/**
 * @file ReportSettings.tsx
 * @description Settings → Reports: scheduled report definitions (`/api/reports`)
 * — create/edit (name, window, daily/weekly + weekday, local hour, HTML/JSON),
 * enable switch, Run now, a confirmed Delete, and each report's run history
 * with download links. Every row action is also on a right-click menu. The
 * browser's timezone offset is saved with the definition, so its hour is the
 * user's local hour.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { useCallback, useEffect, useState } from "react";
import { useTranslation } from "react-i18next";
import { Download, History, Pencil, Play, Plus, Trash2 } from "lucide-react";
import { api } from "../../lib/api";
import { formatDateTime } from "../../lib/format";
import type { ReportDefinition, ReportInput, ReportRun } from "../../lib/types";
import { Checkbox } from "../Checkbox";
import { ConfirmModal } from "../ConfirmModal";
import { ContextMenu, MenuItem, MenuSeparator, useContextMenu } from "../ContextMenu";
import { Select } from "../Select";
import { Switch } from "../Switch";
import { SettingsSection } from "./SettingsRow";

const EMPTY: ReportInput = {
  name: "",
  window_days: 7,
  frequency: "weekly",
  hour: 8,
  weekday: 1,
  tz_offset: 0,
  formats: ["html"],
  enabled: true,
};
const HOURS = Array.from({ length: 24 }, (_, h) => h);
const pad = (n: number) => String(n).padStart(2, "0");

export function ReportSettings() {
  const { t, i18n } = useTranslation("settings");
  const [items, setItems] = useState<ReportDefinition[] | null>(null);
  const [error, setError] = useState<string | null>(null);
  /** The form: a new report (id null) or the one being edited. */
  const [form, setForm] = useState<{ id: number | null; value: ReportInput } | null>(null);
  const [deleting, setDeleting] = useState<ReportDefinition | null>(null);
  const [busy, setBusy] = useState<number | "form" | null>(null);
  const [history, setHistory] = useState<{ id: number; runs: ReportRun[] } | null>(null);
  const ctx = useContextMenu<ReportDefinition>();

  const weekday = (d: number) =>
    new Intl.DateTimeFormat(i18n.resolvedLanguage ?? i18n.language, { weekday: "long" }).format(
      new Date(Date.UTC(2026, 0, 4 + d))
    );
  const fail = (err: unknown) => setError(err instanceof Error ? err.message : String(err));

  const load = useCallback(() => {
    api.reports
      .list()
      .then((r) => setItems(r.reports))
      .catch(fail);
  }, []);
  useEffect(load, [load]);

  const showHistory = async (id: number) => {
    try {
      const r = await api.reports.runs(id);
      setHistory({ id, runs: r.runs });
    } catch (err) {
      fail(err);
    }
  };

  const save = async () => {
    if (!form) return;
    setBusy("form");
    const value = { ...form.value, tz_offset: new Date().getTimezoneOffset() };
    try {
      if (form.id === null) await api.reports.create(value);
      else await api.reports.update(form.id, value);
      setForm(null);
      setError(null);
      load();
    } catch (err) {
      fail(err);
    } finally {
      setBusy(null);
    }
  };

  const toggle = async (r: ReportDefinition, enabled: boolean) => {
    try {
      await api.reports.update(r.id, { enabled });
      load();
    } catch (err) {
      fail(err);
    }
  };

  const runNow = async (r: ReportDefinition) => {
    setBusy(r.id);
    try {
      const { run } = await api.reports.run(r.id);
      if (run.status === "error") setError(run.error);
      load();
      if (history?.id === r.id) await showHistory(r.id);
    } catch (err) {
      fail(err);
    } finally {
      setBusy(null);
    }
  };

  const remove = async () => {
    if (!deleting) return;
    try {
      await api.reports.remove(deleting.id);
      if (history?.id === deleting.id) setHistory(null);
      load();
    } catch (err) {
      fail(err);
    } finally {
      setDeleting(null);
    }
  };

