import { useEffect, useRef, useState } from "react";
import {
  Button,
  Column,
  Grid,
  InlineLoading,
  NumberInput,
  Table,
  TableBody,
  TableCell,
  TableContainer,
  TableHead,
  TableHeader,
  TableRow,
  Tag,
  TextInput,
} from "@carbon/react";
import { confirm } from "@tauri-apps/plugin-dialog";
import { api } from "../lib/api";
import type { InvoiceSeries } from "../lib/types";
import { useToast } from "../components/ToastProvider";

export default function SeriesSettings({
  active: visible,
  embedded = false,
}: {
  active: boolean;
  /** Rendered inside Settings: no page wrapper or title. */
  embedded?: boolean;
}) {
  const toast = useToast();
  const [, setActive] = useState<InvoiceSeries | null>(null);
  const [all, setAll] = useState<InvoiceSeries[]>([]);
  const [loading, setLoading] = useState(true);

  const [prefix, setPrefix] = useState(`INV/${new Date().getFullYear()}-`);
  const [padding, setPadding] = useState(3);
  const [busy, setBusy] = useState(false);

  const seeded = useRef(false);

  const load = async () => {
    try {
      const [current, list] = await Promise.all([api.getActiveSeries(), api.listSeries()]);
      setActive(current);
      setAll(list);
      // Only seed the form once, so a refetch on re-entry does not overwrite what was typed.
      if (current && !seeded.current) {
        setPrefix(current.prefix);
        setPadding(current.padding);
        seeded.current = true;
      }
    } catch (e) {
      toast.error("Could not load series", String(e));
    } finally {
      setLoading(false);
    }
  };

  // The view stays mounted, so refetch every time it is shown again.
  useEffect(() => {
    if (visible) void load();
  }, [visible]);

  const startNew = async () => {
    const ok = await confirm(
      `Start a new series from ${prefix}${String(1).padStart(padding, "0")}? ` +
        "The current series will be retired and the counter resets to 1.",
      { title: "Start new series", kind: "warning" },
    );
    if (!ok) return;
    setBusy(true);
    try {
      const created = await api.startNewSeries(prefix, padding);
      toast.success("New series started", `Next invoice: ${created.nextInvoiceNumber}`);
      await load();
    } catch (e) {
      toast.error("Could not start a new series", String(e));
    } finally {
      setBusy(false);
    }
  };

  const pageClass = embedded ? undefined : "voiced-page";

  if (loading) {
    return (
      <div className={pageClass}>
        <InlineLoading description="Loading series" />
      </div>
    );
  }

  return (
    <div className={pageClass}>
      {embedded ? null : <h1 className="voiced-page__title">Invoice series</h1>}
      <p className={embedded ? "voiced-muted" : "voiced-page__subtitle"}>
        The active series drives the automatic invoice numbers. Start a new series to reset the counter.
      </p>

      <Grid narrow style={{ marginBottom: "2rem" }}>
        <Column sm={4} md={4} lg={6}>
          <TextInput
            id="seriesPrefix"
            labelText="New series prefix"
            helperText={`Next: ${prefix}${String(1).padStart(padding, "0")}`}
            value={prefix}
            onChange={(e) => setPrefix(e.target.value)}
          />
        </Column>
        <Column sm={4} md={4} lg={4}>
          <NumberInput
            id="seriesPadding"
            label="Serial digits"
            min={1}
            max={8}
            value={padding}
            onChange={(_e, { value }) => setPadding(Number(value) || 3)}
          />
        </Column>
        <Column sm={4} md={8} lg={6} style={{ display: "flex", alignItems: "flex-end" }}>
          <Button onClick={startNew} disabled={busy || !prefix.trim()}>
            {busy ? "Starting…" : "Start new series"}
          </Button>
        </Column>
      </Grid>

      <TableContainer title="Series history">
        <Table aria-label="Invoice series">
          <TableHead>
            <TableRow>
              <TableHeader>Prefix</TableHeader>
              <TableHeader>Next number</TableHeader>
              <TableHeader>Digits</TableHeader>
              <TableHeader>Status</TableHeader>
              <TableHeader>Created</TableHeader>
            </TableRow>
          </TableHead>
          <TableBody>
            {all.map((series) => (
              <TableRow key={series.id}>
                <TableCell>{series.prefix}</TableCell>
                <TableCell>{series.nextInvoiceNumber}</TableCell>
                <TableCell>{series.padding}</TableCell>
                <TableCell>
                  {series.isActive ? <Tag type="green">Active</Tag> : <Tag type="gray">Retired</Tag>}
                </TableCell>
                <TableCell>{new Date(series.createdAt).toLocaleDateString("en-GB")}</TableCell>
              </TableRow>
            ))}
          </TableBody>
        </Table>
      </TableContainer>
    </div>
  );
}