'use client'

import { useState } from 'react'
import { useParams } from 'next/navigation'
import { REDUCTION_TYPES, Mitigation } from './_components/types'
import { HierarchyWarning } from './_components/HierarchyWarning'
import { MeasuresLibraryModal } from './_components/MeasuresLibraryModal'
import { SuggestMeasuresModal } from './_components/SuggestMeasuresModal'
import { MitigationForm } from './_components/MitigationForm'
import { StatusBadge } from './_components/StatusBadge'
import { ProtectiveMeasure } from './_components/types'
import { useMitigations } from './_hooks/useMitigations'

export default function MitigationsPage() {
  const params = useParams()
  const projectId = params.projectId as string

  const {
    hazards, loading, hierarchyWarning, setHierarchyWarning,
    measures, byType,
    fetchMeasuresLibrary, handleSubmit, handleAddSuggestedMeasure, handleVerify, handleDelete,
  } = useMitigations(projectId)

  const [showForm, setShowForm] = useState(false)
  const [preselectedType, setPreselectedType] = useState<'design' | 'protection' | 'information' | undefined>()
  const [showLibrary, setShowLibrary] = useState(false)
  const [libraryFilter, setLibraryFilter] = useState<string | undefined>()
  const [showSuggest, setShowSuggest] = useState(false)
  const [expanded, setExpanded] = useState<Record<string, boolean>>({ design: true, protection: true, information: true })
  const [mitPages, setMitPages] = useState<Record<string, number>>({ design: 1, protection: 1, information: 1 })
  const [selected, setSelected] = useState<Set<string>>(new Set())
  const [batchAction, setBatchAction] = useState<'verify' | 'delete' | null>(null)

  function toggleSection(type: string) {
    setExpanded((prev) => ({ ...prev, [type]: !prev[type] }))
  }

  function toggleSelect(id: string) {
    setSelected((prev) => {
      const next = new Set(prev)
      if (next.has(id)) next.delete(id); else next.add(id)
      return next
    })
  }

  function selectAllInType(type: string) {
    const items = byType[type as keyof typeof byType]
    setSelected((prev) => {
      const next = new Set(prev)
      const allSelected = items.every((m) => next.has(m.id))
      if (allSelected) { items.forEach((m) => next.delete(m.id)) }
      else { items.forEach((m) => next.add(m.id)) }
      return next
    })
  }

  async function handleBatchVerify() {
    setBatchAction('verify')
    for (const id of selected) { await handleVerify(id) }
    setSelected(new Set())
    setBatchAction(null)
  }

  async function handleBatchDelete() {
    if (!confirm(`${selected.size} Massnahmen wirklich loeschen?`)) return
    setBatchAction('delete')
    for (const id of selected) { await handleDelete(id) }
    setSelected(new Set())
    setBatchAction(null)
  }

  function handleOpenLibrary(type?: string) {
    setLibraryFilter(type)
    fetchMeasuresLibrary(type)
    setShowLibrary(true)
  }

  function handleSelectMeasure(measure: ProtectiveMeasure) {
    setShowLibrary(false)
    setShowForm(true)
    setPreselectedType(measure.reduction_type as 'design' | 'protection' | 'information')
  }

  if (loading) {
    return (
      <div className="flex items-center justify-center h-64">
        <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-purple-600" />
      </div>
    )
  }

  const totalMeasures = byType.design.length + byType.protection.length + byType.information.length

  return (
    <div className="space-y-4">
      {/* Header */}
      <div className="flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-bold text-gray-900 dark:text-white">Massnahmen</h1>
          <p className="mt-1 text-sm text-gray-500">
            {totalMeasures} Massnahmen nach 3-Stufen-Verfahren: Design ({byType.design.length}) &rarr; Schutz ({byType.protection.length}) &rarr; Information ({byType.information.length})
          </p>
        </div>
        <div className="flex items-center gap-2">
          {selected.size > 0 && (
            <>
              <span className="text-xs text-gray-500">{selected.size} ausgewaehlt</span>
              <button onClick={handleBatchVerify} disabled={batchAction !== null}
                className="px-3 py-1.5 text-xs bg-green-600 text-white rounded-lg hover:bg-green-700 disabled:opacity-50">
                {batchAction === 'verify' ? 'Verifiziere...' : 'Verifizieren'}
              </button>
              <button onClick={handleBatchDelete} disabled={batchAction !== null}
                className="px-3 py-1.5 text-xs bg-red-600 text-white rounded-lg hover:bg-red-700 disabled:opacity-50">
                Loeschen
              </button>
              <button onClick={() => setSelected(new Set())} className="px-2 py-1.5 text-xs text-gray-500 hover:text-gray-700">
                Abbrechen
              </button>
            </>
          )}
          {selected.size === 0 && (
            <>
              <button onClick={() => setShowSuggest(true)}
                className="px-3 py-1.5 text-xs border border-green-300 text-green-700 rounded-lg hover:bg-green-50">
                Vorschlaege
              </button>
              <button onClick={() => handleOpenLibrary()}
                className="px-3 py-1.5 text-xs border border-purple-300 text-purple-700 rounded-lg hover:bg-purple-50">
                Bibliothek
              </button>
              <button onClick={() => { setPreselectedType(undefined); setShowForm(true) }}
                className="px-3 py-1.5 text-xs bg-purple-600 text-white rounded-lg hover:bg-purple-700">
                + Hinzufuegen
              </button>
            </>
          )}
        </div>
      </div>