  const edit = (r: ReportDefinition) =>
    setForm({
      id: r.id,
      value: {
        name: r.name,
        window_days: r.window_days,
        frequency: r.frequency,
        hour: r.hour,
        weekday: r.weekday,
        tz_offset: r.tz_offset,
        formats: r.formats,
        enabled: r.enabled,
      },
    });
  const pick = (fn: (r: ReportDefinition) => void) => () => {
    const r = ctx.menu?.item;
    ctx.close();
    if (r) fn(r);
  };
  const schedule = (r: ReportInput) =>
    [
      r.frequency === "daily"
        ? t("reports.everyDay", { time: `${pad(r.hour)}:00` })
        : t("reports.everyWeek", { day: weekday(r.weekday), time: `${pad(r.hour)}:00` }),
      t("reports.window", { count: r.window_days }),
      r.formats.map((f) => f.toUpperCase()).join(", "),
    ].join(" · ");

  const set = (patch: Partial<ReportInput>) =>
    setForm((f) => (f ? { ...f, value: { ...f.value, ...patch } } : f));
  const toggleFormat = (f: "html" | "json", on: boolean) =>
    set({
      formats: on
        ? [...(form?.value.formats ?? []), f]
        : (form?.value.formats ?? []).filter((x) => x !== f),
    });

  return (
    <SettingsSection title={t("reports.title")} description={t("reports.description")}>
      {error && (
        <p role="alert" className="py-2 text-xs text-status-danger">
          {error}
        </p>
      )}

      {form ? (
        <div
          className="my-2 space-y-3 rounded-md border border-border p-3"
          data-testid="report-form"
        >
          <label className="block text-xs text-fg-muted">
            {t("reports.name")}
            <input
              className="input mt-1 w-full text-sm"
              value={form.value.name}
              maxLength={200}
              onChange={(e) => set({ name: e.target.value })}
            />
          </label>
          <div className="flex flex-wrap items-end gap-3">
            <label className="text-xs text-fg-muted">
              {t("reports.windowDays")}
              <input
                type="number"
                min={1}
                max={366}
                className="input mt-1 block w-24 text-sm"
                value={form.value.window_days}
                onChange={(e) => set({ window_days: Math.trunc(Number(e.target.value)) })}
              />
            </label>
            <div className="w-36">
              <Select
                value={form.value.frequency}
                onChange={(v) => set({ frequency: v })}
                label={t("reports.frequency")}
                options={[
                  { value: "daily", label: t("reports.daily") },
                  { value: "weekly", label: t("reports.weekly") },
                ]}
              />
            </div>
            {form.value.frequency === "weekly" && (
              <div className="w-40">
                <Select
                  value={String(form.value.weekday)}
                  onChange={(v) => set({ weekday: Number(v) })}
                  label={t("reports.weekday")}
                  options={[1, 2, 3, 4, 5, 6, 0].map((d) => ({
                    value: String(d),
                    label: weekday(d),
                  }))}
                />
              </div>
            )}
            <div className="w-28">
              <Select
                value={String(form.value.hour)}
                onChange={(v) => set({ hour: Number(v) })}
                label={t("reports.hour")}
                options={HOURS.map((h) => ({ value: String(h), label: `${pad(h)}:00` }))}
              />
            </div>
          </div>
          <div className="flex flex-wrap items-center gap-4">
            <Checkbox
              checked={form.value.formats.includes("html")}
              onChange={(v) => toggleFormat("html", v)}
              label="HTML"
            />
            <Checkbox
              checked={form.value.formats.includes("json")}
              onChange={(v) => toggleFormat("json", v)}
              label="JSON"
            />
          </div>
          <p className="text-[11px] text-fg-muted">{t("reports.windowHint")}</p>
          <div className="flex gap-2">
            <button
              type="button"
              className="btn-primary text-xs"
              disabled={
                busy === "form" || !form.value.name.trim() || form.value.formats.length === 0
              }
              onClick={() => void save()}
            >
              {t("reports.save")}
            </button>
            <button type="button" className="btn-ghost text-xs" onClick={() => setForm(null)}>
              {t("reports.cancel")}
            </button>
          </div>
        </div>
      ) : (
        <button
          type="button"
          className="btn-ghost my-2 text-xs"
          onClick={() => setForm({ id: null, value: { ...EMPTY, name: t("reports.defaultName") } })}
        >
          <Plus className="h-3.5 w-3.5" />
          {t("reports.add")}
        </button>
      )}

