import { useState, useEffect, useCallback, useRef } from 'react'
import DrawCanvas, { type DrawCanvasHandle } from '../components/DrawCanvas'
import Topbar from '../components/Topbar'
import {
  getDirectusPictures, directusAssetUrl, type DirectusPicture,
  getDirectusObjects, createDirectusObject, updateDirectusObject, deleteDirectusObject,
} from '../api'
import { useAuth } from '../context/AuthContext'
import type { DirectusObject, Selection, CanvasObject } from '../types'

const ChevronLeftIcon = () => (
  <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.5" strokeLinecap="round" strokeLinejoin="round">
    <polyline points="15 18 9 12 15 6" />
  </svg>
)
const ChevronRightIcon = () => (
  <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.5" strokeLinecap="round" strokeLinejoin="round">
    <polyline points="9 18 15 12 9 6" />
  </svg>
)
const TrashIcon = () => (
  <svg width="13" height="13" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
    <polyline points="3 6 5 6 21 6" /><path d="M19 6l-1 14H6L5 6" /><path d="M10 11v6M14 11v6" /><path d="M9 6V4h6v2" />
  </svg>
)

export default function DrawIt() {
  const { token } = useAuth()

  const [pictureList, setPictureList] = useState<DirectusPicture[]>([])
  const [currentIndex, setCurrentIndex] = useState(-1)
  const [objects, setObjects] = useState<DirectusObject[]>([])
  const [selectedObjectId, setSelectedObjectId] = useState<string | null>(null)
  const [currentSelections, setCurrentSelections] = useState<Selection[]>([])
  const [userNotes, setUserNotes] = useState('')
  const [parentId, setParentId] = useState<string | null>(null)
  const [editingNotes, setEditingNotes] = useState<{ id: string; notes: string } | null>(null)
  const [mode, setMode] = useState<'rect' | 'polygon'>('polygon')
  const [hasSelection, setHasSelection] = useState(false)
  const [saving, setSaving] = useState(false)
  const [status, setStatus] = useState('')
  const [statusError, setStatusError] = useState(false)

  const canvasRef = useRef<DrawCanvasHandle>(null)

  const currentPicture: DirectusPicture | null =
    currentIndex >= 0 && currentIndex < pictureList.length ? pictureList[currentIndex] : null

  // Map DirectusObject → CanvasObject for rendering
  const canvasObjects: CanvasObject[] = objects.map((obj, i) => ({
    id: obj.id,
    visible: obj.visible !== false,
    bbox: obj.bbox,
    polygon: obj.polygon,
    index: i + 1,
    hierarchy: 1,
  }))

  useEffect(() => {
    if (!token) return
    getDirectusPictures(token)
      .then(pics => { setPictureList(pics); setCurrentIndex(pics.length > 0 ? 0 : -1) })
      .catch(console.error)
  }, [token])

  useEffect(() => {
    if (!currentPicture || !token) { setObjects([]); setSelectedObjectId(null); return }
    getDirectusObjects(currentPicture.id, token)
      .then(objs => { setObjects(objs.map(o => ({ ...o, visible: true }))); setSelectedObjectId(null) })
      .catch(console.error)
  }, [currentPicture?.id, token])

  const showStatus = (msg: string, isError = false) => {
    setStatus(msg); setStatusError(isError)
  }

  const handleHasSelection = useCallback((has: boolean) => setHasSelection(has), [])

  const addSelection = () => {
    const sel = canvasRef.current?.getCurrentSelection()
    if (!sel) { showStatus('Bitte zuerst einen Bereich auswählen.', true); return }
    setCurrentSelections(prev => { const next = [...prev, sel]; showStatus(`Auswahl ${next.length} hinzugefügt.`); return next })
    canvasRef.current?.resetSelection()
    setHasSelection(false)
  }

  const saveObject = async () => {
    if (!currentPicture || !token || currentSelections.length === 0) return
    setSaving(true)
    try {
      const first = currentSelections[0]
      const obj = await createDirectusObject({
        picture: currentPicture.id,
        bbox: first.mode === 'rect' ? (first.bbox ?? null) : null,
        polygon: first.mode === 'polygon' ? (first.polygon ?? null) : null,
        selections: currentSelections,
        user_notes: userNotes.trim() || null,
        parent: parentId,
      }, token)
      setObjects(prev => [...prev, { ...obj, visible: true }])
      setCurrentSelections([])
      setUserNotes('')
      setParentId(null)
      canvasRef.current?.resetSelection()
      showStatus('Objekt gespeichert.')
    } catch (e) {
      showStatus(e instanceof Error ? e.message : 'Fehler beim Speichern.', true)
    } finally {
      setSaving(false)
    }
  }

  const saveNoteEdit = async () => {
    if (!editingNotes || !token) return
    try {
      await updateDirectusObject(editingNotes.id, { user_notes: editingNotes.notes }, token)
      setObjects(prev => prev.map(o => o.id === editingNotes.id ? { ...o, user_notes: editingNotes.notes } : o))
      setEditingNotes(null)
      showStatus('Notizen gespeichert.')
    } catch (e) {
      showStatus(e instanceof Error ? e.message : 'Fehler.', true)
    }
  }

