/**
 * Planungs-KI Phase C3: Ziel → Übungspfad vorschlagen → in Progressionsgraph speichern.
 */
import React, { useCallback, useState } from 'react'
import api from '../utils/api'

function emptyPathStep() {
  return { exerciseId: null, exerciseTitle: '', variantId: null, variants: [], reasons: [] }
}

function mapApiStepToRow(step) {
  const variants = Array.isArray(step?.variants) ? step.variants : []
  const rawVid = step?.variant_id ?? step?.suggested_variant_id ?? null
  const variantId =
    rawVid != null && Number.isFinite(Number(rawVid)) && Number(rawVid) > 0 ? Number(rawVid) : null
  return {
    exerciseId: step?.exercise_id != null ? Number(step.exercise_id) : null,
    exerciseTitle: (step?.title || '').trim() || (step?.exercise_id ? `Übung #${step.exercise_id}` : ''),
    variantId,
    variants,
    reasons: Array.isArray(step?.reasons) ? step.reasons : [],
    isBridge: Boolean(step?.is_bridge),
    semanticScore: step?.semantic_score,
  }
}

export default function ExerciseProgressionPathBuilder({
  graphId,
  disabled = false,
  onSaved,
}) {
  const [goalQuery, setGoalQuery] = useState('')
  const [maxSteps, setMaxSteps] = useState(5)
  const [segmentNotes, setSegmentNotes] = useState('')
  const [loading, setLoading] = useState(false)
  const [saving, setSaving] = useState(false)
  const [error, setError] = useState('')
  const [targetSummary, setTargetSummary] = useState(null)
  const [semanticBrief, setSemanticBrief] = useState(null)
  const [pathQa, setPathQa] = useState(null)
  const [pathSteps, setPathSteps] = useState([])

  const patchStep = useCallback((idx, patch) => {
    setPathSteps((prev) => prev.map((row, i) => (i === idx ? { ...row, ...patch } : row)))
  }, [])

  const removeStep = useCallback((idx) => {
    setPathSteps((prev) => (prev.length <= 2 ? prev : prev.filter((_, i) => i !== idx)))
  }, [])

  const moveStep = useCallback((idx, dir) => {
    setPathSteps((prev) => {
      const j = idx + dir
      if (j < 0 || j >= prev.length) return prev
      const next = [...prev]
      const t = next[idx]
      next[idx] = next[j]
      next[j] = t
      return next
    })
  }, [])

  const suggestPath = async () => {
    const q = (goalQuery || '').trim()
    if (q.length < 3) {
      alert('Ziel-Anfrage: mindestens 3 Zeichen.')
      return
    }
    if (!graphId) {
      alert('Zuerst einen Graphen wählen.')
      return
    }
    setLoading(true)
    setError('')
    try {
      const res = await api.suggestProgressionPath({
        query: q,
        max_steps: Number(maxSteps),
        include_llm_intent: true,
        include_path_qa: true,
        include_llm_path_qa: true,
        progression_graph_id: Number(graphId),
      })
      const rows = (Array.isArray(res?.steps) ? res.steps : []).map(mapApiStepToRow)
      if (rows.length < 2) {
        throw new Error('Zu wenig Schritte im Vorschlag.')
      }
      setPathSteps(rows)
      setTargetSummary(res?.target_profile_summary || null)
      setSemanticBrief(res?.semantic_brief_summary || null)
      setPathQa(res?.path_qa || null)
      if (!segmentNotes.trim() && q) setSegmentNotes(q.slice(0, 400))
    } catch (e) {
      console.error(e)
      setError(e.message || 'Pfad-Vorschlag fehlgeschlagen')
      setPathSteps([])
      setTargetSummary(null)
      setSemanticBrief(null)
      setPathQa(null)
    } finally {
      setLoading(false)
    }
  }

  const savePathToGraph = async () => {
    if (!graphId) {
      alert('Zuerst einen Graphen wählen.')
      return
    }
    const steps = pathSteps.filter((s) => s.exerciseId != null)
    if (steps.length < 2) {
      alert('Mindestens zwei Schritte mit Übung nötig.')
      return
    }
    const n = steps.length - 1
    const noteRaw = segmentNotes.trim()
    const segment_notes = Array.from({ length: n }, (_, i) => {
      const reasons = (steps[i + 1]?.reasons || []).slice(0, 2).join(' · ')
      if (reasons) return reasons
      return noteRaw || null
    })

