import { useState } from 'react';
import { useAuthStore } from '../../auth/auth-store';
import { useAuditLog, type AuditLogParams } from '../../api/queries/admin/audit';
import layout from '../../styles/AdminLayout.module.css';
import styles from './AuditLogPage.module.css';

function defaultFrom(): string {
  const d = new Date();
  d.setDate(d.getDate() - 7);
  return d.toISOString().slice(0, 10);
}

function defaultTo(): string {
  return new Date().toISOString().slice(0, 10);
}

export function AuditLogPage() {
  const roles = useAuthStore((s) => s.roles);

  if (!roles.includes('ADMIN')) {
    return (
      <div className={layout.page}>
        <div className={layout.accessDenied}>
          Access Denied -- this page requires the ADMIN role.
        </div>
      </div>
    );
  }

  return <AuditLogContent />;
}

function AuditLogContent() {
  const [from, setFrom] = useState(defaultFrom);
  const [to, setTo] = useState(defaultTo);
  const [username, setUsername] = useState('');
  const [category, setCategory] = useState('');
  const [search, setSearch] = useState('');
  const [page, setPage] = useState(0);
  const [selectedEventId, setSelectedEventId] = useState<number | null>(null);
  const [filtersVisible, setFiltersVisible] = useState(true);
  const pageSize = 25;

  const params: AuditLogParams = {
    from: from || undefined,
    to: to || undefined,
    username: username || undefined,
    category: category || undefined,
    search: search || undefined,
    page,
    size: pageSize,
  };

  const audit = useAuditLog(params);
  const data = audit.data;
  const totalPages = data?.totalPages ?? 0;
  const showingFrom = data && data.totalCount > 0 ? page * pageSize + 1 : 0;
  const showingTo = data ? Math.min((page + 1) * pageSize, data.totalCount) : 0;

  const selectedEvent = data?.items.find((e) => e.id === selectedEventId) ?? null;

  return (
    <div className={layout.page}>
      <div className={layout.panelHeader}>
        <div>
          <div className={layout.panelTitle}>Audit Log</div>
          {data && (
            <div className={layout.panelSubtitle}>
              {data.totalCount.toLocaleString()} events
            </div>
          )}
        </div>
      </div>

      <div className={layout.split}>
        {/* Left pane — event list */}
        <div className={layout.listPane}>
          {/* Collapsible filter bar */}
          <div style={{ flexShrink: 0 }}>
            <button
              type="button"
              className={styles.filterToggle}
              onClick={() => setFiltersVisible((v) => !v)}
            >
              {filtersVisible ? 'Hide Filters' : 'Show Filters'}
            </button>
            <div
              className={`${styles.filters} ${!filtersVisible ? styles.filtersCollapsed : ''}`}
            >
              <div className={styles.filterGroup}>
                <label className={styles.filterLabel}>From</label>
                <input
                  type="date"
                  className={styles.filterInput}
                  value={from}
                  onChange={(e) => { setFrom(e.target.value); setPage(0); }}
                />
              </div>
              <div className={styles.filterGroup}>
                <label className={styles.filterLabel}>To</label>
                <input
                  type="date"
                  className={styles.filterInput}
                  value={to}
                  onChange={(e) => { setTo(e.target.value); setPage(0); }}
                />
              </div>
              <div className={styles.filterGroup}>
                <label className={styles.filterLabel}>User</label>
                <input
                  type="text"
                  className={styles.filterInput}
                  placeholder="Username..."
                  value={username}
                  onChange={(e) => { setUsername(e.target.value); setPage(0); }}
                />
              </div>
              <div className={styles.filterGroup}>
                <label className={styles.filterLabel}>Category</label>
                <select
                  className={styles.filterSelect}
                  value={category}
                  onChange={(e) => { setCategory(e.target.value); setPage(0); }}
                >
                  <option value="">All</option>
                  <option value="INFRA">INFRA</option>
                  <option value="AUTH">AUTH</option>
                  <option value="USER_MGMT">USER_MGMT</option>
                  <option value="CONFIG">CONFIG</option>
                </select>
              </div>
              <div className={styles.filterGroup}>
                <label className={styles.filterLabel}>Search</label>
                <input
                  type="text"
                  className={styles.filterInput}
                  placeholder="Search..."
                  value={search}
                  onChange={(e) => { setSearch(e.target.value); setPage(0); }}
                />
              </div>
            </div>
          </div>

