import React, { useState, useRef, useEffect } from 'react'
import ReactMarkdown from 'react-markdown'

const QUICK_REACTIONS = ['👍', '❤️', '🔥', '😂', '👏', '😮']

/**
 * Individual message bubble with:
 * - Markdown rendering (no raw HTML allowed)
 * - Hover reaction picker + unreact on click
 * - Inline edit for own messages
 * - Soft-delete display
 */
export default function MessageBubble({ message, isMine, showAvatar, onReact, onUnreact, onEdit, onReport = null, seenText = null }) {
  const [showPicker, setShowPicker] = useState(false)
  const [editing, setEditing]       = useState(false)
  const [editBody, setEditBody]     = useState(message.body ?? '')
  const [savingEdit, setSavingEdit] = useState(false)
  const editRef                     = useRef(null)

  const isDeleted = !!message.deleted_at
  const isEdited  = !!message.edited_at
  const username  = message.sender?.username ?? 'Unknown'
  const time      = formatTime(message.created_at)

  // Focus textarea when entering edit mode
  useEffect(() => {
    if (editing) {
      editRef.current?.focus()
      editRef.current?.setSelectionRange(editBody.length, editBody.length)
    }
  }, [editing])

  const reactionGroups = groupReactions(message.reactions ?? [])

  const handleSaveEdit = async () => {
    const trimmed = editBody.trim()
    if (!trimmed || trimmed === message.body || savingEdit) return
    setSavingEdit(true)
    try {
      await onEdit(message.id, trimmed)
      setEditing(false)
    } finally {
      setSavingEdit(false)
    }
  }

  const handleEditKeyDown = (e) => {
    if (e.key === 'Enter' && !e.shiftKey) { e.preventDefault(); handleSaveEdit() }
    if (e.key === 'Escape') { setEditing(false); setEditBody(message.body) }
  }

  return (
    <div
      className={`group flex gap-2 items-end ${isMine ? 'flex-row-reverse' : 'flex-row'} ${showAvatar ? 'mt-3' : 'mt-0.5'}`}
      onMouseEnter={() => !isDeleted && !editing && setShowPicker(true)}
      onMouseLeave={() => setShowPicker(false)}
    >
      {/* Avatar */}
      <div className={`flex-shrink-0 w-7 h-7 ${showAvatar ? 'visible' : 'invisible'}`}>
        <div className="w-7 h-7 rounded-full bg-gradient-to-br from-indigo-400 to-pink-400 flex items-center justify-center text-white text-xs font-medium select-none">
          {username.charAt(0).toUpperCase()}
        </div>
      </div>

      <div className={`max-w-[75%] flex flex-col ${isMine ? 'items-end' : 'items-start'}`}>
        {/* Sender name & time */}
        {showAvatar && (
          <div className={`flex items-center gap-1.5 mb-1 ${isMine ? 'flex-row-reverse' : ''}`}>
            <span className="text-xs font-medium text-gray-700 dark:text-gray-300">{username}</span>
            <span className="text-xs text-gray-400">{time}</span>
          </div>
        )}

        {/* Bubble */}
        <div className="relative">
          {editing ? (
            <div className="w-72">
              <textarea
                ref={editRef}
                value={editBody}
                onChange={e => setEditBody(e.target.value)}
                onKeyDown={handleEditKeyDown}
                rows={3}
                maxLength={5000}
                className="w-full resize-none rounded-xl border border-blue-400 bg-white dark:bg-gray-800 px-3 py-2 text-sm text-gray-900 dark:text-gray-100 outline-none focus:ring-2 focus:ring-blue-500"
              />
              <div className="flex gap-2 mt-1 justify-end">
                <button
                  type="button"
                  onClick={() => { setEditing(false); setEditBody(message.body) }}
                  className="text-xs text-gray-400 hover:text-gray-600"
                >
                  Cancel
                </button>
                <button
                  type="button"
                  onClick={handleSaveEdit}
                  disabled={savingEdit || !editBody.trim() || editBody.trim() === message.body}
                  className="text-xs text-blue-500 hover:text-blue-700 font-medium disabled:opacity-40"
                >
                  {savingEdit ? 'Saving…' : 'Save'}
                </button>
              </div>
            </div>
          ) : (
            <div
              className={`px-3 py-2 rounded-2xl text-sm leading-relaxed break-words ${
                isMine
                  ? 'bg-blue-500 text-white rounded-br-sm'
                  : 'bg-gray-100 dark:bg-gray-800 text-gray-900 dark:text-gray-100 rounded-bl-sm'
              } ${isDeleted ? 'italic opacity-60' : ''} ${message._optimistic ? 'opacity-70' : ''}`}
            >
              {isDeleted ? (
                <span>This message was deleted.</span>
              ) : (
                <>
                  {message.attachments?.length > 0 && (
                    <div className="mb-2 space-y-1">
                      {message.attachments.map(att => (
                        <div key={att.id}>
                          {att.type === 'image' ? (
                            <a href={`/messages/attachments/${att.id}`} target="_blank" rel="noopener noreferrer">
                              <img
                                src={`/messages/attachments/${att.id}`}
                                alt={att.original_name}
                                className="max-h-44 rounded-lg border border-white/20"
                                loading="lazy"
                              />
                            </a>
                          ) : (
                            <a
                              href={`/messages/attachments/${att.id}`}
                              target="_blank"
                              rel="noopener noreferrer"
                              className={`inline-flex items-center gap-1 rounded-md px-2 py-1 text-xs ${isMine ? 'bg-blue-600 text-white' : 'bg-gray-200 dark:bg-gray-700 text-gray-800 dark:text-gray-100'}`}
                            >
                              📎 {att.original_name}
                            </a>
                          )}
                        </div>
                      ))}
                    </div>
                  )}
                  <div className={`prose prose-sm max-w-none prose-p:my-0 prose-pre:my-1 ${isMine ? 'prose-invert' : 'dark:prose-invert'}`}>
                    <ReactMarkdown
                      allowedElements={['p', 'strong', 'em', 'code', 'pre', 'ul', 'ol', 'li', 'blockquote', 'a', 'br']}
                      unwrapDisallowed
                      components={{
                        a: ({ href, children }) => (
                          <a href={href} target="_blank" rel="noopener noreferrer"
                            className={isMine ? 'text-blue-200 underline' : 'text-blue-600 dark:text-blue-400 underline'}>
                            {children}
                          </a>
                        ),
                        code: ({ children, className }) => className
                          ? <code className={`${className} text-xs`}>{children}</code>
                          : <code className={`px-1 py-0.5 rounded text-xs ${isMine ? 'bg-blue-600' : 'bg-gray-200 dark:bg-gray-700'}`}>{children}</code>,
                      }}
                    >
                      {message.body}
                    </ReactMarkdown>
                  </div>
                  {isEdited && (
                    <span className={`text-xs ml-1 ${isMine ? 'text-blue-200' : 'text-gray-400'}`}>(edited)</span>
                  )}
                </>
              )}
            </div>
          )}

