/**
 * Schnellansicht einer Übung aus dem Katalog (ohne die Planungsseite zu verlassen).
 * Unterstützt Drill-down zu Kandidaten-Übungen bei Kombinationen inkl. „Zurück“ (PWA-sicher).
 */
import React, { useEffect, useMemo, useRef, useState } from 'react'
import { Link } from 'react-router-dom'
import api from '../utils/api'
import ExerciseRichTextBlock from './ExerciseRichTextBlock'
import CombinationPlanBracket from './CombinationPlanBracket'
import { effectiveComboMethodProfile } from '../utils/comboPlanningMethodProfile'

function TagMini({ exercise }) {
  const parts = []
  ;(exercise.focus_areas || []).slice(0, 5).forEach((f) => {
    parts.push(f.name)
  })
  if (parts.length === 0) return null
  return (
    <div className="exercise-tag-row" style={{ marginTop: '10px' }}>
      {parts.map((p, i) => (
        <span key={i} className="exercise-tag exercise-tag--accent">
          {p}
        </span>
      ))}
    </div>
  )
}

/** @typedef {{ exerciseId: number, variantId?: number | null, peekExtras?: object | null }} PeekStackEntry */

export default function ExercisePeekModal({
  open,
  exerciseId,
  variantId,
  onClose,
  titleFallback,
  /** Nur Planung: effektives method_profile aus Zeilen-Katalog + Planungs-Override */
  peekExtras,
}) {
  const [loading, setLoading] = useState(false)
  const [err, setErr] = useState(null)
  const [exercise, setExercise] = useState(null)
  /** @type {[PeekStackEntry[], React.Dispatch<React.SetStateAction<PeekStackEntry[]>>]} */
  const [stack, setStack] = useState([])

  /** @type {React.MutableRefObject<boolean>} */
  const wasOpenRef = useRef(false)

  useEffect(() => {
    if (!open) {
      setStack([])
      wasOpenRef.current = false
      return
    }
    if (exerciseId == null || exerciseId === '') return
    if (!wasOpenRef.current) {
      wasOpenRef.current = true
      setStack([
        {
          exerciseId: Number(exerciseId),
          variantId: variantId ?? null,
          peekExtras: peekExtras ?? null,
        },
      ])
    }
  }, [open, exerciseId, variantId, peekExtras])

  const top = stack.length ? stack[stack.length - 1] : null

  useEffect(() => {
    if (!open || !top?.exerciseId) {
      setExercise(null)
      setErr(null)
      return
    }
    let cancelled = false
    ;(async () => {
      setLoading(true)
      setErr(null)
      try {
        const data = await api.getExercise(top.exerciseId)
        if (!cancelled) setExercise(data)
      } catch (e) {
        if (!cancelled) setErr(e.message || 'Laden fehlgeschlagen')
      } finally {
        if (!cancelled) setLoading(false)
      }
    })()
    return () => {
      cancelled = true
    }
  }, [open, top?.exerciseId])

  const variant =
    top?.variantId != null &&
    top.variantId !== '' &&
    exercise?.variants?.length
      ? exercise.variants.find((v) => String(v.id) === String(top.variantId)) || null
      : null

  const isCombination =
    exercise && String(exercise.exercise_kind || 'simple').toLowerCase().trim() === 'combination'

  const comboMethodProfileEffective = useMemo(() => {
    if (!exercise || !isCombination) return {}
    const fromPeek =
      top?.peekExtras?.catalog_method_profile &&
      typeof top.peekExtras.catalog_method_profile === 'object' &&
      !Array.isArray(top.peekExtras.catalog_method_profile) &&
      Object.keys(top.peekExtras.catalog_method_profile).length > 0
        ? top.peekExtras.catalog_method_profile
        : exercise.method_profile || {}
    return effectiveComboMethodProfile(fromPeek, top?.peekExtras?.planning_method_profile ?? null)
  }, [exercise, isCombination, top?.peekExtras])

  const planningAdjustedBadge =
    top?.peekExtras?.planning_method_profile != null &&
    typeof top.peekExtras.planning_method_profile === 'object' &&
    !Array.isArray(top.peekExtras.planning_method_profile)

  const pushCandidatePeek = (id) => {
    const n = Number(id)
    if (!Number.isFinite(n)) return
    setStack((s) => [...s, { exerciseId: n, variantId: null, peekExtras: null }])
  }

  if (!open) return null

  const sheetWide = Boolean(isCombination && exercise && !loading)

