import { FileDown, Filter, Plus, Search } from 'lucide-react'
import { useEffect, useState } from 'react'
import { NavLink, useSearchParams } from 'react-router-dom'
import { incidentStatuses, incidentTypes, severities } from '../../shared/enums.ts'
import { IncidentTable } from '../components/IncidentTable'
import { Page } from '../components/Page'
import { PageIntro } from '../components/PageIntro'
import { Pagination } from '../components/Pagination'
import { SavedViews } from '../components/SavedViews'
import { Empty, ErrorMessage, Loading } from '../components/QueryState'
import { filterBox, panel, primaryButton, secondaryButton } from '../components/styles'
import { incidentTypeLabel, severityLabel, statusLabel } from '../lib/labels'
import { filtersToQuery, useIncidents, useSites, type IncidentFilters } from '../lib/queries'

const PAGE_SIZE = 25
const select = 'bg-transparent text-xs text-ink outline-none'

export function Incidents() {
  const [params, setParams] = useSearchParams()
  const sites = useSites()
  const filters: IncidentFilters = {
    q: params.get('q') ?? undefined,
    type: params.get('type') ?? undefined,
    severity: params.get('severity') ?? undefined,
    status: params.get('status') ?? undefined,
    siteId: params.get('siteId') ?? undefined,
  }
  const page = Number(params.get('page') ?? 1)
  const incidents = useIncidents({ ...filters, page, pageSize: PAGE_SIZE })

  // Search box updates the URL after a short pause
  const [query, setQuery] = useState(filters.q ?? '')
  useEffect(() => setQuery(params.get('q') ?? ''), [params])
  useEffect(() => {
    const handle = setTimeout(() => {
      if ((params.get('q') ?? '') !== query.trim()) setFilter('q', query.trim())
    }, 300)
    return () => clearTimeout(handle)
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [query])

  function setFilter(key: string, value: string) {
    const next = new URLSearchParams(params)
    if (value) next.set(key, value)
    else next.delete(key)
    next.delete('page')
    setParams(next, { replace: true })
  }

  const setPage = (value: number) => {
    const next = new URLSearchParams(params)
    next.set('page', String(value))
    setParams(next)
  }

  return (
    <Page>
      <PageIntro
        eyebrow="Safety register"
        title="Incidents"
        copy="Every reported event, hazard and near miss, and where each one stands."
        action={
          <NavLink className={primaryButton} to="/report">
            <Plus size={17} /> Report incident
          </NavLink>
        }
      />
      <section className={`${panel} overflow-hidden`}>
        <div className="flex flex-wrap items-center gap-2.5 border-b border-line px-[17px] py-3.5 sm:px-6 sm:py-[18px]">
          <div className={`${filterBox} basis-full lg:max-w-[300px] lg:flex-1 lg:basis-auto`}>
            <Search size={17} />
            <input className="w-full bg-transparent text-xs text-ink outline-none" value={query} onChange={(event) => setQuery(event.target.value)} placeholder="Search title, location or INC number" aria-label="Search incidents" />
          </div>
          <div className={filterBox}>
            <Filter size={16} />
            <select className={select} value={filters.type ?? ''} onChange={(event) => setFilter('type', event.target.value)} aria-label="Filter by type">
              <option value="">All types</option>
              {incidentTypes.map((type) => (
                <option key={type} value={type}>
                  {incidentTypeLabel[type]}
                </option>
              ))}
            </select>
          </div>
          <div className={filterBox}>
            <select className={select} value={filters.severity ?? ''} onChange={(event) => setFilter('severity', event.target.value)} aria-label="Filter by severity">
              <option value="">All severities</option>
              {severities.map((severity) => (
                <option key={severity} value={severity}>
                  {severityLabel[severity]}
                </option>
              ))}
            </select>
          </div>
          <div className={filterBox}>
            <select className={select} value={filters.status ?? ''} onChange={(event) => setFilter('status', event.target.value)} aria-label="Filter by status">
              <option value="">All statuses</option>
              {incidentStatuses.map((status) => (
                <option key={status} value={status}>
                  {statusLabel[status]}
                </option>
              ))}
            </select>
          </div>
          {(sites.data?.length ?? 0) > 1 && (
            <div className={filterBox}>
              <select className={select} value={filters.siteId ?? ''} onChange={(event) => setFilter('siteId', event.target.value)} aria-label="Filter by site">
                <option value="">All sites</option>
                {sites.data?.map((site) => (
                  <option key={site.id} value={site.id}>
                    {site.name}
                  </option>
                ))}
              </select>
            </div>
          )}
          <div className="lg:ml-auto">
            <SavedViews page="incidents" keys={['q', 'type', 'severity', 'status', 'siteId']} />
          </div>
          <a className={secondaryButton} href={`/api/incidents/export${filtersToQuery(filters)}`} download>
            <FileDown size={16} /> Export CSV
          </a>
        </div>
        <ErrorMessage error={incidents.error} className="m-4" />
        {incidents.isPending ? (
          <Loading />
        ) : incidents.data?.items.length ? (
          <>
            <IncidentTable incidents={incidents.data.items} wide />
            <Pagination page={page} pageSize={PAGE_SIZE} total={incidents.data.total} onPage={setPage} />
          </>
        ) : (
          <Empty>{Object.values(filters).some(Boolean) ? 'No incidents match these filters.' : 'No incidents reported yet.'}</Empty>
        )}
      </section>
    </Page>
  )
}