import React, { useCallback, useEffect, useMemo, useState } from 'react'
import api from '../utils/api'
import NavStateLink from '../components/NavStateLink'
import { useAuth } from '../context/AuthContext'
import { getTenantClubDependencyKey } from '../utils/activeClub'
import { buildFrameworkProgramsListReturnContext } from '../utils/navReturnContext'

function dashIfEmpty(val) {
  const s = (val ?? '').toString().trim()
  return s.length ? s : '—'
}

function FrameworkSummaryMeta({ r }) {
  const trainingTypes =
    typeof r.training_type_names_agg === 'string' ? r.training_type_names_agg.trim() : ''
  const targetGroups =
    typeof r.target_group_names_agg === 'string' ? r.target_group_names_agg.trim() : ''
  const styleDir = typeof r.style_direction_name === 'string' ? r.style_direction_name.trim() : ''
  const focus = typeof r.focus_area_name === 'string' ? r.focus_area_name.trim() : ''

  const rowStyle = {
    display: 'grid',
    gridTemplateColumns: 'minmax(6.5rem, 32%) 1fr',
    gap: '0.25rem 0.75rem',
    alignItems: 'start',
    marginTop: '0.35rem',
    lineHeight: 1.45,
  }

  return (
    <dl style={{ margin: '0.5rem 0 0', padding: 0, fontSize: '0.875rem', color: 'var(--text2)' }}>
      <div style={rowStyle}>
        <dt style={{ margin: 0, fontWeight: 600, color: 'var(--text3)' }}>Fokusbereich</dt>
        <dd style={{ margin: 0 }}>{dashIfEmpty(focus)}</dd>
      </div>
      {styleDir ? (
        <div style={rowStyle}>
          <dt style={{ margin: 0, fontWeight: 600, color: 'var(--text3)' }}>Stilrichtung</dt>
          <dd style={{ margin: 0 }}>{styleDir}</dd>
        </div>
      ) : null}
      <div style={rowStyle}>
        <dt style={{ margin: 0, fontWeight: 600, color: 'var(--text3)' }}>Trainingsarten</dt>
        <dd style={{ margin: 0 }}>{trainingTypes.length ? trainingTypes : '—'}</dd>
      </div>
      <div style={rowStyle}>
        <dt style={{ margin: 0, fontWeight: 600, color: 'var(--text3)' }}>Zielgruppen</dt>
        <dd style={{ margin: 0 }}>{targetGroups.length ? targetGroups : '—'}</dd>
      </div>
      <div style={{ ...rowStyle, marginTop: '0.5rem' }}>
        <dt style={{ margin: 0, fontWeight: 600, color: 'var(--text3)' }}>Kurzbeschreibung</dt>
        <dd style={{ margin: 0, whiteSpace: 'pre-wrap' }}>
          {(r.description && String(r.description).trim()) || '—'}
        </dd>
      </div>
    </dl>
  )
}

export default function TrainingFrameworkProgramsListPage() {
  const { user } = useAuth()
  const tenantClubDepKey = useMemo(() => getTenantClubDependencyKey(user), [user])
  const frameworkListReturn = useMemo(() => buildFrameworkProgramsListReturnContext(), [])
  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, tenantClubDepKey])

  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
          style={{
            display: 'flex',
            flexWrap: 'wrap',
            alignItems: 'flex-start',
            justifyContent: 'space-between',
            gap: '1rem',
            marginBottom: '1.25rem',
          }}
        >
          <div>
            <h1 className="page-title" style={{ marginBottom: '0.35rem' }}>
              Trainingsrahmenprogramme
            </h1>
            <p style={{ color: 'var(--text2)', fontSize: '0.95rem', maxWidth: '36rem', margin: 0 }}>
              Vorlagen für Ziele und Sessions — die Verknüpfung mit Gruppenterminen erfolgt in der
              Trainingsplanung (Registerkarte oben).
            </p>
            <details className="planning-filter-help" style={{ marginTop: '10px', maxWidth: '36rem' }}>
              <summary className="planning-filter-help__summary">Mehr zur Übernahme in die Planung</summary>
              <div className="planning-filter-help__body">
                Unter <strong>Planung</strong> wählst du eine Gruppe und übernimmst Slots aus einem Rahmenprogramm in
                echte Termine. So bleibt die Bibliothek wiederverwendbar, ohne dass Einzelgruppen fest verdrahtet sind.
              </div>
            </details>
          </div>
          <NavStateLink
            to="/planning/framework-programs/new"
            returnContext={frameworkListReturn}
            className="btn btn-primary"
            style={{ textDecoration: 'none', whiteSpace: 'nowrap' }}
          >
            Rahmenprogramm anlegen
          </NavStateLink>
        </div>

        {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>
            <NavStateLink
              to="/planning/framework-programs/new"
              returnContext={frameworkListReturn}
              className="btn btn-primary btn-full"
              style={{ textDecoration: 'none' }}
            >
              Rahmenprogramm anlegen
            </NavStateLink>
          </div>
        ) : (
          <ul className="framework-programs-list">
            {rows.map((r) => (
              <li key={r.id} className="card">
                <div
                  style={{
                    display: 'flex',
                    flexWrap: 'wrap',
                    alignItems: 'flex-start',
                    justifyContent: 'space-between',
                    gap: '0.75rem',
                  }}
                >
                  <div style={{ minWidth: 0, flex: '1 1 220px' }}>
                    <NavStateLink
                      to={`/planning/framework-programs/${r.id}`}
                      returnContext={frameworkListReturn}
                      style={{ fontWeight: 600, fontSize: '1.05rem', color: 'var(--text1)' }}
                    >
                      {r.title || `Rahmen #${r.id}`}
                    </NavStateLink>
                    <div style={{ fontSize: '0.85rem', color: 'var(--text2)', marginTop: '0.35rem' }}>
                      <span>
                        {(r.goals_count ?? '—') + ' Ziele · '}
                        {(r.slots_count ?? '—') + ' Slots'}
                      </span>
                    </div>
                    <FrameworkSummaryMeta r={r} />
                  </div>
                  <div style={{ display: 'flex', flexWrap: 'wrap', gap: '0.5rem' }}>
                    <NavStateLink
                      to={`/planning/framework-programs/${r.id}`}
                      returnContext={frameworkListReturn}
                      className="btn btn-secondary"
                      style={{ textDecoration: 'none' }}
                    >
                      Bearbeiten
                    </NavStateLink>
                    <button type="button" className="btn btn-secondary" onClick={() => handleDelete(r.id, r.title)}>
                      Löschen
                    </button>
                  </div>
                </div>
              </li>
            ))}
          </ul>
        )}
    </>
  )
}