'use client'

import { useState } from 'react'
import { Button } from '@/components/ui/button'
import { Textarea } from '@/components/ui/textarea'
import { Card, CardContent } from '@/components/ui/card'
import { Badge } from '@/components/ui/badge'
import { MessageSquare, Lock, Send, User } from 'lucide-react'
import { cn } from '@/lib/utils'

interface Comment {
  id: string
  author: string
  content: string
  createdAt: string
}

interface DiscussionThreadProps {
  comments: Comment[]
  onAddComment?: (content: string) => void
  isLocked?: boolean
  maxLength?: number
  isSubmitting?: boolean
}

function formatRelativeTime(dateStr: string): string {
  const date = new Date(dateStr)
  const now = new Date()
  const diffMs = now.getTime() - date.getTime()
  const diffMinutes = Math.floor(diffMs / 60000)
  const diffHours = Math.floor(diffMinutes / 60)
  const diffDays = Math.floor(diffHours / 24)

  if (diffMinutes < 1) return 'just now'
  if (diffMinutes < 60) return `${diffMinutes}m ago`
  if (diffHours < 24) return `${diffHours}h ago`
  if (diffDays < 7) return `${diffDays}d ago`
  return date.toLocaleDateString()
}

export function DiscussionThread({
  comments,
  onAddComment,
  isLocked = false,
  maxLength = 2000,
  isSubmitting = false,
}: DiscussionThreadProps) {
  const [newComment, setNewComment] = useState('')

  const handleSubmit = () => {
    const trimmed = newComment.trim()
    if (!trimmed || !onAddComment) return
    onAddComment(trimmed)
    setNewComment('')
  }

  const handleKeyDown = (e: React.KeyboardEvent) => {
    if (e.key === 'Enter' && (e.ctrlKey || e.metaKey)) {
      e.preventDefault()
      handleSubmit()
    }
  }

  return (
    <div className="space-y-4">
      {/* Locked banner */}
      {isLocked && (
        <div className="flex items-center gap-2 rounded-lg bg-muted p-3 text-sm text-muted-foreground">
          <Lock className="h-4 w-4 shrink-0" />
          Discussion is closed. No new comments can be added.
        </div>
      )}

      {/* Comments list */}
      {comments.length === 0 ? (
        <div className="flex flex-col items-center justify-center py-8 text-center">
          <MessageSquare className="h-10 w-10 text-muted-foreground/50" />
          <p className="mt-2 text-sm font-medium text-muted-foreground">No comments yet</p>
          <p className="text-xs text-muted-foreground">
            Be the first to share your thoughts on this project.
          </p>
        </div>
      ) : (
        <div className="space-y-3">
          {comments.map((comment) => (
            <Card key={comment.id}>
              <CardContent className="p-4">
                <div className="flex items-start gap-3">
                  <div className="flex h-8 w-8 shrink-0 items-center justify-center rounded-full bg-muted">
                    <User className="h-4 w-4 text-muted-foreground" />
                  </div>
                  <div className="flex-1 min-w-0">
                    <div className="flex items-center gap-2 flex-wrap">
                      <span className="text-sm font-medium">{comment.author}</span>
                      <span className="text-xs text-muted-foreground">
                        {formatRelativeTime(comment.createdAt)}
                      </span>
                    </div>
                    <p className="mt-1 text-sm whitespace-pre-wrap break-words">
                      {comment.content}
                    </p>
                  </div>
                </div>
              </CardContent>
            </Card>
          ))}
        </div>
      )}

      {/* Add comment form */}
      {!isLocked && onAddComment && (
        <div className="space-y-2">
          <Textarea
            placeholder="Add a comment... (Ctrl+Enter to send)"
            value={newComment}
            onChange={(e) => setNewComment(e.target.value.slice(0, maxLength))}
            onKeyDown={handleKeyDown}
            rows={3}
            disabled={isSubmitting}
          />
          <div className="flex items-center justify-between">
            <span
              className={cn(
                'text-xs',
                newComment.length > maxLength * 0.9
                  ? 'text-destructive'
                  : 'text-muted-foreground'
              )}
            >
              {newComment.length}/{maxLength}
            </span>
            <Button
              size="sm"
              onClick={handleSubmit}
              disabled={!newComment.trim() || isSubmitting}
            >
              <Send className="mr-2 h-4 w-4" />
              {isSubmitting ? 'Sending...' : 'Comment'}
            </Button>
          </div>
        </div>
      )}
    </div>
  )
}