import { useEffect, useState } from "react";
import { api, type DiagLogEntry } from "../api/client";
import { formatDateTime, parseDbTimestamp } from "../utils/date";
import { useSortable } from "../hooks/useSortable";
import SortableTh from "../components/SortableTh";
import { downloadCsv } from "../utils/csv";
import { confirmDialog } from "../utils/dialogs";

const SOURCE_LABELS: Record<string, string> = {
  cloudflare: "Cloudflare",
  loopia: "Loopia",
  pihole: "Pi-hole",
  azure: "Azure DNS",
  cpanel: "cPanel",
  technitium: "Technitium",
  tailscale: "Tailscale",
  proxmox: "Proxmox",
  synology: "Synology",
  semaphore: "Semaphore",
  gitea: "Gitea",
  dockhand: "Dockhand",
};

const PAGE_SIZE = 100;

export default function DiagLog() {
  const [entries, setEntries] = useState<DiagLogEntry[] | null>(null);
  const [total, setTotal] = useState(0);
  const [page, setPage] = useState(0);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [filterSource, setFilterSource] = useState("");
  const [filterOk, setFilterOk] = useState("");
  const [clearing, setClearing] = useState(false);

  function load(pg: number) {
    setLoading(true);
    setError(null);
    api.diagLog
      .list({
        source: filterSource || undefined,
        ok: filterOk === "" ? undefined : filterOk === "true",
        limit: PAGE_SIZE,
        offset: pg * PAGE_SIZE,
      })
      .then((res) => {
        setEntries(res.entries);
        setTotal(res.total);
      })
      .catch((err) => setError(err instanceof Error ? err.message : String(err)))
      .finally(() => setLoading(false));
  }

  useEffect(() => {
    setPage(0);
    load(0);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [filterSource, filterOk]);

  function goToPage(pg: number) {
    setPage(pg);
    load(pg);
  }

  async function handleClear() {
    if (!(await confirmDialog({ title: "Clear diagnostic log", message: "Clear the entire diagnostic log? This cannot be undone.", confirmLabel: "Clear log", danger: true }))) return;
    setClearing(true);
    try {
      await api.diagLog.clear();
      setEntries([]);
      setTotal(0);
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
    } finally {
      setClearing(false);
    }
  }

  const { sorted, sortKey, sortDir, requestSort } = useSortable(entries, "createdAt", "desc");
  const totalPages = Math.ceil(total / PAGE_SIZE);
  const errorCount = entries?.filter((e) => !e.ok).length ?? 0;

  function exportCsv() {
    if (!sorted) return;
    downloadCsv(
      "diagnostic-log.csv",
      ["Time", "Source", "Operation", "OK", "Latency (ms)", "Error"],
      sorted.map((e) => [formatDateTime(parseDbTimestamp(e.createdAt)), e.source, e.operation, e.ok ? "yes" : "no", e.latencyMs, e.error ?? ""]),
    );
  }

  return (
    <>
      <div className="d-flex align-items-center mb-3">
        <div>
          <h2 className="page-title mb-0">Diagnostic Log</h2>
          <div className="text-secondary small mt-1">
            Every call this app makes to a DNS provider or integration — the last 500 calls are kept. Use this to
            troubleshoot connectivity issues.
          </div>
        </div>
        <button className="btn btn-outline-danger ms-auto" onClick={handleClear} disabled={clearing || total === 0}>
          {clearing ? "Clearing…" : "Clear log"}
        </button>
      </div>
      {error && <div className="alert alert-danger">{error}</div>}

      <div className="card mb-3">
        <div className="card-body">
          <div className="row g-2 align-items-end">
            <div className="col-md-3">
              <label className="form-label">Source</label>
              <select className="form-select" value={filterSource} onChange={(e) => setFilterSource(e.target.value)}>
                <option value="">All sources</option>
                {Object.entries(SOURCE_LABELS).map(([value, label]) => (
                  <option key={value} value={value}>
                    {label}
                  </option>
                ))}
              </select>
            </div>
            <div className="col-md-3">
              <label className="form-label">Result</label>
              <select className="form-select" value={filterOk} onChange={(e) => setFilterOk(e.target.value)}>
                <option value="">All results</option>
                <option value="false">Errors only</option>
                <option value="true">Success only</option>
              </select>
            </div>
            <div className="col-md-6 d-flex justify-content-end gap-2">
              <button className="btn btn-outline-secondary" onClick={() => load(page)} disabled={loading}>
                {loading ? "Refreshing…" : "Refresh"}
              </button>
              <button className="btn btn-outline-secondary" onClick={exportCsv} disabled={!sorted || sorted.length === 0}>
                Export CSV
              </button>
            </div>
          </div>
        </div>
      </div>

      <div className="card">
        <div className="card-header">
          <h3 className="card-title">
            {total} entries
            {errorCount > 0 && <span className="text-red fw-normal ms-2">{errorCount} errors on this page</span>}
          </h3>
        </div>
        <div className="table-responsive">
          <table className="table table-vcenter card-table">
            <thead>
              <tr>
                <SortableTh<DiagLogEntry> label="Time" sortKeyName="createdAt" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                <SortableTh<DiagLogEntry> label="Source" sortKeyName="source" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                <SortableTh<DiagLogEntry> label="Operation" sortKeyName="operation" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                <SortableTh<DiagLogEntry> label="Result" sortKeyName="ok" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                <SortableTh<DiagLogEntry>
                  label="Latency"
                  sortKeyName="latencyMs"
                  activeKey={sortKey}
                  direction={sortDir}
                  onSort={requestSort}
                />
                <th>Error</th>
              </tr>
            </thead>
            <tbody>
              {sorted?.map((e) => (
                <tr key={e.id}>
                  <td className="text-secondary" style={{ whiteSpace: "nowrap" }}>
                    {formatDateTime(parseDbTimestamp(e.createdAt))}
                  </td>
                  <td>{SOURCE_LABELS[e.source] ?? e.source}</td>
                  <td className="text-secondary">{e.operation}</td>
                  <td>
                    {e.ok ? (
                      <span className="badge bg-green-lt text-green">OK</span>
                    ) : (
                      <span className="badge bg-red-lt text-red">Error</span>
                    )}
                  </td>
                  <td className={`text-secondary ${e.latencyMs > 2000 ? "text-yellow" : ""}`}>{e.latencyMs}ms</td>
                  <td className="text-red small" title={e.error ?? ""} style={{ maxWidth: 320, overflow: "hidden", textOverflow: "ellipsis", whiteSpace: "nowrap" }}>
                    {e.error ?? ""}
                  </td>
                </tr>
              ))}
              {sorted?.length === 0 && (
                <tr>
                  <td colSpan={6} className="text-secondary text-center">
                    No diagnostic entries{filterSource || filterOk ? " match these filters" : " yet"}.
                  </td>
                </tr>
              )}
            </tbody>
          </table>
        </div>
        {totalPages > 1 && (
          <div className="card-footer d-flex align-items-center justify-content-between">
            <button className="btn btn-outline-secondary" onClick={() => goToPage(page - 1)} disabled={page === 0}>
              ← Prev
            </button>
            <span className="text-secondary">
              Page {page + 1} of {totalPages}
            </span>
            <button className="btn btn-outline-secondary" onClick={() => goToPage(page + 1)} disabled={page >= totalPages - 1}>
              Next →
            </button>
          </div>
        )}
      </div>
    </>
  );
}