"use client";

// Core React imports
import { useState, useEffect } from "react";
// Local component imports
import ChatBotCard from "./chat-bot-card";
// Type definitions and data
import { ChatBot } from "@/app/(audiences)/for-students/data/chatbots";

/**
 * Props interface for the Section component that displays a group of chatbots
 * in a responsive grid layout with a title and subtitle
 */
interface SectionProps {
  title: string;
  subtitle: string;
  bots: ChatBot[];
  columns?: number;
}

/**
 * Renders a section of chatbots with a header and responsive grid layout
 * Returns null if no bots are provided
 */
function Section({ title, subtitle, bots, columns = 4 }: SectionProps) {
  if (bots.length === 0) return null;

  return (
    <div className="mb-16">
      <div className="mb-8">
        <h2 className="text-2xl font-bold text-text-primary mb-2">{title}</h2>
        <p className="text-text-secondary">{subtitle}</p>
      </div>
      {/* Responsive grid: 1 column on mobile, 2 on sm screens, configurable columns on lg */}
      <div className={`grid gap-4 sm:grid-cols-2 lg:grid-cols-${columns}`}>
        {bots.map((chatbot) => (
          <ChatBotCard key={chatbot.id} chatbot={chatbot} />
        ))}
      </div>
    </div>
  );
}

/**
 * Props interface for the main ChatBotGrid component
 * Includes filter criteria and functions to fetch different bot categories
 */
interface ChatBotGridProps {
  selectedCategories: string[];
  selectedSubjects: string[];
  searchQuery: string;
  getPopularBots: () => ChatBot[];
  getTrendingBots: () => ChatBot[];
  getAllBots: () => ChatBot[];
}

/**
 * Main component that displays a filterable grid of chatbots
 * Supports filtering by category, subject, and search query
 * Shows different sections based on filter state
 */
export default function ChatBotGrid({
  selectedCategories,
  selectedSubjects,
  searchQuery,
  getPopularBots,
  getTrendingBots,
  getAllBots,
}: ChatBotGridProps) {
  // Initialize state with lazy evaluation using callback functions
  const [filteredPopularBots, setFilteredPopularBots] = useState<ChatBot[]>(
    () => getPopularBots(),
  );
  const [filteredTrendingBots, setFilteredTrendingBots] = useState<ChatBot[]>(
    () => getTrendingBots(),
  );
  const [filteredAllBots, setFilteredAllBots] = useState<ChatBot[]>(() =>
    getAllBots(),
  );

  /**
   * Effect to filter bots whenever filter criteria or bot data changes
   * Applies search query, category, and subject filters
   */
  useEffect(() => {
    const filterBots = (bots: ChatBot[]) => {
      let filtered = bots;

      // Apply text search filter across multiple fields
      if (searchQuery) {
        const query = searchQuery.toLowerCase();
        filtered = filtered.filter(
          (bot) =>
            bot.title.toLowerCase().includes(query) ||
            bot.description.toLowerCase().includes(query) ||
            bot.subject.toLowerCase().includes(query) ||
            bot.category.toLowerCase().includes(query),
        );
      }

      // Apply category filter if categories are selected
      if (selectedCategories.length > 0) {
        filtered = filtered.filter(
          (bot) => bot.category && selectedCategories.includes(bot.category),
        );
      }

      // Apply subject filter if subjects are selected
      if (selectedSubjects.length > 0) {
        filtered = filtered.filter((bot) =>
          selectedSubjects.includes(bot.subject),
        );
      }

      return filtered;
    };

    // Update all filtered bot lists
    setFilteredPopularBots(filterBots(getPopularBots()));
    setFilteredTrendingBots(filterBots(getTrendingBots()));
    setFilteredAllBots(filterBots(getAllBots()));
  }, [
    selectedCategories,
    selectedSubjects,
    searchQuery,
    getPopularBots,
    getTrendingBots,
    getAllBots,
  ]);

  // Check if any filters are active
  const hasFiltersOrSearch =
    selectedCategories.length > 0 || selectedSubjects.length > 0 || searchQuery;

  // When filters are active, show only search results
  if (hasFiltersOrSearch) {
    return (
      <Section
        title="搜尋結果"
        subtitle={`符合 ${searchQuery ? '"' + searchQuery + '" ' : ""}的工具`}
        bots={filteredAllBots}
        columns={4}
      />
    );
  }

  // Filter bots by category and subject for different sections
  const tutorBots = filteredAllBots.filter((bot) => bot.category === "教育");
  const teachingBots = filteredAllBots.filter((bot) => bot.subject === "教學");
  const assessmentBots = filteredAllBots.filter(
    (bot) => bot.subject === "評量",
  );

  // Default view showing multiple sections of categorized bots
  return (
    <div className="space-y-8">
      <Section
        title="精選"
        subtitle="歷來最多人使用的工具"
        bots={filteredPopularBots}
        columns={4}
      />
      <Section
        title="熱門"
        subtitle="近期最多人使用的工具"
        bots={filteredTrendingBots}
        columns={4}
      />
      <Section
        title="教學輔助"
        subtitle="教學規劃與課程設計工具"
        bots={teachingBots}
        columns={4}
      />
      <Section
        title="評量工具"
        subtitle="作業與評量相關工具"
        bots={assessmentBots}
        columns={4}
      />
      <Section
        title="教育資源"
        subtitle="其他教育相關工具"
        bots={tutorBots}
        columns={4}
      />
    </div>
  );
}