import { useEffect, useMemo, useRef, useState } from 'react'
import { Button, Container, Form } from 'react-bootstrap'
import { Link, useParams } from 'react-router-dom'
import { createPost, getThread, listPostsByThread } from '../api/client'
import { useAuth } from '../context/AuthContext'
import { useTranslation } from 'react-i18next'

export default function ThreadView() {
  const { id } = useParams()
  const { token } = useAuth()
  const [thread, setThread] = useState(null)
  const [posts, setPosts] = useState([])
  const [error, setError] = useState('')
  const [loading, setLoading] = useState(true)
  const [body, setBody] = useState('')
  const [saving, setSaving] = useState(false)
  const { t } = useTranslation()
  const replyRef = useRef(null)

  useEffect(() => {
    setLoading(true)
    Promise.all([getThread(id), listPostsByThread(id)])
      .then(([threadData, postData]) => {
        setThread(threadData)
        setPosts(postData)
      })
      .catch((err) => setError(err.message))
      .finally(() => setLoading(false))
  }, [id])

  const handleSubmit = async (event) => {
    event.preventDefault()
    setSaving(true)
    setError('')
    try {
      await createPost({ body, threadId: id })
      setBody('')
      const updated = await listPostsByThread(id)
      setPosts(updated)
    } catch (err) {
      setError(err.message)
    } finally {
      setSaving(false)
    }
  }

  const replyCount = posts.length
  const formatDate = (value) => {
    if (!value) return '—'
    const date = new Date(value)
    if (Number.isNaN(date.getTime())) return '—'
    const day = String(date.getDate()).padStart(2, '0')
    const month = String(date.getMonth() + 1).padStart(2, '0')
    const year = String(date.getFullYear())
    return `${day}.${month}.${year}`
  }
  const allPosts = useMemo(() => {
    if (!thread) return posts
    const rootPost = {
      id: `thread-${thread.id}`,
      body: thread.body,
      created_at: thread.created_at,
      user_name: thread.user_name,
      user_avatar_url: thread.user_avatar_url,
      user_posts_count: thread.user_posts_count,
      user_created_at: thread.user_created_at,
      user_location: thread.user_location,
      user_rank_name: thread.user_rank_name,
      user_rank_badge_type: thread.user_rank_badge_type,
      user_rank_badge_text: thread.user_rank_badge_text,
      user_rank_badge_url: thread.user_rank_badge_url,
      isRoot: true,
    }
    return [rootPost, ...posts]
  }, [posts, thread])

  const handleJumpToReply = () => {
    replyRef.current?.scrollIntoView({ behavior: 'smooth', block: 'start' })
  }

  const totalPosts = allPosts.length

  return (
    <Container fluid className="py-4 bb-shell-container">
      {loading && <p className="bb-muted">{t('thread.loading')}</p>}
      {error && <p className="text-danger">{error}</p>}
      {thread && (
        <div className="bb-thread">
          <div className="bb-thread-titlebar">
            <h1 className="bb-thread-title">{thread.title}</h1>
            <div className="bb-thread-meta">
              <span>{t('thread.by')}</span>
              <span className="bb-thread-author">
                {thread.user_name || t('thread.anonymous')}
              </span>
              {thread.created_at && (
                <span className="bb-thread-date">{thread.created_at.slice(0, 10)}</span>
              )}
            </div>
          </div>

          <div className="bb-thread-toolbar">
            <div className="bb-thread-actions">
              <Button className="bb-accent-button" onClick={handleJumpToReply}>
                <i className="bi bi-reply-fill" aria-hidden="true" />
                <span>{t('form.post_reply')}</span>
              </Button>
              <button type="button" className="bb-thread-icon-button" aria-label={t('thread.reply')}>
                <i className="bi bi-arrow-counterclockwise" aria-hidden="true" />
              </button>
              <button type="button" className="bb-thread-icon-button" aria-label={t('thread.views')}>
                <i className="bi bi-wrench" aria-hidden="true" />
              </button>
              <button type="button" className="bb-thread-icon-button" aria-label={t('thread.last_post')}>
                <i className="bi bi-gear" aria-hidden="true" />
              </button>
            </div>
            <div className="bb-thread-meta-right">
              <span>{totalPosts} {totalPosts === 1 ? 'post' : 'posts'}</span>
              <span>•</span>
              <span>Page 1 of 1</span>
            </div>
          </div>

