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

const TYPE_COUNT = (r) =>
  typeof r.training_types_count === 'number' ? r.training_types_count : null
const TG_COUNT = (r) =>
  typeof r.target_groups_count === 'number' ? r.target_groups_count : null

function contextTeaser(r) {
  const bits = []
  if (r.focus_area_name) bits.push(r.focus_area_name)
  if (r.style_direction_name) bits.push(r.style_direction_name)
  const tn = TYPE_COUNT(r)
  const gn = TG_COUNT(r)
  if (tn != null && tn > 0) bits.push(`${tn} Trainingsart${tn === 1 ? '' : 'en'}`)
  if (gn != null && gn > 0) bits.push(`${gn} Zielgruppe${gn === 1 ? '' : 'n'}`)
  return bits.length ? bits.join(' · ') : null
}
export default function TrainingFrameworkProgramsListPage() {
  const [rows, setRows] = useState([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState('')

  const load = useCallback(async () => {
    setLoading(true)
    setError('')
    try {
      const list = await api.listTrainingFrameworkPrograms()
      setRows(Array.isArray(list) ? list : [])
    } catch (e) {
      setError(e.message || 'Laden fehlgeschlagen')
      setRows([])
    } finally {
      setLoading(false)
    }
  }, [])

  useEffect(() => {
    load()
  }, [load])

  async function handleDelete(id, title) {
    if (!confirm(`Rahmenprogramm „${title || id}“ wirklich löschen?`)) return
    try {
      await api.deleteTrainingFrameworkProgram(id)
      await load()
    } catch (e) {
      alert(e.message || 'Löschen fehlgeschlagen')
    }
  }

  return (
    <div className="app-page">
        <div
          style={{
            display: 'flex',
            flexWrap: 'wrap',
            alignItems: 'flex-start',
            justifyContent: 'space-between',
            gap: '1rem',
            marginBottom: '1.25rem',
          }}
        >
          <div>
            <h1 style={{ marginBottom: '0.35rem' }}>Trainingsrahmenprogramme</h1>
            <p style={{ color: 'var(--text2)', fontSize: '0.95rem', maxWidth: '36rem' }}>
              Wiederverwendbare Vorlagen für Ziele und Sessions. Die Verknüpfung mit{' '}
              <strong>konkreten Gruppeneinheiten</strong> erfolgt aus der <strong>Planung der Gruppe</strong> (Übernahme
              mit Bezug zum Rahmen).
            </p>
          </div>
          <Link
            to="/planning/framework-programs/new"
            className="btn btn-primary"
            style={{ textDecoration: 'none', whiteSpace: 'nowrap' }}
          >
            Rahmenprogramm anlegen
          </Link>
        </div>

        <p style={{ marginBottom: '1rem' }}>
          <Link to="/planning" style={{ color: 'var(--accent-dark)' }}>
            ← Zurück zur Trainingsplanung
          </Link>
        </p>

        {error && (
          <div className="card" style={{ borderLeft: '4px solid var(--danger)', marginBottom: '1rem' }}>
            {error}
          </div>
        )}

        {loading ? (
          <div style={{ textAlign: 'center', padding: '2rem' }}>
            <div className="spinner" />
            <p>Laden…</p>
          </div>
        ) : rows.length === 0 ? (
          <div className="card">
            <p style={{ color: 'var(--text2)', marginBottom: '1rem' }}>
              Noch kein Rahmenprogramm gespeichert. Lege ein neues an — mit Titel, mindestens einem Ziel und optional
              Slots samt Übungen.
            </p>
            <Link
              to="/planning/framework-programs/new"
              className="btn btn-primary btn-full"
              style={{ textDecoration: 'none' }}
            >
              Rahmenprogramm anlegen
            </Link>
          </div>
        ) : (
          <ul style={{ listStyle: 'none' }}>
            {rows.map((r) => (
              <li key={r.id} className="card" style={{ marginBottom: '12px' }}>
                <div
                  style={{
                    display: 'flex',
                    flexWrap: 'wrap',
                    alignItems: 'flex-start',
                    justifyContent: 'space-between',
                    gap: '0.75rem',
                  }}
                >
                  <div>
                    <Link
                      to={`/planning/framework-programs/${r.id}`}
                      style={{ fontWeight: 600, fontSize: '1.05rem', color: 'var(--text1)' }}
                    >
                      {r.title || `Rahmen #${r.id}`}
                    </Link>
                    <div style={{ fontSize: '0.85rem', color: 'var(--text2)', marginTop: '0.35rem' }}>
                      <span>
                        {r.goals_count ?? '—'} Ziele · {r.slots_count ?? '—'} Slots
                      </span>
                      {contextTeaser(r) ? (
                        <span style={{ display: 'block', marginTop: '0.25rem', color: 'var(--text3)' }}>
                          {contextTeaser(r)}
                        </span>
                      ) : null}
                    </div>
                    {r.description ? (
                      <p style={{ marginTop: '0.5rem', fontSize: '0.9rem', color: 'var(--text2)' }}>{r.description}</p>
                    ) : null}
                  </div>
                  <div style={{ display: 'flex', flexWrap: 'wrap', gap: '0.5rem' }}>
                    <Link
                      to={`/planning/framework-programs/${r.id}`}
                      className="btn btn-secondary"
                      style={{ textDecoration: 'none' }}
                    >
                      Bearbeiten
                    </Link>
                    <button type="button" className="btn btn-secondary" onClick={() => handleDelete(r.id, r.title)}>
                      Löschen
                    </button>
                  </div>
                </div>
              </li>
            ))}
          </ul>
        )}
    </div>
  )
}