    setSaving(true)
    setError('')
    try {
      await api.createExerciseProgressionSequence(Number(graphId), {
        steps: steps.map((s) => ({
          exercise_id: s.exerciseId,
          variant_id: s.variantId || null,
        })),
        segment_notes,
      })
      setPathSteps([])
      setTargetSummary(null)
      setSemanticBrief(null)
      setPathQa(null)
      if (typeof onSaved === 'function') await onSaved()
      alert(`${n} Nachfolger-Kante(n) aus KI-Pfad gespeichert.`)
    } catch (e) {
      console.error(e)
      setError(e.message || 'Speichern fehlgeschlagen')
    } finally {
      setSaving(false)
    }
  }

  return (
    <div
      className="card"
      style={{
        marginBottom: '12px',
        borderColor: 'color-mix(in srgb, var(--accent) 35%, var(--border))',
      }}
    >
      <h3 style={{ marginTop: 0, fontSize: '1rem' }}>KI: Pfad zum Ziel</h3>
      <p style={{ fontSize: '12px', color: 'var(--text3)', marginTop: 0, lineHeight: 1.45 }}>
        Ziel in Freitext formulieren — die Planungs-KI schlägt eine semantisch passende, aufbauende Reihenfolge vor,
        prüft Lücken (ggf. Brücken-Übungen) und optional per LLM-QS. Nach Review in den Graph speichern.
      </p>
      <div style={{ display: 'flex', flexWrap: 'wrap', gap: '10px', alignItems: 'flex-end' }}>
        <div className="form-row" style={{ flex: '2 1 240px', marginBottom: 0 }}>
          <label className="form-label">Ziel / Entwicklungsrichtung</label>
          <input
            className="form-input"
            value={goalQuery}
            onChange={(e) => setGoalQuery(e.target.value)}
            placeholder="z. B. sichere Reaktion im Partnertraining aufbauen …"
            disabled={disabled || loading || saving}
          />
        </div>
        <div className="form-row" style={{ flex: '0 1 120px', marginBottom: 0 }}>
          <label className="form-label">Schritte</label>
          <input
            type="number"
            min={2}
            max={10}
            className="form-input"
            value={maxSteps}
            onChange={(e) => setMaxSteps(Math.max(2, Math.min(10, Number(e.target.value) || 5)))}
            disabled={disabled || loading || saving}
          />
        </div>
        <button
          type="button"
          className="btn btn-primary"
          disabled={disabled || loading || saving || !graphId}
          onClick={suggestPath}
        >
          {loading ? 'Vorschlag …' : 'Pfad vorschlagen'}
        </button>
      </div>

      {error ? (
        <p className="form-error" style={{ marginTop: '10px' }}>
          {error}
        </p>
      ) : null}

      {(semanticBrief || targetSummary) && pathSteps.length > 0 ? (
        <div style={{ marginTop: '10px', display: 'flex', flexWrap: 'wrap', gap: '6px' }}>
          {semanticBrief?.primary_topic ? (
            <span className="exercise-tag" style={{ borderColor: 'var(--accent)' }}>
              Thema: {semanticBrief.primary_topic}
            </span>
          ) : null}
          {Array.isArray(semanticBrief?.development_arc) &&
            semanticBrief.development_arc.slice(0, 3).map((phase) => (
              <span key={phase} className="exercise-tag">
                {phase}
              </span>
            ))}
          {Array.isArray(targetSummary?.focus_areas) &&
            targetSummary.focus_areas.slice(0, 1).map((fa) => (
              <span key={fa} className="exercise-tag">
                Fokus: {fa}
              </span>
            ))}
        </div>
      ) : null}

      {pathQa && pathSteps.length > 0 ? (
        <div
          style={{
            marginTop: '10px',
            padding: '10px 12px',
            borderRadius: '8px',
            background: pathQa.overall_ok ? 'color-mix(in srgb, var(--accent) 8%, var(--surface2))' : 'color-mix(in srgb, var(--danger) 8%, var(--surface2))',
            fontSize: '12px',
            lineHeight: 1.45,
          }}
        >
          <strong>
            Pfad-QS: {pathQa.overall_ok ? 'OK' : 'Hinweise'}
            {pathQa.quality_score != null ? ` (${Math.round(Number(pathQa.quality_score) * 100)} %)` : ''}
          </strong>
          {pathQa.topic_coverage ? (
            <p style={{ margin: '6px 0 0', color: 'var(--text2)' }}>{pathQa.topic_coverage}</p>
          ) : null}
          {Array.isArray(pathQa.issues) && pathQa.issues.length > 0 ? (
            <ul style={{ margin: '6px 0 0', paddingLeft: '16px', color: 'var(--text2)' }}>
              {pathQa.issues.slice(0, 4).map((issue) => (
                <li key={issue}>{issue}</li>
              ))}
            </ul>
          ) : null}
          {Number(pathQa.bridge_insert_count) > 0 ? (
            <p style={{ margin: '6px 0 0', color: 'var(--accent-dark)' }}>
              {pathQa.bridge_insert_count} Brücken-Übung(en) eingefügt (Lückenfüller).
            </p>
          ) : null}
          {Array.isArray(targetSummary?.top_skills) &&
            targetSummary.top_skills.slice(0, 2).map((sk) => (
              <span key={sk.skill_id} className="exercise-tag">
                {sk.name}
              </span>
            ))}
        </div>
      ) : null}

