// DashboardPage — home page at `/`.
//
// Converged onto the `/reports/cartes` model (Issue #279, epic #260): the KPI
// row, top movers and budget adherence are the exact Cartes presentational
// components, sourced from the same `getCartesSnapshot` reference-month
// snapshot. Two Dashboard-specific widgets remain: the top-expense-categories
// ranked bar chart (replacing the former expense-only pie) and the net-worth
// tile (from the Bilan — a different metric from every transactional widget
// here, see NetWorthTile's own header comment).
//
// Onboarding (#352): the page branches on the getting-started checklist
// `status`, never on a bare counter. While it loads, only the title and the
// categories banner are rendered (no flash of 0 $ widgets nor of the empty state). A
// profile without any transaction gets `DashboardEmptyState` instead of the
// widgets, outside the `isLoading` veil so its link stays clickable. With
// transactions, the page shows no list of its own: the getting-started banner
// that `AppShell` puts on top of every page replaced the compact bar (#397,
// D7). A first load that fails falls back to the v0.15.0 page without the
// list; the provider logs it.
//
// Since #396 the checklist comes from `OnboardingProvider` (AppShell), shared
// by every page and re-read live, instead of a load of its own at mount.
import { useState, useCallback, useMemo } from "react";
import { useTranslation } from "react-i18next";
import { useDashboard } from "../hooks/useDashboard";
import { useOnboarding } from "../contexts/OnboardingContext";
import { PageHelp } from "../components/shared/PageHelp";
import PeriodSelector from "../components/dashboard/PeriodSelector";
import CategoryBarChart from "../components/reports/CategoryBarChart";
import CategoriesV1DiscoveryBanner from "../components/dashboard/CategoriesV1DiscoveryBanner";
import DashboardEmptyState from "../components/dashboard/DashboardEmptyState";
import NetWorthTile from "../components/dashboard/NetWorthTile";
import FilterPanel from "../components/reports/FilterPanel";
import KpiCard from "../components/reports/cards/KpiCard";
import IncomeExpenseOverlayChart from "../components/reports/cards/IncomeExpenseOverlayChart";
import TopMoversList from "../components/reports/cards/TopMoversList";
import BudgetAdherenceCard from "../components/reports/cards/BudgetAdherenceCard";
import CategoryOverTimeChart from "../components/reports/CategoryOverTimeChart";
import TransactionDetailModal from "../components/shared/TransactionDetailModal";
import type { CategoryBreakdownItem } from "../shared/types";
import { computeDateRange, buildMonthOptions } from "../utils/dateRange";

export default function DashboardPage() {
  const { t, i18n } = useTranslation();
  const {
    state,
    setPeriod,
    setCustomDates,
    setReferencePeriod,
    setAccountIds,
  } = useDashboard();
  const { categoryBreakdown, categoryOverTime, cartesSnapshot, period, isLoading } = state;
  const onboarding = useOnboarding();

  const [hiddenCategories, setHiddenCategories] = useState<Set<string>>(new Set());
  const [detailModal, setDetailModal] = useState<CategoryBreakdownItem | null>(null);

  const toggleHidden = useCallback((name: string) => {
    setHiddenCategories((prev) => {
      const next = new Set(prev);
      if (next.has(name)) next.delete(name);
      else next.add(name);
      return next;
    });
  }, []);

  const showAll = useCallback(() => setHiddenCategories(new Set()), []);

  const viewDetails = useCallback((item: CategoryBreakdownItem) => {
    setDetailModal(item);
  }, []);

  const monthOptions = useMemo(() => buildMonthOptions(i18n.language), [i18n.language]);

  const { dateFrom, dateTo } = computeDateRange(period, state.customDateFrom, state.customDateTo);

  const header = (
    <>
      <CategoriesV1DiscoveryBanner />
      <div className="relative flex items-center gap-3 mb-6">
        <h1 className="text-2xl font-bold">{t("dashboard.title")}</h1>
        <PageHelp helpKey="dashboard" />
      </div>
    </>
  );

  if (onboarding.status === "loading") {
    return <div>{header}</div>;
  }

  const { checklist } = onboarding;
  const checklistReady = onboarding.status === "ready" && checklist !== null;

  if (checklistReady && onboarding.counters?.transactions === 0) {
    return (
      <div>
        {header}
        <DashboardEmptyState
          checklist={checklist}
          budgetReady={onboarding.budgetReady}
          hidden={onboarding.hidden}
          onHide={onboarding.hide}
          onResume={onboarding.resume}
        />
      </div>
    );
  }

  return (
    <div className={isLoading ? "opacity-50 pointer-events-none" : ""}>
      {header}

