import { useEffect, useMemo, useState, type FormEvent } from 'react'
import type { AreaRead, ProjectRead } from '../../types'

const AREA_CATALOG_PAGE_SIZE = 12

function projectDisplayName(project: ProjectRead | null): string {
  if (project?.name === 'Belgium and North Sea Workbench') {
    return 'België en Belgische Noordzee'
  }
  if (project?.name === 'Kempen Regional Workbench') {
    return 'Kempen · volledige regio'
  }
  if (project?.name === 'Mol Municipality Workbench') {
    return 'Mol · lokale historische werkruimte'
  }
  return project?.name ?? 'Geen werkruimte actief'
}

interface AreaFormState {
  name: string
  geometry: string
  crs: string
}

interface AreaPanelProps {
  areas: AreaRead[]
  selectedProject: ProjectRead | null
  selectedProjectId: string | null
  loadingAreas: boolean
  areaForm: AreaFormState
  selectedMapAreaId: string
  onCreateArea: (event: FormEvent<HTMLFormElement>) => void
  onUpdateAreaForm: (areaForm: AreaFormState) => void
  onSelectMapArea: (areaId: string) => void
}

export function AreaPanel({
  areas,
  selectedProject,
  selectedProjectId,
  loadingAreas,
  areaForm,
  selectedMapAreaId,
  onCreateArea,
  onUpdateAreaForm,
  onSelectMapArea,
}: AreaPanelProps): JSX.Element {
  const [catalogOpen, setCatalogOpen] = useState(false)
  const [searchQuery, setSearchQuery] = useState('')
  const [page, setPage] = useState(1)
  const selectedArea = areas.find((area) => area.id === selectedMapAreaId)
  const filteredAreas = useMemo(() => {
    const query = searchQuery.trim().toLocaleLowerCase('nl-BE')
    if (!query) return areas
    return areas.filter((area) => area.name.toLocaleLowerCase('nl-BE').includes(query))
  }, [areas, searchQuery])
  const pageCount = Math.max(1, Math.ceil(filteredAreas.length / AREA_CATALOG_PAGE_SIZE))
  const visibleAreas = filteredAreas.slice(
    (page - 1) * AREA_CATALOG_PAGE_SIZE,
    page * AREA_CATALOG_PAGE_SIZE,
  )

  useEffect(() => {
    setPage((current) => Math.min(current, pageCount))
  }, [pageCount])

  useEffect(() => {
    setSearchQuery('')
    setPage(1)
    setCatalogOpen(false)
  }, [selectedProjectId])

  return (
    <section data-testid="area-panel">
      <div className="panel-title-row">
        <div>
          <p className="eyebrow">Geografisch bereik</p>
          <h2>Gebieden</h2>
        </div>
        <span className="count-pill">{areas.length}</span>
      </div>
      <p className="muted">{projectDisplayName(selectedProject)}</p>

      <div className="data-selection-summary data-selection-summary-area">
        <span>Getoond op de kaart</span>
        <strong>{selectedArea?.name ?? 'Geen gebied geselecteerd'}</strong>
        <small>{selectedArea?.area_m2 ? `${(selectedArea.area_m2 / 1_000_000).toLocaleString('nl-BE', { maximumFractionDigits: 2 })} km2` : 'Kies een gemeente, gewest, zeezone of teken een eigen selectie.'}</small>
      </div>

      <details className="data-panel-form-block">
        <summary>Eigen gebied toevoegen (GeoJSON)</summary>
        <form className="compact-form" onSubmit={onCreateArea}>
          <label>
            Naam
            <input
              value={areaForm.name}
              onChange={(event) => onUpdateAreaForm({ ...areaForm, name: event.target.value })}
              placeholder="Naam van het gebied"
            />
          </label>
          <label>
            CRS
            <input
              value={areaForm.crs}
              onChange={(event) => onUpdateAreaForm({ ...areaForm, crs: event.target.value })}
              placeholder="EPSG:4326"
            />
          </label>
          <label>
            GeoJSON-geometrie
            <textarea
              value={areaForm.geometry}
              onChange={(event) => onUpdateAreaForm({ ...areaForm, geometry: event.target.value })}
              rows={4}
            />
          </label>
          <button className="primary-action" type="submit" disabled={!selectedProjectId}>
            Gebied toevoegen
          </button>
        </form>
      </details>

      {loadingAreas ? <p>Gebieden laden...</p> : null}
      {areas.length === 0 ? <p>Nog geen gebieden beschikbaar.</p> : null}
      <details
        className="data-panel-list-block area-catalog-disclosure"
        onToggle={(event) => setCatalogOpen(event.currentTarget.open)}
      >
        <summary>{areas.length} beschikbare gemeenten en regiogrenzen</summary>
        {catalogOpen ? (
          <>
            <div className="catalog-browser-toolbar">
              <label className="catalog-search-field">
                Zoek gemeente of regio
                <input
                  type="search"
                  value={searchQuery}
                  onChange={(event) => {
                    setSearchQuery(event.target.value)
                    setPage(1)
                  }}
                  placeholder="Bijvoorbeeld Brussel, Namen of Noordzee"
                />
              </label>
              <div className="catalog-pagination" aria-label="Paginering van gebieden">
                <span>{filteredAreas.length} gevonden</span>
                <button
                  className="secondary-action"
                  type="button"
                  disabled={page === 1}
                  onClick={() => setPage((current) => Math.max(1, current - 1))}
                >
                  Vorige
                </button>
                <strong>{page} / {pageCount}</strong>
                <button
                  className="secondary-action"
                  type="button"
                  disabled={page === pageCount}
                  onClick={() => setPage((current) => Math.min(pageCount, current + 1))}
                >
                  Volgende
                </button>
              </div>
            </div>
            {visibleAreas.length > 0 ? (
              <ul className="entity-list">
                {visibleAreas.map((area) => (
                  <li className={selectedMapAreaId === area.id ? 'entity-card entity-card-active' : 'entity-card'} key={area.id}>
                    <strong>{area.name}</strong>
                    <div className="entity-meta">
                      <span>{area.area_m2 ? `${(area.area_m2 / 1_000_000).toLocaleString('nl-BE', { maximumFractionDigits: 2 })} km2` : 'Oppervlakte onbekend'}</span>
                      <span>{area.geometry?.type ?? area.geometry_type ?? 'Geometrie onbekend'}</span>
                    </div>
                    <button
                      className="secondary-action"
                      type="button"
                      onClick={() => onSelectMapArea(area.id)}
                      disabled={!area.geometry}
                      data-testid={`area-show-${area.id}`}
                    >
                      {selectedMapAreaId === area.id ? 'Op kaart' : 'Toon op kaart'}
                    </button>
                  </li>
                ))}
              </ul>
            ) : (
              <p className="muted">Geen gebied gevonden voor deze zoekterm.</p>
            )}
          </>
        ) : null}
      </details>
    </section>
  )
}