import { useEffect, useState } from 'react'
import { Button, Card, Col, Container, Form, Row } from 'react-bootstrap'
import { Link, useParams } from 'react-router-dom'
import { createThread, getForum, listForumsByParent, listThreadsByForum } from '../api/client'
import { useAuth } from '../context/AuthContext'
import { useTranslation } from 'react-i18next'

export default function ForumView() {
  const { id } = useParams()
  const { token } = useAuth()
  const [forum, setForum] = useState(null)
  const [children, setChildren] = useState([])
  const [threads, setThreads] = useState([])
  const [error, setError] = useState('')
  const [loading, setLoading] = useState(true)
  const [title, setTitle] = useState('')
  const [body, setBody] = useState('')
  const [saving, setSaving] = useState(false)
  const { t } = useTranslation()

  useEffect(() => {
    let active = true

    const loadData = async () => {
      setLoading(true)
      setError('')
      try {
        const forumData = await getForum(id)
        if (!active) return
        setForum(forumData)
        const childData = await listForumsByParent(id)
        if (!active) return
        setChildren(childData)
        if (forumData.type === 'forum') {
          const threadData = await listThreadsByForum(id)
          if (!active) return
          setThreads(threadData)
        } else {
          setThreads([])
        }
      } catch (err) {
        if (active) setError(err.message)
      } finally {
        if (active) setLoading(false)
      }
    }

    loadData()

    return () => {
      active = false
    }
  }, [id])

  const handleSubmit = async (event) => {
    event.preventDefault()
    setSaving(true)
    setError('')
    try {
      await createThread({ title, body, forumId: id })
      setTitle('')
      setBody('')
      const updated = await listThreadsByForum(id)
      setThreads(updated)
    } catch (err) {
      setError(err.message)
    } finally {
      setSaving(false)
    }
  }

  return (
    <Container className="py-5">
      {loading && <p className="bb-muted">{t('forum.loading')}</p>}
      {error && <p className="text-danger">{error}</p>}
      {forum && (
        <>
          <div className="bb-hero mb-4">
            <p className="bb-chip">
              {forum.type === 'forum' ? t('forum.type_forum') : t('forum.type_category')}
            </p>
            <h2 className="mt-3">{forum.name}</h2>
            <p className="bb-muted mb-0">
              {forum.description || t('forum.no_description')}
            </p>
          </div>

          <Row className="g-4">
            <Col lg={7}>
              <h4 className="bb-section-title mb-3">{t('forum.children')}</h4>
              {children.length === 0 && (
                <p className="bb-muted">{t('forum.empty_children')}</p>
              )}
              {children.map((child) => (
                <Card className="bb-card mb-3" key={child.id}>
                  <Card.Body>
                    <Card.Title>{child.name}</Card.Title>
                    <Card.Text className="bb-muted">
                      {child.description || t('forum.no_description')}
                    </Card.Text>
                    <Link to={`/forum/${child.id}`} className="stretched-link">
                      {t('forum.open')}
                    </Link>
                  </Card.Body>
                </Card>
              ))}

              {forum.type === 'forum' && (
                <>
                  <h4 className="bb-section-title mb-3 mt-4">{t('forum.threads')}</h4>
                  {threads.length === 0 && (
                    <p className="bb-muted">{t('forum.empty_threads')}</p>
                  )}
                  {threads.map((thread) => (
                    <Card className="bb-card mb-3" key={thread.id}>
                      <Card.Body>
                        <Card.Title>{thread.title}</Card.Title>
                        <Card.Text className="bb-muted">
                          {thread.body.length > 160
                            ? `${thread.body.slice(0, 160)}...`
                            : thread.body}
                        </Card.Text>
                        <Link to={`/thread/${thread.id}`} className="stretched-link">
                          {t('thread.view')}
                        </Link>
                      </Card.Body>
                    </Card>
                  ))}
                </>
              )}
            </Col>
            <Col lg={5}>
              <h4 className="bb-section-title mb-3">{t('forum.start_thread')}</h4>
              <div className="bb-form">
                {forum.type !== 'forum' && (
                  <p className="bb-muted mb-3">{t('forum.only_forums')}</p>
                )}
                {forum.type === 'forum' && !token && (
                  <p className="bb-muted mb-3">{t('forum.login_hint')}</p>
                )}
                <Form onSubmit={handleSubmit}>
                  <Form.Group className="mb-3">
                    <Form.Label>{t('form.title')}</Form.Label>
                    <Form.Control
                      type="text"
                      placeholder={t('form.thread_title_placeholder')}
                      value={title}
                      onChange={(event) => setTitle(event.target.value)}
                      disabled={!token || saving || forum.type !== 'forum'}
                      required
                    />
                  </Form.Group>
                  <Form.Group className="mb-3">
                    <Form.Label>{t('form.body')}</Form.Label>
                    <Form.Control
                      as="textarea"
                      rows={5}
                      placeholder={t('form.thread_body_placeholder')}
                      value={body}
                      onChange={(event) => setBody(event.target.value)}
                      disabled={!token || saving || forum.type !== 'forum'}
                      required
                    />
                  </Form.Group>
                  <Button
                    type="submit"
                    variant="dark"
                    disabled={!token || saving || forum.type !== 'forum'}
                  >
                    {saving ? t('form.posting') : t('form.create_thread')}
                  </Button>
                </Form>
              </div>
            </Col>
          </Row>
        </>
      )}
    </Container>
  )
}