  return (
    <div className="admin-modal-backdrop" role="presentation" onClick={(e) => e.target === e.currentTarget && onClose()}>
      <div
        className="admin-modal-sheet"
        role="dialog"
        aria-modal="true"
        aria-labelledby="exercise-peek-title"
        style={{
          maxWidth: sheetWide ? 'min(840px, 96vw)' : '620px',
          width: '100%',
          maxHeight: '88vh',
          display: 'flex',
          flexDirection: 'column',
        }}
        onClick={(e) => e.stopPropagation()}
      >
        <div className="admin-modal-sheet__header" style={{ gap: '8px', flexWrap: 'wrap' }}>
          {stack.length > 1 ? (
            <button
              type="button"
              className="btn btn-secondary"
              style={{ flexShrink: 0, fontWeight: 600 }}
              onClick={() => setStack((s) => (s.length > 1 ? s.slice(0, -1) : s))}
            >
              ← Zurück
            </button>
          ) : null}
          <h3 id="exercise-peek-title" className="admin-modal-sheet__title" style={{ flex: '1 1 200px', minWidth: 0 }}>
            {loading ? '…' : exercise?.title || titleFallback || (top?.exerciseId != null ? `Übung #${top.exerciseId}` : 'Übung')}
          </h3>
          <button type="button" className="btn btn-secondary admin-modal-sheet__close" onClick={onClose}>
            Schließen
          </button>
        </div>
        <div style={{ overflowY: 'auto', padding: '1rem', flex: 1 }}>
          {loading && (
            <div style={{ textAlign: 'center', color: 'var(--text2)' }}>
              <div className="spinner" />
              <p style={{ marginTop: '0.65rem' }}>Laden…</p>
            </div>
          )}
          {!loading && err && <p style={{ color: 'var(--danger)' }}>{err}</p>}
          {!loading && exercise && (
            <>
              {isCombination ? (
                <>
                  <CombinationPlanBracket
                    methodArchetype={exercise.method_archetype || ''}
                    methodProfile={comboMethodProfileEffective}
                    combinationSlots={Array.isArray(exercise.combination_slots) ? exercise.combination_slots : []}
                    planningAdjusted={planningAdjustedBadge}
                    candidateInteraction="button"
                    onCandidatePeek={pushCandidatePeek}
                  />
                  <hr style={{ border: 'none', borderTop: '1px solid var(--border)', margin: '1rem 0' }} />
                </>
              ) : null}

              {variant ? (
                <div
                  style={{
                    marginBottom: '0.75rem',
                    padding: '8px 10px',
                    borderRadius: '8px',
                    background: 'var(--surface2)',
                    border: '1px solid var(--border)',
                  }}
                >
                  <div style={{ fontSize: '0.78rem', fontWeight: 700, color: 'var(--text3)', marginBottom: 4 }}>
                    Variante
                  </div>
                  <div style={{ fontWeight: 700, fontSize: '0.95rem' }}>
                    {variant.variant_name || `Variante #${variant.id}`}
                  </div>
                  {variant.description ? (
                    <div style={{ marginTop: 8, fontSize: '0.9rem', color: 'var(--text2)' }}>
                      <ExerciseRichTextBlock html={variant.description} exerciseId={exercise.id} media={exercise.media} />
                    </div>
                  ) : null}
                  {variant.execution_changes ? (
                    <div style={{ marginTop: 10 }}>
                      <h4 style={{ fontSize: '0.85rem', color: 'var(--text3)', marginBottom: 6 }}>
                        Durchführung (Variante)
                      </h4>
                      <ExerciseRichTextBlock html={variant.execution_changes} exerciseId={exercise.id} media={exercise.media} />
                    </div>
                  ) : null}
                </div>
              ) : null}
              {exercise.summary && (
                <div style={{ fontSize: '0.95rem', color: 'var(--text2)' }}>
                  <ExerciseRichTextBlock html={exercise.summary} exerciseId={exercise.id} media={exercise.media} />
                </div>
              )}
              <TagMini exercise={exercise} />
              {(exercise.goal || exercise.preparation || exercise.execution || exercise.trainer_notes) && (
                <hr style={{ border: 'none', borderTop: '1px solid var(--border)', margin: '1rem 0' }} />
              )}
              {exercise.goal && (
                <>
                  <h4 style={{ fontSize: '0.85rem', color: 'var(--text3)', marginBottom: 6 }}>Ziel</h4>
                  <ExerciseRichTextBlock html={exercise.goal} exerciseId={exercise.id} media={exercise.media} />
                </>
              )}
              {exercise.preparation && (
                <>
                  <h4 style={{ fontSize: '0.85rem', color: 'var(--text3)', margin: '14px 0 6px' }}>Vorbereitung</h4>
                  <ExerciseRichTextBlock html={exercise.preparation} exerciseId={exercise.id} media={exercise.media} />
                </>
              )}
              {exercise.execution && (
                <>
                  <h4 style={{ fontSize: '0.85rem', color: 'var(--text3)', margin: '14px 0 6px' }}>Ablauf</h4>
                  <ExerciseRichTextBlock html={exercise.execution} exerciseId={exercise.id} media={exercise.media} />
                </>
              )}
              {exercise.trainer_notes && (
                <>
                  <h4 style={{ fontSize: '0.85rem', color: 'var(--text3)', margin: '14px 0 6px' }}>Trainer-Hinweise</h4>
                  <ExerciseRichTextBlock html={exercise.trainer_notes} exerciseId={exercise.id} media={exercise.media} />
                </>
              )}
            </>
          )}
        </div>
        {top?.exerciseId != null ? (
          <div style={{ padding: '0 1rem 1rem', flexShrink: 0 }}>
            <Link
              to={`/exercises/${top.exerciseId}`}
              className="btn btn-secondary"
              style={{ width: '100%', textDecoration: 'none', textAlign: 'center', display: 'block' }}
            >
              Vollständige Übungsseite öffnen
            </Link>
          </div>
        ) : null}
      </div>
    </div>
  )
}