import { Link } from 'react-router-dom'
import { useMemo, useState } from 'react'
import { EmptyState } from './EmptyState.jsx'
import { StatusBadge } from './StatusBadge.jsx'
import { PriorityBadge } from './PriorityBadge.jsx'
import { Modal } from './Modal.jsx'
import { ActionForm } from './ActionForm.jsx'
import { ActionTaskPanel } from './ActionTaskPanel.jsx'
import { gateTitleById } from './GateSelect.jsx'
import { buildProjectPath, collectProjectSubtreeIds } from '../utils/projectTree.js'
import { actionPath } from '../utils/routes.js'
import {
  formatBlockedByTitles,
  getActionExecutionMeta,
  sortActionsForExecutionPlan,
} from '../utils/executionGraph.js'
import { ExecutionFlowBadge } from './ExecutionFlowBadge.jsx'

function formatProjectContext(projects, projectId) {
  if (!projectId) return 'Direkt am Vorhaben'
  const path = buildProjectPath(projects, projectId)
  return path.map((p) => p.title).join(' → ')
}

export function PlanActionsSection({
  actions,
  projects = [],
  roadmapItems = [],
  scopeProjectId = '',
  hideDone,
  onHideDoneChange,
  canManage,
  onCreateAction,
  actors,
  actorsLoading,
  actorsError,
  actorsUsedFallback,
  onReloadActors,
  busy,
  executionGraph = null,
  sectionTitle = 'Arbeit',
  sectionLead = 'Committete Arbeitspakete und zugehörige Aufgaben — Ausführung über die Objektseite.',
}) {
  const [showCreate, setShowCreate] = useState(false)
  const [expandedActions, setExpandedActions] = useState(() => new Set())

  const visibleActions = useMemo(() => {
    let list = hideDone
      ? actions.filter((a) => a.status !== 'done' && a.status !== 'discarded')
      : [...actions]

    if (scopeProjectId) {
      const subtreeIds = collectProjectSubtreeIds(projects, scopeProjectId)
      list = list.filter((a) => a.project_id && subtreeIds.has(a.project_id))
    }

    return sortActionsForExecutionPlan(list)
  }, [actions, hideDone, scopeProjectId, projects])

  async function handleCreate(payload) {
    await onCreateAction(payload)
    setShowCreate(false)
  }

  function toggleActionTasks(actionId) {
    setExpandedActions((prev) => {
      const next = new Set(prev)
      if (next.has(actionId)) next.delete(actionId)
      else next.add(actionId)
      return next
    })
  }

  return (
    <section className="card plan-actions-section">
      <div className="section-header">
        <div>
          <h2>{sectionTitle}</h2>
          <p className="section-lead muted">{sectionLead}</p>
        </div>
        <div className="section-actions">
          <label className="checkbox-label inline-filter">
            <input
              type="checkbox"
              checked={hideDone}
              onChange={(e) => onHideDoneChange(e.target.checked)}
            />
            Erledigte ausblenden
          </label>
          {canManage && (
            <button
              type="button"
              className="btn btn-primary btn-block-mobile"
              onClick={() => setShowCreate(true)}
            >
              Arbeitspaket
            </button>
          )}
        </div>
      </div>

      {scopeProjectId && (
        <p className="muted plan-actions-section__scope-hint">
          Gefiltert nach Projekt im Scope — Scope oben leeren für alle Arbeitspakete.
        </p>
      )}

      {visibleActions.length === 0 && (
        <EmptyState message="Noch keine Arbeitspakete — lege welche an oder wandle Backlog-Items um." />
      )}

      <ul className="item-list plan-actions-list">
        {visibleActions.map((action) => {
          const execMeta = getActionExecutionMeta(executionGraph, action.id)
          const blockedHint =
            execMeta?.blocked_by?.length > 0
              ? formatBlockedByTitles(actions, execMeta.blocked_by)
              : null

          return (
          <li key={action.id} className="list-item card-list-item plan-actions-list__item">
            <div className="plan-actions-list__header">
              <div className="list-item-main">
                <Link to={actionPath(action.id)} className="plan-actions-list__title">
                  <strong>{action.title}</strong>
                </Link>
                {action.action_kind === 'planning' && (
                  <span className="badge execution-flow-badge execution-flow-badge--planning">
                    Planung
                  </span>
                )}
                <p className="list-item-sub muted">
                  {formatProjectContext(projects, action.project_id)}
                </p>
                {action.roadmap_item_id && (
                  <p className="list-item-sub muted">
                    Gate: {gateTitleById(roadmapItems, action.roadmap_item_id)}
                  </p>
                )}
                {blockedHint && (
                  <p className="list-item-sub muted">Wartet auf: {blockedHint}</p>
                )}
                {action.description && (
                  <p className="list-item-desc">{action.description}</p>
                )}
              </div>
              <div className="list-item-meta action-controls">
                <ExecutionFlowBadge meta={execMeta} actionStatus={action.status} />
                <StatusBadge kind="action" status={action.status} />
                <PriorityBadge priority={action.priority} />
                <Link to={actionPath(action.id)} className="btn btn-secondary btn-sm">
                  Öffnen
                </Link>
              </div>
            </div>
            <ActionTaskPanel
              actionId={action.id}
              roadmapItems={roadmapItems}
              canManage={canManage}
              expanded={expandedActions.has(action.id)}
              onToggle={() => toggleActionTasks(action.id)}
            />
          </li>
          )
        })}
      </ul>

      <Modal open={showCreate} title="Arbeitspaket anlegen" onClose={() => setShowCreate(false)} size="lg">
        <ActionForm
          projects={projects}
          roadmapItems={roadmapItems}
          actors={actors}
          actorsLoading={actorsLoading}
          actorsError={actorsError}
          actorsUsedFallback={actorsUsedFallback}
          onReloadActors={onReloadActors}
          onSubmit={handleCreate}
          onCancel={() => setShowCreate(false)}
          busy={busy}
          submitLabel="Anlegen"
        />
      </Modal>
    </section>
  )
}