import { Link } from 'react-router-dom'
import { RECURRING_STATUS_LABELS } from '../constants/status.js'
import { EmptyState } from './EmptyState.jsx'
import { scopedPath } from '../utils/routes.js'

function formatDueAt(iso) {
  if (!iso) return null
  try {
    return new Date(iso).toLocaleString('de-DE')
  } catch {
    return iso
  }
}

function activeMaturityStage(roadmapItems = []) {
  return [...roadmapItems]
    .filter((item) => item.item_type === 'maturity_stage' && item.status === 'active')
    .sort((a, b) => (a.sort_order ?? 0) - (b.sort_order ?? 0))[0]
}

function practicesForStage(recurringItems = [], stageId) {
  if (!stageId) {
    return (recurringItems || []).filter((item) => item.roadmap_item_id)
  }
  return (recurringItems || []).filter((item) => item.roadmap_item_id === stageId)
}

export function RecurringRhythmPanel({
  initiativeId,
  roadmapItems = [],
  recurringItems = [],
  canManage = false,
  embedded = true,
}) {
  const stage = activeMaturityStage(roadmapItems)
  const stagePractices = practicesForStage(recurringItems, stage?.id)
  const active = stagePractices.filter((item) => item.status === 'active')
  const paused = stagePractices.filter((item) => item.status === 'paused')

  const body =
    !stage ? (
      <EmptyState message="Keine aktive Reifegrad-Stufe — Plan → Stufen prüfen." />
    ) : stagePractices.length === 0 ? (
      <EmptyState message="Keine Übungen für diese Stufe — Starter-Kit oder Stufenwechsel prüfen." />
    ) : (
      <>
        <p className="recurring-rhythm-summary muted">
          Stufe <strong>{stage.title}</strong> — {active.length} aktiv
          {paused.length > 0 ? `, ${paused.length} pausiert` : ''}.
        </p>
        <ul className="item-list recurring-rhythm-list">
          {[...active, ...paused].map((item) => (
            <li
              key={item.id}
              className={
                'list-item card-list-item recurring-rhythm-item' +
                (item.status === 'active' ? ' recurring-rhythm-item--active' : '') +
                (item.today_completed ? ' recurring-rhythm-item--done-today' : '')
              }
            >
              <div className="list-item-main">
                <strong>{item.title}</strong>
                <span className="muted list-item-sub">
                  {RECURRING_STATUS_LABELS[item.status] || item.status}
                  {item.today_completed ? ' · heute erledigt' : ''}
                  {!item.today_completed && item.next_due_at
                    ? ` · Fällig: ${formatDueAt(item.next_due_at)}`
                    : ''}
                </span>
                {item.today_measurement_note && (
                  <span className="muted list-item-sub">Messwert: {item.today_measurement_note}</span>
                )}
              </div>
            </li>
          ))}
        </ul>
        <p className="muted recurring-rhythm-hint">
          {canManage
            ? 'Übungen anlegen, pausieren oder löschen unter '
            : 'Rhythmen pflegen unter '}
          <Link to={scopedPath('/control/journey', { initiativeId })} className="link-inline">
            Kontrolle → Journey → Wiederkehrend
          </Link>
          .
        </p>
      </>
    )

  if (!embedded) return body

  return (
    <section className="card recurring-rhythm-panel">
      <div className="section-header">
        <div>
          <h2>Übungen der Stufe</h2>
          <p className="section-lead muted">
            Activity Set der aktiven Reifegrad-Stufe — nicht die Gates selbst (A1).
          </p>
        </div>
      </div>
      {body}
    </section>
  )
}