          {/* Hover action strip: reactions + edit pencil */}
          {showPicker && !editing && !isDeleted && (
            <div
              className={`absolute bottom-full mb-1 ${isMine ? 'right-0' : 'left-0'} flex items-center gap-1 bg-white dark:bg-gray-900 border border-gray-200 dark:border-gray-700 rounded-full px-2 py-1 shadow-md z-10 whitespace-nowrap`}
              onMouseEnter={() => setShowPicker(true)}
              onMouseLeave={() => setShowPicker(false)}
            >
              {QUICK_REACTIONS.map(emoji => (
                <button key={emoji} onClick={() => onReact(message.id, emoji)}
                  className="text-base hover:scale-125 transition-transform" title={`React ${emoji}`}>
                  {emoji}
                </button>
              ))}
              {isMine && (
                <button
                  onClick={() => { setEditing(true); setShowPicker(false) }}
                  className="ml-1 text-gray-400 hover:text-gray-700 dark:hover:text-gray-200"
                  title="Edit message"
                >
                  <svg xmlns="http://www.w3.org/2000/svg" className="h-3.5 w-3.5" viewBox="0 0 20 20" fill="currentColor">
                    <path d="M13.586 3.586a2 2 0 112.828 2.828l-.793.793-2.828-2.828.793-.793zM11.379 5.793L3 14.172V17h2.828l8.38-8.379-2.83-2.828z" />
                  </svg>
                </button>
              )}
              {!isMine && onReport && (
                <button
                  onClick={() => { onReport(message.id); setShowPicker(false) }}
                  className="ml-1 text-gray-400 hover:text-red-500"
                  title="Report message"
                >
                  ⚑
                </button>
              )}
            </div>
          )}
        </div>

        {/* Reactions bar */}
        {reactionGroups.length > 0 && !isDeleted && (
          <div className={`flex flex-wrap gap-1 mt-1 ${isMine ? 'justify-end' : 'justify-start'}`}>
            {reactionGroups.map(({ emoji, count, iReacted }) => (
              <button
                key={emoji}
                onClick={() => iReacted ? onUnreact(message.id, emoji) : onReact(message.id, emoji)}
                title={iReacted ? 'Remove reaction' : `React ${emoji}`}
                className={`flex items-center gap-0.5 px-1.5 py-0.5 rounded-full text-xs transition-colors ${
                  iReacted
                    ? 'bg-blue-100 dark:bg-blue-900/40 border border-blue-300 dark:border-blue-700 text-blue-700 dark:text-blue-300'
                    : 'bg-gray-100 dark:bg-gray-800 hover:bg-gray-200 dark:hover:bg-gray-700 text-gray-600 dark:text-gray-300'
                }`}
              >
                <span>{emoji}</span>
                <span>{count}</span>
              </button>
            ))}
          </div>
        )}

        {isMine && seenText && (
          <div className="mt-1 text-[11px] text-gray-400 dark:text-gray-500">
            {seenText}
          </div>
        )}
      </div>
    </div>
  )
}

function formatTime(iso) {
  return new Date(iso).toLocaleTimeString(undefined, { hour: '2-digit', minute: '2-digit' })
}

function groupReactions(reactions) {
  const map = new Map()
  for (const r of reactions) {
    if (!map.has(r.reaction)) map.set(r.reaction, { count: 0, iReacted: false })
    const entry = map.get(r.reaction)
    entry.count++
    if (r._iMine) entry.iReacted = true
  }
  return Array.from(map.entries()).map(([emoji, { count, iReacted }]) => ({ emoji, count, iReacted }))
}