      {hierarchyWarning && <HierarchyWarning onDismiss={() => setHierarchyWarning(false)} />}

      {showForm && (
        <MitigationForm
          onSubmit={async (data) => { const ok = await handleSubmit(data); if (ok) setShowForm(false) }}
          onCancel={() => setShowForm(false)} hazards={hazards} preselectedType={preselectedType} onOpenLibrary={handleOpenLibrary}
        />
      )}
      {showLibrary && <MeasuresLibraryModal measures={measures} onSelect={handleSelectMeasure} onClose={() => setShowLibrary(false)} filterType={libraryFilter} />}
      {showSuggest && <SuggestMeasuresModal hazards={hazards} projectId={projectId} onAddMeasure={handleAddSuggestedMeasure} onClose={() => setShowSuggest(false)} />}

      {/* 3-Step Accordions */}
      {(['design', 'protection', 'information'] as const).map((type) => {
        const config = REDUCTION_TYPES[type]
        const items = byType[type]
        const isExpanded = expanded[type]
        const allSelected = items.length > 0 && items.every((m) => selected.has(m.id))

        return (
          <div key={type} className="bg-white dark:bg-gray-800 rounded-xl border border-gray-200 dark:border-gray-700 overflow-hidden">
            {/* Accordion Header */}
            <button onClick={() => toggleSection(type)}
              className={`w-full flex items-center gap-3 px-4 py-3 text-left transition-colors ${config.headerColor}`}>
              <svg className={`w-4 h-4 transition-transform ${isExpanded ? 'rotate-90' : ''}`} fill="none" viewBox="0 0 24 24" stroke="currentColor">
                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 5l7 7-7 7" />
              </svg>
              {config.icon}
              <div className="flex-1">
                <span className="text-sm font-semibold">{config.label}</span>
                <span className="ml-2 text-xs opacity-75">{config.description}</span>
              </div>
              <span className="text-sm font-bold">{items.length}</span>
            </button>

            {/* Accordion Content — Table rows */}
            {isExpanded && items.length > 0 && (
              <div className="border-t border-gray-100 dark:border-gray-700">
                {/* Table header */}
                <div className="grid grid-cols-[24px_2fr_1fr_80px] gap-2 px-4 py-2 bg-gray-50 dark:bg-gray-750 text-xs font-medium text-gray-500 uppercase tracking-wider">
                  <div>
                    <input type="checkbox" checked={allSelected} onChange={() => selectAllInType(type)}
                      className="accent-purple-600" title="Alle auswaehlen" />
                  </div>
                  <div>Massnahme</div>
                  <div>Gefaehrdung</div>
                  <div>Status</div>
                </div>
                {/* Rows — paginated */}
                {items.slice(0, (mitPages[type] || 1) * 50).map((m) => (
                  <div key={m.id}
                    className={`grid grid-cols-[24px_2fr_1fr_80px] gap-2 px-4 py-2 border-t border-gray-50 dark:border-gray-700 hover:bg-gray-50 dark:hover:bg-gray-750 transition-colors ${selected.has(m.id) ? 'bg-purple-50 dark:bg-purple-900/10' : ''}`}>
                    <div className="pt-0.5">
                      <input type="checkbox" checked={selected.has(m.id)} onChange={() => toggleSelect(m.id)}
                        className="accent-purple-600" />
                    </div>
                    <div className="min-w-0">
                      <div className="text-sm text-gray-900 dark:text-white">{m.title || ''}</div>
                      {m.description && <div className="text-xs text-gray-400 mt-0.5">{m.description}</div>}
                    </div>
                    <div className="text-xs text-gray-500">
                      {(m.linked_hazard_names || []).join(', ') || '-'}
                    </div>
                    <div>
                      <StatusBadge status={m.status} />
                    </div>
                  </div>
                ))}
                {items.length > (mitPages[type] || 1) * 50 && (
                  <button onClick={() => setMitPages(prev => ({ ...prev, [type]: (prev[type] || 1) + 1 }))}
                    className="w-full py-2 text-xs text-purple-600 hover:bg-purple-50 border-t border-gray-100 transition-colors">
                    Weitere {Math.min(50, items.length - (mitPages[type] || 1) * 50)} von {items.length} laden...
                  </button>
                )}
              </div>
            )}

            {isExpanded && items.length === 0 && (
              <div className="px-4 py-6 text-center text-sm text-gray-400 border-t border-gray-100">
                Keine Massnahmen in dieser Stufe
              </div>
            )}
          </div>
        )
      })}
    </div>
  )
}