      {state.error && (
        <div className="bg-[var(--negative)]/10 text-[var(--negative)] rounded-xl p-4 mb-6">
          {state.error}
        </div>
      )}

      <FilterPanel
        temporalControl={
          <PeriodSelector
            value={period}
            onChange={setPeriod}
            customDateFrom={state.customDateFrom}
            customDateTo={state.customDateTo}
            onCustomDateChange={setCustomDates}
          />
        }
        accountIds={state.accountIds}
        onAccountIdsChange={setAccountIds}
        accounts={state.accounts}
      />

      <div className="flex items-center gap-2 mb-3 flex-wrap">
        <h2 className="text-lg font-semibold">{t("dashboard.kpiSectionTitle")}</h2>
        <select
          value={`${state.referenceYear}-${state.referenceMonth}`}
          onChange={(e) => {
            const [y, m] = e.target.value.split("-").map(Number);
            setReferencePeriod(y, m);
          }}
          className="text-sm font-medium bg-[var(--card)] border border-[var(--border)] rounded-lg px-2 py-0.5 cursor-pointer hover:bg-[var(--muted)] transition-colors"
        >
          {monthOptions.map((opt) => (
            <option key={opt.key} value={opt.value}>
              {opt.label}
            </option>
          ))}
        </select>
      </div>

      <div className="flex flex-wrap gap-3 mb-6">
        <NetWorthTile data={state.netWorth} />
        {cartesSnapshot && (
          <>
            <div className="flex-1 min-w-[180px]">
              <KpiCard
                id="income"
                title={t("reports.cartes.income")}
                kpi={cartesSnapshot.kpis.income}
                format="currency"
                deltaIsBadWhenUp={false}
              />
            </div>
            <div className="flex-1 min-w-[180px]">
              <KpiCard
                id="expenses"
                title={t("reports.cartes.expenses")}
                kpi={cartesSnapshot.kpis.expenses}
                format="currency"
                deltaIsBadWhenUp={true}
              />
            </div>
            <div className="flex-1 min-w-[180px]">
              <KpiCard
                id="net"
                title={t("reports.cartes.net")}
                kpi={cartesSnapshot.kpis.net}
                format="currency"
                deltaIsBadWhenUp={false}
              />
            </div>
            <div className="flex-1 min-w-[180px]">
              <KpiCard
                id="savingsRate"
                title={t("reports.cartes.savingsRate")}
                kpi={cartesSnapshot.kpis.savingsRate}
                format="percent"
                deltaIsBadWhenUp={false}
              />
            </div>
          </>
        )}
      </div>

      {cartesSnapshot && (
        <>
          <div className="mb-6">
            <IncomeExpenseOverlayChart flow={cartesSnapshot.flow12Months} />
          </div>

          <div className="grid grid-cols-1 lg:grid-cols-3 gap-3 mb-6">
            <TopMoversList movers={cartesSnapshot.topMoversUp} direction="up" />
            <TopMoversList movers={cartesSnapshot.topMoversDown} direction="down" />
            <BudgetAdherenceCard adherence={cartesSnapshot.budgetAdherence} />
          </div>
        </>
      )}

      <div className="mb-6">
        <h2 className="text-lg font-semibold mb-3">{t("dashboard.expensesByCategory")}</h2>
        <CategoryBarChart
          data={categoryBreakdown}
          hiddenCategories={hiddenCategories}
          onToggleHidden={toggleHidden}
          onShowAll={showAll}
          onViewDetails={viewDetails}
        />
      </div>

      <div className="mb-6">
        <h2 className="text-lg font-semibold mb-3">{t("dashboard.expensesOverTime")}</h2>
        <CategoryOverTimeChart
          data={categoryOverTime}
          hiddenCategories={hiddenCategories}
          onToggleHidden={toggleHidden}
          onShowAll={showAll}
          onViewDetails={viewDetails}
        />
      </div>

      {detailModal && (
        <TransactionDetailModal
          categoryId={detailModal.category_id}
          categoryName={detailModal.category_name}
          categoryColor={detailModal.category_color}
          dateFrom={dateFrom}
          dateTo={dateTo}
          onClose={() => setDetailModal(null)}
        />
      )}
    </div>
  );
}