      {items?.length === 0 && <p className="py-2 text-sm text-fg-muted">{t("reports.empty")}</p>}
      {items && items.length > 0 && (
        <ul className="divide-y divide-border/60" data-testid="report-list">
          {items.map((r) => (
            <li key={r.id} onContextMenu={(e) => ctx.open(e, r)} className="py-2.5">
              <div className="flex items-center gap-3">
                <div className="min-w-0 flex-1">
                  <p className="truncate text-sm text-fg-secondary">{r.name}</p>
                  <p className="text-[11px] text-fg-muted">{schedule(r)}</p>
                  {r.last_run && (
                    <p
                      className={`text-[11px] ${
                        r.last_run.status === "error" ? "text-status-danger" : "text-fg-muted"
                      }`}
                    >
                      {t("reports.lastRun", { at: formatDateTime(r.last_run.created_at) })}
                      {r.last_run.status === "error" && ` · ${r.last_run.error ?? ""}`}
                    </p>
                  )}
                </div>
                <Switch
                  checked={r.enabled}
                  onChange={(v) => void toggle(r, v)}
                  label={t("reports.enabled")}
                  title={t("reports.enabled")}
                />
                <button
                  type="button"
                  className="btn-ghost text-xs"
                  disabled={busy === r.id}
                  onClick={() => void runNow(r)}
                  title={t("reports.runNow")}
                  aria-label={t("reports.runNow")}
                >
                  <Play className="h-3.5 w-3.5" />
                </button>
                <button
                  type="button"
                  className="btn-ghost text-xs"
                  onClick={() => (history?.id === r.id ? setHistory(null) : void showHistory(r.id))}
                  title={t("reports.history")}
                  aria-label={t("reports.history")}
                >
                  <History className="h-3.5 w-3.5" />
                </button>
                <button
                  type="button"
                  className="btn-ghost text-xs"
                  onClick={() => edit(r)}
                  title={t("reports.edit")}
                  aria-label={t("reports.edit")}
                >
                  <Pencil className="h-3.5 w-3.5" />
                </button>
                <button
                  type="button"
                  className="btn-ghost text-xs text-status-danger"
                  onClick={() => setDeleting(r)}
                  title={t("reports.delete")}
                  aria-label={t("reports.delete")}
                >
                  <Trash2 className="h-3.5 w-3.5" />
                </button>
              </div>
              {history?.id === r.id && (
                <ul
                  className="mt-2 space-y-1 border-l border-border pl-3"
                  data-testid="report-runs"
                >
                  {history.runs.length === 0 && (
                    <li className="text-[11px] text-fg-muted">{t("reports.noRuns")}</li>
                  )}
                  {history.runs.map((run) => (
                    <li key={run.id} className="flex flex-wrap items-center gap-2 text-[11px]">
                      <span className="text-fg-secondary">{formatDateTime(run.created_at)}</span>
                      <span className="text-fg-muted">
                        {t(`reports.trigger.${run.trigger}`)} · {run.window_from} → {run.window_to}
                      </span>
                      {run.status === "error" ? (
                        <span className="text-status-danger">{run.error}</span>
                      ) : (
                        run.files.map((f) => (
                          <a
                            key={f}
                            href={api.reports.fileUrl(r.id, run.id, f)}
                            download
                            className="inline-flex items-center gap-0.5 text-accent hover:underline"
                            title={t("reports.download", { format: f.toUpperCase() })}
                          >
                            <Download className="h-3 w-3" />
                            {f.toUpperCase()}
                          </a>
                        ))
                      )}
                    </li>
                  ))}
                </ul>
              )}
            </li>
          ))}
        </ul>
      )}

      {ctx.menu && (
        <ContextMenu x={ctx.menu.x} y={ctx.menu.y} onClose={ctx.close} testId="report-menu">
          <MenuItem onSelect={pick((r) => void runNow(r))}>{t("reports.runNow")}</MenuItem>
          <MenuItem onSelect={pick((r) => void showHistory(r.id))}>{t("reports.history")}</MenuItem>
          <MenuItem onSelect={pick(edit)}>{t("reports.edit")}</MenuItem>
          <MenuSeparator />
          <MenuItem danger onSelect={pick(setDeleting)}>
            {t("reports.delete")}
          </MenuItem>
        </ContextMenu>
      )}
      <ConfirmModal
        open={deleting !== null}
        title={t("reports.deleteTitle")}
        message={t("reports.deleteBody")}
        confirmLabel={t("reports.delete")}
        cancelLabel={t("reports.cancel")}
        onConfirm={() => void remove()}
        onCancel={() => setDeleting(null)}
      />
    </SettingsSection>
  );
}