      {pathSteps.length > 0 ? (
        <>
          <div style={{ marginTop: '14px' }}>
            {pathSteps.map((step, idx) => (
              <div
                key={`${step.exerciseId}-${idx}`}
                style={{
                  display: 'grid',
                  gridTemplateColumns: 'repeat(auto-fit, minmax(200px, 1fr))',
                  gap: '10px',
                  alignItems: 'end',
                  marginBottom: '12px',
                  paddingBottom: '12px',
                  borderBottom: idx < pathSteps.length - 1 ? '1px dashed var(--border)' : 'none',
                }}
              >
                <div className="form-row" style={{ marginBottom: 0 }}>
                  <label className="form-label">
                    Schritt {idx + 1}
                    {step.isBridge ? ' (Brücke)' : ''}
                    {idx === 0 ? ' (Einstieg)' : idx === pathSteps.length - 1 ? ' (Zielnähe)' : ''}
                  </label>
                  <div style={{ fontSize: '13px' }}>
                    <strong>{step.exerciseTitle}</strong>
                    <span style={{ color: 'var(--text3)' }}> (#{step.exerciseId})</span>
                  </div>
                  {step.reasons?.length ? (
                    <ul
                      style={{
                        margin: '6px 0 0',
                        paddingLeft: '16px',
                        fontSize: '11px',
                        color: 'var(--accent-dark)',
                      }}
                    >
                      {step.reasons.slice(0, 2).map((r) => (
                        <li key={r}>{r}</li>
                      ))}
                    </ul>
                  ) : null}
                </div>
                <div className="form-row" style={{ marginBottom: 0 }}>
                  <label className="form-label">Variante</label>
                  <select
                    className="form-input"
                    value={step.variantId ?? ''}
                    onChange={(e) =>
                      patchStep(idx, {
                        variantId: e.target.value === '' ? null : parseInt(e.target.value, 10),
                      })
                    }
                    disabled={!step.exerciseId}
                  >
                    <option value="">Gesamte Übung</option>
                    {(step.variants || []).map((v) => (
                      <option key={v.id} value={v.id}>
                        {v.variant_name || `Variante #${v.id}`}
                      </option>
                    ))}
                  </select>
                </div>
                <div style={{ display: 'flex', gap: '6px', flexWrap: 'wrap' }}>
                  <button type="button" className="btn" style={{ fontSize: '12px', padding: '4px 8px' }} onClick={() => moveStep(idx, -1)}>
                    ↑
                  </button>
                  <button type="button" className="btn" style={{ fontSize: '12px', padding: '4px 8px' }} onClick={() => moveStep(idx, 1)}>
                    ↓
                  </button>
                  <button type="button" className="btn" style={{ fontSize: '12px', padding: '4px 8px' }} onClick={() => removeStep(idx)}>
                    Entfernen
                  </button>
                </div>
              </div>
            ))}
          </div>
          <div className="form-row">
            <label className="form-label">Notiz für Kanten (Fallback, optional)</label>
            <textarea
              className="form-input"
              rows={2}
              value={segmentNotes}
              onChange={(e) => setSegmentNotes(e.target.value)}
              placeholder="Wird pro Kante genutzt, wenn keine KI-Begründung vorliegt."
            />
          </div>
          <div style={{ display: 'flex', flexWrap: 'wrap', gap: '8px' }}>
            <button
              type="button"
              className="btn btn-primary"
              disabled={disabled || saving || pathSteps.filter((s) => s.exerciseId).length < 2}
              onClick={savePathToGraph}
            >
              {saving ? 'Speichern …' : 'Pfad in Graph speichern'}
            </button>
            <button
              type="button"
              className="btn btn-secondary"
              disabled={loading || saving}
              onClick={() => {
                setPathSteps([])
                setTargetSummary(null)
              }}
            >
              Vorschlag verwerfen
            </button>
          </div>
        </>
      ) : null}
    </div>
  )
}