import Link from "next/link";
import { getAssets } from "@/lib/server-data";
import { serverAuth } from "@/lib/pb";
import { ZAR } from "@/lib/utils";
import { Wrench, TriangleAlert } from "lucide-react";
import { RunningView } from "@/components/RunningView";
import { buildRunningRows } from "@/lib/rows";
import { MONTH_NAMES } from "@/lib/data";
import { machineRunningCosts, RUNNING_VAT_PCT } from "@/lib/running-costs";
import type {
  FinancingTerm, InsuranceRate, MonthlyRunningCost, Purchase, PurchaseLine,
} from "@/lib/data";

// Reads PocketBase on every request. Without this Next tries to prerender the
// page at build time, which makes `docker build` depend on the database being
// reachable and then serves a frozen build-time snapshot to users.
export const dynamic = "force-dynamic";

/**
 * Running Costs Overview — everything a vehicle costs to run, per machine per month.
 *
 * Client ruling, 2026-10-09: insurance, finance, purchases and repairs ALL belong here.
 * A machine with no repairs and no purchase order still carries an insurance premium
 * and a monthly instalment while it is financed, so it still has a figure.
 *
 * Everything is read from POCKETBASE — the registers the client maintains in the app.
 * The original spreadsheet only bootstrapped the page; it is not a source here.
 *
 * ⚠️ This is a RE-CUT, not new spend: insurance and instalments are already inside
 * `monthly_income.fixed_expenses`. Adding this total to fixed expenses would count the
 * same premium twice.
 */
export default async function RunningPage() {
  const pb = await serverAuth();
  const [assets, repairs, purchases, lines, insurance, finance] = await Promise.all([
    getAssets(),
    pb.collection("monthly_running_costs").getFullList<MonthlyRunningCost>(),
    pb.collection("purchases").getFullList<Purchase>(),
    pb.collection("purchase_lines").getFullList<PurchaseLine>(),
    pb.collection("insurance_rates").getFullList<InsuranceRate>(),
    pb.collection("financing_terms").getFullList<FinancingTerm>(),
  ]);

  // Never project past the month we are IN — see lib/running-costs.ts.
  const now = new Date();
  const lastMonth = now.getFullYear() === 2026 ? now.getMonth() + 1 : 12;

  const { byAsset, undatedPurchases } = machineRunningCosts({
    assets, repairs, purchases, purchaseLines: lines, insurance, finance,
  }, lastMonth);
  const rows = buildRunningRows(assets, byAsset);

  const monthTotals = Array(12).fill(0);
  const monthTotalsExcl = Array(12).fill(0);
  const monthByKind = { repairs: Array(12).fill(0), purchases: Array(12).fill(0), insurance: Array(12).fill(0), finance: Array(12).fill(0) };
  for (const r of rows) {
    r.months.forEach((v, i) => (monthTotals[i] += v));
    r.monthsExcl.forEach((v, i) => (monthTotalsExcl[i] += v));
    for (const k of ["repairs", "purchases", "insurance", "finance"] as const)
      r.byKind[k].forEach((v, i) => (monthByKind[k][i] += v));
  }
  const grand = monthTotals.reduce((s, v) => s + v, 0);
  const grandExcl = monthTotalsExcl.reduce((s, v) => s + v, 0);
  const unallocated = lines.filter((l) => !l.asset).length;

  return (
    <div className="p-4 sm:p-8 max-w-[1400px]">
      <div className="flex flex-col sm:flex-row sm:items-end sm:justify-between gap-4 mb-6">
        <div>
          <div className="flex items-center gap-3 mb-1">
            <div className="w-10 h-10 shrink-0 rounded-xl bg-gradient-to-br from-[#EDAE49]/15 to-[#D1495B]/15 grid place-items-center text-[#EDAE49]">
              <Wrench className="w-5 h-5" />
            </div>
            <h1 className="text-2xl font-semibold text-[#003D5B] dark:text-white">Running Costs</h1>
          </div>
          <p className="text-gray-500 dark:text-gray-400 text-sm">
            Everything a vehicle costs to run · repairs, purchases, insurance, finance · 2026
          </p>
          <p className="text-xs text-gray-400 dark:text-text-soft mt-1">
            Shown to {MONTH_NAMES.slice(0, lastMonth).join(", ")}. A month ahead is not shown —
            it cannot be calculated, only guessed at, and the last month keeps growing as
            things are entered.
          </p>
          <p className="text-xs text-gray-400 dark:text-text-soft mt-1">
            A re-cut of costs already counted in fixed expenses — do not add this to them.
            Figures are incl VAT, with the excl figure derived at {RUNNING_VAT_PCT}%.
          </p>
        </div>
        <div className="bg-gradient-to-br from-[#EDAE49] to-[#D1495B] rounded-2xl px-5 py-3 text-white shadow-lg shadow-orange-500/20 self-start sm:self-auto">
          <div className="text-xs text-white/80">YTD running cost · incl VAT</div>
          <div className="text-2xl font-semibold tabular-nums">{ZAR(grand)}</div>
          <div className="text-xs text-white/75 tabular-nums mt-0.5">excl VAT {ZAR(grandExcl)}</div>
        </div>
      </div>

      {undatedPurchases.length > 0 && (
        <div className="mb-4 flex items-start gap-2 rounded-2xl border border-[#EDAE49]/30 bg-[#EDAE49]/[0.06] p-4 text-xs text-gray-600 dark:text-gray-400">
          <TriangleAlert className="w-4 h-4 mt-0.5 shrink-0 text-[#EDAE49]" />
          <span>
            <span className="font-semibold text-[#003D5B] dark:text-white">
              {undatedPurchases.length} purchase line{undatedPurchases.length !== 1 && "s"} could not be filed
            </span>{" "}
            — no readable PO date ({undatedPurchases.slice(0, 3).join(", ")}). Excluded rather than
            guessed into January.
          </span>
        </div>
      )}

      {unallocated > 0 && (
        <div className="mb-4 rounded-2xl border border-[#30638E]/25 bg-[#30638E]/[0.05] p-4 text-xs text-gray-600 dark:text-gray-400">
          <span className="font-semibold text-[#003D5B] dark:text-white">
            {unallocated} purchase line{unallocated !== 1 && "s"} not yet allocated
          </span>{" "}
          to a machine, so they are{" "}
          <span className="font-medium">not</span> in these totals — see{" "}
          <Link href="/running/purchases" className="underline inline-block py-4 -my-4">
            Purchases
          </Link>
          .
        </div>
      )}

      <RunningView
        rows={rows}
        palette={{ income: "#EDAE49", profit: "#EDAE49", loss: "#EDAE49" }}
        monthTotals={monthTotals}
        monthTotalsExcl={monthTotalsExcl}
        byKind={monthByKind}
        visibleMonths={lastMonth}
      />
    </div>
  );
}