// <SchedulesPage> — the swarm's scheduled prompts, one card per schedule.
// Backed by swarm-controller's `GET/POST /api/schedules` and
// `PATCH/DELETE /api/schedules/{id}`; the controller is the only writer of
// the schedule store and computes each schedule's `next_fire_unix`, so
// nothing here derives a fire time except the form's preview. Operator-only:
// the click is the approval, there is no approval queue behind it.
//
// Filtering reuses `FilterableView`'s card bar (name text, agent and state
// multiselects). A card being edited keeps its form state across the
// periodic refetch because `FilterableView` keys cards by schedule id and
// the open edit is held here by id, not by position.
import { useCallback, useEffect, useMemo, useState } from "preact/hooks";
import { ApiErrorPanel } from "@hive/shared/api-error-panel.js";
import { readApiError, type ProblemDetails } from "@hive/shared/api-error.js";
import { Button } from "../../ui/button/Button.js";
import { ConfirmDialog } from "../../ui/confirm-dialog/ConfirmDialog.js";
import { FilterableView } from "../../ui/filterable-view/FilterableView.js";
import { Panel } from "../../ui/panel/Panel.js";
import {
  RefreshIntervalPicker,
  useRefreshInterval,
  type RefreshIntervalMs,
} from "../../ui/refresh-interval/RefreshInterval.js";
import type { TableColumn } from "../../ui/table/Table.js";
import type { AgentRow } from "../agents/AgentTypes.js";
import { ScheduleCard } from "./ScheduleCard.js";
import { ScheduleForm } from "./ScheduleForm.js";
import { scheduleState, type Schedule } from "./ScheduleTypes.js";

// A refetch never touches an open form's own state (it lives in the form),
// so the usual 30s default is safe here too.
const DEFAULT_INTERVAL_MS: RefreshIntervalMs = 30_000;

const COLUMNS: TableColumn<Schedule>[] = [
  {
    key: "name",
    header: "name",
    render: (s) => s.name,
    sortBy: (s) => s.name,
    filterValue: (s) => s.name,
  },
  {
    key: "agents",
    header: "agents",
    render: (s) => s.agents.join(", "),
    filterValues: (s) => s.agents,
    filterMode: "multiselect",
  },
  {
    key: "state",
    header: "state",
    render: (s) => scheduleState(s),
    sortBy: (s) => scheduleState(s),
    filterValues: (s) => [scheduleState(s)],
    filterMode: "multiselect",
  },
];

// The agent names a schedule can target, from the same roster the agents
// page lists. A failed load leaves the picker empty rather than blocking
// the page: the cards themselves do not need it.
async function loadAgentNames(): Promise<string[]> {
  const r = await fetch("/api/agents/status");
  if (!r.ok) return [];
  const rows = (await r.json()) as AgentRow[];
  return rows.map((a) => a.name).sort();
}

export function SchedulesPage() {
  const [intervalMs, setIntervalMs] =
    useState<RefreshIntervalMs>(DEFAULT_INTERVAL_MS);
  const [schedules, setSchedules] = useState<Schedule[] | null>(null);
  const [error, setError] = useState<ProblemDetails | null>(null);
  const [agentNames, setAgentNames] = useState<string[]>([]);
  // The schedule whose card is currently its edit form, and whether the
  // "new schedule" form is open above the list.
  const [editingId, setEditingId] = useState<string | null>(null);
  const [creating, setCreating] = useState(false);
  const [pendingIds, setPendingIds] = useState<Set<string>>(new Set());
  const [removeTarget, setRemoveTarget] = useState<Schedule | null>(null);
  const [actionError, setActionError] = useState<ProblemDetails | null>(null);

  const load = useCallback(async () => {
    try {
      const r = await fetch("/api/schedules");
      if (!r.ok) {
        setError(await readApiError(r));
        return;
      }
      setSchedules((await r.json()) as Schedule[]);
      setError(null);
    } catch (err) {
      setError({ detail: String(err) });
    }
  }, []);

  useRefreshInterval(intervalMs, load);

  useEffect(() => {
    loadAgentNames().then(setAgentNames, () => setAgentNames([]));
  }, []);

  function markPending(id: string, on: boolean) {
    setPendingIds((cur) => {
      const next = new Set(cur);
      if (on) next.add(id);
      else next.delete(id);
      return next;
    });
  }

