    capacity_bess_mwh?: number;
    capacity_bess_mw?: number;
    land_acres?: number;
    cod_year?: number;
    cod_date?: string | null;
    solar_cod_date?: string | null;
    wind_cod_date?: string | null;
    bess_cod_date?: string | null;
  };
  solar?: {
    location_id: string;
    capacity_dc_mwp: number;
    capacity_ac_mw: number;
    dc_ac_ratio?: number;
    availability_fraction?: number;
    dc_loss_fraction?: number;
    soiling_fraction?: number;
    degradation_y1?: number;
    degradation_annual?: number;
    stabilization_days?: number;
    stabilization_energy_loss_frac?: number;
    stabilization_dsm_addon_pct?: number;
  } | null;
  wind?: {
    location_id: string;
    capacity_mw: number;
    hub_height_m?: number;
    availability_fraction?: number;
    wake_loss_fraction?: number;
    stabilization_days?: number;
    stabilization_energy_loss_frac?: number;
    stabilization_dsm_addon_pct?: number;
  } | null;
  bess?: {
    capacity_mwh: number;
    power_mw: number;
    rte?: number;
    dod?: number;
  } | null;
  rtc?: {
    rtc_mw?: number;
    mcp_enabled?: boolean;
    initial_soc_frac?: number;
  } | null;
  commercial?: {
    tariff_inr_per_kwh?: number;
    aux_consumption_pct?: number;
    transmission_loss_pct?: number;
    dsm_loss_pct?: number;
    bad_debt_pct?: number;
    receivable_days?: number;
    payable_days?: number;
  };
  opex?: {
    om_solar_cr_per_mw?: number;
    om_wind_cr_per_mw?: number;
    om_bess_cr_per_mwh?: number;
    insurance_pct_of_capex?: number;
    land_lease_cr?: number;
    om_escalation_pct?: number;
    om_solar_escalation_pct?: number;
    om_solar_escalation_after_year?: number;
    om_wind_escalation_pct?: number;
    om_wind_escalation_after_year?: number;
    om_bess_pct_of_capex?: number | null;
    am_fee_pct_of_revenue?: number;
    misc_cr?: number;
  };
  capex?: {
    cost_items?: CostItem[];
    debt_fraction?: number;
    interest_rate_annual?: number;
    construction_months?: number;
    upfront_fee_pct?: number;
  };
  debt?: {
    interest_rate_annual?: number;
    tenor_years?: number;
    moratorium_years?: number;
    de_ratio?: number;
    min_dscr?: number;
    avg_dscr?: number;
    schedule_shape?: string;
  };
  tax?: {
    rate?: number;
    wdv_plant_rate?: number;
    wdv_bess_rate?: number;
    wdv_building_rate?: number;
    wdv_intangible_rate?: number;
  };
  solver?: {
    mode: "solve_tariff" | "fixed_tariff";
    target_equity_irr?: number;
    fixed_tariff?: number | null;
  };
}

export interface ProgressEvent {
  stage: string;
  pct: number;
}

// ---------------------------------------------------------------------------
// API helpers
// ---------------------------------------------------------------------------

async function apiFetch<T>(url: string, options?: RequestInit): Promise<T> {
  const res = await fetch(`${API_BASE}${url}`, options);
  if (!res.ok) throw new Error(`API error ${res.status}: ${await res.text()}`);
  return res.json() as Promise<T>;
}

// ---------------------------------------------------------------------------
// Scenario functions
// ---------------------------------------------------------------------------

export async function createScenario(
  name: string,
  inputs?: ScenarioInputPayload,
): Promise<Scenario> {
  return apiFetch<Scenario>("/api/scenarios", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ name, inputs }),
  });
}

export async function getScenario(id: string): Promise<ScenarioDetail> {
  return apiFetch<ScenarioDetail>(`/api/scenarios/${id}`);
}

export async function listScenarios(): Promise<Scenario[]> {
  return apiFetch<Scenario[]>("/api/scenarios");
}

export async function getKpis(id: string): Promise<KpiSummary> {
  return apiFetch<KpiSummary>(`/api/scenarios/${id}/kpis`);
}

export async function getStatements(id: string): Promise<Statements> {
  return apiFetch<Statements>(`/api/scenarios/${id}/statements`);
}

export async function archiveScenario(id: string): Promise<void> {
  await apiFetch(`/api/scenarios/${id}`, { method: "DELETE" });
}

export async function updateScenarioInputs(
  id: string,
  inputs: ScenarioInputPayload,
): Promise<Scenario> {
  return apiFetch<Scenario>(`/api/scenarios/${id}/inputs`, {
    method: "PATCH",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ inputs }),
  });
}

export function scenarioEventsUrl(id: string): string {
  return `${API_BASE}/api/scenarios/${id}/events`;
}

export function scenarioExcelUrl(id: string): string {
  return `${API_BASE}/api/scenarios/${id}/export/excel`;
}