import React, { useEffect, useState } from 'react'
import { Link, useNavigate, useParams } from 'react-router-dom'
import api from '../utils/api'

const API_BASE = (import.meta.env.VITE_API_URL || '').replace(/\/$/, '')

function resolveMediaUrl(filePath) {
  if (!filePath) return null
  if (filePath.startsWith('http://') || filePath.startsWith('https://')) return filePath
  const p = filePath.startsWith('/') ? filePath : `/${filePath}`
  return `${API_BASE}${p}`
}

function MediaBlock({ media }) {
  if (media.embed_url) {
    return (
      <div style={{ marginTop: '0.5rem' }}>
        <a href={media.embed_url} target="_blank" rel="noreferrer">
          {media.embed_url}
        </a>
        {media.embed_platform && (
          <span style={{ color: 'var(--text2)', marginLeft: '0.5rem', fontSize: '0.8rem' }}>
            ({media.embed_platform})
          </span>
        )}
      </div>
    )
  }
  const src = resolveMediaUrl(media.file_path)
  if (!src) return null
  if (media.media_type === 'image' || (media.mime_type && media.mime_type.startsWith('image/'))) {
    return (
      <img
        src={src}
        alt={media.title || media.original_filename || ''}
        style={{ maxWidth: '100%', borderRadius: '8px', marginTop: '0.5rem' }}
      />
    )
  }
  if (media.media_type === 'video' || (media.mime_type && media.mime_type.startsWith('video/'))) {
    return <video src={src} controls style={{ width: '100%', marginTop: '0.5rem', borderRadius: '8px' }} />
  }
  return (
    <a href={src} target="_blank" rel="noreferrer" style={{ display: 'inline-block', marginTop: '0.5rem' }}>
      {media.title || media.original_filename || 'Datei öffnen'}
    </a>
  )
}

function ExerciseDetailPage() {
  const { id } = useParams()
  const navigate = useNavigate()
  const [exercise, setExercise] = useState(null)
  const [error, setError] = useState(null)
  const [loading, setLoading] = useState(true)

  useEffect(() => {
    let cancelled = false
    const load = async () => {
      setLoading(true)
      setError(null)
      try {
        const data = await api.getExercise(id)
        if (!cancelled) setExercise(data)
      } catch (err) {
        if (!cancelled) setError(err)
      } finally {
        if (!cancelled) setLoading(false)
      }
    }
    if (id) load()
    return () => {
      cancelled = true
    }
  }, [id])

  if (loading) {
    return (
      <div style={{ padding: '2rem', textAlign: 'center' }}>
        <div className="spinner"></div>
        <p>Laden...</p>
      </div>
    )
  }

  if (error) {
    const msg = error.message || String(error)
    return (
      <div style={{ padding: '2rem', maxWidth: '720px', margin: '0 auto' }}>
        <div className="card">
          <h2>Übung</h2>
          <p style={{ color: 'var(--danger)' }}>{msg}</p>
          <button type="button" className="btn btn-secondary" onClick={() => navigate('/exercises')}>
            Zur Übersicht
          </button>
        </div>
      </div>
    )
  }

  if (!exercise) return null

  const chips = (items, labelKey = 'name') =>
    (items || []).length ? (items || []).map((x) => x[labelKey]).join(', ') : '—'

  return (
    <div style={{ padding: '2rem' }}>
      <div style={{ maxWidth: '800px', margin: '0 auto' }}>
        <div style={{ marginBottom: '1rem' }}>
          <button type="button" className="btn btn-secondary" onClick={() => navigate('/exercises')}>
            ← Übersicht
          </button>
        </div>

        <div className="card" style={{ marginBottom: '1rem' }}>
          <div
            style={{
              display: 'flex',
              justifyContent: 'space-between',
              alignItems: 'flex-start',
              gap: '1rem',
              flexWrap: 'wrap',
            }}
          >
            <h1 style={{ margin: 0 }}>{exercise.title}</h1>
            <Link to={`/exercises/${exercise.id}/edit`} className="btn btn-primary">
              Bearbeiten
            </Link>
          </div>
          {exercise.summary && (
            <p style={{ color: 'var(--text2)', marginTop: '1rem' }}>{exercise.summary}</p>
          )}
          <div style={{ display: 'flex', gap: '0.5rem', flexWrap: 'wrap', marginTop: '1rem' }}>
            <span className="badge">{exercise.visibility}</span>
            <span className="badge">{exercise.status}</span>
            {exercise.club_name && <span className="badge">{exercise.club_name}</span>}
          </div>
        </div>

