// Shared types and pure data transforms. Safe for client components.
import type { RecordModel } from "pocketbase";

export type Asset = {
  id: string;
  code: string;
  name: string;
  category: string;
  type: string;
  gl_account: string;
  supplier: string;
  monthly_excl: number;
  monthly_incl: number;
  purchase_value: number;
  is_provisional: boolean;
  is_active: boolean;
  // TRUE when this machine appears on the client's operator sheet, i.e. it belongs on
  // /running/operators. Containers, generators and truck trailers are FALSE — they are
  // in the register but nobody is ever allocated to them. Set by the seed from
  // data/source/operators.json, not edited by hand.
  on_operator_sheet?: boolean;
  // The text on the vehicle's QR sticker, typed in the Plant Register. Empty = the sticker
  // carries the register code itself.
  qr_code?: string;
  // Which yard this machine is parked at. Empty until assigned in
  // /plant → Edit → Site. cascadeDelete is OFF, so removing a site never
  // removes the machines that referenced it.
  site: string;
  // Plant Map. Null until the on-site scan sheet supplies them. 0/0 counts as
  // "not located" — see `hasCoords` in components/PlantMap.
  latitude: number | null;
  longitude: number | null;
} & RecordModel;

export type CostLine = {
  id: string;
  asset: string;
  year: number;
  month: number;
  kind: "instalment" | "insurance" | "tracking" | "operator" | "running";
  amount: number;
} & RecordModel;

/**
 * A finance agreement for one plant vehicle: a monthly instalment, a term, and
 * whether it has been settled.
 *
 * Deliberately NOT part of `insurance_rates` and NOT a `cost_lines` row. Insurance
 * and financing are independent commitments that happen to share a rate sheet; the
 * date and settled fields here are typed in by a human and must survive a re-seed.
 *
 * A year or month of `0` means UNKNOWN — never "January". See `lib/financing.ts`.
 */
export type FinancingTerm = {
  id: string;
  asset: string;
  installment: number;
  start_year: number;
  start_month: number;
  end_year: number;
  end_month: number;
  is_settled: boolean;
  plant: string;
  source: string;
} & RecordModel;

/**
 * An operator, and which plant vehicle they are allocated to.
 *
 * TERM 3 of the fixed-expense formula — the wage that varies per machine per month,
 * and the last unknown in the workbook cost model (see AGENTS.md).
 *
 * An empty `asset` means UNASSIGNED, which is a normal state on this register: two
 * operators had no machine on the sheet. It never means "deleted".
 */
export type Operator = {
  id: string;
  name: string;
  employee_code: string;
  rate: number;
  asset: string;
  source: string;
} & RecordModel;

/**
 * A mechanic on the payroll, with the employee number their badge QR encodes.
 *
 * Not a plant item and not an operator: an operator is allocated TO a machine, a
 * mechanic is not. The employee code is the identity — it must be unique, because it
 * is what a scanner reads.
 */
export type Mechanic = {
  id: string;
  name: string;
  employee_code: string;
  role: string;
  photo: string;
  source: string;
} & RecordModel;

/**
 * A tracked consumable oil, held in bulk and drawn down from a drum.
 *
 * `store_cost_code` is the code the oil PO prints against the line — "MPLANT, ENGOIL".
 * It is what tells an uploaded PO line apart as OIL rather than spend against a
 * machine, and the two namespaces cannot collide because a store is never a machine.
 */
export type OilItem = {
  id: string;
  code: string;
  name: string;
  detail: string;
  supplier: string;
  material_code: string;
  store_cost_code: string;
  drum_litres: number;
  colour: string;
  qr_payload: string;
  source: string;
} & RecordModel;

/**
 * One movement in oil stock. "received" when a purchase order delivers oil, "used"
 * when a drum is drawn down. Stock is the sum of both, so usage stays auditable.
 */
export type OilMovement = {
  id: string;
  item: string;
  purchase: string;
  kind: string;
  litres: number;
  occurred_on: string;
  note: string;
} & RecordModel;

/** A purchase order header: what was ordered, from whom, for how much. */
export type Purchase = {
  id: string;
  po_no: string;
  supplier: string;
  supplier_code: string;
  po_date: string;
  required_by: string;
  req_no: string;
  currency: string;
  subtotal: number;
  vat: number;
  total: number;
  source_pdf: string;
  source_file: string;
} & RecordModel;

/**
 * One line of a purchase order, allocated to a plant vehicle by its COST CODE.
 *
 * `cost_code` is kept exactly as printed (hyphenation and all) so the document can
 * still be checked line by line; `asset` is where it landed. An EMPTY `asset` means the
 * code matched no machine in the register — money that exists but is not yet on a plant
 * item. It is never a zero and never a guess.
 */
export type PurchaseLine = {
  id: string;
  purchase: string;
  line_no: number;
  material_code: string;
  cost_code: string;
  asset: string;
  description: string;
  qty: number;
  rate: number;
  disc_pct: number;
  vat_pct: number;
  amount_excl: number;
  vat: number;
  total_incl: number;
} & RecordModel;

export type MonthlyIncome = {
  id: string;
  asset: string;
  year: number;
  month: number;
  income: number;
  fixed_expenses: number;
  running_cost: number;
} & RecordModel;

export type MonthlyRunningCost = {
  id: string;
  asset: string;
  year: number;
  month: number;
  amount: number;
} & RecordModel;

