'use client';

import React, { useState } from 'react';
import { Loader2, Mail, Search, X } from 'lucide-react';
import { Email } from '@/hooks/use-courrier';
import EmailListItem from './EmailListItem';
import EmailListHeader from './EmailListHeader';
import BulkActionsToolbar from './BulkActionsToolbar';
import { Input } from '@/components/ui/input';

interface EmailListProps {
  emails: Email[];
  selectedEmailIds: string[];
  selectedEmail: Email | null;
  currentFolder: string;
  isLoading: boolean;
  totalEmails: number;
  hasMoreEmails: boolean;
  onSelectEmail: (emailId: string, accountId: string, folder: string) => void;
  onToggleSelect: (emailId: string) => void;
  onToggleSelectAll: () => void;
  onBulkAction: (action: 'delete' | 'mark-read' | 'mark-unread' | 'archive') => void;
  onToggleStarred: (emailId: string) => void;
  onLoadMore: () => void;
  onSearch?: (query: string) => void;
}

export default function EmailList({
  emails,
  selectedEmailIds,
  selectedEmail,
  currentFolder,
  isLoading,
  totalEmails,
  hasMoreEmails,
  onSelectEmail,
  onToggleSelect,
  onToggleSelectAll,
  onBulkAction,
  onToggleStarred,
  onLoadMore,
  onSearch
}: EmailListProps) {
  const [scrollPosition, setScrollPosition] = useState(0);
  const [searchQuery, setSearchQuery] = useState('');

  // Handle scroll to detect when user reaches the bottom
  const handleScroll = (event: React.UIEvent<HTMLDivElement>) => {
    const target = event.target as HTMLDivElement;
    const { scrollTop, scrollHeight, clientHeight } = target;
    
    setScrollPosition(scrollTop);
    
    // Calculate how close to the bottom we are (in pixels)
    const distanceToBottom = scrollHeight - scrollTop - clientHeight;
    
    // DEBUG: Log scroll positions
    console.log(`[DEBUG] Scroll metrics - Distance to bottom: ${distanceToBottom}px, scrollHeight: ${scrollHeight}, scrollTop: ${scrollTop}, clientHeight: ${clientHeight}`);
    
    // CRITICAL FIX: Much more aggressive threshold - load more when within 500px of bottom
    // Also add double-check with percentage to handle all screen sizes
    const scrollPercentage = (scrollTop + clientHeight) / scrollHeight;
    
    // DEBUG: Log scroll percentage and conditions
    console.log(`[DEBUG] Scroll percentage: ${Math.round(scrollPercentage * 100)}%, hasMoreEmails: ${hasMoreEmails}, isLoading: ${isLoading}`);
    
    // Trigger loading when within 500px OR at 80% of the scroll distance
    if ((distanceToBottom < 500 || scrollPercentage > 0.8) && hasMoreEmails && !isLoading) {
      console.log(`[DEBUG-TRIGGER] Loading more emails - distance: ${distanceToBottom}px, percentage: ${Math.round(scrollPercentage * 100)}%`);
      onLoadMore();
    } else if ((distanceToBottom < 500 || scrollPercentage > 0.8) && hasMoreEmails && isLoading) {
      console.log(`[DEBUG-BLOCKED] Not loading more emails because isLoading is true`);
    } else if ((distanceToBottom < 500 || scrollPercentage > 0.8) && !hasMoreEmails) {
      console.log(`[DEBUG-BLOCKED] Not loading more emails because hasMoreEmails is false`);
    }
  };

  // Handle search
  const handleSearch = (e: React.FormEvent) => {
    e.preventDefault();
    onSearch?.(searchQuery);
  };

  const clearSearch = () => {
    setSearchQuery('');
    onSearch?.('');
  };

  // Render loading state
  if (isLoading && emails.length === 0) {
    return (
      <div className="flex justify-center items-center h-full p-8 bg-white/95 backdrop-blur-sm">
        <div className="animate-spin rounded-full h-8 w-8 border-t-2 border-b-2 border-blue-500"></div>
      </div>
    );
  }

  // Render empty state
  if (emails.length === 0) {
    return (
      <div className="flex flex-col justify-center items-center h-64 p-8 text-center bg-white/95 backdrop-blur-sm">
        <Mail className="h-8 w-8 text-gray-400 mb-2" />
        <p className="text-gray-500 text-sm">
          {searchQuery 
            ? 'No emails match your search'
            : currentFolder === 'INBOX' 
              ? "Your inbox is empty. You're all caught up!" 
              : 'No emails in this folder'}
        </p>
      </div>
    );
  }

  // Are all emails selected
  const allSelected = selectedEmailIds.length === emails.length && emails.length > 0;
  
  // Are some (but not all) emails selected
  const someSelected = selectedEmailIds.length > 0 && selectedEmailIds.length < emails.length;

  return (
    <div className="w-[320px] bg-white/95 backdrop-blur-sm border-r border-gray-100 flex flex-col">
      {/* Sticky toolbar - always visible at the top when emails are selected */}
      {selectedEmailIds.length > 0 && (
        <div className="sticky top-0 z-10">
          <BulkActionsToolbar 
            selectedCount={selectedEmailIds.length}
            onBulkAction={onBulkAction}
          />
        </div>
      )}
      
      {/* Search header */}
      <div className="border-b border-gray-100">
        <div className="px-4 py-2">
          <div className="relative">
            <Search className="absolute left-2 top-2.5 h-4 w-4 text-gray-400" />
            <form onSubmit={handleSearch}>
              <Input
                type="search"
                placeholder="Search in folder..."
                className="pl-8 h-9 bg-gray-50"
                value={searchQuery}
                onChange={(e) => setSearchQuery(e.target.value)}
              />
              {searchQuery && (
                <button
                  type="button"
                  onClick={clearSearch}
                  className="absolute right-2 top-1/2 transform -translate-y-1/2"
                >
                  <X className="h-4 w-4 text-gray-400" />
                </button>
              )}
            </form>
          </div>
        </div>
        <EmailListHeader 
          allSelected={allSelected}
          someSelected={someSelected}
          onToggleSelectAll={onToggleSelectAll}
          currentFolder={currentFolder}
          totalEmails={totalEmails}
        />
      </div>
      
      <div 
        className="flex-1 overflow-y-auto"
        onScroll={handleScroll}
      >
        <div className="divide-y divide-gray-100">
          {emails.map((email) => (
            <EmailListItem
              key={email.id}
              email={email}
              isSelected={selectedEmailIds.includes(email.id)}
              isActive={selectedEmail?.id === email.id}
              onSelect={() => onSelectEmail(email.id, email.accountId || '', email.folder || '')}
              onToggleSelect={(e: React.MouseEvent) => {
                e.stopPropagation();
                onToggleSelect(email.id);
              }}
              onToggleStarred={(e: React.MouseEvent) => {
                e.stopPropagation();
                onToggleStarred(email.id);
              }}
            />
          ))}
          
          {isLoading && emails.length > 0 && (
            <div className="flex items-center justify-center p-4">
              <div className="animate-spin rounded-full h-4 w-4 border-t-2 border-b-2 border-blue-500"></div>
            </div>
          )}
        </div>
      </div>
    </div>
  );
}