  const deleteObject = async (objId: string) => {
    if (!token) return
    try {
      await deleteDirectusObject(objId, token)
      setObjects(prev => prev.filter(o => o.id !== objId))
      if (selectedObjectId === objId) setSelectedObjectId(null)
      showStatus('Objekt gelöscht.')
    } catch (e) {
      showStatus(e instanceof Error ? e.message : 'Fehler beim Löschen.', true)
    }
  }

  const imageNav = (
    <div className="image-nav">
      <button className="btn-icon" onClick={() => setCurrentIndex(i => i - 1)} disabled={currentIndex <= 0}>
        <ChevronLeftIcon />
      </button>
      <span className="image-counter">
        {pictureList.length > 0
          ? <><span className="image-counter-num">{currentIndex + 1}</span><span className="image-counter-sep">/</span><span className="image-counter-total">{pictureList.length}</span></>
          : <span className="image-counter-empty">Keine Bilder</span>}
      </span>
      <button className="btn-icon" onClick={() => setCurrentIndex(i => i + 1)} disabled={currentIndex >= pictureList.length - 1}>
        <ChevronRightIcon />
      </button>
    </div>
  )

  return (
    <div className="app-shell">
      <Topbar page="draw" center={imageNav} />

      <div className="workspace">
        {/* Left sidebar: saved objects */}
        <aside className="sidebar">
          <div className="sidebar-panel" style={{ flex: 1 }}>
            <h3 className="sidebar-heading">
              Objekte
              {objects.length > 0 && <span className="badge">{objects.length}</span>}
            </h3>

            {objects.length === 0 ? (
              <div className="empty-state">Noch keine Objekte für dieses Bild.</div>
            ) : (
              <div className="objects-list">
                {objects.map((obj, i) => (
                  <div
                    key={obj.id}
                    className={`object-item${selectedObjectId === obj.id ? ' selected' : ''}`}
                    onClick={() => setSelectedObjectId(obj.id === selectedObjectId ? null : obj.id)}
                  >
                    <div className="object-item-header">
                      <input
                        type="checkbox"
                        checked={obj.visible !== false}
                        onClick={e => e.stopPropagation()}
                        onChange={e => setObjects(prev => prev.map(o => o.id === obj.id ? { ...o, visible: e.target.checked } : o))}
                      />
                      <div className="object-item-text">
                        <strong>Objekt {i + 1}</strong>
                        <span>{obj.bbox ? `Rect ${Math.round(obj.bbox.width)}×${Math.round(obj.bbox.height)}` : obj.polygon ? `Poly ${obj.polygon.length} Pkt.` : '–'}</span>
                        {obj.parent && <span style={{ color: 'var(--primary-muted-fg)', fontSize: 11 }}>↳ Kind von #{objects.findIndex(o => o.id === obj.parent) + 1}</span>}
                      </div>
                      <button
                        className="object-icon-button"
                        onClick={e => { e.stopPropagation(); setEditingNotes({ id: obj.id, notes: obj.user_notes ?? '' }) }}
                        title="Notizen bearbeiten"
                      >✏️</button>
                      <button
                        className="object-icon-button"
                        onClick={e => { e.stopPropagation(); deleteObject(obj.id) }}
                        title="Löschen"
                      ><TrashIcon /></button>
                    </div>

                    {obj.user_notes && (
                      <div style={{ padding: '4px 8px 6px 32px', fontSize: 11.5, color: 'var(--text-2)', lineHeight: 1.4, borderTop: '1px solid var(--border)' }}>
                        {obj.user_notes}
                      </div>
                    )}

                    {editingNotes?.id === obj.id && (
                      <div style={{ padding: '8px', borderTop: '1px solid var(--border)', display: 'flex', flexDirection: 'column', gap: 6 }} onClick={e => e.stopPropagation()}>
                        <textarea
                          value={editingNotes.notes}
                          onChange={e => setEditingNotes({ ...editingNotes, notes: e.target.value })}
                          rows={3}
                          style={{ width: '100%', resize: 'vertical', padding: '6px 8px', borderRadius: 'var(--r-sm)', border: '1px solid var(--border)', background: 'var(--surface)', color: 'var(--text-1)', fontFamily: 'var(--font)', fontSize: 12 }}
                          placeholder="Notizen zum Objekt…"
                          autoFocus
                        />
                        <div style={{ display: 'flex', gap: 4 }}>
                          <button className="btn-primary btn-sm" style={{ flex: 1 }} onClick={saveNoteEdit}>Speichern</button>
                          <button className="btn-ghost btn-sm" onClick={() => setEditingNotes(null)}>Abbrechen</button>
                        </div>
                      </div>
                    )}
                  </div>
                ))}
              </div>
            )}
          </div>
        </aside>