          <div className="bb-posts">
            {allPosts.map((post, index) => {
              const authorName = post.author?.username
                || post.user_name
                || post.author_name
                || t('thread.anonymous')
              const topicLabel = thread?.title
                ? post.isRoot
                  ? thread.title
                  : `${t('thread.reply_prefix')} ${thread.title}`
                : ''
              const postNumber = index + 1

              return (
                <article className="bb-post-row" key={post.id}>
                  <aside className="bb-post-author">
                    <div className="bb-post-avatar">
                      {post.user_avatar_url ? (
                        <img src={post.user_avatar_url} alt="" />
                      ) : (
                        <i className="bi bi-person" aria-hidden="true" />
                      )}
                    </div>
                    <div className="bb-post-author-name">{authorName}</div>
                    <div className="bb-post-author-role">
                      {post.user_rank_name || ''}
                    </div>
                    {(post.user_rank_badge_text || post.user_rank_badge_url) && (
                      <div className="bb-post-author-badge">
                        {post.user_rank_badge_type === 'image' && post.user_rank_badge_url ? (
                          <img src={post.user_rank_badge_url} alt="" />
                        ) : (
                          <span>{post.user_rank_badge_text}</span>
                        )}
                      </div>
                    )}
                    <div className="bb-post-author-meta">
                      <div className="bb-post-author-stat">
                        <span className="bb-post-author-label">{t('thread.posts')}:</span>
                        <span className="bb-post-author-value">
                          {post.user_posts_count ?? 0}
                        </span>
                      </div>
                      <div className="bb-post-author-stat">
                        <span className="bb-post-author-label">{t('thread.registered')}:</span>
                        <span className="bb-post-author-value">
                          {formatDate(post.user_created_at)}
                        </span>
                      </div>
                      <div className="bb-post-author-stat">
                        <span className="bb-post-author-label">{t('thread.location')}:</span>
                        <span className="bb-post-author-value">
                          {post.user_location || '-'}
                        </span>
                      </div>
                      <div className="bb-post-author-stat">
                        <span className="bb-post-author-label">Thanks given:</span>
                        <span className="bb-post-author-value">7</span>
                      </div>
                      <div className="bb-post-author-stat">
                        <span className="bb-post-author-label">Thanks received:</span>
                        <span className="bb-post-author-value">5</span>
                      </div>
                      <div className="bb-post-author-stat bb-post-author-contact">
                        <span className="bb-post-author-label">Contact:</span>
                        <span className="bb-post-author-value">
                          <i className="bi bi-chat-dots" aria-hidden="true" />
                        </span>
                      </div>
                    </div>
                  </aside>
                  <div className="bb-post-content">
                    <div className="bb-post-header">
                      <div className="bb-post-header-meta">
                        {topicLabel && (
                          <span className="bb-post-topic">
                            #{postNumber} {topicLabel}
                          </span>
                        )}
                        <span>{t('thread.by')} {authorName}</span>
                        {post.created_at && (
                          <span>{post.created_at.slice(0, 10)}</span>
                        )}
                      </div>
                      <div className="bb-post-actions">
                        <button type="button" className="bb-post-action" aria-label="Edit post">
                          <i className="bi bi-pencil" aria-hidden="true" />
                        </button>
                        <button type="button" className="bb-post-action" aria-label="Delete post">
                          <i className="bi bi-x-lg" aria-hidden="true" />
                        </button>
                        <button type="button" className="bb-post-action" aria-label="Report post">
                          <i className="bi bi-exclamation-lg" aria-hidden="true" />
                        </button>
                        <button type="button" className="bb-post-action" aria-label="Post info">
                          <i className="bi bi-info-lg" aria-hidden="true" />
                        </button>
                        <button type="button" className="bb-post-action" aria-label="Quote post">
                          <i className="bi bi-quote" aria-hidden="true" />
                        </button>
                      </div>
                    </div>
                    <div className="bb-post-body">{post.body}</div>
                  </div>
                </article>
              )
            })}
          </div>

          <div className="bb-thread-reply" ref={replyRef}>
            <div className="bb-thread-reply-title">{t('thread.reply')}</div>
            {!token && (
              <p className="bb-muted mb-3">{t('thread.login_hint')}</p>
            )}
            <Form onSubmit={handleSubmit}>
              <Form.Group className="mb-3">
                <Form.Label>{t('form.message')}</Form.Label>
                <Form.Control
                  as="textarea"
                  rows={6}
                  placeholder={t('form.reply_placeholder')}
                  value={body}
                  onChange={(event) => setBody(event.target.value)}
                  disabled={!token || saving}
                  required
                />
              </Form.Group>
              <div className="bb-thread-reply-actions">
                <Button type="submit" className="bb-accent-button" disabled={!token || saving}>
                  {saving ? t('form.posting') : t('form.post_reply')}
                </Button>
              </div>
            </Form>
          </div>
        </div>
      )}
    </Container>
  )
}