          {/* Event list */}
          <div className={layout.entityList}>
            {audit.isLoading ? (
              <div className={layout.loading}>Loading...</div>
            ) : !data || data.items.length === 0 ? (
              <div className={layout.loading}>No events found.</div>
            ) : (
              data.items.map((event) => (
                <div
                  key={event.id}
                  className={`${layout.entityItem} ${
                    selectedEventId === event.id ? layout.entityItemSelected : ''
                  }`}
                  onClick={() => setSelectedEventId(event.id)}
                >
                  <div className={layout.entityInfo}>
                    <div className={styles.eventTimestamp}>
                      {formatTimestamp(event.timestamp)}
                    </div>
                    <div className={styles.eventCompact}>
                      <span>{event.username}</span>
                      <span className={styles.eventAction}>{event.action}</span>
                    </div>
                    <div className={styles.eventCompact}>
                      <span
                        className={`${styles.resultBadge} ${
                          event.result === 'SUCCESS'
                            ? styles.resultSuccess
                            : styles.resultFailure
                        }`}
                      >
                        {event.result}
                      </span>
                    </div>
                  </div>
                </div>
              ))
            )}
          </div>

          {/* Pagination */}
          {data && data.totalCount > 0 && (
            <div className={layout.pagination}>
              <button
                type="button"
                className={layout.pageBtn}
                disabled={page === 0}
                onClick={() => setPage((p) => p - 1)}
              >
                Previous
              </button>
              <span className={layout.pageInfo}>
                {showingFrom}-{showingTo} of {data.totalCount.toLocaleString()}
              </span>
              <button
                type="button"
                className={layout.pageBtn}
                disabled={page >= totalPages - 1}
                onClick={() => setPage((p) => p + 1)}
              >
                Next
              </button>
            </div>
          )}
        </div>

        {/* Right pane — detail view */}
        <div className={layout.detailPane}>
          {!selectedEvent ? (
            <div className={layout.detailEmpty}>
              Select an event to view details
            </div>
          ) : (
            <>
              <div className={layout.detailSection}>
                <div className={layout.detailSectionTitle}>Event Info</div>
                <div className={layout.fieldRow}>
                  <span className={layout.fieldLabel}>Timestamp</span>
                  <span className={`${layout.fieldVal} ${styles.mono}`}>
                    {formatTimestamp(selectedEvent.timestamp)}
                  </span>
                </div>
                <div className={layout.fieldRow}>
                  <span className={layout.fieldLabel}>User</span>
                  <span className={layout.fieldVal}>{selectedEvent.username}</span>
                </div>
                <div className={layout.fieldRow}>
                  <span className={layout.fieldLabel}>Category</span>
                  <span className={layout.fieldVal}>
                    <span className={styles.categoryBadge}>{selectedEvent.category}</span>
                  </span>
                </div>
                <div className={layout.fieldRow}>
                  <span className={layout.fieldLabel}>Action</span>
                  <span className={layout.fieldVal}>{selectedEvent.action}</span>
                </div>
                <div className={layout.fieldRow}>
                  <span className={layout.fieldLabel}>Target</span>
                  <span className={`${layout.fieldVal} ${styles.mono}`}>
                    {selectedEvent.target}
                  </span>
                </div>
                <div className={layout.fieldRow}>
                  <span className={layout.fieldLabel}>Result</span>
                  <span className={layout.fieldVal}>
                    <span
                      className={`${styles.resultBadge} ${
                        selectedEvent.result === 'SUCCESS'
                          ? styles.resultSuccess
                          : styles.resultFailure
                      }`}
                    >
                      {selectedEvent.result}
                    </span>
                  </span>
                </div>
                <div className={layout.fieldRow}>
                  <span className={layout.fieldLabel}>IP Address</span>
                  <span className={`${layout.fieldVal} ${styles.mono}`}>
                    {selectedEvent.ipAddress}
                  </span>
                </div>
                <div className={layout.fieldRow}>
                  <span className={layout.fieldLabel}>User Agent</span>
                  <span className={layout.fieldVal}>{selectedEvent.userAgent}</span>
                </div>
              </div>

              <div className={layout.detailSection}>
                <div className={layout.detailSectionTitle}>Detail Payload</div>
                <pre className={styles.detailJson}>
                  {JSON.stringify(selectedEvent.detail, null, 2)}
                </pre>
              </div>
            </>
          )}
        </div>
      </div>
    </div>
  );
}

function formatTimestamp(iso: string): string {
  try {
    const d = new Date(iso);
    return d.toLocaleString(undefined, {
      year: 'numeric',
      month: '2-digit',
      day: '2-digit',
      hour: '2-digit',
      minute: '2-digit',
      second: '2-digit',
    });
  } catch {
    return iso;
  }
}