import { serverAuth } from "./pb";
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;
} & RecordModel;

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

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_month: number;
  booked_year: number;
} & RecordModel;

export async function getAssets(): Promise<Asset[]> {
  const pb = await serverAuth();
  return pb.collection("assets").getFullList<Asset>({ sort: "category,name" });
}

export async function getAssetsByCategory(category: string): Promise<Asset[]> {
  const all = await getAssets();
  return all.filter((a) => a.category === category);
}

export async function getMonthlyIncome(year = 2026): Promise<MonthlyIncome[]> {
  const pb = await serverAuth();
  return pb.collection("monthly_income").getFullList<MonthlyIncome>({
    filter: `year = ${year}`,
    sort: "month",
  });
}

// Part 1.2: YTD aggregations operate on actuals only by default.
// `is_forecast` is a boolean field on monthly_income; rows where it's true are excluded.
export async function getActualMonthlyIncome(year = 2026): Promise<MonthlyIncome[]> {
  const all = await getMonthlyIncome(year);
  return all.filter((r) => !(r as any).is_forecast);
}

// 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;
}

export async function getRunningCosts(year = 2026): Promise<MonthlyRunningCost[]> {
  const pb = await serverAuth();
  return pb.collection("monthly_running_costs").getFullList<MonthlyRunningCost>({
    filter: `year = ${year}`,
    sort: "month",
  });
}

export async function getOverheads(): Promise<Overhead[]> {
  const pb = await serverAuth();
  return pb.collection("overheads").getFullList<Overhead>({ sort: "section,description" });
}

export async function getOverheadsBySection(section: string): Promise<Overhead[]> {
  const all = await getOverheads();
  return all.filter((o) => o.section === section);
}

export async function getInvoices(): Promise<Invoice[]> {
  const pb = await serverAuth();
  return pb.collection("invoices").getFullList<Invoice>({ sort: "-invoice_date,-invoice_no" });
}

export async function getInvoiceLines(invoiceId?: string): Promise<InvoiceLine[]> {
  const pb = await serverAuth();
  return pb.collection("invoice_lines").getFullList<InvoiceLine>({
    filter: invoiceId ? `invoice = "${invoiceId}"` : "",
    sort: "line_no",
  });
}

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