/**
 * An insurance premium for one plant vehicle over a PERIOD of months.
 *
 * This is deliberately a different grain from `cost_lines`: a premium changes
 * every month or three (client ruling, 2026-10-08), so it is recorded once per
 * change and the per-month cost is derived from it. `month_to === 0` means the
 * period is OPEN — this is the premium currently being charged. See `lib/insurance.ts`.
 */
export type InsuranceRate = {
  id: string;
  asset: string;
  year: number;
  month_from: number;
  month_to: number;
  rate: number;
  plant: string;
  source: string;
} & RecordModel;

export type Overhead = {
  id: string;
  section: string;
  description: string;
  gl_account: string;
  supplier: string;
  qty: number;
  unit_price: number;
  amount_excl: number;
  vat: number;
  amount_incl: number;
} & RecordModel;

// Invoice header. `booked_month`/`booked_year` record the period the invoice was
// posted into monthly_income; `is_booked` flips once every line has a target asset.
export type Invoice = {
  id: string;
  invoice_no: string;
  invoice_date: string;
  order_no: string;
  debtor: string;
  debtor_no: string;
  period_from: string;
  period_to: string;
  description: string;
  site: string;
  section: string;
  category: string;
  currency: string;
  vat_reg_no: string;
  source_file: string;
  subtotal: number;
  escalation: number;
  vat: number;
  vat_pct: number;
  total_excl: number;
  total_incl: number;
  source_pdf: string;
  booked_month: number;
  booked_year: number;
  is_booked: boolean;
} & RecordModel;

// Invoice line. `machine_code` is what the invoice prints; `asset_code` is the
// register match; `booked_asset` is the machine the income is actually booked to.
// These can differ — an invoice line may legitimately be charged to another machine.
export type InvoiceLine = {
  id: string;
  invoice: string;
  line_no: number;
  machine_code: string;
  asset_code: string;
  description: string;
  qty: number;
  unit: string;
  rate: number;
  rate_type: string;
  amount_excl: number;
  vat: number;
  total_incl: number;
  booked_asset: string;
  booked_site: string;
  booked_month: number;
  booked_year: number;
} & RecordModel;

// Returns the last month that has any actual income — used to label forecast ranges.
export function lastActualMonth(rows: MonthlyIncome[]): number {
  let m = 0;
  for (const r of rows) if (r.income > 0 && r.month > m) m = r.month;
  return m;
}

// An invoice line joined to the asset it is booked against. Kept as a plain derived
// type so the page never has to deal with PocketBase expand payloads.
export type BookedLine = InvoiceLine & {
  bookedCode: string;
  bookedName: string;
  isBooked: boolean;
};

export function joinBookedLines(lines: InvoiceLine[], assets: Asset[]): BookedLine[] {
  const byId = new Map(assets.map((a) => [a.id, a]));
  return lines.map((l) => {
    const a = l.booked_asset ? byId.get(l.booked_asset) : undefined;
    return {
      ...l,
      bookedCode: a?.code || "",
      bookedName: a?.name || "",
      isBooked: Boolean(a),
    };
  });
}

// One machine can legitimately be hired to several sites in the same month — that is
// multi-site use, not a duplicate. These are flagged so the reader can see the pattern,
// NOT as a data error, so nothing here is styled as a problem.
//
// Returns a map of line id → the other (invoice, site) pairs this same machine code was
// billed on over an overlapping period.
export function findDuplicateMachineCodes(
  invoices: Invoice[],
  lines: BookedLine[],
): Map<string, string[]> {
  const byId = new Map(invoices.map((i) => [i.id, i]));
  const groups = new Map<string, BookedLine[]>();
  for (const l of lines) {
    if (!l.machine_code) continue;
    if (!groups.has(l.machine_code)) groups.set(l.machine_code, []);
    groups.get(l.machine_code)!.push(l);
  }

  const out = new Map<string, string[]>();
  for (const [, group] of groups) {
    if (group.length < 2) continue;
    for (const line of group) {
      const inv = byId.get(line.invoice);
      if (!inv) continue;
      const others = new Set<string>();
      for (const other of group) {
        if (other.id === line.id) continue;
        const oInv = byId.get(other.invoice);
        if (!oInv || oInv.id === inv.id) continue;
        const overlaps = inv.period_from <= oInv.period_to && oInv.period_from <= inv.period_to;
        if (overlaps) others.add(oInv.invoice_no);
      }
      if (others.size) out.set(line.id, [...others]);
    }
  }
  return out;
}

export type Site = {
  id: string;
  name: string;
  code: string;
  notes: string;
  latitude: number;
  longitude: number;
  container_asset: string;
  container_code: string;
  is_active: boolean;
} & RecordModel;

export const MONTH_NAMES = [
  "Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec",
];