        <section className="card" style={{ marginBottom: '1rem' }}>
          <h2 style={{ marginTop: 0 }}>Zuordnung</h2>
          <p>
            <strong>Fokusbereiche:</strong> {chips(exercise.focus_areas)}
          </p>
          <p>
            <strong>Stilrichtungen:</strong> {chips(exercise.training_styles)}
          </p>
          <p>
            <strong>Zielgruppen:</strong> {chips(exercise.target_groups)}
          </p>
          <p>
            <strong>Altersgruppen:</strong>{' '}
            {(exercise.age_groups || []).length ? exercise.age_groups.join(', ') : '—'}
          </p>
        </section>

        {exercise.goal && (
          <section className="card" style={{ marginBottom: '1rem' }}>
            <h2 style={{ marginTop: 0 }}>Ziel</h2>
            <p style={{ whiteSpace: 'pre-wrap' }}>{exercise.goal}</p>
          </section>
        )}

        {exercise.execution && (
          <section className="card" style={{ marginBottom: '1rem' }}>
            <h2 style={{ marginTop: 0 }}>Durchführung</h2>
            <p style={{ whiteSpace: 'pre-wrap' }}>{exercise.execution}</p>
          </section>
        )}

        {(exercise.preparation || exercise.trainer_notes) && (
          <section className="card" style={{ marginBottom: '1rem' }}>
            <h2 style={{ marginTop: 0 }}>Trainer</h2>
            {exercise.preparation && (
              <>
                <h3 style={{ fontSize: '1rem' }}>Vorbereitung</h3>
                <p style={{ whiteSpace: 'pre-wrap' }}>{exercise.preparation}</p>
              </>
            )}
            {exercise.trainer_notes && (
              <>
                <h3 style={{ fontSize: '1rem' }}>Hinweise</h3>
                <p style={{ whiteSpace: 'pre-wrap' }}>{exercise.trainer_notes}</p>
              </>
            )}
          </section>
        )}

        {exercise.equipment && exercise.equipment.length > 0 && (
          <section className="card" style={{ marginBottom: '1rem' }}>
            <h2 style={{ marginTop: 0 }}>Material</h2>
            <ul>
              {exercise.equipment.map((x, i) => (
                <li key={i}>{x}</li>
              ))}
            </ul>
          </section>
        )}

        {(exercise.skills || []).length > 0 && (
          <section className="card" style={{ marginBottom: '1rem' }}>
            <h2 style={{ marginTop: 0 }}>Fähigkeiten</h2>
            <ul style={{ paddingLeft: '1.25rem' }}>
              {exercise.skills.map((s) => (
                <li key={s.id}>
                  {s.skill_name}
                  {s.skill_category ? ` (${s.skill_category})` : ''}
                  {s.is_primary ? ' · primär' : ''}
                  {s.intensity ? ` · ${s.intensity}` : ''}
                </li>
              ))}
            </ul>
          </section>
        )}

        {(exercise.variants || []).length > 0 && (
          <section className="card" style={{ marginBottom: '1rem' }}>
            <h2 style={{ marginTop: 0 }}>Varianten</h2>
            {exercise.variants.map((v) => (
              <div key={v.id} style={{ marginBottom: '1rem', paddingBottom: '1rem', borderBottom: '1px solid var(--border)' }}>
                <strong>{v.variant_name}</strong>
                {v.description && <p style={{ color: 'var(--text2)' }}>{v.description}</p>}
                {v.execution_changes && (
                  <p style={{ whiteSpace: 'pre-wrap' }}>{v.execution_changes}</p>
                )}
              </div>
            ))}
          </section>
        )}

        {(exercise.media || []).length > 0 && (
          <section className="card">
            <h2 style={{ marginTop: 0 }}>Medien</h2>
            {exercise.media.map((m) => (
              <div key={m.id} style={{ marginBottom: '1.5rem' }}>
                <strong>{m.title || m.original_filename || m.media_type}</strong>
                {m.description && <p style={{ color: 'var(--text2)', fontSize: '0.9rem' }}>{m.description}</p>}
                <MediaBlock media={m} />
              </div>
            ))}
          </section>
        )}
      </div>
    </div>
  )
}

export default ExerciseDetailPage