  // One mutation on one schedule: pending while in flight, the error kept
  // for the banner, a refetch on success so the card shows the controller's
  // own answer rather than a guessed one.
  async function act(id: string, request: () => Promise<Response>) {
    markPending(id, true);
    setActionError(null);
    try {
      const r = await request();
      if (!r.ok) {
        setActionError(await readApiError(r));
        return;
      }
      await load();
    } catch (err) {
      setActionError({ detail: String(err) });
    } finally {
      markPending(id, false);
    }
  }

  function togglePaused(s: Schedule) {
    return act(s.id, () =>
      fetch(`/api/schedules/${encodeURIComponent(s.id)}`, {
        method: "PATCH",
        headers: { "content-type": "application/json" },
        body: JSON.stringify({ paused: !s.paused }),
      }),
    );
  }

  async function confirmRemove() {
    const target = removeTarget;
    if (!target) return;
    setRemoveTarget(null);
    await act(target.id, () =>
      fetch(`/api/schedules/${encodeURIComponent(target.id)}`, {
        method: "DELETE",
      }),
    );
  }

  // A schedule may still target an agent that has since left the roster;
  // its own agents stay pickable so an edit can keep or drop them.
  const optionsFor = useMemo(
    () => (s?: Schedule) =>
      [...new Set([...agentNames, ...(s?.agents ?? [])])].sort(),
    [agentNames],
  );

  async function saved() {
    setCreating(false);
    setEditingId(null);
    await load();
  }

  return (
    <Panel
      title="schedules"
      icon="⏰"
      actions={
        <>
          <Button
            variant="primary"
            onClick={() => setCreating(true)}
            disabled={creating}
          >
            + schedule
          </Button>
          <RefreshIntervalPicker
            id="schedules-refresh"
            value={intervalMs}
            onChange={setIntervalMs}
          />
        </>
      }
    >
      {error ? (
        <ApiErrorPanel
          context="failed to load the schedules"
          problem={error}
        />
      ) : null}
      {actionError ? (
        <ApiErrorPanel
          context="the schedule was not changed"
          problem={actionError}
        />
      ) : null}
      {creating ? (
        <ScheduleForm
          agentOptions={optionsFor()}
          onSaved={saved}
          onCancel={() => setCreating(false)}
        />
      ) : null}
      {!error && schedules === null ? <p>loading…</p> : null}
      {schedules ? (
        <FilterableView
          columns={COLUMNS}
          rows={schedules}
          rowKey={(s) => s.id}
          storageKey="swarm-ui:schedules:table-filters"
          view="cards"
          emptyMessage="no schedules yet — add one with + schedule"
          renderCard={(s) =>
            editingId === s.id ? (
              <ScheduleForm
                schedule={s}
                agentOptions={optionsFor(s)}
                onSaved={saved}
                onCancel={() => setEditingId(null)}
              />
            ) : (
              <ScheduleCard
                schedule={s}
                pending={pendingIds.has(s.id)}
                onEdit={() => setEditingId(s.id)}
                onTogglePaused={() => togglePaused(s)}
                onRemove={() => setRemoveTarget(s)}
              />
            )
          }
        />
      ) : null}
      <ConfirmDialog
        open={removeTarget !== null}
        label="remove schedule"
        confirmLabel="remove"
        onCancel={() => setRemoveTarget(null)}
        onConfirm={confirmRemove}
      >
        {removeTarget ? (
          <p>
            Remove <strong>{removeTarget.name}</strong>? It stops firing for{" "}
            {removeTarget.agents.join(", ")} and cannot be brought back.
          </p>
        ) : null}
      </ConfirmDialog>
    </Panel>
  );
}