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

function targetLabel(e: AuditLogEntry): string {
  if (!e.targetType) return "—";
  let detail: Record<string, unknown> | null = null;
  if (e.detail) {
    try {
      detail = JSON.parse(e.detail);
    } catch {
      detail = null;
    }
  }
  const name = detail?.name ?? detail?.targetLabel ?? detail?.ipAddress;
  const typeLabel = e.targetType.replace(/_/g, " ");
  if (typeof name === "string" && name) return `${typeLabel} "${name}"`;
  return `${typeLabel}${e.targetId ? ` #${e.targetId}` : ""}`;
}

/** What was done, beyond the target — the link's label and URL, a scan's address and range, and so on. The name is already in the Target column. */
function detailSummary(e: AuditLogEntry): string {
  if (!e.detail) return "";
  let parsed: unknown;
  try {
    parsed = JSON.parse(e.detail);
  } catch {
    return e.detail;
  }
  if (parsed === null || typeof parsed !== "object" || Array.isArray(parsed)) return String(parsed);
  return Object.entries(parsed as Record<string, unknown>)
    .filter(([key, value]) => key !== "name" && value !== null && value !== undefined && value !== "" && !(Array.isArray(value) && value.length === 0))
    .map(([key, value]) => `${key}: ${typeof value === "object" ? JSON.stringify(value) : String(value)}`)
    .join(" · ");
}

export default function AuditLog() {
  const [entries, setEntries] = useState<AuditLogEntry[] | null>(null);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    api.auditLog
      .list()
      .then((res) => setEntries(res.entries))
      .catch((err) => setError(String(err)));
  }, []);

  const { sorted, sortKey, sortDir, requestSort } = useSortable(entries, "createdAt", "desc");
  const { pageItems, page, setPage, pageCount, totalCount } = usePagination(sorted);

  function exportCsv() {
    if (!sorted) return;
    downloadCsv(
      "audit-log.csv",
      ["When", "Actor", "Category", "Action", "Target", "Details"],
      sorted.map((e) => [formatDateTime(parseDbTimestamp(e.createdAt)), e.actorLabel ?? "", e.category, e.action, targetLabel(e), detailSummary(e)]),
    );
  }

  return (
    <>
      <div className="d-flex align-items-center mb-3">
        <h2 className="page-title mb-0">Audit Log</h2>
        <button className="btn btn-outline-secondary ms-auto" onClick={exportCsv} disabled={!sorted || sorted.length === 0}>
          Export CSV
        </button>
      </div>
      {error && <div className="alert alert-danger">{error}</div>}
      <div className="card">
        <div className="table-responsive">
          <table className="table table-vcenter card-table">
            <thead>
              <tr>
                <SortableTh<AuditLogEntry> label="When" sortKeyName="createdAt" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                <SortableTh<AuditLogEntry> label="Actor" sortKeyName="actorLabel" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                <SortableTh<AuditLogEntry> label="Category" sortKeyName="category" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                <SortableTh<AuditLogEntry> label="Action" sortKeyName="action" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                <SortableTh<AuditLogEntry> label="Target" sortKeyName="targetType" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                <th>Details</th>
              </tr>
            </thead>
            <tbody>
              {pageItems?.map((e) => (
                <tr key={e.id}>
                  <td>{formatDateTime(parseDbTimestamp(e.createdAt))}</td>
                  <td>{e.actorLabel ?? "—"}</td>
                  <td>
                    <span className="badge bg-blue-lt">{e.category}</span>
                  </td>
                  <td>{e.action}</td>
                  <td>{targetLabel(e)}</td>
                  <td className="text-secondary small text-break" style={{ maxWidth: 420 }}>
                    {detailSummary(e) || "—"}
                  </td>
                </tr>
              ))}
              {sorted?.length === 0 && (
                <tr>
                  <td colSpan={6} className="text-secondary text-center">
                    No activity recorded yet.
                  </td>
                </tr>
              )}
            </tbody>
          </table>
        </div>
        <Pagination page={page} pageCount={pageCount} totalCount={totalCount} onPageChange={setPage} />
      </div>
    </>
  );
}