import type { PowerOverview } from "@dci/core";
import { HonestEmpty } from "@/components/intelligence/shared";
import { CountryFlag } from "@/components/ui/country-flag";
import { RowLink, TBody, THead, Table, Td, Th, Tr } from "@/components/ui/table";
import { fmtInt, fmtMw, fmtPct } from "@/lib/format";
import { routes } from "@/lib/routes";
import { compareBy, parseSort, sortTh, type SearchParams } from "@/lib/sort";

export const ENERGY_SORTS = ["name", "renewable", "twh", "year", "carbon", "mw", "facilities"] as const;
export type EnergySort = (typeof ENERGY_SORTS)[number];
type Row = PowerOverview["countryEnergy"][number];

function getter(k: EnergySort): (r: Row) => number | string | null {
  switch (k) {
    case "name":
      return (r) => r.name;
    case "renewable":
      return (r) => r.energy.renewableShare;
    case "twh":
      return (r) => r.energy.electricityTwh;
    case "year":
      return (r) => r.energy.statsYear;
    case "carbon":
      return (r) => r.energy.gridCarbonIntensity;
    case "mw":
      return (r) => r.knownMw;
    case "facilities":
      return (r) => r.facilities;
  }
}

/** National electricity context per country (World Bank vintage) next to the known DC load — sortable via ?sort=&order=. */
export function CountryEnergyTable({ rows, sp }: { rows: Row[]; sp: SearchParams }) {
  if (!rows.length) return <HonestEmpty title="No national energy statistics loaded" detail="the World Bank connector has not populated any country yet" />;
  const sort = parseSort<EnergySort>(sp, ENERGY_SORTS, { key: "facilities", order: "desc" });
  const sorted = [...rows].sort(compareBy(getter(sort.key), sort.order));
  const th = (k: EnergySort) => sortTh(routes.power(), sp, sort, k);
  const source = rows.find((r) => r.energy.sourceName)?.energy.sourceName ?? null;
  return (
    <div>
      <Table dense mobileCollapse={{ total: sorted.length, label: "countries" }}>
        <THead>
          <tr>
            <Th {...th("name")}>Country</Th>
            <Th numeric {...th("renewable")}>
              Renewable share
            </Th>
            <Th numeric className="hidden sm:table-cell" {...th("twh")}>
              Electricity
            </Th>
            <Th numeric className="hidden md:table-cell" {...th("year")}>
              Year
            </Th>
            <Th numeric className="hidden lg:table-cell" {...th("carbon")}>
              Grid carbon
            </Th>
            <Th numeric {...th("mw")}>
              Known DC MW
            </Th>
            <Th numeric className="hidden sm:table-cell" {...th("facilities")}>
              Facilities
            </Th>
          </tr>
        </THead>
        <TBody>
          {sorted.map((r) => (
            <Tr key={r.iso2}>
              <Td primary>
                <RowLink href={routes.country(r.slug)}>
                  <span className="inline-flex items-center gap-1.5">
                    <CountryFlag iso2={r.iso2} size={12} />
                    {r.name}
                  </span>
                </RowLink>
              </Td>
              <Td label="Renewable share" numeric lead>
                {r.energy.renewableShare === null ? <span className="text-ink-4">—</span> : fmtPct(r.energy.renewableShare / 100, 1)}
              </Td>
              <Td label="Electricity" numeric className="hidden sm:table-cell">
                {r.energy.electricityTwh === null ? <span className="text-ink-4">—</span> : `${fmtInt(r.energy.electricityTwh)} TWh`}
              </Td>
              <Td label="Year" numeric className="hidden text-ink-3 md:table-cell">
                {r.energy.statsYear ?? <span className="text-ink-4">—</span>}
              </Td>
              <Td label="Grid carbon" numeric className="hidden lg:table-cell">
                {r.energy.gridCarbonIntensity === null ? <span className="text-ink-4" title="No reliable public source connected">not available</span> : `${fmtInt(r.energy.gridCarbonIntensity)} gCO₂/kWh`}
              </Td>
              <Td label="Known DC MW" numeric>
                {r.knownMw === null ? <span className="text-ink-4">—</span> : fmtMw(r.knownMw)}
              </Td>
              <Td label="Facilities" numeric className="hidden sm:table-cell">
                {fmtInt(r.facilities)}
              </Td>
            </Tr>
          ))}
        </TBody>
      </Table>
      <p className="mt-2 text-[11.5px] text-ink-4">{source ? `Source: ${source} (latest available vintage per country). ` : ""}Grid carbon intensity reads “not available” until a reliable public source is connected — it is never estimated.</p>
    </div>
  );
}