import React, { useState } from 'react';
import { Category, Feed, FilterState, Stats } from '../types';
import {
  Inbox,
  Star,
  Layers,
  Folder,
  FolderOpen,
  Rss,
  ChevronRight,
  ChevronDown,
} from 'lucide-react';

interface SidebarProps {
  filter: FilterState;
  onFilterChange: (newFilter: Partial<FilterState>) => void;
  categories: Category[];
  feeds: Feed[];
  stats: Stats | null;
}

export const Sidebar: React.FC<SidebarProps> = ({
  filter,
  onFilterChange,
  categories,
  feeds,
  stats,
}) => {
  const [collapsedCats, setCollapsedCats] = useState<Record<string, boolean>>({});

  const toggleCategoryCollapse = (catId: string, e: React.MouseEvent) => {
    e.stopPropagation();
    setCollapsedCats((prev) => ({ ...prev, [catId]: !prev[catId] }));
  };

  // Group feeds by category
  const categorizedFeeds: Record<string, Feed[]> = {};
  const uncategorizedFeeds: Feed[] = [];

  feeds.forEach((f) => {
    if (f.category_id) {
      if (!categorizedFeeds[f.category_id]) {
        categorizedFeeds[f.category_id] = [];
      }
      categorizedFeeds[f.category_id].push(f);
    } else {
      uncategorizedFeeds.push(f);
    }
  });

  return (
    <div className="sidebar-scroll-area">
      {/* Core Navigation Items */}
      <div
        className={`sidebar-nav-item ${
          filter.view === 'inbox' && !filter.feedId && !filter.categoryId
            ? 'active'
            : ''
        }`}
        onClick={() =>
          onFilterChange({
            view: 'inbox',
            feedId: undefined,
            categoryId: undefined,
          })
        }
      >
        <div className="sidebar-nav-label">
          <Inbox size={16} />
          <span>Inbox</span>
        </div>
        {stats && stats.total_unread > 0 && (
          <span className="badge unread">{stats.total_unread}</span>
        )}
      </div>

      <div
        className={`sidebar-nav-item ${
          filter.view === 'starred' && !filter.feedId && !filter.categoryId
            ? 'active'
            : ''
        }`}
        onClick={() =>
          onFilterChange({
            view: 'starred',
            feedId: undefined,
            categoryId: undefined,
          })
        }
      >
        <div className="sidebar-nav-label">
          <Star size={16} style={{ color: 'var(--star)' }} />
          <span>Starred</span>
        </div>
        {stats && stats.total_starred > 0 && (
          <span className="badge">{stats.total_starred}</span>
        )}
      </div>

      <div
        className={`sidebar-nav-item ${
          filter.view === 'all' && !filter.feedId && !filter.categoryId
            ? 'active'
            : ''
        }`}
        onClick={() =>
          onFilterChange({
            view: 'all',
            feedId: undefined,
            categoryId: undefined,
          })
        }
      >
        <div className="sidebar-nav-label">
          <Layers size={16} />
          <span>All Articles</span>
        </div>
      </div>

      {/* Categories Section */}
      {categories.length > 0 && (
        <div style={{ marginTop: '0.6rem' }}>
          <div className="sidebar-section-header">
            <span>Categories</span>
          </div>

          {categories.map((cat) => {
            const catFeeds = categorizedFeeds[cat.id] || [];
            const isCollapsed = collapsedCats[cat.id];
            const isCatActive = filter.categoryId === cat.id && !filter.feedId;
            const catUnread = catFeeds.reduce((sum, f) => sum + f.unread_count, 0);

            return (
              <div key={cat.id}>
                <div
                  className={`sidebar-nav-item ${isCatActive ? 'active' : ''}`}
                  onClick={() =>
                    onFilterChange({
                      categoryId: cat.id,
                      feedId: undefined,
                    })
                  }
                >
                  <div className="sidebar-nav-label">
                    <button
                      style={{
                        background: 'none',
                        border: 'none',
                        color: 'inherit',
                        cursor: 'pointer',
                        display: 'flex',
                        alignItems: 'center',
                        padding: 0,
                        marginRight: -3,
                      }}
                      onClick={(e) => toggleCategoryCollapse(cat.id, e)}
                    >
                      {isCollapsed ? <ChevronRight size={13} /> : <ChevronDown size={13} />}
                    </button>
                    {isCollapsed ? <Folder size={15} /> : <FolderOpen size={15} />}
                    <span>{cat.title}</span>
                  </div>

                  {catUnread > 0 && <span className="badge unread">{catUnread}</span>}
                </div>

                {/* Category feeds */}
                {!isCollapsed &&
                  catFeeds.map((feed) => {
                    const isFeedActive = filter.feedId === feed.id;
                    return (
                      <div
                        key={feed.id}
                        className={`feed-item ${isFeedActive ? 'active' : ''}`}
                        onClick={() =>
                          onFilterChange({
                            feedId: feed.id,
                            categoryId: undefined,
                          })
                        }
                      >
                        <div
                          style={{
                            display: 'flex',
                            alignItems: 'center',
                            gap: 6,
                            overflow: 'hidden',
                          }}
                        >
                          <Rss size={12} style={{ flexShrink: 0, color: 'var(--text-muted)' }} />
                          <span className="feed-title-text" title={feed.title}>
                            {feed.title}
                          </span>
                        </div>

                        {feed.unread_count > 0 && (
                          <span className="badge unread">{feed.unread_count}</span>
                        )}
                      </div>
                    );
                  })}
              </div>
            );
          })}
        </div>
      )}

      {/* Uncategorized Feeds */}
      {uncategorizedFeeds.length > 0 && (
        <div style={{ marginTop: '0.6rem' }}>
          <div className="sidebar-section-header">
            <span>Feeds</span>
          </div>

          {uncategorizedFeeds.map((feed) => {
            const isFeedActive = filter.feedId === feed.id;
            return (
              <div
                key={feed.id}
                className={`sidebar-nav-item ${isFeedActive ? 'active' : ''}`}
                style={{ paddingLeft: '0.65rem' }}
                onClick={() =>
                  onFilterChange({
                    feedId: feed.id,
                    categoryId: undefined,
                  })
                }
              >
                <div className="sidebar-nav-label">
                  <Rss size={14} style={{ flexShrink: 0, color: 'var(--text-muted)' }} />
                  <span className="feed-title-text" title={feed.title}>
                    {feed.title}
                  </span>
                </div>

                {feed.unread_count > 0 && (
                  <span className="badge unread">{feed.unread_count}</span>
                )}
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
};