        {/* Center: Canvas */}
        <main className="canvas-area">
          <div className="canvas-frame">
            <DrawCanvas
              ref={canvasRef}
              imageSrc={currentPicture && token ? directusAssetUrl(currentPicture.media, token) : null}
              objects={canvasObjects}
              selectedObjectId={selectedObjectId}
              mode={mode}
              onHasSelection={handleHasSelection}
            />
          </div>
        </main>

        {/* Right sidebar: drawing tools */}
        <aside className="sidebar sidebar--right">
          <div className="sidebar-panel">
            <h3 className="sidebar-heading">Modus</h3>
            <div className="mode-group">
              <label className={`mode-btn${mode === 'rect' ? ' active' : ''}`}>
                <input type="radio" name="mode" value="rect" checked={mode === 'rect'} onChange={() => setMode('rect')} />
                <span>Rechteck</span>
              </label>
              <label className={`mode-btn${mode === 'polygon' ? ' active' : ''}`}>
                <input type="radio" name="mode" value="polygon" checked={mode === 'polygon'} onChange={() => setMode('polygon')} />
                <span>Polygon</span>
              </label>
            </div>
            <div className="action-group">
              {mode === 'polygon' && (
                <button
                  className="btn-primary btn-sm btn-block"
                  onClick={() => canvasRef.current?.closePolygon()}
                  disabled={!hasSelection}
                >
                  Polygon schließen
                </button>
              )}
              <button className="btn-ghost btn-sm btn-block" onClick={() => canvasRef.current?.resetSelection()}>
                Auswahl zurücksetzen
              </button>
            </div>
          </div>

          <div className="sidebar-panel">
            <h3 className="sidebar-heading">Notizen zum Objekt</h3>
            <textarea
              value={userNotes}
              onChange={e => setUserNotes(e.target.value)}
              rows={4}
              placeholder="Beschreibung, Besonderheiten, Kontext…"
              style={{
                width: '100%', resize: 'vertical', padding: '7px 10px',
                borderRadius: 'var(--r-md)', border: '1px solid var(--border)',
                background: 'var(--surface-2)', color: 'var(--text-1)',
                fontFamily: 'var(--font)', fontSize: 13, lineHeight: 1.5,
                transition: 'border-color .15s, box-shadow .15s', outline: 'none',
              }}
              onFocus={e => { e.target.style.borderColor = 'var(--primary)'; e.target.style.boxShadow = '0 0 0 3px rgba(92,108,246,.12)' }}
              onBlur={e => { e.target.style.borderColor = 'var(--border)'; e.target.style.boxShadow = 'none' }}
            />
          </div>

          <div className="sidebar-panel">
            <h3 className="sidebar-heading">Parent-Objekt</h3>
            <select
              value={parentId ?? ''}
              onChange={e => setParentId(e.target.value || null)}
            >
              <option value="">— kein Parent —</option>
              {objects.map((obj, i) => (
                <option key={obj.id} value={obj.id}>
                  Objekt {i + 1}{obj.user_notes ? ` – ${obj.user_notes.slice(0, 30)}` : ''}
                </option>
              ))}
            </select>
          </div>

          <div className="sidebar-panel">
            <h3 className="sidebar-heading">
              Auswahlen
              {currentSelections.length > 0 && <span className="badge">{currentSelections.length}</span>}
            </h3>
            <div className="selections-list">
              {currentSelections.length === 0
                ? <div className="empty-state">Noch keine Auswahlen</div>
                : currentSelections.map((sel, i) => (
                  <div className="selection-chip" key={i}>
                    <span className="selection-chip-num">{i + 1}</span>
                    <span className="selection-chip-type">{sel.mode === 'rect' ? 'Rect' : 'Poly'}</span>
                    <span className="selection-chip-info">
                      {sel.mode === 'rect' && sel.bbox
                        ? `${Math.round(sel.bbox.width)}×${Math.round(sel.bbox.height)}`
                        : `${sel.polygon?.length ?? 0} Pkt.`}
                    </span>
                  </div>
                ))}
            </div>
            <div className="action-group">
              <button className="btn-primary btn-sm btn-block" onClick={addSelection} disabled={!hasSelection || !currentPicture}>
                + Auswahl hinzufügen
              </button>
              <button
                className="btn-primary btn-sm btn-block"
                onClick={saveObject}
                disabled={!currentPicture || currentSelections.length === 0 || saving}
              >
                {saving ? 'Speichere…' : `${currentSelections.length > 1 ? currentSelections.length + ' Objekte' : 'Objekt'} speichern`}
              </button>
              <button
                className="btn-ghost btn-sm btn-block btn-danger"
                onClick={() => { setCurrentSelections([]); canvasRef.current?.resetSelection(); showStatus('Alle Auswahlen gelöscht.') }}
              >
                Alle löschen
              </button>
            </div>
            {status && <div className={`status-msg ${statusError ? 'error' : 'ok'}`}>{status}</div>}
          </div>
        </aside>
      </div>
    </div>
  )
}